A three-phase two-level inverter bus current zero-point drift self-correction device and method

Abstract

The invention discloses a three-phase two-level inverter bus current zero-point drift self-correction device and method. The method includes the following steps: (1) installing a single current sensor on the DC bus to collect phase current information and undergoing static coordinate transformation , the synthetic reference voltage vector V ref ; (2) According to the reference voltage vector V ref The amplitude and phase angle determine the sector; the sector includes the normal operation area and the error self-correction area; (3) when the reference voltage vector V ref When located in the error self-correction area, modify the PWM wave transmission mode in the sector; (4) perform zero-point error self-correction on the collected complementary phase current. The self-calibration method of the invention can keep the control system with good steady-state performance and is easy to implement.

Description

technical field [0001] The invention relates to the technical field of zero-point drift correction in three-phase power supplies, in particular to a three-phase two-level inverter bus current zero-point drift self-correction device and method. Background technique [0002] In the high-performance AC drive system, it is very important to realize the real-time control of the load current of the three-phase voltage source inverter (VSI). figure 1 shown. Usually, current sensors such as shunts or Hall sensors are installed on the AC output side of the VSI to collect phase current information for closed-loop control. At the same time, it can also be installed on the DC bus side to realize overload protection and DC short circuit protection. However, multiple current sensors not only increase the system cost, but also affect the control performance of the electric drive system due to the inconsistency among the sensors. The single-current sensor phase current sampling technolog...

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Problems solved by technology

[0010] In order to solve the above problems, the present invention provides a three-phase two-level inverter bus current zero-point drift self-correction device and method, which is mainly composed of a new zero-point drift error detection PWM wave generation and complementary current sampling error self-correction. Accurately and efficiently realize the calculation of the zero drift error and the self-correction of the reconstructed phase current, and at the same time have little influence on the torque fluctuation of the motor, low noise, no phase reversal of the bus current, and good stability

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