Pulse width modulated inductive load controller

A pulse width modulated motor control for controlling power to a three phase motor comprising:

• a load switching circuit including three pairs of switch means, each pair including first and second switch devices for controlling power from a power source to said motor during a predetermined period;
• said three phase motor having three load coils, each of said three load coils connected to a respective pair of first and second switch devices;
• each of said switch means including a unidirectional discharge shunt in parallel with said switch devices, for providing a shunt path for regenerated current from the load coils;
• commutation means for enabling sequential combinations of first and second switch devices in different pairs for energizing various combinations of pairs of load coils;
• pulse width modulation means for selectively shortening the period during which both of said first and second switch devices are enabled for controlling the amount of power applied to the selected load coils;
• and
• transition control means, responsive to the shortening of the period by said pulse width modulation means, for maintaining closed, until after the current in the load coils has generally discharged, one of said first and second switch devices in a sequential combination of switch device pairs, for maintaining a path through the load, and external to the power supply, through which regenerative current from said load coils may recirculate until such time as the regenerated current has generally decayed.