Research And Design Of A Variable Voltage AC Power Supply With Chopping Control

With the development of economy, the needing of electricity is increasing, and the requirements of power quality is also getting higher and higher, which put forward higher requirements for the stability of the electrical equipment. In order to ensure the stability of the power system, the electricity sector need some preventive texts for the electrical equipments. The AC voltage withstand test is one of the most important tests. According to national standards, the frequency of AC voltage withstand test is between45Hz and65Hz. The output waveform must be approach sine wave, the deviation must maintain between-5%and5%. The power frequency voltage withstand test generally start from the low voltage and can be uniform fast rise. If the regulator can adjust the output voltage stable, then the output voltage of the test can meet this standard. The non-power electronic regulator is mainly measure now, but it not accurate enough because it’s bulky and difficult to filter characteristics. Chopping AC voltage regulator as a new high-performance regulator has the advantage of simple circuit topology, the output harmonic filter is easy, high power factor, and good dynamic performance, it has become the future direction of development of the voltage regulator.The first, analysis the principle of the phase voltage regulator with chop-control and comparison several common topology Chopping regulator, and determine the topologies of the main circuit in the paper. Analysis the harmonic content of the circuit by mathematical, then design the appropriate filter.Secondly, analysis the control strategy of the main circuit, and determined the control mode in the paper is the control mode of chop-controlled AC voltage regulator which adopts the non-complementary control mode with current voltage and current.the paper deeply analysis the control method and output character of PWM inverter. The application of Digital PID alogorithm in feedback control is presented. The paper proposes the whole scheme of the main circuit, then select DSP as the control core of the AC voltage regulator and the system software design are introduced by software flow diagram.Lastly, through the MATLAB software the paper build the main circuit of the chopper circuit and the control circuit to verify the correctness of the design in this paper. The experiment result shows that the design of the AC voltage regulator with chopper-control can meet the various requirements of the AC voltage withstand test, achieve the expected goals.