Study On The Coordinated Control Strategy Of Dual PWM Converter In PMSG System

Nowadays, the energy crisis and environmental pollution are attracting increasing social attention, and the development of new energy technologies, such as solar, wind, hydro and tidal energy, has been concerned all over the word. As a clean, sustainable developmental energy, wind energy has huge potential to develop,and can alleviate the current energy shortage situation. Having the feature of wind turbine directly coupled with generator, direct-drive permanent magnet synchronous wind power system, as one of the important member of the wind power system,eliminates gearbox and improves the performance of unit greatly, enhances the efficiency. At the same time, through isolating the converter and power in generator, it can operate safely. This paper studies wind power system simulation platform in direct-drive permanent magnet synchronous generator(PMSG), and also has comprehensively depth study on mathematical model of the system, simulation and practice.Compared with the traditional cycle of the converter, double back to back PWM converter has the characteristics such as better output, low power harmonics and wider speed range. machine side use the Rotor flux orientation of Zero d-axis space vector control strategies to achieve maximum wind energy capturing and Independent adjustment of the reactive power for stator output; Network side use a voltage vector oriented control(VOC) to achieve stable DC bus voltage and power grid energy exchanging. DC bus voltage rises suddenly when the wind speed changes,and this causing the DC capacitor voltage fluctuations, Typically the solution to solving this problem is to increase the capacity of the capacitor, But it has drawbacks such as, big size, heavy and poor performance. In order to reduce the volatility of the DC voltage, this paper presents a double-back PWM converter coordinated control strategy.Firstly, this paper introduced the principle of PMSG Wind Power Generation System, detailed analysis of the three-phase static and two-phase rotating coordinate mathematical model of PMSG. It describes the advantages of dual PWM convertercontrol, and focuses on the dual PWM-side and network-side control strategy, by MATLAB / Simulink simulation, the correctness and validity-side and network-side control method. To prevent natural wind mutations caused instability of the DC bus voltage, In the control strategy adding the Dual PWM coordinated front-side power fed into the grid-side control strategy. Analysis of the DC voltage, current, power control before and after coordination control, and verify the validity of the control strategy. Finally, the design of a digital signal processor TMS320F2812 DSP as the core control system, by programming the hardware design and software and the control strategy validation. Experiments process in a permanent magnet direct-drive wind power 7.5KW and the network test platform. The experimental results verify the feasibility and correctness of the control scheme.