Research On Harmonics And Reactive Power Integrated Compensation Method Based On SHAPF-TCR Structure

Active power filter(APF)is considered as an ideal equipment to improve power quality,and it has been applied in practice.Shunt hybrid APF can achieve integrated management of both harmonic and reactive power,and improve power factor,but also reduce the capacity of APF and costs.Static var compensation device,as the traditional device of compensating reactive power,occupies an important position in the power system,but it is gradually replaced because when it compensates reactive power,because it increases the line loss and line voltage drop.Considering the above problems,three-phase three-wire parallel hybrid APF and thyristor control reactor are researched and analyzed to achieve harmonic and reactive power integrated compensation.In this paper,the topology of active power filter and thyristor control reactor(TCR)is firstly introduced,and their working principle is analyzed.Aiming at the problem of harmonic and reactive power integrated compensation,a harmonic and reactive power integrated compensation system is proposed based on SHAPF-TCR structure which consists of SHAPF and TCR.In this system,the SHAPF consists of a fifth-harmonic-tuned LC passive filter and a small-rating APF.APF is used to improve the filtering characteristics and suppress the possibility of resonance among PF,TCR and power supply impedance.PF is consist of an inductance and a capacitor,its main role is to compensate the fifth harmonic in the grid.TCR is composed by two anti-parallel thyristor and a reactor in series,and then parallel in the capacitor at both ends,its main role is to adjust the reactive power.On the basis of constructing SHAPF-TCR system,the mathematical model of this system is established.In this paper,the control method of SHAPF-TCR integrated compensation system is based on current control strategy,whole system adopts double closed-loop controllers,which respectively are the DC bus voltage control loop and harmonic and reactive current tracking control loop.The ip-iq method which is based on the instantaneous reactive power theory is used to detect harmonic and reactive current.A hysteresis loop control method with variable width is used to achieve the command current tracking control to generate the main-circuit control PWM signal.The command current can be calculated by the compensation susceptance,and then through the look-up table to obtain the TCR pulse signal which controls of the thyristor.The control method of SHAPF-TCR integrated compensation system is simulated in MATLAB/Simulink,the simulation results show that after compensating,the current distortion rate is only 2.83%,and the power factor is approximately equal to one,so the proposed system can realize harmonic and reactive power comprehensive management,and has good dynamic characteristics.Finally,the SHAPF-TCR experimental platform is built in the lab environment.The experimental results show that the integrated compensation system based on SHAPF-TCR structure can effectively control the harmonic and reactive power and has good dynamic performance.