Two-level inverter common-mode voltage suppression method and system

Abstract

The embodiment of the invention provides a two-level inverter common-mode voltage suppression method and system, and the method comprises the steps: carrying out the Clark transformation of a three-phase modulation wave, converting the three-phase modulation wave from a three-phase static coordinate system to a two-phase static coordinate system, obtaining a current reference voltage vector, and carrying out the Clark transformation of the current reference voltage vector; determining a sector where the current reference voltage vector is located by using the current reference voltage vector and a sector division rule; according to the current reference voltage vector, the sector where the current reference voltage vector is located and the direct current side voltage of the two-level inverter, the duty ratio of a zero voltage vector and the duty ratio of an odd effective voltage vector to be selected are obtained; and according to the duty ratio of the zero voltage vector and the duty ratio of the odd effective voltage vector to be selected, generating a corresponding PWM driving waveform to drive an inverter switching tube. The common-mode voltage can be effectively suppressed, sector selection of the reference voltage vector is reduced, the calculation amount is reduced, and the method is easier to implement.

Description

technical field [0001] The invention relates to the technical field of motor control, in particular to a method and system for suppressing a common-mode voltage of a two-level inverter. Background technique [0002] The motor drive system is the main executive structure in the driving of new energy vehicles. Its driving characteristics determine the main performance indicators of the vehicle. It is an important part of the electric vehicle. Among them, the PWM motor drive system has been widely used in industrial systems and civil devices due to its good operating characteristics. However, the PWM frequency converter will generate high-frequency common-mode voltage during use, which will induce on the motor shaft. Shaft voltage will damage the bearing of the motor in a short time and shorten the service life of the motor, and the power electronic devices of high-speed switching will generate strong electromagnetic interference, which will interfere with the normal operation ...

AI Technical Summary

Problems solved by technology

Adding a common-mode voltage filter at the output end of the two-level inverter can effectively suppress the common-mode voltage, but this setting destroys the compact structure of the two-level inverter, increases the manufacturing cost, and reduces the Reliability of Inverter Operation

The space vector modulation method that abandons the zero voltage vector uses a pair of redundant voltage vectors that are equal in size and opposite in direction to equivalently replace the zero voltage vector. Due to the introduction of redundant voltage vectors, the output performance of the two-level inverter is extremely high. big drop

At the same time, the space vector modulation method that abandons the zero-voltage vector does not consider the magnitude of the common-mode current generated by the common-mode voltage. The common-mode voltage generated by the two-level inverter will generate a common-mode current inside the motor, which will reduce the performance and performance of the motor. operational reliability

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