Study Of 3-phase Power Electronic Load Based On Back To Back Topology

The rapid development in science and technology today, from factory production to daily life requires a stable and reliable power supply a steady stream of delivery. Power equipment corresponding national standards. In order to meet the appropriate requirements of these standards, the need for a range of performance products manufactured before the power of the test. Before power electronics technology development people tested aging and loading capacity with combinations made by the purely resistive resistors, inductors, capacitors,rectifier and other components, inductive resistive, capacitive and resistive typical Nonlinear four kinds of conventional load. However, this test method requires large amounts of energy.Most consume a lot of power into heat. This is not only a waste of energy, also because of the heat generating element parameters change leaving the test is not accurate enough. Therefore,the power test laboratory need good cooling equipment or cooling equipment. Second, the lack of such transmission test method good mobility and flexibility, but also may be very cumbersome that it severely limits the efficiency of the power test is not in line with energy saving requirementsBased on modern power electronics technology, digital control technology, this Dissertation presents a capable power consumption back to the grid three-phase power electronic load simulation system. It topology of two back to back style bridge structure. In the middle of it is a capacitor as a connecting link; Front half of it is a voltage-type three-phase full-bridge PWM converter; second half of it is a single-phase full-bridge PWM converter. The energy feedback power electronic load simulator can quickly and flexibly to the three-phase load performance of the power of the test to be tested. Also it feedback the power absorbed from power resource to the grid achieving the energy reduction targets. This is ideal for the requirements of modern science and technology development.While for non-linear loads such as non-controlled rectifier load simulation, the "repeat +proportion" regulator, to corrected the system before measuring the current level of exchange.The core of the system is a three-phase voltage source PWM rectifier known as VSR.In this Dissertation, the basic model is derived mathematical Rectifier. Then analyzed in the d/q coordinate system operation principle and control mode. This Dissertation presents the current single system closed loop control system simulation of power electronic converter unit.When designing pure resistive, inductive and resistive-capacitive resistive linear load was simulated using the current single closed loop of PI regulator.The second half of the system is grid-connected inverter. This dissertation analyzes the impact of superimposed ripple on the DC bus current feedback Because of the tested power it may contain a lot of harmonics,the traditional power grid converter might produce pollution. For this, I use second-order notch filter and a second-order low-pass filtering. I use Double-loop control as the control strategy, that voltage outer loop using online parameters tuning fuzzy regulator and inner current loop using proportional + quasi-resonant controller, to correct the grid current effectively. Finally, I analyze the single-phase digital phase-locked loop works in the second half unit.The dissertation simulate the designed system in simulation software platform. verifying all aspects of the design.