Search Results (401)

Although electric vehicles are being vigorously promoted around the world, the mileage anxiety problem is an important hindrance to their development. Thus, this paper proposes an auxiliary half-bridge dual active bridge (AH-DAB) converter between different electric vehicles, which is based on nonlinear virtual power predictive control. For the converter, characteristics of high power density, wide voltage gain range, and high efficiency are necessary. Firstly, an AH-DAB converter is applied to improve the control variable. Under this effect, the converter can switch between the half-bridge and the full-bridge converter. Secondly, a duty ratio design method is proposed to improve zero-voltage switching (ZVS) performance. Therefore, wide voltage gain range, decoupling of control variables, and high efficiency can be achieved in the nonlinear AH-DAB system. Thirdly, the nonlinear virtual power predictive control is proposed to ensure energy transfer between two electric vehicles. Based on this, the phase shift angle can be predicted and adjusted by ensuring that the actual power is consistently maintained close to the reference power. Moreover, the virtual power is generated to represent the reference power, which can reduce the number of current sensors. Finally, simulation and experiment results collectively show the wide voltage gain range and high efficiency of the proposed AH-DAB converter. Full article

The wide voltage range of energy storage batteries, as currently required in the electric vehicle industry, presents significant challenges for the optimal design of the dual active bridge (DAB) converters used in bidirectional DC–DC (BCD) plug-in electric vehicle (PEV) chargers and home energy management systems (HEMS) applications. This article proposes a DAB converter with an enhanced single-phase-shift (ESPS) modulation that extends the operating voltage range while maintaining zero-voltage-switching (ZVS) conditions by including a DC-blocking capacitor and modifying the trigger sequence of the bridge converter on the secondary side. The operational modes of this modulation scheme are presented, and a control strategy is developed to extend the ZVS range. To validate the concept, a 3.7 kW, 100 kHz prototype is designed and tested, interfacing a 400 V DC bus with a 400–800 V battery. Using 1200 V silicon carbide (SiC) devices, the prototype achieves a peak efficiency of 95.5%. Full article

Multiport DC–AC converters are widely used in photovoltaic-energy storage–charging systems, but traditional two-stage schemes face challenges in circuit cost and efficiency improvements. To address this issue, a novel three-port single-stage DC–AC converter is proposed for grid-connected applications. The proposed converter integrates two DC ports and one AC port through circuit multiplexing, eliminating the high-voltage DC bus and reducing system complexity. An unfolding bridge is employed at the AC port, and full bridge circuits are used at DC ports, reducing the number of high-frequency switches. The proposed single-stage topology inherently achieves galvanic isolation and bidirectional power conversion. To achieve accurate grid current regulation and wide-range zero-voltage-switching, a multiple-phase-shift modulation method is developed to ensure a sinusoidal current waveform. The effectiveness of the proposed converter and modulation method is verified through simulation results, demonstrating a peak efficiency of 97% and a total harmonic distortion of 2.91%. Full article

This paper presents a dual-phase dual-path hybrid buck–boost (DPBB) converter with an offset-controlled zero-current detector for Li-ion battery applications. Compared with inductive buck–boost converters, the proposed hybrid converter has a continuous input current, reducing the input voltage (V_IN) ripple, which is caused by the parasitic inductance of the bonding wire. The proposed switching operation of the DPBB topology shows a low inductor current ripple with the continuous output delivery current; therefore, the ripple of the output voltage (V_OUT) is reduced with the efficiency improvement. Compared with the prior hybrid buck–boost converters, it supports the buck and boost modes only by adjusting the duty cycle, so this addresses the issues of mode transitions. The proposed work utilizes the dual-phase operation to lower the conduction loss and improve the dynamic range. The proposed offset-controlled zero-current detector compensates for the timing error owing to the propagation delay of the control signals to reduce the reverse current from the output. The chip is fabricated using a 180-nm BCD process. It regulates V_OUT at 3.3 V with a wide V_IN range of 2.8 V to 4.2 V. Peak efficiencies of 95.88% and 93.08% are achieved in the buck and boost modes, respectively, with 140 mΩ of inductor DC resistance. Full article

