Power conversion system and common mode voltage suppression method thereof

Abstract

The invention discloses a power conversion system and a common mode voltage suppression method thereof. The power conversion system comprises a grid-side converter, a machine-side converter, a bus capacitor, a first electric reactor, a second electric reactor and a third electric reactor, wherein the bus capacitor is electrically connected between the grid-side converter and the machine-side converter; the first electric reactor comprises first ends and second ends, and the first ends of the first electric reactor are electrically connected to the machine-side converter; the second electric reactor comprises first ends and second ends, the first ends of the second electric reactor are electrically connected to the second ends of the first electric reactor, and the second ends of the secondelectric reactor are electrically connected to a motor; the third electric reactor comprises first ends and second ends, the first ends of the third electric reactor are electrically connected to a power grid, and the second ends of the third electric reactor are electrically connected to the grid-side converter. According to the power conversion system and the common mode voltage suppression method thereof, the common mode voltage of the power conversion system is effectively suppressed, and the voltage to earth of the grid side and the voltage to earth of the machine side are reduced; meanwhile, the size of the power conversion system is reduced, and the cost is reduced.

Description

technical field [0001] The invention relates to a power conversion system, in particular to a power conversion system capable of reducing common-mode voltage and a suppression method for common-mode voltage. Background technique [0002] The output voltage of the voltage source inverter system has less harmonic content and large output capacity. It is suitable for medium and high voltage occasions and has been widely used in modern industrial occasions. Compared with the cascaded high-voltage general-purpose inverter system, under the same input and output voltage levels, the voltage jump of the voltage source inverter system is higher. Therefore, the common mode voltage of the voltage source inverter system It will also be more serious. The common mode voltage in the voltage source inverter system generates ground current or motor bearing current through the coupling capacitance between the motor stator and rotor, and the large bearing current is likely to affect the servi...

AI Technical Summary

Problems solved by technology

To eliminate the common-mode voltage of the voltage source inverter system, the traditional method is to improve the withstand voltage capacity of the isolation transformer so that it can withstand the common-mode voltage, which increases the size of the isolation transformer and increases the cost, and also makes the voltage source inverter System efficiency becomes lower, power density becomes smaller, and reliability decreases, etc.

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