Throttle controlled generator system

• US 5,886,504 A
• Filed: 11/19/1996
• Issued: 03/23/1999
• Est. Priority Date: 09/14/1994
• Status: Expired due to Fees

• Current Assignee: Powermate Corporation (Pramac America LLC)
• Original Assignee: Coleman Company Incorporated (Newell Brands Inc.)
• Inventors: Scott, Harold C., Anderson, William J., Sun, Chiping, Pandya, Kandarp I.
• Primary Examiner(s): Dougherty, Thomas M.
• Assistant Examiner(s): Ponomarenko, Nicholas
• Application Number:
  US08/752,230
• Time in Patent Office: 854 Days
• Field of Search: 322/15, 322/28, 322/46, 322/24
• US Class Current: 322/15
• CPC Class Codes: B23K 9/1062 with computing means
• CPC Class Codes: F02B 2063/045 Frames for generator-engine sets
• CPC Class Codes: F02B 2063/046 Handles adapted therefor, e.g. handles or grips for movable units
• CPC Class Codes: F02B 63/04 for electric generators
• CPC Class Codes: F02B 75/16 Engines characterised by number of cylinders, e.g. single-cylinder engines F02B75/26 takes precedence
• CPC Class Codes: F05C 2201/021 Aluminium
• CPC Class Codes: H02K 1/278 Surface mounted magnets; Inset magnets
• CPC Class Codes: H02K 21/48 Generators with two or more outputs
• CPC Class Codes: H02K 3/28 Layout of windings or of connections between windings windings for pole-changing H02K17/06, H02K17/14, H02K19/12, H02K19/32
• CPC Class Codes: H02K 7/1815 structurally associated with reciprocating piston engines general aspects of generating sets, e.g. housing, F02B63/04
• CPC Class Codes: H02M 1/0085 Partially controlled bridges
• CPC Class Codes: H02M 7/00 Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
• CPC Class Codes: H02M 7/483 Converters with outputs that each can have more than two voltages levels
• CPC Class Codes: H02P 2101/45 for motor vehicles, e.g. car alternators
• CPC Class Codes: H02P 25/188 wherein the motor windings are switched from series to parallel or vice versa to control speed or torque
• CPC Class Codes: H02P 9/04 Control effected upon non-electric prime mover and dependent upon electric output value of the generator
• CPC Class Codes: H02P 9/107 for limiting effects of overloads
• CPC Class Codes: H02P 9/14 by variation of field H02P9/08, H02P9/10 take precedence
• CPC Class Codes: H02P 9/30 using semiconductor devices
• CPC Class Codes: H02P 9/48 Arrangements for obtaining a constant output value at varying speed of the generator, e.g. on vehicle H02P9/04 - H02P9/46 take precedence

Abstract

An improved method and system of increasing the effective electrical load capacity of a power converter is disclosed. Potential damage due to current surges from variation in load is avoided by sensing an impending over-current condition, decreasing the system output by a predetermined amount or to a predetermined level, and then gradually increasing the output to bring the system back to desired operating conditions. Such control can be affected by varying the throttle setting to adjust rotor speed, controlling the DC rail level, or a combination of both methods.

Claims

1. A method of increasing effective electrical load capacity of an apparatus for converting mechanical energy into electrical energy at respective output terminals, the apparatus including an engine and a generator, the method comprising the steps of:

sensing the occurrence of an output current in excess of a predetermined level;

responsive to the occurrence of an output current in excess of the predetermined level,

decreasing the output voltage of the generator to a predetermined lower value, and gradually increasing the output voltage from the predetermined lower value until the voltage reaches a predetermined set point value,

wherein the step of decreasing the output voltage comprises;

decreasing the engine speed to a predetermined level, maintaining the engine speed at the predetermined level for a predetermined time period, then gradually increasing the engine speed.

2. A method of increasing the effective electrical load capacity of an apparatus for converting mechanical energy into electrical energy at respective output terminals, the apparatus including an engine and a generator, the method comprising the steps of:

sensing the occurrence of an output current in excess of a predetermined level;

responsive to the occurrence of an output current in excess of the predetermined level, decreasing the output voltage of the generator to a predetermined lower value, and

gradually increasing the output voltage from the predetermined lower value until the voltage reaches a predetermined set point value, and

the engine includes an output shaft, a throttle, and an actuator, the output shaft, in operation, rotating at a speed in accordance with the setting of the throttle, the actuator, responsive to control signals applied thereto, for controlling the setting of the throttle; and

the generator includes a rotor, rotationally driven by said output shaft, and a stator including at least one stator winding disposed such that rotation of the rotor induces current in the stator windings;

and the step of gradually increasing the output voltage comprises the steps of;

generating control signals to said actuator to establish a predetermined first throttle setting, corresponding to a first predetermined rotational speed; and

thereafter generating control signals to said actuator to vary the throttle setting to incrementally increase the rotational speed.

3. The method of claim 2 wherein the step of gradually increasing the output voltage further comprises the step of:

maintaining the first throttle setting for a predetermined period of time.