Existing model predictive control (MPC) schemes based on virtual voltage vectors (VVVs) for dual three-phase permanent magnet synchronous motors (DT-PMSMs) typically employ a limited set of voltage vectors, which restricts further improvement in steady-state performance. Moreover, the design of switching sequences lacks systematic consideration, focusing mainly on harmonic current suppression while neglecting practical engineering challenges associated with software-layer implementation. This paper proposes an optimized model predictive torque control (MPTC) method for DT-PMSMs using an expanded voltage vector set. First, to enhance steady-state performance, an extended control set of voltage vectors is designed, which introduces not only new directions but also two distinct voltage amplitude levels, resulting in a total of 48 voltage vectors. Second, to alleviate the significant computational burden caused by traversing the extended set for prediction, a candidate voltage vector selection table is constructed based on the sector position of the stator flux linkage and the requirements for torque and flux adjustment. This approach reduces the computational load to only 10 predictive calculations per control cycle, avoiding exhaustive traversal of the extended set. Furthermore, for all VVVs in the control set, a switching sequence combining active voltage vectors with zero vectors is designed to facilitate straightforward digital implementation. Finally, experimental results are provided to validate the effectiveness of the proposed method. Full article

In conventional CLLC topologies, CC/CV charging is typically implemented using closed-loop control strategies based on phase shift modulation. This not only increases control complexity but also requires additional voltage and current sensing circuits, thereby raising the overall system cost. To address these issues, this paper proposes a novel CC/CV charging strategy. By analyzing the inherent characteristics of the coupled network, the switching frequencies corresponding to the CC and CV operating points are derived. By jointly applying frequency modulation and phase shift control to the CLLC converter, the system not only realizes CC/CV charging, but also enables the regulation of both the magnitude and the direction of power flow. Furthermore, to improve the system’s efficiency, a fine frequency tuning method is introduced to ensure operation under the critical zero-voltage switching (ZVS) condition. Finally, a 500 W prototype is constructed to validate the effectiveness of the proposed control strategy. Full article

Intelligence, surveillance, and reconnaissance (ISR) platforms and electric vertical take-off and landing (eVTOL) aircraft demand onboard power conversion systems that simultaneously achieve high gravimetric power density, robustness, and fault-tolerance. In this context, modular battery architectures based on per-string power electronic interfaces emerge as a key enabler for voltage regulation, fault isolation, and in-flight reconfiguration. However, the stringent mass and volume constraints of electric aviation place magnetic components among the primary limiting factors of converter scalability. This paper presents a design methodology for interleaved converters with coupled inductors that explicitly decompose common-mode, differential-mode, and uncoupled inductance components. The proposed approach enables independent adjustment of current ripple and dynamic response, allowing zero-voltage switching (ZVS) operation while ensuring stable and controllable behavior under close-loop current regulation. The methodology is experimentally validated on a 4 kW two-phase interleaved GaN-based boost converter operating at 500 kHz. Experimental results demonstrate a peak efficiency of 97%, with less than 1% variation across the operating range, and stable dynamic behavior under load transients. These results confirm the effectiveness of the proposed design methodology as a scalable solution for high-power-density, high-reliability power converters in electric aviation battery systems. Full article

Switched-inductor converters are ubiquitous in modern electronics. Their switching behavior makes them inherently nonlinear and unsuitable for classical linear frequency-response models, requiring linearization for stability analysis. Common approaches—such as state-space averaging, circuit averaging, and signal-flow graphs—can be algebraically intensive and may offer limited circuit-level interpretability. This paper proposes a direct small-signal AC response model for switched inductors in both CCM and DCM that preserves circuit intuition while maintaining the accuracy of conventional methods. The proposed framework enables the systematic derivation of the duty-cycle-to-output-voltage, duty-cycle-to-output-current, and duty-cycle-to-inductor-current transfer functions within a unified circuit representation. Bode plots of the duty-cycle-to-voltage and duty-cycle-to-current gains confirm that the model accurately captures the LC double pole and associated zeros, including the shift of the load-related zero in the reconstructed inductor-current gain. The resulting model remains straightforward to use, analyze, and simulate and may facilitate control-loop design as well as integration into automated synthesis or optimization tools. In DCM, the model further provides an analytical expression for the duty-cycle-to-inductor-current gain, contributing to a clearer understanding of this relationship in the literature. Results validated in SIMPLIS show excellent agreement with state-space averaging predictions. Full article

