Research On The Waveform Control Of 400Hz Inverter

The 400Hz inverter which is a kind of inverters is used in many special situations. In that important situations, where fast response, little distorted output voltage and high reliability is required. It is needed and significative to improve the quality of output voltage and the reliability of power supply. This dissertation focuses on the method to improve the dynamic performance and the uninterrupted power supply strategy to advance the reliability of power supply.Based on the state-space averaging and linearization technique the continuous and discrete models of single-phase inverter are established with the load current treated as a disturbance. The reasons of the distorted of the output voltage are analyzed and the methods to improve the quality of output voltage are discussed in chapter 2. Some basic techniques to improve the dynamic performance of the inverter are introduced later.The repetitive control technique is a good technique which is used to improve the quality of output voltage. The constituent parts of repetitive control are analyzed and the design methods of those parts are studied. And then the basic principle and design method of the state-feedback-with-integral control strategy are analyzed particularly. In order to conquer the limitations of the digital control technology, the state-observer and disturbance-observer are designed in the control system. The design method of state-observer and disturbance-observer is researched in this dissertation. The advantages of the repetitive control technique and the state-feedback-with-integral control strategy are combined to design a complex control system base on the state-observer. The simulation and experimental results show that the inverter which is controlled by the complex control system can achieve good steady and dynamic performances.In some situations, an inverter provides several loads. The working inverter must't stop when one of the loads takes place of short circuit. In order to achieve this aim, the current limited strategy is studied. Combining the fast response of the analog current limited circuit and the flexible of the digital control technology, a new current limited strategy which makes up of analog current limited circuit and current loop is designed. The experimental results show that the new current limited method can not only have fast response but also have good output load current. So the short circuit can be cut off quickly and the inverters can comeback normal state also. It presents an uninterrupted power supply system using the switch-equipment to advance the reliability of power supply. The synchronization signal transmission-circuit based on current-signal is designed is the dissertation. The master-slave control strategy is used to make them synchronization between the two inverters.Sliding mode control technique is a new strategy in the control theory, many scholars are studying in this area today. The three basic problems of sliding mode control are discussed particularly, and the dynamic performances of sliding mode control are analyzed. A sliding mode control system of single-phase inverter is designed to improve its dynamic performance. It studies the reachability, existing and stabilization of sliding mode. The criterions of selecting switching surface coefficient and switching frequency for the practical implementation are considered and the corresponding design procedure is presented. The MATLAB/Simulink software is used to validate the control system. The simulations results show that the output voltage of the sliding mode control inverter tracks the reference sinusoidal signal fast, and exhibits good dynamic property and robustness under load perturbations.