4. The method of claim 2 wherein the actuator comprises:

a throttle lever arm adapted to cooperate with the throttle such that the throttle setting varies in accordance with the position of the throttle lever arm;

an elongated magnet, magnetized through the length thereof, a non-magnetic coupling between the magnet and throttle arm, such that movement of the magnet effects a corresponding movement of the throttle arm;

an electrical coil, receptive of a control signal applied thereto, and disposed such that current flow therethrough effects magnetic interaction with the magnet, causing the magnet to assume a position in accordance with the power through the coil, to control the position of the throttle arm;

and the steps of generating control signals to said actuator comprise;

applying control signals to the coil, the power provided by the control signals to the coil being in accordance with the desired throttle setting.

5. The method of claim 4 wherein the magnet is cylindrical.

6. The method of claim 4 wherein the magnet is formed of Alnico.

7. The method of claim 4 wherein the coupling comprises an elongated non-magnetic push rod, coupled to, and in general axial alignment with the magnet.

8. The method of claim 4 wherein the actuator further comprises a spring disposed to bias the throttle arm into a designated idle position, and the steps of generating control signals to said actuator comprise:

applying a control signal of a predetermined polarity to the coil such that magnetic interaction with the magnet, causes the magnet to move against the bias of the spring to control the position of the throttle arm.

9. The method of claim 4 wherein the steps of generating control signals to said actuator comprise:

applying, as the control signals to the winding, a pulse width modulated (PWM) signal, the pulse width being in accordance with the desired throttle setting.

10. The method of claim 3 wherein:

the actuator comprises a stepping motor having an output shaft mechanically coupled to the throttle; and

the steps of generating control signals to said actuator comprise selectively generating signals to said stepping motor to effect incremental rotation of the stepping motor output shaft.

11. The method of claim 10 wherein:

the stepping motor includes;

a rotor having magnetic components, cooperating with the output shaft; and

a plurality of stator coils; and

the steps of generating control signals to said actuator comprise the step of effecting current paths through the stator coils in predetermined sequences to generate magnetic fields which interact with the magnetic components of the rotor, and cause the rotor to move in predetermined increments.

12. The method of claim 10 wherein the steps of generating control signals to said actuator further comprise the step of inhibiting adjustment of the throttle setting until at least a predetermined time has elapsed since the last preceding adjustment to the throttle.

13. The method of claim 10 wherein the stator coils have stator poles associated therewith, and the step of selectively generating signals to said stepping motor to effect incremental rotation of the stepping motor output shaft comprises generating signals to said stepping motor to effect current flow through single coils, in sequence to incrementally advance the shaft by a full step, from stator pole to stator pole.

14. The method of claim 10 wherein the stator coils have stator poles associated therewith, and the step of selectively generating signals to said stepping motor to effect incremental rotation of the stepping motor output shaft comprises:

generating signals to said stepping motor to effect pairs of current paths in adjacent coils, in sequence, to incrementally advance the shaft by a full step, at full torque, from midpoint between adjacent stator poles to midpoint between next successive pair of stator poles.

15. The method of claim 11 wherein the stator coils have stator poles associated therewith, and the step of selectively generating signals to said stepping motor to effect incremental rotation of the stepping motor output shaft comprises:

generating signals to energize a single coil, to bring the rotor into alignment with the stator pole associated with the coil, then generating signals to energize a pair of coils, to bring the rotor into alignment with the midpoint between that stator pole and the next successive stator pole.

16. The method of claim 2 wherein:

the actuator comprises;

a stepping motor having a rotary output shaft and plurality of coils, rotational movement of the shaft being effected by selective application of current through the coils;

a drive circuit, responsive to control signals applied thereto for selectively effecting current flow through at least portions of the respective individual coils; and

a mechanical coupling between the stepping motor shaft and the engine throttle, such that rotary movement of the stepping motor shaft effects control of the throttle setting; and

the steps of generating control signals to said actuator comprise;

selectively generating signals to said drive circuit to effect current paths through at least portions of the respective stepping motor coils in predetermined sequences to cause the rotary shaft to move in predetermined increments.

17. The method of claim 16 wherein the step of generating signals to effect current paths through the respective stepping motor coils in predetermined sequences comprises the steps of:

maintaining indicia of the predetermined sequences, generating indicia of the desired activation state of the stepping motor coils, and generating control signals to the coils in accordance with the desired activation state.

18. The method of claim 16 wherein the drive circuit comprises an unidirectional driver.

19. The method of claim 16 wherein:

the respective stepping motor coils each include a center tap;

the drive circuit comprises respective switching devices, responsive to control signals applied thereto, disposed to selectively complete a current path from each end of the respective stepping motor coils to a common node; and

the step of selectively generating signals to the drive circuit comprises;

establishing a potential difference between the center taps and the common node; and

selectively providing control signals to the switching devices to selectively effect current paths from the center tap of the coils to the common node in predetermined sequences to cause the rotary shaft to move in predetermined increments.

