Effective hydrogen transport propositions rely on accurate production and demand forecasts. In order to provide different managers tailored hydrogen transport propositions, data-driven forecasting of hydrogen production and demand via weather-clustered and day-weighted optimization for advance scheduling is presented. First, the historical weather data are preprocessed through anomalous data detection and normalization to ensure robustness in subsequent modelling. Then Centre-Radial means (CR-means) is presented for classifying weather data into six distinct weather-relevant clusters. Next, a forecasting model for hydrogen production based on the clusters divided by CR-means is presented. The comparative results verify the feasibility and advantages of CR-means with lower root mean squared error and absolute error of each hour between the predicted and actual values of hydrogen production by each means. Moreover, a forecasting model for hydrogen demand is presented, and the efficacy of the model demonstrates that it provides highly credible hydrogen demand predictions with a more precise temporal scale. Finally, based on the foregoing models, effective hydrogen transport propositions for helping managers schedule ahead response are presented.

Wireless power transfer (WPT) charger with constant current (CC) output and constant voltage (CV) output has gained significant attention in battery charging applications. The coil misalignment and wide load resistance range present challenges to the design and control of WPT charger. A single-switch LCC-LCC compensated WPT system with inherent CC output and CV output is proposed in this paper. In the proposed WPT system, only one switch is used, which reduces the number of switches and the corresponding driver circuits. The shoot-through risk in the half/full-bridge inverter can be avoided. The asymmetric coil structure is adopted to smooth the variations of the coupling coefficient of the loosely coupled transformer (LCT), which improves the system's misalignment tolerance. In addition, the transition from CC output to CV output is automatically completed according to the load conditions, which eliminates battery state detection and control strategy. The proposed WPT system has advantages of low cost, low complexity, high reliability, and wide zero voltage switching (ZVS) and misalignment tolerance range. A laboratory prototype with 3-A output current in CC mode and 72-V output voltage in CV mode is constructed to verify the analysis. The experimental results show that the system can achieve the required inherent CC and CV outputs when the misalignment distance in the horizontal direction is within 70 mm, and the peak efficiency of 90.9% is realized.

To balance the power difference between the pulsed output power and constant input power, the cascaded pulsed load power supply (PLPS) has been proposed in pulsed load applications. In the cascaded PLPS, since the back-end converter is designed with high bandwidth to track pulsed load current, the pulsed power would be easily propagated into the front-end converter. Hence, the pulsed power leads to a large input current ripple and affects the operation of the sensitive power source. In this article, the performance of the control scheme to suppress the input current ripple is investigated from the perspective of the impedance model, and the requirements of the expected impedance are given. To further reduce the input current ripple and improve the dynamic response, impedance-shaping control (ISC) is proposed to reshape the inductor branch impedance. The design considerations for the proposed control schemes are studied. Finally, the cascaded PLPS comprising a phase shift full-bridge (PSFB) converter and an interleaved buck converter are fabricated to verify the validity of the proposed control schemes.

ABSTRACT This article studies a DC‐DC cascaded topology of pulsed load power supply (PLPS) system with the first stage of phase‐shifted full bridge (PSFB) and the second stage of buck converter. Despite DC‐DC converters' notable nonlinear characteristics, most studies on PLPSs propose linear controllers to address them. This study proposes a simplified V 2 control technique for the fast‐stage converter to address the system's nonlinear characteristics and enhance its transient response. The input impedance of the fast‐stage buck converter in the cascaded system is adjusted to maintain the system in a stable region and avoid the possible impedance‐based instability issue. Additionally, a lead compensator is designed and incorporated into its control loop to improve the phase margin to prevent the impact of buck input impedance behavior as negative resistance on the stability for lower frequencies. Furthermore, an I 2 average current control is employed to reduce input‐current fluctuations and compensate for the PSFB's weak response. The PLPS system is experimentally verified for a peak power of 784 W and a pulsed load frequency from 150 to 300 Hz. The results of this article are compared to those of relevant papers and validate its dominance over other control methods.

In wireless power transfer (WPT) systems, active rectifiers (ARs) are widely used for output-power regulation without dual-side communication. Their main drawback is the additional reactance introduced at the receiver side, which perturbs the resonant condition, reduces power-transfer capability, and degrades system efficiency. This article proposes a hybrid mode rectifier (HMR) that combines full-bridge rectifier with voltage-doubler rectifier to regulate the output with substantially less impact on the tuning condition. The regulation characteristics of the HMR are derived for both current-source-mode compensation topologies (CMCTs) and voltage-source-mode compensation topologies (VMCTs). Compared with conventional ARs, the proposed HMR maintains a lower input-impedance phase deviation and lower reactive-power circulation, thereby enabling high power factor and high efficiency. Zero-voltage switching is also achieved, which reduces switching loss. Comparative analysis with conventional ARs is provided, and a concept-of-proof 600 W laboratory prototype is built to validate the proposed method.

