Research On PWM Control Timing Based On AC Chopping Regulator

With the rapid development of social economy and power electronics technology, the application of electrical equipment is more extensive, high performance AC voltage regulation technology is also becoming more mature. In recent years, the development of power electronic devices is advancing by leaps and bounds, the use of power electronic devices as the voltage control element has also become voltage regulation mode for the most extensive, but general power electronic devices, such as uesing thyristor phase to control output voltage and output current contains a large number of harmonics, it makes power factor lower,high electrical power generation creation means the requirement of AC adjustable pressure device performance still continue to improve as people, which prompted AC adjustable pressure device towards high voltage, large capacity development. AC chopping circuit is used to control the duty cycle of the output signal by using the control technology of the complex programmable logic device, thereby regulating the output voltage of the chopper circuit.First of all, the paper introduces the AC chopping regulator related background and development of the status, and expounds the AC chopping voltage regulation technology basic principle analysis of circuit parameters design communication chopping control part of the system design. Description of the design of the system can be applied to the object.Secondly, according to the system design requirements and parameters of the circuit analysis results, select single-phase AC chopping circuit topology structure as the design of main circuit topology, and select the appropriate power electronic devices and hardware circuit design of the external circuit, including IGBT and the IGBT drive circuit, filter circuit and protection circuit design.Then, we discuss and analyze the different load types cut control, phase control type, complementary and non complementary and based on zero detection technology to control the timing and the AC chopper regulator control system hardware design, including control system and zero detection circuit design and analysis of AC chopping voltage regulation of phase frequency adjusting. Using CPLD as the main chip, and the design of the control system software, so as to control the AC chopping voltage regulator control system duty cycle, and can change the control sequence by changing the duty cycle, adjust the output voltage.Finally,in the design simulation,software Quartus ii and MATLAB are used to simulate the relevant CPLD internal graphics program and related circuit. The prototype is made and the long time experiment is carried out to analyze the obtained waveform. The experimental results show that the AC chopping voltage regulator designed in this paper meet the requirements of the practical application, achieve the purpose of soft over voltage, and there is no short circuit, over voltage and over current phenomenon. Essentially solve the traditional AC chopper circuit in the short circuit, voltage overshoot and over current phenomenon, to extend the life of electrical equipment 2-3 times, the maximum energy saving up to 40%, has a very good application prospects.