Current chopping strategy for generating action in switched reluctance machines

摘要

A method and apparatus are provided for controlling the switching devices in a switched reluctance machine bridge inverter, which inverter has at least two switching devices per phase leg, during generating operation. At the start of the conduction interval for a particular machine phase, both switching devices of that phase are turned on, causing the phase current to build up. When the phase current reaches an upper hysteresis band level, both switching devices are turned off, resulting in the application of a reverse voltage across the phase winding and directing the phase current into the power source via flyback diodes. At relatively low and medium speeds, the phase current decreases until it reaches a lower hysteresis band level, at which point only one switching device is turned back on to form a freewheeling loop through that device and the corresponding flyback diode. The process repeats until the turn-off angle of the active phase is reached, at which point both switches are turned off in order to discharge the corresponding phase winding.