Active damping method for basic voltage vector compensation

Abstract

The invention provides an active damping method for basic voltage vector compensation (BVC). Firstly, a high-pass filter (HPF) and a delay link are used for extracting a direct-current link oscillation small signal; then, subtracting a small signal value from the direct current link voltage; and finally, the voltage difference value is used as a direct-current link voltage value for calculating a basic voltage vector of finite control set model prediction current control (FCS-MPCC). Besides, under a small signal model, the input impedance of the system after BVC compensation is deduced, and then the stability of the system before and after compensation is analyzed in detail according to an impedance matching criterion and a Nyquist stability criterion. The BVC active damping method not only has the advantages of FCS-MPCC high-speed dynamic response and good steady-state performance, but also can effectively suppress the DC link voltage oscillation phenomenon caused by a constant-power load. The method is not influenced by the bandwidth of a current loop; the influence on the motor performance is smaller; extra power electronic devices are not needed, and the influence on the efficiency of the inverter is small.

Description

technical field [0001] The invention relates to a DC propulsion system, in particular to a method for suppressing DC link voltage oscillation caused by constant power loads in the DC propulsion system. Background technique [0002] With the development of power electronics technology, DC propulsion system has attracted much attention in ships. Meanwhile, permanent magnet synchronous motors (PMSMs) are widely used as propulsion motors due to their simple structure, high power density, and low loss. Therefore, the LC filter-PMSM cascade system is more common in DC propulsion ships. However, the PMSM drive system has negative impedance characteristics under strict speed regulation and constant load torque, which causes the DC link voltage of the cascaded system to oscillate. This oscillation phenomenon is caused by the mismatch between the output impedance of the LC filter and the input impedance of the load. [0003] Compensation strategy based on reference current (RCC) an...

AI Technical Summary

Problems solved by technology

However, RCC injects a damping term into the q-axis reference current, which causes coupling between the damping term and the current loop, resulting in a decrease in motor performance; in addition, the compensation effect of RCC is also affected by the bandwidth of the current loop

RVC injects a damping term into the q-axis reference voltage, which has a great influence on the starting performance of the motor

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