Research On Parallel Inverter

With the development of economy, many fields have an increasing requirement of speed regulation and reliability of the motor. However, parallel inverter can not only enhance the capacity but also greatly improve the reliability of the system.It analyzed the principle of parallel inverter, established the mathematical model of parallel inverter, and researched the circulating current of parallel inverter. Through simulation, It interpreted the relation between circulating current and amplitude difference, phase difference, frequency difference while inverters worked in parallel.IMC (Internal Model Control) technology was studied, and the stator current decoupling control of induction-motor was realized by the IMC technology. The result of simulation indicated that IMC has a good traceability of the current even though the parameter is not accurately estimated.The method of parallel inverter was designed based on IMC, and the current loop, flux loop, speed loop, speed sensor-less and LC filters were designed. And then the simulation model of parallel inverter was established according to the method. The result of simulation explained that the method not only has a very good restraint of circulating current, but also has a very good performance of the motor speed regulation.It established the experimental platform of parallel inverter, designed the control circuitry and DSP software, and showed the waveform of experiment at 50Hz, 40Hz and 20Hz. The result of experiment was satisfying and it proved the feasibility of the method.