20. The method of claim 16 wherein the drive circuit comprises a bipolar driver.

21. The method of claim 16 wherein the drive circuit comprises:

a first set of switching devices disposed to selectively effect connections between the respective ends of the stepping motor coils to a common node, and

a second set of switching devices disposed to selectively effect connections between the respective ends of the stepping motor coils and a positive potential relative to the common node; and

the step of selectively generating signals to the drive circuit comprises;

selectively providing control signals to the switching devices to selectively effect current flows of selected polarity through the coils.

22. The method of claim 2 wherein the generator comprises:

a rotor, adapted for selective rotation responsive to the input drive;

a stator, including at least one stator winding, disposed such that rotation of the rotor induces current in the stator winding;

a regulator, associated with the winding, the regulator including a switching device, responsive to control signals applied thereto, and the step of gradually increasing the output voltage comprises the steps of;

generating control signals to said switching devices to actuate the switching device for predetermined periods of time to generate output current pulses of predetermined pulse width on a periodic basis;

varying the number of output current pulses per unit time to vary the average output voltage.

23. The method of claim 2 wherein the generator comprises

a rotor, adapted for selective rotation responsive to the input drive;

a stator, including at least one multi-phase group of stator windings, disposed such that rotation of the rotor induces current in the stator windings;

a multi-phase regulator, associated with the winding group, the multi-phase regulator including a respective switching device, responsive to control signals applied thereto, associated with each phase, and the step of gradually increasing the output voltage comprises the steps of;

generating control signals to said switching devices to actuate the switching devices for predetermined periods of time to generate output current pulses of predetermined pulse width on a periodic basis;

varying the number of output current pulses per unit time to vary the average output voltage.

37. The method of claim 10 wherein the steps of generating control signals to said actuator comprise, selectively generating signals to said stepping motor to effect incremental rotation of the stepping motor output shaft comprises:

generating signals to said stepping motor to effect pairs of current paths in adjacent coils, in sequence, and effecting currents of different magnitudes through the respective coils.

38. The method of claim 10 wherein current paths through the stator coils are effected in accordance with a predetermined sequence of coil activation states, and the method further comprises the step of dithering between respective coil activation states.

39. The method of claim 38 wherein:

the engine has a mechanical response time associated therewith;

the actuator stator coils have an inductive rise time associated therewith; and

dithering between respective coil actuation states is effected at a rate faster than the mechanical response time of the engine but less than the inductive rise time of the actuator stator coils.

40. The method of claim 38 wherein:

the actuator stator coils have an inductive rise time associated therewith;

the actuator rotor has a mechanical response time associated therewith when coupled to the throttle; and

dithering between respective coil actuation states is effected at a rate faster than the mechanical response time of the actuator but less than the inductive rise time of the stator coils.

41. The method of claim 38 wherein dithering between respective coil actuation states is effected at a rate sufficient to permit the throttle to assume a desired static position intermediate the positions associated the respective coil actuation states.

42. The method of claim 38 wherein dithering between respective coil actuation states is effected at a frequency that is equal to the lowest frequency that permits the throttle to assume a desired static position intermediate the positions associated the respective coil actuation states.

43. The method of claim 38 wherein the first and second coil activation states are maintained for equal time periods.

44. The method of claim 38 wherein the first and second coil activation states are maintained for different relative time periods.

45. The method of claim 16 wherein the step of inhibiting adjustment of the throttle setting until at least a predetermined time has elapsed since the last preceding adjustment to the throttle comprises the steps of:

maintaining a count indicative of the time elapsed since the last change in throttle setting;

selectively inhibiting generation responsive to said count.

46. The method of claim 10 wherein the step motor is directly coupled to the throttle.

47. The method of claim 10 wherein the step motor is directly coupled to the throttle by a flexible coupling.

48. The method of claim 10 wherein the step motor is directly coupled to the throttle by a rubber tube.

49. The method of claim 10 wherein the step motor is coupled to the throttle by a mechanical linkage providing a mechanical advantage such that the throttle moves through a first angle in response to a larger angle of movement of the step motor shaft.

50. The method of claim 10 wherein the step motor is coupled to the throttle by an step motor actuator arm, a linkage rod and a throttle actuator arm, the step motor actuator arm being mounted for rotation with, and extending radially outward from the step motor shaft, the throttle actuator arm being mounted for rotation with and extending radially outward from the throttle, and the linkage rod coupling the distal ends of the actuator arms.

51. The method of claim 50 wherein the step motor actuator arm moves through a first predetermined range to effect a second predetermined range of movement of the throttle actuator arm.

52. The method of claim 51 wherein the first predetermined range is 140 degrees.

53. The method of claim 51 wherein the second predetermined range is 70 degrees.

54. The method of claim 51 wherein the first predetermined range is 140 degrees and the second predetermined range is 70 degrees.

55. The method of claim 50 further including respective stops cooperating with at least one of the actuator arms to limit the range of motion permitted the throttle.

56. The method of claim 10 wherein the step motor is coupled to the throttle by a cam drive comprising a cam actuator, and cooperating cam follower throttle actuator arm.

