The Research On Four-quadrant Converter Vector Control System

With the development of electronic and computer technology, the PWM rectifiercomposed of fully controlled devices is the most noticeable. Voltage source rectifier (VSR)has constantly been focused recent years, for its advantages of sinusoidal input current,high power factor and bidirectional power flow. However, it still has a long way to applythe voltage source rectifier to voltage source inverter (VSR-VSI) into AC motor drive andcontrol system to attain the four-quadrant operation and energy regeneration. Therefore,the PWM-VSR Rectifier is selected in this paper to have a deep research on the controlstrategy of VSR active front end (AFE) and the new features of controllable DC-busvoltage and energy reversible flowing.This paper first analyzes the basic principles of the four-quadrant inverter andexplains its working principles, then introduces the principles of SVPWM modulation,afterwards, analyzes the vector control method of permanent magnet synchronous motor(PMSM) and asynchronous motors detailedly, respectively, and shows the control blockdiagram. On this basis, this paper focuses on the control strategy of PWM-VSR in thefour-quadrant inverter. According to the mathematical model of PWM-VSR under d, qcoordinate system, it can achieve current decoupling after the Laplace transform. Then thispaper conducts a quantitative derivation and calculation or qualitative analysis on the PIparameters of the current inner loop, outer voltage loop and the filter inductor of grid sideand the DC bus capacitor in the main circuit, then shows the control block diagram of thePWM-VSR.This paper briefly introduces the function of the TMS320F28335, then analyzes thehardware circuit of the control board detailedly, including the sampling circuit, theminimum system board, the peripheral interface circuit and the driving circuit. Afterwards,the paper introduces the control software of the four-quadrant inverter, shows the mainprogram flowchart of the PWM-VSR, and the A/D interrupt service subroutine flowchart.Then this paper explains the communication program between the10.2-inch touch screen(PC) and the control panel, including QTouch configuration software introduction, standard Modbus protocol, and the communication protocol between the DSP and thetouch screen.In the end, this paper introduces the experiments, especially for the PWM-VSR, andshows some waveforms. The waveforms include grid-side voltage and current waveformswhen PWM-VSR working as a high-frequency rectifier or an active inverter, grid-sidecurrent and DC bus voltage waveforms when suddenly load increasing or load reducing.The experimental waveforms and results are good, we achieve the desired purpose.