This paper investigated a cascaded pulsed load power supply (PLPS) with optimized control schemes for pulsed power loads (PPLs). The first stage of the PLPS is a phase-shifted full-bridge converter (PSFB) to provide the average power for PPL. A buck converter is selected for the second stage to facilitate the pulsed load current. The cascaded PLPSs usually select a buck converter at the second stage, while the second-stage buck converter's input impedance acts as a negative resistor that leads the cascaded system to instability. Therefore, a series virtual impedance (SVI) based optimization is utilized to improve the system stability, and an output current feedforward path is added to the control loop of the fast response-stage to raise the load tracking speed. Moreover, to reduce the system input current fluctuations and overcome the PSFB converter's slow response and bandwidth limitation, an I2 average current control is used. An experimental-based analysis is performed to confirm the validity of the control scheme. The results on the prototype of cascaded PLPS with 784 W peak and 117.6 W average powers, 100 V input voltage, 28 A output pulsed current, and a pulse repeating frequency (PRF) of 100-300 Hz validated that the proposed optimization scheme outperforms other leading available schemes.

Since the periodic pulsed power is a strong disturbance to the power system, the pulsed power must be suppressed by the pulsed load power supply (PLPS). In general, an additional converter with a storage capacitor is formed as the active capacitor in the original PLPS to reduce storage capacitance and achieve pulsed power decoupling. However, since the introduction of additional converters, the existing PLPS still faces high power loss, large volume, more components, etc. In this article, an active capacitor unit is proposed to be embedded in the original converter to form a new pulsed power suppression topology, in which only two switches and one storage capacitor are introduced to establish an energy storage port with bidirectional power flow characteristics. By doing so, the active capacitor-embedded PLPS (ACE-PLPS) can be developed, which features a compact structure and fewer components. Furthermore, the process of pulsed power decoupling is integrated into the switching states, resulting in a significant reduction in power loss. The implementation topology and control scheme are presented. Design guidelines are also developed. The effectiveness and feasibility of the ACE-PLPS are validated by the experimental results.

A bridgeless boost power factor correction (PFC) converter has improved efficiency compared with its bridged boost PFC topology counterparts, which has earned increasing attention in the past decade. However, most of the bridgeless boost converters are based on the same converter cells to achieve bridgeless operation and they typically have to use two rectifier diodes. This paper proposes a novel true bridgeless boost PFC topology with a coupled inductor, which has boost and buck-boost operation modes in the positive and negative half-line cycles. In this way, the proposed true bridgeless topology has eliminated all rectifier diodes. The operation modes and the control schematic are introduced in detail. Finally, the simulation is conducted to show the effectiveness of the proposed circuit and the control schematic.

With the prevalence of renewable energy and DC storage units, DC-DC converters are widely used in power distribution systems (PDSs), which has raised concerns about bus voltage stability over a wide load range. This paper proposes a current perturbation-based impedance ratio (CPBIR) method for stability analysis of bus voltage to estimate stability in a wide operation range. Without any internal converter topology control information, the proposed approach can offer a visible stability estimation over a wide load range by merging each load’s test result. Besides, current perturbation injection is used to avoid increasing the source voltage impedance and breaking the bus wire connection, which occurs in voltage perturbation injection. Simulations based on a boost and buck cascaded power system are provided to validate the effectiveness of the proposed method.

A constant current (CC) and constant voltage (CV) inductive power transfer (IPT) charging system has become popular for battery charging applications. To achieve inherent CC-to-CV charging, the primary-side resonant current-/ voltage-clamped IPT systems are proposed in this article. Two configurations of the primary-side resonant current-/voltage-clamped IPT systems are introduced and analyzed based on the two-port network. In the proposed IPT systems, the clamping coil and isolation transformer are not required, which reduce the system cost and design difficulty of the loosely coupled transformer (LCT). By combining IPT topologies with input zero phase angle (ZPA) and load-independent CC or CV output, a family of IPT systems with inherent CC-to-CV charging can be obtained, which significantly simplifies the control complexity. The secondary-side compensation network is a first-order compensation circuit, which reduces the volume and weight of the charging device. Two primary-side resonant current-/voltage-clamped IPT systems are selected to analyze the sensitivity of the parameters to the input impedance, as well as CC and CV outputs. Soft switching and minimized reactive power can be achieved, which reduce the power rating of the power supply and minimizes the switching loss. Finally, experimental prototypes are built to verify the proposed IPT systems.

