Electric Motor Control
First Claim
1. A drive system for a multi-phase brushless electric motor comprising a plurality of phases, said drive system comprising a drive circuit including switch means arranged to vary a phase voltage applied to each of said phases so as to switch said motor between a plurality of active states, and control means arranged to control said switch means so as to provide PWM control of said phase voltages to control a mechanical output of said motor, wherein said control means is arranged to define a sequence for all of said active states in which states appear in an order and, said PWM control defining PWM periods, and for each of said PWM periods, to allocate state times for states required for said each period to generate a desired net voltage, and to order said required states in said order in which they occur in said sequence.
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Accused Products
Abstract
A drive system, for a multi-phase brushless electric motor comprising a plurality of phases, comprises: a drive circuit including switch means arranged to vary the phase voltage applied to each of the phases so as to switch the motor between a plurality of active states; and control means. The control means is arranged to control the switch means so as to provide PWM control of the phase voltages to control the mechanical output of the motor. The control means is arranged to define a sequence for all of the active states and, for each PWM period, to allocate state times for the states required for that period to generate a desired net voltage, and to order the required states in the same order as they occur in the sequence.
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Citations
13 Claims
- 1. A drive system for a multi-phase brushless electric motor comprising a plurality of phases, said drive system comprising a drive circuit including switch means arranged to vary a phase voltage applied to each of said phases so as to switch said motor between a plurality of active states, and control means arranged to control said switch means so as to provide PWM control of said phase voltages to control a mechanical output of said motor, wherein said control means is arranged to define a sequence for all of said active states in which states appear in an order and, said PWM control defining PWM periods, and for each of said PWM periods, to allocate state times for states required for said each period to generate a desired net voltage, and to order said required states in said order in which they occur in said sequence.
Specification