全控电流源换流器稳态功率特性分析与主参数设计OA

The steady-state power characteristic analysis and main parameter design for controlled current source converter(CCSC)are essential for achieving decoupled active and reactive power control.However,existing studies often overlook certain constraints,leading to inaccurate SSOR estimation and parameter designs that fail to incorporate SSOR requirements.Based on a systematic analysis of CCSC steady-state power characteristics,this paper proposes an optimized design method for CCSC main parameters by integrating SSOR requirements with harmonic current limits. First,a per-unit steady-state model is established.Then the SSOR is derived by mapping one-dimensional operational limits—including DC voltage(Ud),DC current(Id),modulation index(M),and capacitor voltage(Uv)—to a two-dimensional feasible region on the P-Q plane through intersection operations of these constraints.The SSOR boundaries are shaped by combinations of these constraints:the Ud-M joint constraint,the Id-M joint constraint,the P constraint and Uv constraint.The influence of parameters such as grid voltage(U),transformer ratio(K),susceptance(Bv),and resonant frequency(ωr)on the reactive power boundaries is systematically analyzed,revealing monotonic trends and critical transition points. Second,a universal design framework is proposed by combining SSOR requirements with harmonic limits.For a specified SSOR Ωd,the expressions for ranges of M and maximum capacitor voltage UvH is derived.Then the nth harmonic current distortion in percent of normal demand load current at the point of common coupling is defined as kn.The relationship among kn,main parameters and operating points(P,Q)is established,ensuring kn remains below the permissible limit kn H across Ωd,in compliance with IEEE 519. Third,the method is applied to the improved phase control(IPC)based CCSC for HVDC systems.The IPC modulation enables decoupled power control at a low switching frequency(150 Hz)with 0.8＜M＜1.1.For SSOR requirement,unity power factor(UPF)operation is adopted to prevent wide-range variation of harmonics.Harmonic limits are set to k5H=20%and k11H=0.7%.main parameters(K,Bv,and ωᵣ)—are optimized with dual objectives:minimizing the maximum capacitor voltage and the L-C filter's peak energy storage per unit power.Parametric sweeping within feasible ranges are performed under SSOR and harmonic constraints.Results indicated that the lower UPF boundary(PuLd)expands the operating range but increases capacitor voltage and filter size.A practical trade-off is identified when PuLd lies between 0.80(pu)～1.00(pu).For PuLd=0.80(pu),optimal parameters are K=1.40,Bv=0.19(pu)and ωᵣ=3.80(pu). Finally,PSCAD simulations validate the SSOR boundaries and parameter design.Electrical variables in simulations match theoretical predictions with errors below 0.5%.Harmonic distortions k5 and k11 align with expectations,and the grid currents'total demand distortion remains below 1.12%,meeting IEEE 519.Compared to existing designs,the proposed method yields a lower maximum capacitor voltage(183.77 kV vs.201.39 kV)and comparable filter energy storage(1.80 kJ/(MV·A)vs.1.79 kJ/(MV·A)),improving cost-effectiveness and harmonic performance across the UPF range. In conclusion,the integrated SSOR analysis and multi-objective optimization approach enables CCSCs to achieve reliable power decoupling and harmonic compliance in HVDC systems.The methodology is adaptable to other modulation strategies and voltage levels,offering a systematic design framework for high-performance CCSCs.