Motor drive filter damping
AssigneeRockwell Automation Technologies, Inc.
InventorsYuan Xiao, Zhongyuan Cheng, Lixiang Wei, Navid R. Zargari
Life of this patent
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Abstract
Disclosed examples include methods, power converters and damping circuits to control damping of an input filter circuit, in which a low-voltage secondary winding is wound around a common core with a primary winding connected between an AC input and a rectifier input of the converter, where the secondary winding is coupled in a series circuit with a damping resistor and a switch, and a controller selectively closes the switch with a controlled on-time at system power up and/or in response to detection of oscillation or transients in the power converter.
Claims20
A power conversion system, comprising:
- an AC input coupleable to receive AC input power from a power source;
- a rectifier, including an input to receive AC input power, and an output to provide a DC output signal;
- an inverter, including an input coupled with the output of the rectifier, and an output coupleable to a load to provide an AC output signal;
- a filter circuit coupled between the AC input and the rectifier, the filter circuit including:
- a filter inductor to conduct a first current flowing between the AC input and the rectifier, and
- a filter capacitor coupled with the filter inductor;
- a damping circuit, including:
- a secondary winding magnetically coupled with the filter inductor to conduct a second current induced by the first current flowing in the filter inductor,
- a damping resistor, and
- a switch coupled in a series circuit with the secondary winding and the damping resistor, the switch operative when a damping control signal is in a first state to allow the second current to flow through the damping resistor, and the switch operative when the damping control signal is in a second state to prevent the second current from flowing through the damping resistor;
- and
- a controller to provide the damping control signal to the switch to control damping of the filter circuit.
A method to automatically control damping of a filter circuit of a power conversion system, the method comprising:
- providing a damping resistor and a switch in a series circuit with a secondary winding magnetically coupled with a filter inductor of a filter circuit of the power conversion system to conduct a second current induced by a first current flowing in the filter inductor;
- selectively turning the switch on to allow the second current to flow in the damping resistor to control damping of the filter circuit.
A damping circuit to control damping of a filter circuit in a power conversion system, comprising:
- a transformer, including:
- a primary winding wound around a core conduct a first current flowing in a filter circuit between an AC input and a rectifier of a power conversion system,
- a secondary winding wound around the core to conduct a second current induced by current flowing in the primary winding,
- a damping resistor, and
- a switch coupled in a series circuit with the secondary winding and the damping resistor;
- and
- a controller to selectively close the switch to control damping of the filter circuit.
Dependencies are inferred from the claim text.