In comparison with full-bridge inverter, half-bridge inverter, and single-switch inverter, class-D inverter presents a simpler structure with fewer switches and lower voltage stresses of switches, which makes class-D inverter suitable for wireless power transfer (WPT) systems. However, the class-D inverter may suffer from a large output current due to accidental variations of the load resistance and mutual inductance, which may potentially lead to device damage. Two passive overcurrent protection (OCP) circuits for WPT systems with class-D inverter are proposed in this article. The class-D inverter's output current can be automatically protected to a safe value by the proposed OCP circuits. Compared to active protection, the current detection circuit and related control circuit are not required in the proposed method, which reduces the control complexity and is easy to implement. In addition, the proposed system can automatically return to the normal operation mode after the overcurrent event is over. The proposed OCP will not affect the inherent characteristics of the original compensation topologies, such as load-independent constant output and zero phase angle (ZPA). The operating principle of the proposed OCP circuits is analyzed. An experimental prototype is designed and established to validate the feasibility of the proposed method.

To address the efficiency loss caused by the need for an additional central converter in traditional photovoltaic-isolated port (PV-IP) architecture, the concepts of differential power processing (DPP) and series-connected partial power processing are introduced, and then, a multi-degree-of-freedom DPP (MF-DPP) architecture for photovoltaic (PV) systems is proposed. In the proposed architecture, the auxiliary converter is introduced to be paralleled with the DPP converters and connected in series with the PV modules so that the bus port can directly connect the loads with specific voltage requirements and the efficiency of the entire system can be improved. A control algorithm for the new architecture is also proposed, which can simultaneously achieve maximum power point tracking (MPPT) for PV modules and least power point tracking (LPPT) for the total power processed by the DPP converters. Finally, a PV system experimental platform is built to verify the effectiveness of the proposed architecture and control algorithm. The experimental results show that the proposed architecture can effectively improve the system efficiency under mismatched power conditions.

In order to balance the instantaneous power difference between the pulsed load and the power supply system, a bi-directional DC/DC converter is typically connected in parallel with the pulsed load. However, when the pulsed load varies between light and heavy loads, significant transient current spikes occur in the current of pre-stage power supply system. To solve this problem, previous study has proposed a three-state dual-inductance bi-directional converter topology. However, it requires multiple additional components, resulting in increased cost and reduced power density. Therefore, based on this topology, this paper proposes a novel three-state dual-inductance bi-directional converter, which effectively reduces the number of switching devices by reusing both the inductor freewheeling circuit and the main working circuit. Finally, simulation results show that the proposed novel three-state dual-inductance bi-directional converter can quickly suppress pulsed load power. Moreover, with fewer switching devices, it achieves the same current spike suppression performance as the traditional three-state dual-inductance bi-directional converter topology. Therefore, the proposed topology can effectively reduce costs, ensure the stability of the power supply system, and facilitate the miniaturization of power supply systems.

For the pulsed power load (PPL) with low frequency, which requires single-phase ac input voltage, such as ground radar, its input power presents double-line-frequency fluctuation and output power is pulsed, resulting in high input current harmonic and ripple. To balance the instantaneous power difference, the required storage capacitor is usually large, which leads to an increase in the size of the converter. A two-stage single-phase ac-dc PPL converter is proposed in this article, with the high fluctuation over than the hundred volts of bus capacitor voltage, which greatly reduces the capacitance and size. The causes of input current distortion were derived from the harmonic transmission in detail, and the bus capacitor design process considering the phase shift between input and output power is given. To suppress the input current harmonic and ripple, a low input current harmonic control strategy is proposed by replacing the outer-voltage loop with the proportion of the average load current, and verified by an experimental prototype with 1 kW peak power. The results show that the proposed converter and control strategy have a good performance, obtaining the lowest total harmonic current distortion (THDi) of 2%, the efficiency is up to 92.9%, and the power factor (PF) remains above 0.99 with the pulse repetition frequency of 100-500 Hz.

