Apparatus and method for controlling transition between PWM and linear operation of a motor
First Claim
1. A motor drive control system for operation in both linear and PWM modes with minimized effect of transients upon transitions between modes, comprising:
- a drive circuit for supplying energizing current to motor coils during a first set of time intervals in the linear mode and during a second set of time intervals, that occur between the intervals of the first set, in the PWM mode;
said drive circuit including a compensation network that is switchably connected in the drive circuit during intervals of linear mode operation and not during periods of PWM mode operation.
1 Assignment
0 Petitions
Accused Products
Abstract
A motor drive control circuit for operation in both linear and PWM modes includes a switchably connected compensation network. The compensation network has a capacitor that provides control loop compensation. To avoid transient effects during the settling time upon transitions from one mode to the other, the switch connecting the compensation network in the circuit is closed only during linear operation and not during PWM mode operation. When the switch is open, the capacitor holds a previously attained potential that is reapplied to the circuit when the switch is again closed.
-
Citations
21 Claims
-
1. A motor drive control system for operation in both linear and PWM modes with minimized effect of transients upon transitions between modes, comprising:
-
a drive circuit for supplying energizing current to motor coils during a first set of time intervals in the linear mode and during a second set of time intervals, that occur between the intervals of the first set, in the PWM mode; said drive circuit including a compensation network that is switchably connected in the drive circuit during intervals of linear mode operation and not during periods of PWM mode operation. - View Dependent Claims (2, 3, 4)
-
-
5. A method of operating a motor drive control system with transitions between linear and PWM modes, comprising:
-
connecting a capacitive compensation element in an electrical circuit to the system when a transition from the PWM mode to the linear mode occurs; disconnecting the capacitive compensation element from the circuit when a transition from the linear mode to the PWM mode occurs; and holding a potential on the capacitive compensation element during the time it is disconnected and reapplying that potential to the circuit when the element is again connected in the circuit. - View Dependent Claims (6, 7, 8, 9)
-
-
10. A motor drive control circuit for operation alternatively in a linear mode and in a pulse width modulation (PWM) mode, comprising:
-
motor coils connected to be sequentially energized by application of drive signals to a transistor switching bridge; means for supplying the drive signals in a linear mode during first intervals and in a PWM mode during second intervals with repeated transitions from the linear mode to the PWM mode and from the PWM mode to the linear mode; said means for supplying the drive signals comprising a compensation network, for compensating for inductive reactance, connected by a first switch means at a connection point in the control circuit only during linear mode operation. - View Dependent Claims (11, 12, 13, 14)
-
-
15. A method of operating a primary electrical circuit that operates, alternatively, in linear and nonlinear modes comprising:
-
connecting a signal storage element in the circuit for compensation of impedances in the linear mode of operation; disconnecting the signal storage element so it is absent from the circuit during the nonlinear mode of operation and time for settling transients on mode transitions is reduced; and reconnecting the signal storage element for compensation during the linear mode of operation following operation in the nonlinear mode with the signal storage element having stored a signal representing operating conditions at the time of disconnecting. - View Dependent Claims (16, 17, 18)
-
-
19. A drive circuit for a load comprising:
-
means for driving the load in a linear mode during intervals separated by a nonlinear mode interval; means for connecting a signal storage element in the circuit for compensation in the linear mode of operation, disconnecting the signal storage element so it is absent from the circuit during the nonlinear mode of operation, and reconnecting the signal storage element for compensation during a next interval of linear mode operation, the signal storage element retaining a signal representing linear mode operating conditions between intervals of linear mode operation; said means for connecting, disconnecting, and reconnecting being operated at times determined according to when the circuit senses operation, and cessation of operation, in the respective modes. - View Dependent Claims (20, 21)
-
Specification