Method and apparatus for overvoltage protection and reverse motor speed control for motor drive power loss events
AssigneeRockwell Automation Technologies, Inc.
InventorsRobert J. Breitzmann, Semyon Royak, John M. Kasunich
Life of this patent
Estimating the term…
Abstract
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.
Claims20
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.
A method for mitigating motor drive overvoltage and limiting the reverse rotation of a motor load for motor drive power loss events, the method comprising:
- selectively disabling operation of a motor drive output inverter in response to loss of motor drive system input power;
- selectively coupling a first resistive load circuit to at least two AC nodes between the motor drive output inverter and the motor load in response to loss of the motor drive system input power to limit reverse rotation of the motor load by dissipating power provided to the motor drive from the motor load;
- selectively disabling the first resistive load circuit to discontinue dissipation of power provided to the motor drive from the motor load after restoration of motor drive system input power;
- selectively enabling operation of the motor drive output inverter after restoration of motor drive system input power to drive the motor load to resume rotation in a forward direction;
- selectively connecting a second resistive load to dissipate power in a DC bus circuit of the motor drive after restoration of motor drive system input power;
- and
- thereafter disconnecting the second resistive load to discontinue dissipation of power in the DC bus circuit to resume normal motor drive operation.
A computer readable medium with computer executable instructions for mitigating motor drive overvoltage and limiting the reverse rotation of a motor load for motor drive power loss events, the computer readable medium having computer executable instructions for:
- selectively disabling operation of a motor drive output inverter in response to loss of motor drive system input power;
- selectively coupling a first resistive load circuit to at least two AC nodes between the motor drive output inverter and the motor load in response to loss of the motor drive system input power to limit reverse rotation of the motor load by dissipating power provided to the motor drive from the motor load;
- selectively disabling the first resistive load circuit to discontinue dissipation of power provided to the motor drive from the motor load after restoration of motor drive system input power;
- selectively enabling operation of the motor drive output inverter after restoration of motor drive system input power to drive the motor load to resume rotation in a forward direction;
- selectively connecting a second resistive load to dissipate power in a DC bus circuit of the motor drive after restoration of motor drive system input power;
- and
- thereafter disconnecting the second resistive load to discontinue dissipation of power in the DC bus circuit to resume normal motor drive operation.
Dependencies are inferred from the claim text.