57. The method of claim 56 wherein 5 degrees of step motor shaft rotation effects no more than one degree of throttle actuator arm rotation.

58. The method of claim 56 wherein a first predetermined range of throttle actuator arm rotation is effected in response to second predetermined range of step motor shaft rotation.

59. The method of claim 58 wherein the throttle actuator arm first predetermined range of rotation is 70 degrees.

60. The method of claim 58 wherein the step motor shaft second predetermined range of rotation is 360 degrees.

61. The method of claim 56 wherein 70 degrees of throttle actuator arm rotation is effected in response to 360 degrees of step motor shaft rotation.

62. The method of claim 56 wherein the range of motion permitted the throttle is limited by at least one stop, cooperating with at least one of the actuator arms.

63. The method of claim 10 wherein the stator coils have stator poles associated therewith, and the step of selectively generating signals to said stepping motor to effect incremental rotation of the stepping motor output shaft comprises generating signals to said stepping motor to effect current flow through single coils, in sequence, to incrementally advance the shaft by a full step, from stator pole to stator pole.

64. The method of claim 10 wherein the stator coils have stator poles associated therewith, and the step of selectively generating signals to said stepping motor to effect incremental rotation of the stepping motor output shaft comprises:

generating signals to said stepping motor to effect pairs of current paths in adjacent coils, in sequence, to incrementally advance the shaft by a full step, at full torque, from midpoint between adjacent stator poles to midpoint between next successive pair of stator poles.

65. The method of claim 10 wherein the stator coils have stator poles associated therewith, and the step of selectively generating signals to said stepping motor to effect incremental rotation of the stepping motor output shaft comprises:

generating signals to energize a single coil, to bring the rotor into alignment with the stator pole associated with the coil, then generating signals to energize a pair of coils, to bring the rotor into alignment with the midpoint between that stator pole and the next successive stator pole.

66. The method of claim 10 wherein the step of selectively generating signals to said stepping motor to effect incremental rotation of the stepping motor output shaft comprises:

generating signals to said stepping motor to effect pairs of current paths in adjacent coils, in sequence, and effecting currents of different magnitudes through the respective coils.

67. The method of claim 10 wherein current paths through the stator coils are effected in accordance with a predetermined sequence of coil activation states, and the method further comprises the step of dithering between respective coil activation states.

68. The method of claim 67 wherein:

the engine has a mechanical response time associated therewith;

the actuator stator coils have an inductive rise time associated therewith; and

dithering between respective coil actuation states is effected at a rate faster than the mechanical response time of the engine but less than the inductive rise time of the actuator stator coils.

69. The method of claim 67 wherein:

the actuator stator coils have an inductive rise time associated therewith;

the actuator rotor has a mechanical response time associated therewith when coupled to the throttle; and

dithering between respective coil actuation states is effected at a rate faster than the mechanical response time of the actuator but less than the inductive rise time of the stator coils.

70. The method of claim 67 wherein dithering between respective coil actuation states is effected at a rate sufficient to permit the throttle to assume a desired static position intermediate the positions associated the respective coil actuation states.

71. The method of claim 67 wherein dithering between respective coil actuation states is effected at a frequency that is equal to the lowest frequency that permits the throttle to assume a desired static position intermediate the positions associated the respective coil actuation states.

72. The method of claim 67 wherein the first and second coil activation states are maintained for different relative time periods.

73. The method of claim 2 wherein:

the actuator comprises a stepping motor including;

a plurality of stator coils;

a rotor having magnetic components; and

an output shaft cooperating with the rotor, and mechanically coupled to the throttle, current flow through the stator coils generating magnetic fields to interact with the magnetic components of the rotor, and tending to cause the rotor to assume a predetermined alignment with said fields, and the step of generating control signals to said selectively adjust the setting of the throttle by a predetermined increment comprises the steps of;

(a) effecting, for a first predetermined time period, a first activation state in which current paths are effected through a first coil activation set, including at least one stator coil portion and tending to cause the rotor to assume a first predetermined alignment;

(b) then effecting, for a second predetermined time period, a second activation state in which current paths are effected through a second coil activation set, including at least one stator coil portion and tending to cause the rotor to assume a second predetermined alignment; and

(c) repeating steps (a) and (b).

74. The method of claim 73 wherein the first and second time periods are equal.

75. The method of claim 73 wherein the first time period is a predetermined multiple of the second time period.

76. The method of claim 73 wherein the second time period is a predetermined multiple of the first time period.

77. The method of claim 2 wherein:

the actuator comprises a stepping motor including;

a plurality of stator coils;

a rotor having magnetic components; and

an output shaft cooperating with the rotor, and mechanically coupled to the throttle, current flow through the stator coils generating magnetic fields to interact with the magnetic components of the rotor, and tending to cause the rotor to assume a predetermined alignment with said fields;

and the throttle is adjusted in a first direction by effecting a predetermined sequence of activation states, in each activation state current paths being effected through a corresponding coil activation set, such set including at least one stator coil portion, tending to cause the rotor to assume a corresponding predetermined alignment.

