Research Of PWM Rectifier System Based On Soft Switching Technology

With the extensive applications of power electronic device, currently the DC power supply used by most power electronic devices is obtained though the non-controlled rectifier or phase-controlled rectifier, these devices injected into a large number of harmonics and reactive in the operation of the grid that causing serious pollution of the grid, then the PWM rectifier can make the network of side current sinusoidal and running on the unity power factor and with fast response, therefore PWM rectifier has been more and more attention and application. When the traditional work of PWM rectifier, power electronic switching devices conduction in large voltage, high current turn-off, so there is a large switching loss, low frequency, harmonic pollution.For solve these problems that this paper designed a new type of PWM rectifier, and study the technology based soft-switching PWM rectifier system. First, add the soft-switching circuit to the traditional PWM rectifier, adopted a zero-voltage soft-switching technology to create zero-voltage switching conditions for Switching devices by increasing the auxiliary switch and use the resonance of inductors and capacitors, the device is able to reduced switching losses, decreased current and voltage change rate, suppress harmonic in the process of on and off, the PWM rectifier reduce the output filter inductance and capacitance of the volume at high frequencies thereby reducing the size of the device and improve the efficiency of PWM rectifier. Then uses SVPWM control strategy on the main circuit system, this control method is based on two-phase modulation control strategy with the advantages of high voltage and strong anti-dry performance. On the basis of SVPWM-based two-phase modulation control method and design principle, though control strategy used the main circuit voltage outer loop control system improve the rapid response and anti-jamming performance.Finally, study the system using simulation software, PWM rectifier can be a wide load range with zero voltage switching, significantly reduced switching losses, higher operating frequency from the results and verified the new system is the rationality and superiority. And simulation the control system under different load conditions, this control method used on the system make the system response speed, a strong anti-interference performance, power factor close to 1 to verify the SVPWM control method is the feasibility and efficiency in the PWM rectifier system, finally, the overall operation of the system to achieve the desired effect.