CPC H02P 27/06 (2013.01) | 16 Claims |
1. A motor drive system comprising:
an input portion arranged to receive a DC input voltage across first and second conductors;
an inverter connected across the first and second conductors, said inverter being arranged such that, in a normal mode of operation, the inverter receives the DC input voltage and generates an AC drive voltage therefrom;
a motor connected to the inverter, said motor being arranged such that, in the normal mode of operation, the motor receives the AC drive voltage; and
a first switch connected along the first conductor between the input portion and the inverter, wherein the first switch is a normally-open switch;
a damping controller comprising a second switch and a damping means connected in series between the first and second conductors, wherein the second switch is a normally-closed switch;
wherein the damping controller is arranged such that:
when the motor drive system is operated in the normal mode of operation, the first switch is closed and the second switch is open;
when the motor drive system is operated in a damping mode of operation, the first switch is open and the second switch is closed; and
wherein the second switch is controlled with a control signal having a variable duty cycle.
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