Method and apparatus for overvoltage protection and reverse motor speed control for motor drive power loss events

摘要

Apparatus and methods are presented for mitigating overvoltages and limiting reverse motor speeds for motor drive power loss events, in which a first power dissipation circuit is enabled at the motor drive output to limit reverse rotation of a driven motor load when motor drive power is lost, and a second power dissipation circuit in a DC bus circuit is used to mitigate over voltages following restoration of motor drive power.

主权项

1. A power conversion system, comprising:
an AC output including a plurality of AC output terminals; a DC bus circuit comprising first and second DC bus nodes and at least one DC bus capacitance connected between the first and second DC bus nodes; an inverter comprising a DC input with first and second DC input nodes connected to the first and second DC bus nodes, an inverter output with a plurality of inverter output nodes, and a plurality of inverter switching devices individually coupled between one of the DC input nodes and one of the inverter output nodes, the inverter switching devices individually operative to selectively electrically couple the corresponding DC input node with the corresponding inverter output node according to a corresponding inverter switching control signal; at least one controller operative to provide the inverter switching control signals to cause the inverter to selectively convert DC power from the DC bus circuit to provide AC electrical power to the inverter output; a first power dissipation circuit coupled with the AC output and operative in a first mode to selectively couple at least one resistive load between at least two of the AC output terminals to dissipate power provided to the system from a load; and a second power dissipation circuit operative in a first mode to selectively dissipate power in the DC bus circuit; wherein the at least one controller is operative in response to loss of system input power to provide a first control signal to place the first power dissipation circuit in the first mode to dissipate power provided to the AC output from the load.