Design Of Three-level PV Grid-connected Inverter With DSP And CPLD

With the development of China’s economic and the consumption of non-renewable energy, the shortage of energy has restricted the development of China’s economic. In the Communist Party Congress, China’s leaders clearly put forward the further development of new energy sources to replace the traditional sources. The technology of solar power is not yet ripein in our country because of the lack of high-voltage PV grid-connected inverter.We study the three-level PV grid-connected inverter in this paper, which is also a large capacity products the three-level inverter can improve the input voltage and reduce the harmonic because of the unique topology.The paper is basis on the product and it research the theory.software and hardware,after that it analysis the experiment results.First, we analyzes the advantages and disadvantages of the tradition PV grid-connected inverter, and research the he three-level PV grid-connected inverter.We also propose the new strategy of midpoint voltage and the SVPWM. In this paper, we find the strategy of MPPT by the research of the P-V voltage board. This paper also raises a new control strategy for the lock of network.Second, this paper determine to use digital control on the hardware.we use DSP and CPLD as the control chip.Then we introduce the main circuit and its parameters, at last we introduce the control circuit and the PEM drive circuit and so on.Third, in order to to maximize the advantages of both, we distribute the DSP program and the CPLD program. The DSP program include the SVPWM program, digital filtering program, network lock program, and Pi-sub program. the DSP control singnals input to the CPLD through the operation of DSP. the CPLD generate last PWM wave signal.Fourth, we build a simulation model in the MATLAB/SIMULINK platform to verify the feasibility and stability of the control theory. Then we build a10KW product for the experiment. Because of the complexity of the three-level inverter, we create a new control strategy based on DSP and CPLD.Finally, based on the research of the test results, we prove its reliability and it can be a new product.