Common-mode voltage (CMV) is a critical concern in motor drive applications employing multilevel inverters, as it can lead to significant issues such as high-frequency noise, electromagnetic interference, and motor bearing degradation. These effects can compromise the reliability, reduce the operational lifespan of electric machines, and introduce safety hazards. In this study, an enhanced Direct Torque Control (DTC) strategy incorporating Space Vector Modulation (SVM) is proposed to specifically address CMV-related challenges in induction motors (IM) driven by a three-level Neutral-Point-Clamped (NPC) inverter. The proposed DTC scheme utilizes a specialized modulation technique that effectively mitigates CMV while also minimizing current harmonic content, and torque and flux ripples with a constant switching frequency. The developed SVM algorithm simplifies the three-level space vector representation into six equivalent two-level diagrams, enabling more efficient control. The zero-voltage vector is synthesized virtually by combining two active vectors within a two-level hexagonal structure. The effectiveness of the proposed DTC approach is validated through both simulation and Hardware-In-the-Loop (HIL) testing. Compared to the conventional DTC method, the proposed solution demonstrates superior performance in CMV minimization and leakage current reduction. Notably, it limits the CMV amplitude to V_dc/6, a significant improvement over the V_dc/2 typically observed with the standard DTC approach. Full article

To address the issues of limited soft-switching range and high inductor current peak in traditional single phase shift (SPS) modulation for AC–DC converters under a wide range of voltage conversion ratio conditions, this paper proposes an optimized modulation strategy based on SPS modulation. First, the steady-state operating characteristics under SPS modulation are analyzed, and the current-transfer equation is derived. A conversion coefficient is then introduced to transform the conventional phase-shift ratio into a new variable. Based on this, the time-domain characteristics of the inductor current peak and the constraints for zero voltage switching (ZVS) are analyzed. An analytical expression of the conversion coefficient is obtained, which ensures ZVS operation for all switches in the dual-active-bridge (DAB) converter and minimizes the inductor current peak. Finally, experiments verify the effectiveness and feasibility of the proposed modulation strategy. Full article

Quasi-resonant (QR) DC–DC converters with PWM control achieve soft switching by shaping the commutation transient through a local resonant process. This paper proposes a symmetry-based unified perspective on classical QR converters by interpreting zero-voltage switching (ZVS) and zero-current switching (ZCS) as dual commutation symmetries: ZVS restores voltage symmetry at turn-on, whereas ZCS restores current symmetry at turn-off. Building on this viewpoint, we organize QR Buck, Boost, and Buck–Boost converters through two complementary forms of symmetry: (i) commutation symmetry (ZVS vs. ZCS) and (ii) topological duality (Buck ↔ Boost and the self-dual nature of Buck–Boost). The framework is anchored in normalized parameter spaces commonly used in QR analyses and is illustrated using representative ZVS and ZCS Buck cases, including waveform-stage symmetry and loss/stress implications. Furthermore, we discuss the “cost of symmetry” via stress and conduction-loss metrics, highlighting how soft-switching conditions trade voltage and current stresses in dual fashions. The proposed organization offers a compact conceptual map that links operating regimes, design degrees of freedom, and expected stress/loss trends across the main classical QR-PWM converter families. Full article

