A Novel Single Phase Synchronous Reference Frame Phase-Locked Loop with a Constant Zero Orthogonal Component

Li, Ming,Wang, Yue,Fang, Xiong,Gao, Yuan,Wang, Zhaoan The Korean Institute of Power Electronics 2014 JOURNAL OF POWER ELECTRONICS Vol.14 No.6

A novel single phase Phase-Locked Loop (PLL) is proposed in this paper to accurately and rapidly estimate the instantaneous phase angle of a grid. A conjugate rotating vector pair is proposed and defined to synthesize the single phase signal in the stationary reference frame. With this concept, the proposed PLL innovatively sets one phase input of the PARK transformation to a constant zero. By means of a proper cancellation, a zero steady state phase angle estimation error can be achieved, even under magnitude and frequency variations. The proposed PLL structure is presented together with guidelines for parameters adjustment. The performance of the proposed PLL is verified by comprehensive experiments. Satisfactory phase angle estimation can be achieved within one input signal cycle, and the estimation error can be totally eliminated in four input cycles for the most severe conditions.

CONTROL STRATEGIES FOR SHUNT ACTIVE POWER FILTERS IN DISTORTION SOURCE VOLTAGE SITUATION

Jun Yang,Zhaoan Wang 전력전자학회 1998 ICPE(ISPE)논문집 Vol.- No.-

The compensation strategy of shunt active power filters is one of the most important link that determine its compensation characteristics In this paper, a new interpretation of the instantaneous reactive power theory in three-phase circuits was proposed A compensation strategy (l_p, l_q mode) was introduced on the basis of the new interpretation. This compensation strategy was compared with other two compensation strategies (p, q mode and UPF mode). When source voltage is sinusoidal, the three compensation strategies are equivalent to each other When source voltage is distorted, a sinusoidal source current may result only by using l_p, l_q mode This js the advantage of l_p, l_q mode. The result is verified by simulation.

A SERIES ACTIVE POWER FILTER ADOPTING CONTROL APPROACH OF DETECTING LOAD VOLTAGE

Yao Weizheng,Wang Qun,Liu Jinjun,Wang Zhaoan,Senior Member 전력전자학회 1998 ICPE(ISPE)논문집 Vol.- No.-

In this paper a new control approach of detecting load voltage is proposed. It can directly detect the ac side harmonic voltage of a voltage source load for the series APF to do dynamic compensation for harmonic voltages. In addition, the control methods of PWM inverter and its dc side voltage are discussed. According to these, a prototype of the series APF is manufactured and corresponding experiment studies are done.<br/>

LINE SIDE HARMONIC ANALYSIS OF SINGLE-PHASE DIODE BRIDGE RECTIFIER WITH A DC FILTER CAPACITOR

Jinjun Liu,Zhaoan Wang 전력전자학회 1998 ICPE(ISPE)논문집 Vol.- No.-

Single-phase diode bridge rectifiers with dc filter capacitor usually operate in discontinuous mode and generate large amounts of harmonic currents. This paper presents a precise harmonic analysis of the line side current in the case that both the filter inductor and the filter capacitor are not infinite. The analytical expressions of the line side performance parameters associated with harmonics are derived The curves that show the relationship of these parameters as the functions of circuit parameters are illustrated. By simulation the results are verified to be accurate and the conclusion clearly reveals the relations between the line side performance parameters and circuit parameters.

A Family of New Zero-Voltage-Transition PWM Converter with Zero-Current Turnoff Auxiliary Switch

Xu Yang,Zhaoan Wang 전력전자학회 1998 ICPE(ISPE)논문집 Vol.- No.-

The shortcomings of zero-volltage-transition PWM converter is discussed ,and a new family of topologies of zero-voltage-transition PWM converter with soft-switched auxiliary switch is introduced The experiments on a 290W boost converter and a 100W forward converter are carried out to prove the circuit The efficiency increment of the new circuits are 2-5% comparing to hard switching circuits,and the switching noise is also greatly reduced.<br/>

New Control Strategy for Reducing Switching Losses in Three-Phase Voltage-Source PWM Converters

Dong Xiaopeng,Wang Zhaoan 전력전자학회 1998 ICPE(ISPE)논문집 Vol.- No.-

In this paper, a new control strategy to reduce switching losses in three-phase voltage-source PWM converters is proposed according to Modified-Period-Average-Model (MPAM). The basic concept of this strategy is aimed at calculating the phase control voltages for controlling the source currents to be sinusoidal and in phase with the source voltages, and reducing the number of switching in each period.<br/> The phase control voltages of Period-Average-Model(PAM) is obtained according to analyzing the operation of PWM converter In order to reduce the sensitivity to system parameters in PAM, MPAM is deduced Then a square wave whose frequency is three times of utility frequency is added to the phase control voltages derived from MPAM The control strategy reduces the switching losses since there exists about one-third blanking time for every phase in one period. The theoretical derivation and the control strategy are experimentally verified on a 2.5 kW three-phase voltage source converter.

