Journal of Power Electronics最新文献

To enhance the stability, reliability, and efficiency, reduce the operation cycle time, and augment the operation security capability of fully electric and intelligent military special vehicles, a novel segmented pseudo-differential feedback (PDF) control algorithm for the permanent magnet synchronous motors (PMSMs) of special vehicles is introduced. The control algorithm optimizes the differential part of the control system and avoids the direct differential calculation. This enhances the dynamic response and anti-interference capability of the control system, ensuring a rapid and robust performance. At the same time, the control system parameters are determined based on the error and the rate of change of the error in a segmented manner, ensuring precise control of specialized vehicles under various operating conditions. To verify the effectiveness of the proposed control algorithm, a simulation model is established for simulation analysis; an experimental platform is built for experimental verification. Both simulation and experimental results demonstrate that the proposed control algorithm exhibits notable advantages, including a rapid output response, and the absence of overshoot and oscillation. These characteristics effectively enhance the motor efficiency, optimize the output attributes, and elevate the overall operational performance of electric special vehicles.

Under dynamic conditions, the response time of traditional voltage detection methods is relatively lengthy, leading to overshoots in the DC-link voltage of single-phase power converters, which significantly degrades system performance. This study proposes a rapid voltage transient detection method based on reduced-order generalized integrator (ROGI) aimed at improving the response speed of bus voltage peak detection. By reducing the order of the algorithm, this method shortens the generation time of orthogonal signals and accelerates the detection speed of voltage changes. This enables grid power to rapidly compensate for the load power under dynamic conditions while maintaining a high-precision complementarity of the split capacitor voltage. As a result, it effectively diminishes severe fluctuations in DC-link voltage, which increases the stability of the system under dynamic load changes. This paper meticulously derives the relationship between capacitor voltage changes and grid response delays, and constructs the ROGI algorithm and its control scheme, ensuring the robustness of the method in the presence of system parameter variations. Finally, to validate the effectiveness of the proposed method, a hardware experimental platform is established and tested. Results of load step response experiments indicate that the ROGI algorithm, in comparison to traditional detection methods, reduces the detection time by 40.9%.

Investigation into the energy consumption in electric vehicles (EVs) plays a pivotal role in determining their autonomy and assessing the electric system performance across diverse operational scenarios. This study focuses on the concept of energy regeneration, encompassing the recovery and storage of kinetic mechanical energy during braking or descent in EVs. Employing control systems in power electronics becomes necessary to establish a seamless workflow across operational quadrants to ensure efficient energy regeneration in an electric machine functioning as both a motor and a generator. To seamlessly integrate new technologies into practical applications, it is essential to conduct thorough evaluations in laboratories prior to deployment. This paper introduces an experimental platform specifically designed to analyze energy consumption and storage in EVs by emulating their powertrains in a controlled laboratory environment. The platform comprises key components for emulating the powertrain of a single-motor electric vehicle with single-axle traction, including a power converter configured in two quadrants, an energy storage system, a primary rotating electric machine, and a mechanically coupled point load torque (another motor). This paper provides a detailed guide on implementing such a laboratory and for facilitating the testing of diverse motor technologies and controllers under varied operational conditions. This comprehensive approach allows for the assessment of electromechanical system efficiency, focusing on both energy recovery and comprehensive control of electric power converters. Validation tests conducted under urban conditions and on steep terrains demonstrate the effectiveness of the platform in analyzing the energy efficiency of both the induction machine and the power controller.

CHB converters have been intensively considered for various applications. However, a reliability issue has emerged due to the higher number of power devices, particularly power semiconductor devices and capacitors, which have been identified as major sources of failure. Although continuous efforts have been made to enhance the reliability of power semiconductors through methods such as active thermal control, there is a noticeable absence of discussion regarding the reliability of capacitors. This is significant since capacitors are the components most prone to failure in power converters. In this study, the root mean square (RMS) current of the DC-link capacitor in a CHB converter is derived when applying thermally compensated discontinuous modulation for power semiconductors. To validate the obtained findings, the derived equations are experimentally tested using a proof-of-concept setup.

Aiming at the problem caused by the fact that traditional on-board charging systems (OBC) usually use a single form of AC input, this research suggests a suitable isolated OBC for single-phase and three-phase power sources. It adopts a two-stage structure. The front stage can switch between different input modes. Using a single-phase AC input mode, the front stage is a totem pole bridgeless cascade Boost circuit for power factor correction (PFC). It can be switched to a three-phase six-switch PFC circuit in a three-phase AC input mode. A full-bridge LLC resonant converter serves as the rear stage. The system adopts a double closed-loop control strategy and a mixed control mode that consists of pulse width modulation (PWM) and pulse frequency modulation (PFM). In either the single-phase or three-phase AC input mode, the front stage PFC circuit can output a 700 V DC bus voltage, and keep the input current and input voltage in phase. It is possible to achieve soft switching in the rear stage resonant converter, and to output a wide range of voltage to charge the power battery. According to a theoretical analysis, a system simulation model is built and an experimental prototype of the OBC is produced. The accuracies of the simulation and the theoretical analysis are confirmed by experimental findings.

