3MW Wind Power Converter Power Unit Design

Wind as a clean and renewable energy has been paid more and more attention around the world. Converter as an interface combines wind with the power grid not only controls the wind turbine cooperating with the fan controller to achieve the maximum capture of wind energy, but also transmits high-quality power to the grid. As the core device of the wind power system, its core component is IGBT power unit integrated power semiconductor switches, cooling plate and drive module with protection and parallel current sharing functions.Firstly, the whole structure of the power unit is introduced and the design scheme of the main power circuit, drive-protection circuits, cooling system is totally described. Then the drive and protection circuit is deeply analyzed and investigated, the structure of the gate drive, the driving voltage, the selecting principle of the gate resistance and the method of the gate power calculation are introduced in detail. In addition, the gate driver output stage circuit is designed and the required power for specific IGBT type has been calculated.Based on this, we have designed the gate drive power possessing a higher isolation voltage.On the basis of analyzing for over-load, short-circuit, over-voltage, over-temperature and other common faults, combined with the environment situation of the practical application of wind power, the dynamic active clamp protection circuit has been designed and we make use of the method of combining Vce desaturation protection with di/ dt to carry out over-current protection. For the design of parallel scheme, from the perspective of analyzing the factors affecting parallel current sharing, on the basis of comparison of the existing current sharing scheme, we propose the active gate control method achieved through using the parasitic inductance Le E of IGBT and implement current sharing for parallel IGBT modules. Compared to discrete devices, using the digital chip CPLD to process drive, protection, parallel logic signals, it can greatly improve circuit integration and the operation reliability.Through the double pulse and short circuit test, finally, the drive-protection circuit has been verified. The parallel current sharing effect is simulated in Saber simulation software for ensuring the effectiveness and stability of the various parts of the circuit.