On the Control of Active Power Filters

LIU Jinjun,WANG Xiaoyu,YUAN Chang,WANG Zhaoan 전력전자학회 2007 ICPE(ISPE)논문집 Vol.- No.-

This paper compares the popular control methods for two dominant types of active power filters (APFs). With the equivalent transformation of their control diagrams, the recently proposed current-source control method for series active power filter (SAPF) is revealed to have the same control structure as the traditional voltage-source control method therefore have same compensation performances. Similarly, two kinds of popular control methods for parallel active power filter (PAPF) are also compared and found to have the similar control structure. The recently proposed PAPF control scheme without harmonics detection is revealed as a reduced version of the traditional control scheme with harmonics detection. Therefore both have same basic control principles regarding load current harmonics compensation. A general expression of the control methods for PAPF is then proposed in the form of both a control diagram and a set of equations based on current detection. With a particular set of filter gains of the three detected currents, each particular control scheme can be specifically identified and described by the general expression. Subsequently the 64 possible sets of filter gains are examined by the proposed necessary conditions to locate practically valid control schemes. Finally 4 valid control schemes come out and among which some are schemes that have never been reported before. With the comprehensive comparison of the control methods and the proposed general expression in this paper, the essential relationships of the control methods are revealed, some misinterpretations from previous publications are clarified, and some new control schemes are obtained.

A PI Control Algorithm with Zero Static Misadjustment for Tracking the Harmonic Current of Three-Level APFs

Yingjie He,Jinjun Liu,Zhaoan Wang,Yunping Zou 전력전자학회 2014 JOURNAL OF POWER ELECTRONICS Vol.14 No.1

Tracking harmonic current quickly and precisely is one of the keys to designing active power filters (APF). In the past, the current state feedback decoupling PI control was an effective means for three-phase systems in the current control of constant voltage constant frequency inverters and high frequency PWM reversible rectifiers. This paper analyzes in detail the limitation of the conventional PI conditioner in the APF application field and presents a novel PI control method. Canceling the delay of one sampling period and the misadjustment for tracking the harmonic current is the key problem of this PI control. In this PI control, the predictive output current value is obtained by a state observer. The delay of one sampling period is remedied in this digital control system by the state observer. The predictive harmonic command current value is obtained by a repetitive predictor synchronously. The repetitive predictor can achieve better predictions of the harmonic current. By this means, the misadjustment of the conventional PI control for tracking the harmonic current is cancelled. The experiment results with a three-level NPC APF indicate that the steady-state accuracy and dynamic response of this method are satisfying when the proposed control scheme is implemented.

A PI Control Algorithm with Zero Static Misadjustment for Tracking the Harmonic Current of Three-Level APFs

He, Yingjie,Liu, Jinjun,Wang, Zhaoan,Zou, Yunping The Korean Institute of Power Electronics 2014 JOURNAL OF POWER ELECTRONICS Vol.14 No.1

Tracking harmonic current quickly and precisely is one of the keys to designing active power filters (APF). In the past, the current state feedback decoupling PI control was an effective means for three-phase systems in the current control of constant voltage constant frequency inverters and high frequency PWM reversible rectifiers. This paper analyzes in detail the limitation of the conventional PI conditioner in the APF application field and presents a novel PI control method. Canceling the delay of one sampling period and the misadjustment for tracking the harmonic current is the key problem of this PI control. In this PI control, the predictive output current value is obtained by a state observer. The delay of one sampling period is remedied in this digital control system by the state observer. The predictive harmonic command current value is obtained by a repetitive predictor synchronously. The repetitive predictor can achieve better predictions of the harmonic current. By this means, the misadjustment of the conventional PI control for tracking the harmonic current is cancelled. The experiment results with a three-level NPC APF indicate that the steady-state accuracy and dynamic response of this method are satisfying when the proposed control scheme is implemented.

A Novel Single Phase Synchronous Reference Frame Phase-Locked Loop with a Constant Zero Orthogonal Component

Ming Li,Yue Wang,Xiong Fang,Yuan Gao,Zhaoan Wang 전력전자학회 2014 JOURNAL OF POWER ELECTRONICS Vol.14 No.6

A novel single phase Phase-Locked Loop (PLL) is proposed in this paper to accurately and rapidly estimate the instantaneous phase angle of a grid. A conjugate rotating vector pair is proposed and defined to synthesize the single phase signal in the stationary reference frame. With this concept, the proposed PLL innovatively sets one phase input of the PARK transformation to a constant zero. By means of a proper cancellation, a zero steady state phase angle estimation error can be achieved, even under magnitude and frequency variations. The proposed PLL structure is presented together with guidelines for parameters adjustment. The performance of the proposed PLL is verified by comprehensive experiments. Satisfactory phase angle estimation can be achieved within one input signal cycle, and the estimation error can be totally eliminated in four input cycles for the most severe conditions.