Regulator with alternator output current and input drive power control

• US 6,184,661 B1
• Filed: 06/22/1999
• Issued: 02/06/2001
• Est. Priority Date: 06/22/1999
• Status: Expired due to Term

• Current Assignee: C.E. Niehoff & Co.
• Original Assignee: C E Niehoff & Company
• Inventors: Becker, James, Jabaji, Issam
• Primary Examiner(s): Ponomarenko, Nicholas
• Application Number:
  US09/338,320
• Time in Patent Office: 595 Days
• Field of Search: 322/17, 322/22, 322/23, 322/24, 322/25, 322/27, 322/28, 322/29, 322/32, 322/33, 322/34
• US Class Current: 322/25
• CPC Class Codes: H02P 2101/45 for motor vehicles, e.g. car alternators
• CPC Class Codes: H02P 9/30 using semiconductor devices
• CPC Class Codes: H02P 9/305 controlling voltage H02P9/302 takes precedence
• 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 alternator regulator controls both output voltage and output current, limits input drive power and torque, and maintains output power within a prescribed range while operating over a wide ambient temperature range and shaft speed range. Voltage, shaft speed, and temperature signals are monitored, and the results are processed to determine the output current and to control the output power without exceeding the programmed limits for output voltage, output current, temperature, output power, drive power, torque, and shaft speed. This provides a predictable output power characteristic for the alternator and it eliminates high input drive power and torque excursions that occur at low temperature and certain shaft speeds. If programmed limits are exceeded over a specified interval, and the alternator does not respond to the control changes imposed by the regulator, the regulator will turn off the alternator'"'"'s field current, activate an alarm circuit, and set fault codes. The regulator is also capable of communicating with other control systems to provide status, specify needs, and respond to requests.

Claims

1. In combination with an electrical generator comprising a field coil, a winding coupled with a pair of output terminals, and a generator shaft operative to modify electromagnetic interaction of the field coil and the winding when the shaft is rotated, a generator monitor comprising:

a tachometer, responsive to the generator and operative to generate a speed signal indicative of rotational speed of the generator shaft;

a current monitor operative to generate a field current signal indicative of average field current of the generator field coil; and

a first processing element responsive to the speed and field current signals and operative to generate an output current signal indicative of electrical output current supplied by the generator via the output terminals.

2. The invention of claim 1 further comprising:

a temperature sensor operative to generate a temperature signal indicative of temperature;

wherein the first processing element is additionally responsive to the temperature signal.

3. The invention of claim 1 further comprising:

a controller, responsive to the output current signal, and operative to reduce average current of the generator field coil when the output current signal is indicative of excessive output current.

4. The invention of claim 1 further comprising:

a voltage sensor operative to generate a voltage signal indicative of voltage at one of the generator output terminals; and

a second processing element responsive to the output current and voltage signals and operative to generate an input power signal indicative of power applied to the generator.

5. The invention of claim 4 further comprising:

a controller operative to reduce average current of the generator field coil when the input power signal is indicative of excessive input power.

6. The invention of claim 4 further comprising:

a third processing element responsive to the input power signal and the speed signal to generate an input torque signal indicative of torque required to drive the generator shaft.

7. The invention of claim 6 further comprising:

a controller operative to reduce average current of the generator field coil when the input torque signal is indicative of excessive input torque.

8. A method for monitoring an electrical generator comprising a field coil, a winding coupled with a pair of output terminals, and a generator shaft operative to modify electromagnetic interaction of the field coil and the winding when the shaft is rotated, said method comprising:

(a) generating a speed signal indicative of rotational speed of the generator shaft;

(b) generating a field current signal indicative of average field current of the generator field coil; and

(c) generating an output current signal as a function of the speed signal and the field current signal, said output current signal indicative of electrical output current supplied by the generator via the output terminals.

9. The method of claim 8 further comprising:

(d) generating a temperature signal indicative of temperature;

wherein act (d) generates the output current signal as a function of the temperature signal.

10. The method of claim 8 further comprising:

(d) reducing average field coil current of the generator field coil when the output current signal is indicative of excessive output current.

11. The method of claim 8 further comprising:

(d) generating a voltage signal indicative of voltage at one of the generator output terminals; and

(e) generating an input power signal as a function of the output current signal and the voltage signal, said input power signal indicative of electrical power applied to the generator shaft.

12. The method of claim 11 further comprising:

(f) reducing average field coil current of the generator field coil when the input power signal is indicative of excessive input power.

13. The method of claim 11 further comprising:

(f) generating an input torque signal in response to the input power signal and the speed signal, said input torque signal indicative of torque applied to the generator shaft.

14. The method of claim 13 further comprising:

(g) reducing average field coil current of the generator field coil when the input torque signal is indicative of excessive input torque.

15. The method of claim 8 further comprising:

(d) reporting a signal that varies as a function of the output current signal to an external system.

16. In combination with an electrical generator comprising a field coil, a winding coupled with a pair of output terminals, and a generator shaft operative to modify electromagnetic interaction of the field coil and the winding when the shaft is rotated, a generator monitor comprising:

a tachometer, responsive to the generator and operative to generate a speed signal indicative of rotational speed of the generator shaft;

a current monitor operative to generate a field current signal indicative of average field current of the generator field coil; and

a processing element responsive to the speed and field current signals to generate an input torque signal indicative of torque required to drive the input shaft; and

a controller responsive to the input torque signal and operative to reduce average current to the generator field coil when the input torque signal is indicative of excessive input torque.

17. A method for monitoring an electrical generator comprising a field coil, a winding coupled with a pair of output terminals, and a generator shaft operative to modify electromagnetic interaction of the field coil and the winding when the shaft is rotated, said method comprising:

(a) generating a speed signal indicative of rotational speed of the generator shaft;

(b) generating a field current signal indicative of average field current of the generator field coil;

(c) generating an input torque signal in response to the speed and field current signals, said input torque signal indicative of torque applied to the generator shaft; and

(d) reducing average field coil current of the generator field coil when the input torque signal is indicative of excessive input torque.

18. In combination with an electrical generator comprising a field coil, a winding coupled with a pair of output terminals, and a generator shaft operative to modify electromagnetic interaction of the field coil and the winding when the shaft is rotated, a generator monitor comprising:

a tachometer, responsive to the generator and operative to generate a speed signal indicative of rotational speed of the generator shaft;

a current monitor operative to generate a field current signal indicative of average field current of the generator field coil; and

a processing element responsive to the speed and field current signals to generate an input power signal indicative of power required to drive the input shaft; and

a controller responsive to the input power signal and operative to reduce average current to the generator field coil when the input power signal is indicative of excessive input power.

19. A method for monitoring an electrical generator comprising a field coil, a winding coupled with a pair of output terminals, and a generator shaft operative to modify electromagnetic interaction of the field coil and the winding when the shaft is rotated, said method comprising:

(a) generating a speed signal indicative of rotational speed of the generator shaft;

(b) generating a field current signal indicative of average field current of the generator field coil;

(c) generating an input power signal in response to the speed and field current signals, said input power signal indicative of power applied to the generator shaft; and

(d) reducing average field coil current of the generator field coil when the input power signal is indicative of excessive input power.