This paper proposes a virtual inertia control strategy of electro-methanol production system for frequency support, aiming to address the problem of instability in power systems when electro-methanol production system is connected to the grid. First, the concept of virtual rotational inertia is explained based on the operating characteristics of electro-methanol production system. Next, different operating modes are defined according to the impact of various grid disturbances on the power system. Besides, provide inertia support for the grid while ensuring efficient methanol production, specific control methods are proposed for different operating modes: efficient methanol production under no-disturbance conditions, and rapid inertia support to the grid under disturbance conditions. MATLAB/Simulink software and the hardware-in-the-loop (HIL) testing method are used to simulate and verify the proposed strategy under different disturbance scenarios. Results show that the proposed control strategy can quickly respond to grid disturbances and provide inertia support under various disturbance conditions.

In the application of more electric aircraft (MEA), the active power fluctuation is a challenge for the three-phase buck rectifier (3ph-BR) under unbalanced input voltages due to its wide range of ac input frequency. In order to enhance the performance of 3ph-BR in MEA application, an improved constant active power control strategy for 3ph-BR under unbalanced input voltages and wide ac input frequency is proposed in this brief. By analyzing the instantaneous power in the two-phase stationary frame, an improved algorithm to reconstruct input voltages is proposed to realize constant active power. The proposed control strategy does not require phase-lock loop and therefore can be applied in wide ac input frequency application. Experimental results verify the effectiveness of the proposed control strategy.

To suppress the impact of pulsed load power on the power supply system, active capacitor converters (ACC) are connected in parallel with the output port of the DC-DC converter of the PPS to compensate for the AC component of the pulsed load power. Aiming at the problem of limited dynamic response speed of conventional voltage and current dual loop control strategy, which leads to significant output voltage drop and input current fluctuation in pulse power supply (PPS), a control strategy for the ACC with simplified virtual impedance is proposed in this paper. Finally, a prototype with a peak output power of 784W was established and tested under load conditions of 100Hz pulse repetition frequency (RPF) and 0.15 pulse duty cycle, verifying the effectiveness of the proposed control strategy.

Inductive power transfer (IPT) systems with inherent constant current (CC) and constant voltage (CV) battery charging profile have the merits of not requiring wireless communication, detection circuits, and control circuits. However, existing IPT systems with inherent CC and CV battery charging profile require a large number of components or suffer from backflow current, thereby resulting in a bulky and inefficient system. To solve such problems, this paper proposes LCL/CLC resonant rectifier-based IPT systems with inherent CC and CV battery charging profile. The backflow current is eliminated in the proposed rectifiers. A unified analysis method is proposed to analyze LCL/CLC resonant rectifier-based IPT systems. Two LCL/CLC resonant rectifier-based IPT systems with minimum component counts are derived, which maintain near zero phase angle (ZPA) and zero voltage switching (ZVS) operation. The voltage-ampere rating and switching loss are reduced. Two inductors of the LCL network are integrated into the loosely coupled transformer to make the system more compact and to reduce the corresponding cost and volume. There is no compensation inductor or extra rectifier on the receiver side. As a result, the required installation space for the charging equipment can be reduced. A prototype of the LCL resonant rectifier-based IPT system is implemented to validate the analysis. The maximum efficiency of 92.43% is achieved.

Model predictive control (MPC) has shown potential for a wide range of applications in the three-phase full-bridge inverters based on its advantages of easy modelling, excellent dynamic response and rolling optimization. Aiming at the shortcomings of traditional model predictive control that needs to be paired with other controllers, a model predictive voltage control (MPVC) strategy is proposed. This strategy directly controls the output voltage, eliminating the complex outer-loop controller design and simplifying the control process. In order to address the shortcomings of single-vector MPVC, which has a large error between the predicted value and the reference value, a dual-vector MPVC strategy is proposed. This strategy ensures the steady state performance and dynamic performance of the system by improving the number of seeks and increasing the prediction step size. Finally, an experimental platform of three-phase full-bridge inverter is built to validate the proposed strategy.

Abstract Three‐coil inductive power transfer (IPT) charging system can not only achieve inherent constant current (CC) to constant voltage (CV) transition but also tolerate load open‐circuit. However, due to the cross‐coupling between the auxiliary coil and the receiver coil, the output voltage in CV mode may deviate from the CV voltage significantly, which makes the design freedom of the three‐coil coupler low. By replacing the auxiliary coil with a transformer, an improved auxiliary circuit is proposed in this paper to address the cross‐coupling issue and to increase the design freedom of the loosely coupled transformer (LCT). The improved auxiliary circuit can achieve load short‐circuit and open‐circuit protection. Besides, the optimization design of LCT is easy to achieve by load impedance matching. The operating principle and parameters design of the improved auxiliary circuit are discussed. A 1 kW experimental prototype is built to verify the feasibility of the proposed method.