Circuit structure for common-mode inductors with damping resistors applied to energy feedback devices

Abstract

The invention discloses a circuit structure for common-mode inductors with damping resistors applied to energy feedback devices. The circuit consists of an energy feedback device circuit consisting of a filter reactor and a feedback device inverting bridge, a frequency converter circuit consisting of a motor and a frequency converter inverting bridge, a DC bus and a three-phase power network group, wherein common-mode inductors with damping resistors are connected in series between the three-phase power network and the feedback device circuit connected with the three-phase power network or between the feedback device circuit and the frequency converter circuit connected with the feedback device circuit. The common-mode inductors in the circuit structure can effectively suppress common-mode current and reduce EMI interference so as to allow the application range of feedback devices to be wider. Through common-mode chokes designed, the energy feedback devices applying the circuit structure can allow resonance frequency points of common-mode current of main loops to be far from power-tube switching frequency, and the additional damping resistors can greatly reduce the common-mode current near resonance points so as to reduce common-mode interference caused by the work of the feedback devices and allow the feedback devices to be wider in application range and higher in reliability.

Description

Technical field: [0001] The invention relates to the application field of driving potential energy loads such as elevators, in particular to a common-mode inductance circuit structure with damping resistance applied in an energy feedback device. Background technique: [0002] Nowadays, most energy feedback devices on the market adopt PWM (Pulse Width Modulation, pulse width modulation) control technology, which inevitably makes the three-phase output voltage of the feedback device generate high-frequency common-mode voltage, thereby causing common-mode current. If the feedback If the inverter does not take common mode interference suppression measures, it will not only directly affect its application in the electric drive system (not only used in elevators), but also affect the normal operation of other equipment. [0003] When the DC bus side of the inverter is connected to the ground with a Y capacitor ( figure 1 In Cy), after installing a general energy feedback device, ...

AI Technical Summary

Problems solved by technology

If the parameters are not selected properly, the filter reactor L of the feeder will easily resonate with the Y capacitor Cy, resulting in a large common-mode current, which will interfere with the normal operation of the entire system, and in severe cases will cause the system to collapse.

[0008] ②When the grounding Y capacitance of the control cabinet is large, the system will not work due to serious common mode interference

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