| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 524774 | Sustainable Energy, Grids and Networks | 2015 | 14 Pages |
This paper presents a Distribution Static Compensator (DSTATCOM) with interface inductor–capacitor–inductor (LCL) filter controlled using dq0dq0 current controller and Sinusoidal Pulse Width Modulation (SPWM) switching for compensation of unbalanced nonlinear load. Voltage Source Inverter (VSI) of DSTATCOM, connected at the point of common coupling (PCC) through interface filter, injects currents corresponding to load reactive and harmonic powers. These currents consist of switching frequency ripples. LCL filter has superior switching ripple attenuation capability compared to L filter. Moreover, this can be achieved with small value of overall LCL filter inductance than L filter. However, one major concern with LCL filter is its resonating frequency (determined from its L, C, L values), which can create resonance currents and results in improper load compensation. Therefore, in the present study, a proper design of LCL filter for high switching ripple attenuation along with passive damping and proper dq0dq0 current controller are presented. The dq0dq0 current controller is implemented in Synchronous Reference Frame (SRF) rotating at fundamental frequency and consists of Harmonic Compensation (HC) regulator (realized by sum of Sinusoidal Signal Integrators (SSI)) in parallel to Proportional Integrator (PI) regulator. SSI provides high gain to specified tuned harmonic frequency and helps in minimizing filter current tracking error for harmonic load current compensation. Neutral current compensation, which is required for compensating unbalance in load, is carried out through 0-axis controller. SPWM strategy generates constant frequency gating pulses for VSI switches. This will simplify the design of interface LCL filter, reduces stress on switches and switching noise. A Matlab/Simulink model of LCL filter DSTATCOM is developed and detailed simulation results of load compensation are presented. Experimental validation of proposed scheme is done on a three phase DSTATCOM prototype using dSPACE 1104 with Matlab Real Time Interface (RTI).