Inductive power transfer (IPT) systems are playing an increasingly important role in electric vehicles, rail transit, industrial production and daily life. In the above practical applications, the misalignment of coupling coils is a very common phenomenon. To achieve high efficiency and a stable output under coil misalignment, a novel hybrid IPT system with a four-coil coupler is presented in this paper. The presented IPT system only uses a single mode switch to satisfy the battery charging requirements. When compared with existing typical IPT systems, the presented IPT system has fewer compensation components, and does not need complex control, a communication link between the transmitter and the receiver, and frequency switching. Moreover, to ameliorate the misalignment tolerance of the system, a Double-D/Bipolar (DD/BP) four-coil coupler is applied to the presented IPT topology. A 680 W experimental prototype with a 94.7% peak efficiency is built to verify the feasibility of the proposed scheme. Experimental results indicate that the presented IPT system can cope with simultaneous variations of the load and coupling coefficient within a ± 150 mm misalignment in the Y-axis and a ± 15 mm in the X-axis.

Intense field dielectrics (IFD) are widely used in the air purification industry. DC power supplies must be designed to provide a high voltage for IFD products. Therefore, this paper introduces a compact 10 kV high-voltage DC power supply tailored for IFD air purification. It employees a novel controller, which is a fusion of a fixed-frequency PWM-based sliding-mode controller and a phase-shift full-bridge configuration. The superiority of the proposed DC power supply topology is demonstrated. Rigorous simulation analysis employing MATLAB/Simulink shows that the robustness and stability of the new controller are much better than fixed-frequency PWM-based sliding-mode controllers. Subsequently, a high-voltage DC power prototype is fabricated, followed by comprehensive experimental validation. Test results underscore the stability of the DC power supply under normal operating conditions. Notably, when the controller adopts a linear PI configuration, the DC voltage output ripple is contained within a stringent threshold of ≤ 0.4%. Moreover, in the presence of AC power system oscillations, the novel controller showcases its ability to achieve a heightened response speed, which contributes to the robustness of the DC power supply.

An easily extensible interleaved high-voltage gain boost converter is proposed in this paper, which can be applied to electric vehicles, photovoltaic power generation and other fields. The proposed converter is expandable with different voltage multiplication cells according to different gain requirements. The low voltage side of the proposed converter is interleaved with two inductors, and the high voltage side is structured with multiple capacitors in series. The proposed converter has the advantages of low voltage stress for the whole devices, low input current ripple, inductor currents self-averaging, capacitor voltages self-balancing, simple control, and easy extension. First, the structure and principles of the proposed converter are introduced and analyzed. Then the performance of the converter in various aspects is theoretically analyzed and compared with existing converters. Next, the double closed-loop control system is designed. Finally, an experimental prototype with an input of 24 V, an output of 400 V and a rated power of 180 W is built and implemented, and the superior performance of proposed converter is experimentally verified.

The shift and low-frequency oscillations of neutral point potential are key issues in the neutral point clamped (NPC) inverter. The space vector pulse width modulation (SVPWM) algorithm has limited voltage balancing ability at high modulation levels and low power factors. The virtual SVPWM can achieve midpoint potential balance across the entire range, but it has the problem of multiple switching times and poor harmonic characteristics. Parallel three-level NPC inverters can increase the power rating and efficiency of systems, thus being suitable for high-power applications. However, their parallel topology also brings current sharing issues. This paper first proposes several methods of combining varied virtual middle vectors based on five-level vectors, which control the midpoint current by adjusting the action time of the basic vector. Second, different virtual vector combinations are used for voltage commands with different modulation indexes to reduce the switching frequency of the inverter and the synthesis vector error. The proposed hybrid method has fewer switching times, reduces the amplitude of midpoint voltage fluctuation, and has good harmonic characteristics of output current. Finally, the feasibility and effectiveness of the hybrid method are verified through simulation and experiments.

This paper deals with the output voltage tracking problem in DC-DC boost converters under the single-loop structure, emphasizing the need for overcurrent protection. Overcurrent protection is considered as a state constraint that is applied to the inductor current. A novel current-constrained controller is proposed by designing a special dynamic controller gain that is associated with the inductor current. Unlike existing nonlinear control methods capable of implementing state constraints, the controller introduced in this paper has a relatively simple structure that simplifies execution and reduces computational complexity. In contrast to methods that limit the initial states of the system, such as invariant set theory, the proposed method expands the range of the admissible set of the initial states. Experimental results demonstrate that, under the premise of satisfying current constraints, the proposed controller has better dynamic performance and robustness when compared to the nominal controllers that do not take current constraints into account.