78. The method of claim 77 wherein in at least some of the activation states a current path is effected through a single corresponding coil.

79. The method of claim 78 wherein in at least some of the activation states current paths of the same polarity are effected through coils on adjacent stator poles.

80. The method of claim 77 wherein in at least some of the activation states current paths of the same polarity are effected through coils on adjacent stator poles.

81. The method of claim 77 wherein the throttle is adjusted in a second direction, opposite the first direction, by effecting the predetermined sequence of activation states in reverse order.

82. The method of claim 77 wherein the predetermined sequence of activation states includes a first activation state tending to cause the rotor to assume a first predetermined alignment and a second activation state tending to cause the rotor to assume a second predetermined alignment, and at least a first intermediate activation state, the throttle being advanced from a setting corresponding to the first activation state to a setting corresponding to the second activation state through at least a first intermediate setting between the setting corresponding to the first activation state and the setting corresponding to the second activation state, by a sequence comprising the steps of:

(a) effecting, for a first predetermined time period, the first activation state;

(b) then effecting, for a second predetermined time period, the second activation state; and

(c) for so long as the first intermediate activation state is maintained, repeating steps (a) and (b).

83. The method of claim 82 wherein the first and second time periods are equal.

84. The method of claim 82 wherein the intermediate setting is effectively midway between the setting corresponding to the first activation state and the setting corresponding to the second activation state.

85. The method of claim 82 wherein the first time period is a predetermined multiple of the second time period.

86. The method of claim 82 wherein the second time period is a predetermined multiple of the first time period.

87. The method of claim 82 wherein the throttle is advanced from a setting corresponding to the first activation state to a setting corresponding to the second activation state through at least a second setting intermediate the setting corresponding to the first activation state and the setting corresponding to the second activation state, and the sequence further comprises the steps of

(a) effecting, for said second predetermined time period, said first activation state;

(b) then effecting, for said first predetermined time period, said second activation state; and

(c) for so long as the second intermediate activation state is maintained, repeating steps (a) and (b).

88. The method of claim 87 wherein the first time period is a predetermined multiple of the second time period.

89. The method of claim 88 wherein the first time period is three times the second time period.

90. The method of claim 87 wherein the throttle is advanced from a setting corresponding to the first activation state to a setting corresponding to the second activation state through at least a third setting intermediate the setting corresponding to the first activation state and the setting corresponding to the second activation state, and the sequence further comprises the steps of

(a) effecting, for a third predetermined time period, said first activation state;

(b) then effecting, for said third predetermined time period, said second activation state; and

(c) for so long as the third intermediate activation state is maintained, repeating steps (a) and (b).

91. The method of claim 88 wherein the first time period is a predetermined multiple of the second time period.

92. The method of claim 88 wherein the first time period is three times the second time period.

93. The method of claim 88 wherein the first, second and third intermediate settings are effectively 1/4, 3/4 and 1/2 of the way, respectively, between the setting corresponding to the first activation state and the setting corresponding to the second activation state.

94. The method of claim 90 wherein the sum of the first and second periods equals twice the third period.

95. The method of claim 2 further including the step of delaying adjustment of the throttle setting until at least a predetermined time has elapsed since the last preceding adjustment to the throttle.

96. The method of claim 2 wherein the actuator comprises a closed loop servo system.

97. The method of claim 2 wherein:

the actuator comprises;

a servo motor, with a rotary output shaft and positive and negative input terminals;

a first switching device, responsive to control signals applied thereto, connected to selectively effect a current path between a positive voltage node and the servo motor positive input terminal;

a second switching device, responsive to control signals applied thereto, connected to selectively effect a current path between the positive voltage node and the servo motor negative input terminal;

a third switching device, responsive to the second control signal, connected to selectively effect a current path between a relatively negative voltage node and the servo motor positive input terminal;

a fourth switching device, responsive to the first control signal, connected to selectively effect a current path between the common rail and the servo motor negative input terminal;

and the steps of generating control signals to said actuator comprise;

applying, as the control signals to the first and fourth switching devices, a common pulse width modulated (PWM) signal having a relatively positive (high) and a relatively negative (low) portion during a cycle, such that the first and fourth switching devices are rendered conductive during the high portion of the PWM signal cycle;

inverting the common PWM signal;

applying the inverted PWM signal as the control signals to the second and third switching devices such that the second and third switching devices are rendered conductive during the low portion of the PWM signal; and

varying the relative durations of the high and low portions of the PWM signal cycle to effect changes in the throttle setting, the servo motor effecting rotary motion of its output shaft in accordance with the difference between the relative durations of the high and low portions of the PWM signal cycle.

98. The method of claim 97 wherein the steps of generating control signals to said actuator further comprise:

generating a feedback signal indicative of the average voltage of the PWM signal and varying the relative durations of the high and low portions of the PWM signal cycle in accordance with deviations of the average voltage from desired values.

