Research Of Speed Senorless Vector Control Based On SFO For The Direct Drive Wind Power System With CSC

As a renewable energy technology with great potential to be further exploited,wind power generation experienced fast development in the last two decades. Inwhich direct-drive wind power generation systems attract big attention for theunique advantages of the direct coupling of wind turbines and generators. In orderto achieve the variable speed constant frequency operation principle, electronicpower conversion circuits play an important role. Among them, the mature one isvoltage source converter, but current source converter (CSC) used in the windpower generation system is relatively uncommon.In this paper, for the direct-drive wind power generation system with back toback CSCs, by reading a lot of literature, the main speed senorless control methodsof PMSG are analyzed and compared, including the rotor field oriented control, thestator field oriented control and the direct torque control. Researches indicate thatcompared with the rotor field oriented control and the direct torque control method,the stator field oriented control avoids both dependence of stator inductance andother parameters in the the rotor field oriented control and reduces torque ripples inthe direct torque control. This paper uses a more accurate and quicker improvedestimation to improve the traditional speed estimation based on the stator fluxdynamic performance and robustness.By establishing the mathematical model of the PMSG based on the currentsource rectifier (CSR), for the PMSG in the direct-drive wind power system withback to back CSCs, this paper proposes a speed sensorless vector control methodbased on the stator flied orientation (SFO). In the method, the stator flux observeris the core issue of the algorithm. The traditional pure integrator easily producesthe dc drift and saturation due to the initial value and the DC bias, while theone-order low-pass filter can silence the previous problems to some extent, but theerrors in amplitude and phase will be introduced. In this paper, the research on thetheory of the integrator with an adaptive compensation has been made, and it can befound that this integrator can effectively solve this previous problems by simulation.The paper also proposes the realization of unity power factor vector control strategy with the stator flux orientation, which is simple without the complexvector transform and current loops.By Matlab/Simulink, the simulation model of direct-drive wind generationsystem with back-to-back CSC is established. The simulation results verify theeffectiveness of the control scheme. At the same time, the steady state and dynamicperformance is comparable with the rotor flied oriented speed sensorless vectorcontrol based on PLL(id=0). Finally, based on an existing experiment platform forthe10KW direct drive wind power generation system using CSC, control programfor DSP and PWM program for FPGA are designed and partial experiment resultsare given.