The Research On 10KV Cell-Series High-Voltage Inverter And Its Vector Control Strategy

The need in high-voltage motor to increase the performance of speed regulation and energy efficiency leads to the ever-increasing use of the high-voltage inverter. Therefore, the research of the structure and variable frequency speed regulation algorithm in high-voltage inverter has been a key problem in the field of electrical drive. This thesis carries out deep research and design on 10KV cell-series high-voltage inverter, including theories of the circuits and control method, the implementation of analog control circuit, evaluation experiments of 10KV high-voltage inverter, and the speed sensorless vector control strategy on high-voltage inverter.Firstly, the topologic structure of main circuit and the theory of cell circuit in 10KV high-voltage inverter are analyzed. Based on the cell-series structure and multilevel phase-shifting PWM technology, the output voltage of the inverter pocesses the feature of multilevel wave and high switch-frequency. Afterwards, the structure and function of control circuit are analyzed. We focus on the design and implementation of analog control circuit. We carry out simulations of these circuits on Multisim and apply Protel DXP to design the circuits and PCB. Analog control circuit has applied successfully in 10KV high-voltage inverter.The evaluation experiments of 10KV cell-series high-voltage inverter are presented in details. Through the tests with different conditions, we have given the data and waves of the cell and the whole machine. The experiment results show that the performance of the whole machine and the devices in cell are qualified for the design requirements.Finally, we apply speed sensorless vector control strategy in 10KV high-voltage inverter. Based on rotor flux orientation vector control theory, we design the flux close-loop speed sensorless vector control system and apply MATLAB/Simulink to complete simulations of it. By using the design method of setting basis of the expected response, current regulator, flux regulator and speed regulator make the actual output follow the instruction input with good performance. Disturbance observer solves the problem of dynamic speed falling and promotes the performance of dynamic anti-disturbance in system. Two modified voltage model flux observers are compared and analyzed, and the simulation results show that the model with compensation of magnetizing current has better dynamic performance and ability of observation than the model with compensation of flux reference. On the aspect of speed regulation, dynamic speed estimator combines the filter with advanced correcting compensation. The speed and torque have good performance both at high speeds and at low speeds. Furthermore, we study on MRAS and carry out some simulations. The simulation results show that these two speed estimation algorithms are feasible.