99. The method of claim 97 wherein the switching devices comprise MOSFET power switches.

100. The method of claim 97 wherein rotation of 5 degrees by the motor output shaft effects a one degree change in throttle setting.

24. A method of controlling the output of an apparatus for converting mechanical energy into electrical energy at respective output terminals, the apparatus including:

an engine having an output shaft, a throttle for controlling the rotational speed of the output shaft;

an actuator, a coupling effecting a mechanical connection between the actuator and the throttle;

the actuator, responsive to control signals applied thereto, cooperating with the coupling to control the setting of the throttle,

a generator including a rotor and a stator, the rotor being rotationally driven by the engine output shaft;

the stator including at least one stator winding, disposed such that rotation of the rotor induces current in the stator winding;

a controlled rectifier, associated with the winding, the controlled rectifier including at least one switching device, responsive to control signals applied thereto;

the method comprising;

generating control signals to said switching device to actuate the switching device for predetermined periods of time to generate output current pulses of predetermined pulse width on a periodic basis; and

selectively varying the number of output current pulses per unit time to vary the average output voltage, increasing the number of output current pulses if the output voltage drops below a first predetermined set point value and decreasing the number of output current pulses if the output voltage rises above a second predetermined set point value;

responsive to the output voltage exceeding a third predetermined set point value with the number of output current pulses equal to a predetermined minimum number, generating control signals to said actuator to incrementally decrease the rotational speed;

responsive to the output voltage dropping below a fourth predetermined set point value with the number of output current pulses equal to a predetermined maximum number, generating control signals to said actuator to incrementally increase the rotational speed.

25. The method of claim 24, wherein:

the stator includes at least one multi-phase group of stator windings, disposed such that rotation of the rotor induces current in the stator windings;

the regulator comprises a multi-phase regulator, associated with the winding group, the multi-phase regulator including a respective switching device, responsive to control signals applied thereto, associated with each phase, and the method includes the step of generating control signals to said switching devices to actuate the switching devices for predetermined periods of time to generate the output current pulses of predetermined pulse width on a periodic basis.

26. The method of claim 24, wherein the first predetermined set point value equals the second predetermined set point value.

27. The method of claim 24, wherein the third predetermined set point value equals the second predetermined set point value.

28. The method of claim 24, wherein the fourth predetermined set point value equals the first predetermined set point value.

29. An energy conversion system comprising:

an engine having an output shaft and a throttle, the rotational speed of the output shaft being in accordance with the setting of the throttle;

an actuator;

a coupling effecting a mechanical connection between the actuator and the throttle;

the actuator, responsive to control signals applied thereto, cooperating with the coupling to control the setting of the throttle, a generator including a rotor and a stator, the rotor being rotationally driven by the engine output shaft;

the stator including at least one stator winding, disposed such that rotation of the rotor induces current in the stator winding;

a rectifier, associated with the winding, for generating a DC rail voltage;

an inverter, responsive to the DC rail voltage and control signals applied thereto, for generating an AC output signal;

a first comparator, responsive to a signal indicative of a designated upper limit of acceptable values of DC rail voltage, and a feedback signal, indicative of the value of the DC Rail voltage, for generating an output signal indicative of the DC Rail voltage exceeding the upper limit;

a second comparator, responsive to a signal indicative of a designated lower limit of acceptable values of DC rail voltage, and the feedback signal, for generating an output signal indicative of the DC Rail voltage below the lower limit;

a third comparator responsive to a signal indicative of the AC current output of the inverter and a signal indicative of a designated maximum current value, for generating an output signal indicative of the inverter output current exceeding the designated maximum;

a controller, cooperating with the comparators, for generating control signals to the actuator to incrementally increase the throttle setting in response to the DC Rail voltage going below the lower limit, incrementally decrease the throttle setting in response to the DC Rail voltage exceeding the upper limit, and decrease the throttle setting to a predetermined value in response to the inverter output current exceeding the designated maximum.

30. The system of claim 29 wherein the rectifier comprises a controlled rectifier responsive to control signals from the controller.

31. The system of claim 30 wherein the controller generates control signals to the controlled rectifier such that the rectifier selectively generates output current pulses of predetermined pulse width on a periodic basis to control the average DC Rail voltage.

32. The system of claim 30 wherein the controller generates control signals to the controlled rectifier to vary the rectifier output in accordance with a predetermined algorithm in response to the inverter output current exceeding the designated maximum.

33. The system of claim 30 wherein the controller generates control signals to the controlled rectifier to selectively effect modulation of the rectifier output in response to the inverter output current exceeding the designated maximum.

34. The system of claim 30 wherein the controller generates control signals to the controlled rectifier to selectively effect pulse population modulation of the rectifier output.