The Four-Leg Three-Phase Voltage Source Inverter (4LVSI) is a versatile solution for integrating renewable energy sources (RESs) into distribution networks, as it compensates unbalanced voltages and currents while providing a path for zero-sequence components. Accurate current control is essential to ensure power quality and reliable operation under these conditions. Conventional controllers such as proportional–integral, resonant, or feedback-linearization methods achieve acceptable tracking under static dc-link conditions, but their performance degrades when dc-link voltage dynamics arise due to renewable-source fluctuations. This paper proposes a data-driven model reference neural control (MRNC) strategy for a four-leg inverter connected to RESs, explicitly accounting for dc-link voltage variations. The proposed controller reformulates the classical Model Reference Adaptive Control (MRAC) as a lightweight single-layer neural network whose adaptive weights are updated online using the Recursive Least Squares (RLS) algorithm. In this framework, the dc-link variations are not modeled explicitly but are implicitly learned through the data-driven adaptation process, as their influence is captured in the neural network regressors formed from real-time input–output measurements. This allows the controller to continuously identify the inverter dynamics and compensate the effect of dc-link fluctuations without requiring additional observers or prior modeling. The proposed approach is validated through detailed time-domain simulations and real-time Hardware-in-the-Loop (HIL) experiments implemented at a 10 kHz switching frequency. The results indicated that the RLS-based MRNC controller achieved the lowest steady-state current error, reducing it by approximately 1.85% and 1% compared to the Proportional-Resonant (PR) and One-Step-Ahead (OSAC) controllers, respectively. Moreover, under dc-link voltage variations, the proposed controller significantly reduced the current overshoot, achieving decreases of 5.9 A and 6.36 A relative to the PR controller. Full article

The DC converter constitutes a pivotal component within medium-voltage direct current (MVDC) collection systems, performing functions such as voltage boosting, isolation, and power transmission. To accommodate the demand for high-capacity DC converters in MVDC collection systems for new energy sources, a full-bridge medium-frequency converter featuring low voltage and current stress on auxiliary switching devices is proposed. Based on the principles of dual-transformer configuration and component sharing, this converter employs a half-bridge circuit and a full-bridge circuit sharing two switching devices. Utilizing mixed-frequency modulation, the full-bridge main circuit operates at medium frequency to transmit the majority of power, while the half-bridge auxiliary circuit regulates overall power and voltage through high-frequency chopping control. This achieves zero-current switching for the medium-frequency switching devices across the entire load range, significantly reducing switching losses in the converter. This paper details the converter’s operating principles and analyzes key parameter design methodologies. Finally, a 240–6000 V/7200 W prototype was constructed to validate the proposed converter’s performance. Full article

This paper proposes a zero-voltage-switching (ZVS) synchronous buck converter employing a digital hybrid control scheme with variable slope compensation. By using an auxiliary-switch network and a digital controller to sense voltage and current, the system can automatically adjust the slope-compensation parameters according to the input and output conditions, thereby enhancing stability over a wide operating range. The proposed method effectively suppresses the reverse-recovery current spike of the synchronous rectifier during continuous conduction mode (CCM) operation and enables the main switch to achieve ZVS, reducing switching loss and improving efficiency. A laboratory prototype with an input voltage range of 30–160 V and output voltage levels of 24 V, 48 V, and 96 V at 5 A is developed to verify the feasibility of the proposed architecture. Full article

Three-leg AC-DC Vienna rectifiers are susceptible to single open-switch faults, which make DC-link voltage ripple and make three-leg input AC currents distorted and unbalanced. Thus, this paper presents a quick identification method for single open-switch faults based on three-leg fault currents and output capacitors voltage difference. Fault-leg identification depended on zero-plateaus in the three-leg fault currents, whereas fault-side identification was dependent on reconstruction variables obtained through Clark transformation and phase shifting. In order to improve the reliability of the diagnosis system, the harmonic component of capacitor voltage difference is used to realize the missed diagnosis detection and adjust the time threshold automatically. This method requires no additional hardware and is easy to implement. Experimental results verify the effectiveness of this strategy. It is shown that the fault diagnosis method proposed in this paper has the advantages of fast diagnosis speed, high accuracy and good robustness. Full article