The shunt active power filter (SAPF) is widely utilized for harmonic and reactive power control in modern power grid systems. Current SAPF control systems typically consist of two parts: harmonic detection and harmonic control. The output of the harmonic detection serves as the control target for the harmonic control, resulting in a relatively complex system. This study introduces a novel SAPF control algorithm that integrates harmonic detection and control into the current closed-loop using quasi-proportional resonance controllers with leading phases. The proposed control algorithm consists of two control loops: an inner loop providing inverter-side current proportional feedback active damping, and an outer loop managing harmonic and reactive current control. Simulation and experimental results confirm the feasibility and effectiveness of the proposed control algorithm. The novel control algorithm presented in this study offers significant flexibility, eliminates the need for complex harmonic detection, and ensures higher steady-state accuracy and faster dynamic response compared with existing techniques.

The insulated gate bipolar transistor (IGBT), one of the most vulnerable component, is one of the most precious central component in the converter interior. High junction temperature will lead to device failure, which is the main reason of failure of power electronic system. Therefore, on-line high precision measurement of IGBT module junction temperature is the basis of life prediction and reliability evaluation of high-power power conversion equipment. In this paper, the principle of IGBT junction temperature extraction and the latest development of related technologies are summarized. In particular, the working principle and shortcomings of temperature sensitive electrical parameter (TSEP) method are summarized. The change of junction temperature will affect the inter-electrode capacitance in the internal structure of IGBT, which will cause the change of temperature sensitive electrical parameters. The single temperature sensitive electrical parameter method is easily affected by IGBT structure and inter-electrode capacitance. This paper presents an algorithm for high precision on-line detection of IGBT junction temperature. The parameter types are optimized by stepwise regression and the model is established accordingly. In this paper, IGBT: FF50R12RT4 is used as the experimental equipment. By comparing the junction temperature model established based on multiple linear stepwise regression algorithm with the junction temperature model based on traditional temperature sensitive electrical parameters, it is proved that the algorithm has better fitting degree and precision, and the algorithm can be used for high precision online extraction of junction temperature.

An active power filter (APF) is a power electrical equipment that possesses the functions of harmonic suppression and reactive power compensation in the power grid. Its performance is closely related to the adopted topology, harmonic current detection techniques, and harmonic current control methods. In order to promote the use of APF technology in a wider range of industrial applications, we first compare several commonly used APF techniques and highlight the advantages of a shunt active power filter (SAPF) in high-capacity applications. Then, we summarize the harmonic current detection techniques, harmonic current control techniques, and resonance suppression techniques of a single SAPF module and comprehensively compare the merits and demerits of various algorithms. Based on the technologies related to a single SAPF, we introduce the modeling and stability analysis methods of the multiparalleled SAPF system and discuss the existing problems from multiple perspectives. Finally, we provide a detailed description of parallel operation strategies of multiparalleled SAPFs, highlight the advantages, disadvantages, and application scope of various schemes, and prospect the future development of this field.

Temperature-sensitive electrical parameter (TSEP) approaches are widely employed in the junction temperature (T _j ) extraction and prediction of power semiconductor devices. In this paper, the turn-off loss (E _off ) and turn-off time (t _off ) are presented as temperature-sensitive electrical parameters. The abrupt change in the junction temperature of Insulated Gate Bipolar Transistor (IGBT) occurs during switching is proved. Common deficiencies in a single temperature-sensitive electrical parameter were considered, including the necessity of the collector currents exaction, the poor junction detection accuracy. Therefore, after the linear relationship between junction temperature and turn-off time, and turn-off loss is proved, a hybrid model based on turn-off loss (E _off ) and turn-off time (t _off ) is proposed to extract junction temperature accurately. The experimental results show that the proposed method is with the advantages of high accuracy and strong anti-interference ability. Although some high-precision probes are required for parameter extraction, it indicates the internal mechanism of junction temperature mutation of the power device, and it is of great value for the reliability of the power devices that operate continuously.

Temperature-sensitive electrical parameter (TSEP) approaches are widely used in junction temperature ( ${T}_{j}$ ) prediction of insulated gate bipolar transistor (IGBT). Due to different physical characteristics, TSEPs in IGBT may not suitable for power MOSFET. In this article, a novel junction temperature extraction for power MOSFET based on current fall time ( ${t}_{fi}$ ) during turn-off process is proposed. The voltage rise time ( ${t}_{rv}$ ) and ${t}_{fi}$ during turn-off process as power MOSFET’s TSEPs are evaluated, and ${t}_{rv}$ is often used for junction temperature prediction of IGBT. In addition, a method of using parasitic inductance induced voltage in the circuit to extract ${t}_{fi}$ is proposed, and the feasibility of this method has been analyzed. Then, the boost experimental platform is established, and three different types of power MOSFETs were tested. It is established that the model based on ${t}_{fi}$ is a viable model with good linearity and sensitivity, and through induced voltage on parasitic inductance, ${t}_{fi}$ can be well-reflected. Finally, online extraction of power MOSFET junction temperature in the boost circuit is implemented in this article.