35. A system for converting mechanical energy into electrical energy at respective output terminals, the system including:

an engine having an output shaft, a throttle for controlling the rotational speed of the output shaft;

an actuator, a coupling effecting a mechanical connection between the actuator and the throttle, the actuator, responsive to control signals applied thereto, cooperating with the coupling to control the setting of the throttle;

a generator including a rotor and a stator, the rotor being rotationally driven by the engine output shaft;

the stator including at least one stator winding, disposed such that rotation of the rotor induces current in the stator winding;

a controlled rectifier, associated with the winding, the controlled rectifier including at least one switching device, responsive to control signals applied thereto; and

a control system programed to;

generate control signals to said switching devices to actuate the switching devices for predetermined periods of time to generate output current pulses of predetermined pulse width on a periodic basis; and

selectively vary the number of output current pulses per unit time to vary the average output voltage, increasing the number of output current pulses if the output voltage drops below a first predetermined set point value and decreasing the number of output current pulses if the output voltage rises above a second predetermined set point value;

responsive to the output voltage exceeding a third predetermined set point value with the number of output current pulses equal to a predetermined minimum number, generate control signals to said actuator to incrementally decrease the rotational speed;

responsive to the output voltage dropping below a fourth predetermined set point value with the number of output current pulses equal to a predetermined maximum number, generate control signals to said actuator to incrementally increase the rotational speed.

36. The system of claim 35 wherein:

the stator, includes at least one multi-phase group of stator windings, disposed such that rotation of the rotor induces current in the stator windings;

the controlled rectifier comprises a multi-phase regulator, associated with the winding group, the multi-phase regulator including a respective switching device, responsive to control signals applied thereto, associated with each phase, a controller, programed to;

controllably generate control signals to said switching devices to actuate the switching devices for predetermined periods of time to generate output current pulses of predetermined pulse width on a periodic basis; and

selectively vary the number of output current pulses per unit time to vary the average output voltage, increasing the number of output current pulses if the output voltage drops below a first predetermined set point value and decreasing the number of output current pulses if the output voltage rises above a second predetermined set point value;

responsive to the output voltage exceeding a third predetermined set point value with the number of output current pulses equal to a predetermined minimum number, generate control signals to said actuator to incrementally decrease the rotational speed;

responsive to the output voltage dropping below a fourth predetermined set point value with the number of output current pulses equal to a predetermined maximum number, generate control signals to said actuator to incrementally increase the rotational speed.

101. Apparatus for converting mechanical energy into electrical energy at respective output terminals, the apparatus comprising:

an engine;

a generator, cooperating with the engine, for generating an AC signal;

a controlled rectifier, responsive to control signals applied thereto, for developing a DC output signal from the AC signal;

a sensor for generating indicia of rectifier output current;

a control circuit, including a microcomputer, responsive to the indicia of rectifier output current programmed to, upon the occurrence of an output current in excess of a predetermined level, generate control signals to the rectifier to decrease the output voltage of the generator to a predetermined lower value, and then gradually increase the output voltage from the predetermined lower value until the voltage reaches a predetermined set point value, and

wherein the control circuit is programed to;

generate control signals to the controlled rectifier to actuate the controlled rectifier for predetermined periods of time to generate output current pulses of predetermined pulse width on a periodic basis; and

selectively vary the number of output current pulses per unit time to vary the average output voltage, increasing the number of output current pulses to increase the output voltage and decreasing the number of output current pulses to decrease the output voltage.

102. Apparatus for converting mechanical energy into electrical energy at respective output terminals, the apparatus comprising:

an engine;

a generator, cooperating with the engine, for generating an AC signal;

a controlled rectifier, responsive to control signals applied thereto, for developing a DC output signal from the AC signal;

a sensor for generating indicia of rectifier output current;

a control circuit, including a microcomputer, responsive to the indicia of rectifier output current programmed to, upon the occurrence of an output current in excess of a predetermined level, generate control signals to the rectifier to decrease the output voltage of the generator to a predetermined lower value, and then gradually increase the output voltage from the predetermined lower value until the voltage reaches a predetermined set point value, and

wherein the engine includes a throttle for controlling the rotational output speed thereof, and the apparatus further comprises;

an actuator,

a coupling, connecting the actuator and the throttle,

the actuator, responsive to control signals applied thereto, cooperating with the coupling to control the setting of the throttle,

wherein the control circuit is further programed to;

responsive to the output voltage exceeding an upper predetermined value, with the controlled rectifier receptive of control signals corresponding to a predetermined minimum percentage output level, generate control signals to said actuator to incrementally decrease the engine rotational speed;

responsive to the output voltage dropping below a lower predetermined value with the controlled rectifier receptive of control signals corresponding to a predetermined maximum percentage output level, generate control signals to said actuator to incrementally increase the engine rotational speed.

