Researching On Three-phase Voltage Type SVPWM Rectifier

In daily life,a large amount of harmonics and reactive power are injected into the grid with the use of a large number of non-linear loads,which leads to a low power factor of the grid,which seriously affects the quality of the grid.The voltage type SVPWM rectifier can realize the sinusoidal input current of the AC side,the sine wave with the same phase and voltage,and realize the bidirectional flow of unit power factor operation and energy,which plays a key role in improving the economic efficiency of the power grid and reducing electromagnetic pollution.This paper analyzes the topology,working principle and control method of SVPWM rectifier.Firstly,the topology and structure of PWM rectifier are introduced.The conversion relationship between static coordinate system and rotating coordinate system is established.The common control strategies are studied.After analysis and comparison,the double closed loop of voltage outer loop and current inner loop is adopted.The current control mode is used as the control strategy of the SVPWM rectifier.The PI parameters of the regulator are studied through engineering design experience and the design criteria of the classical linear control system.The decoupling of the circuit is realized by feedforward decoupling control.The SVPWM modulation method is studied.The principle and implementation process of SVPWM modulation method are introduced in detail.Finally,through the different design indicators,the parameters of the main circuit,including the voltage on the DC output side,the filter inductance on the AC side,and the value of the filter capacitor on the DC side,are studied in detail,which provides a theoretical basis for the fabrication of the test prototype.In order to verify whether the previously built circuit model and circuit parameters are valid,the system model is built under Matlab/simulink for simulation verification.The simulation of SVPWM modulation mode is built first.The simulation result is that the standard saddle wave is consistent with the theoretical result,and then the complete The SVPWM rectifier circuit is simulated,the output is a stable and adjustable DC voltage,and the AC is measured as a sine wave with the same phase of voltage and current,which determines the theoretical analysis is correct.Secondly,the rectifier hardware circuit is designed,including CPU motherboard circuit,peripheral control circuit,MOSFET drive circuit and protection circuit.Finally,the software part of the rectifier is designed.The control software part of the system is divided into two parts: the main program and the interrupt service program.The main control of the main circuit is controlled by the main program.Interrupt service routines include sub-programs such as DC side voltage and AC voltage and current acquisition,PI closed loop control design,and SVPWM modulated wave generation.The TMS320F28379 chip of TI company is adopted as the core control chip,and the related program is written in C language on the CCS platform.Finally,the effectiveness of the control method is verified.