103. Apparatus for converting mechanical energy into electrical energy at respective output terminals, the apparatus comprising:

an engine;

a generator, cooperating with the engine, for generating an AC signal;

a controlled rectifier, responsive to control signals applied thereto, for developing a DC output signal from the AC signal;

a sensor for generating indicia of rectifier output current;

a control circuit, including a microcomputer, responsive to the indicia of rectifier output current programmed to, upon the occurrence of an output current in excess of a predetermined level, generate control signals to the rectifier to decrease the output voltage of the generator to a predetermined lower value, and then gradually increase the output voltage from the predetermined lower value until the voltage reaches a predetermined set point value, and

wherein the engine includes a throttle for controlling the rotational output speed thereof, and the apparatus further comprises;

an actuator, a coupling, connecting the actuator and the throttle, the actuator, responsive to control signals applied thereto, cooperating with the coupling to control the setting of the throttle, wherein the control circuit is programed to;

generate control signals to said switching device to actuate the switching device for predetermined periods of time to generate output current pulses of predetermined pulse width on a periodic basis;

selectively vary the number of output current pulses per unit time to vary the average output voltage, increasing the number of output current pulses if the output voltage drops below a first predetermined set point value and decreasing the number of output current pulses if the output voltage rises above a second predetermined set point value;

responsive to the output voltage exceeding a third predetermined set point value with the number of output current pulses equal to a predetermined minimum number, generate control signals to the actuator to incrementally decrease the rotational speed;

responsive to the output voltage dropping below a fourth predetermined set point value with the number of output current pulses equal to a predetermined maximum number, generate control signals to said actuator to incrementally increase the rotational speed.

104. The apparatus of claim 103 wherein the control circuit is further programed to delay adjustment of the throttle setting until at least a predetermined time has elapsed since the last preceding adjustment to the throttle.

105. Apparatus for converting mechanical energy into electrical energy at respective output terminals, the apparatus comprising:

an engine including a throttle for controlling the rotational output speed thereof,

an actuator,

a coupling, connecting the actuator and the throttle, the actuator, responsive to control signals applied thereto, cooperating with the coupling to control the setting of the throttle, and

a programable control circuit, responsive to the indicia of output current, programmed to , upon the occurrence of an output current in excess of a predetermined level , generate control signals to the throttle to decrease the rotational output speed of the engine to a predetermined lower value, and then gradually increase the rotational output speed from the predetermined lower value until the voltage reaches a predetermined set point value.

106. The apparatus of claim 105 wherein the control circuit is further programed to delay adjustment of the throttle setting until at least a predetermined time has elapsed since the last preceding adjustment to the throttle.

107. The apparatus of claim 105 wherein the programable control circuit comprises a microcomputer.

108. The apparatus of claim 105 wherein the control circuit is programed to:

responsive to the output voltage exceeding an upper set point value, generate control signals to said actuator to incrementally decrease the engine rotational speed;

responsive to the output voltage dropping below a lower set point value, generate control signals to said actuator to incrementally increase the engine rotational speed.

109. The apparatus of claim 105 wherein the actuator comprises:

a throttle lever arm adapted to cooperate with the throttle such that the throttle setting varies in accordance with the position of the throttle lever arm;

an elongated magnet, magnetized through the length thereof, a non-magnetic coupling between the magnet and throttle arm, such that movement of the magnet effects a corresponding movement of the throttle arm;

an electrical coil, receptive of a control signal applied thereto, and disposed such that current flow therethrough effects magnetic interaction with the magnet, causing the magnet to assume a position in accordance with the power through the coil, to control the position of the throttle arm.

110. The apparatus of claim 109 wherein the magnet is cylindrical.

111. The apparatus of claim 109 wherein the magnet is formed of Alnico.

112. The apparatus of claim 109 wherein the coupling comprises an elongated non-magnetic push rod, coupled to, and in general axial alignment with the magnet.

113. The apparatus of claim 109 wherein the actuator further comprises a spring disposed to bias the throttle arm into a designated idle position, such that applying a control signal of a predetermined polarity to the coil causes the magnet to move against the bias of the spring to control the position of the throttle arm.

114. The apparatus of claim 109, further comprising a fly-back diode provided across the coil.

115. The apparatus of claim 109 wherein the control circuit is further programed to delay adjustment of the throttle setting until at least a predetermined time has elapsed since the last preceding adjustment to the throttle.

116. The apparatus of claim 105 wherein the actuator comprises a stepping motor.

117. The apparatus of claim 105 wherein the actuator comprises:

a stepping motor having a rotor with magnetic components and plurality of stator coils, the stator coils having an inductive rise time associated therewith;

a drive circuit, responsive to control signals applied thereto, for selectively effecting current flow through designated coils, the stepping motor having a plurality of activation states associated therewith, each such activation state corresponding to current flow through a corresponding predetermined activated coil set, each set comprising at least a portion of at least one stepping motor coil, current flow through an activated coil set generating magnetic fields to interact with the magnetic components of the rotor, and tending to cause the rotor to assume a predetermined alignment with said fields;

a mechanical coupling between the stepping motor shaft and the engine throttle, such that rotary movement of the stepping motor shaft effects control of the throttle setting;

a programable control circuit, responsive to the indicia of rectifier output current, programmed to, upon the occurrence of an output current in excess of a predetermined level, generate control signals to the throttle to decrease the rotational output speed of the engine to a predetermined lower value, and then gradually increase the rotational output speed from the predetermined lower value until the voltage reaches a predetermined set point value; and

wherein the control circuit selectively generates signals to the drive circuit to dither between successive coil actuation states.