Autonomous Gate Drivers for TCM-Based Soft-Switched Converters: Design Approach and Experimental Validation

For the power management of a wireless power transfer system for implantable mechanical heart pumps, an additional boost DC-DC converter stage is needed in order to control the power delivered to the implant. Particularly, battery powered and implantable medical devices pose special demands on the efficiency and/or power density of the employed converters. Accordingly, soft-switching and/or high switching frequencies must be targeted. Modulation schemes that allow for Zero-Voltage-Switching (ZVS) such as Triangular Current Mode (TCM) offer a highly efficient operation, but suffer from a large operating frequency variation, which is mainly limited by the digital control. Therefore the Clamp-Switch TCM (CL-TCM) converter can be employed which allows also for the control of the switching frequency variation. In this paper, the CL-TCM and the TCM converter are compared regarding the power conversion efficiency and the power density of the converter. Since the CL-TCM converter is not well known in the literature, the converter is analysed in detail and a modulation scheme is explained that allows for ZVS for all switches in the entire range of operation. In addition, the requirements for ZVS and a control scheme (i.e. timing calculations) are provided for the converter in order to limit the maximum switching frequency. The modulation and control scheme are verified with a hardware prototype. Finally, the performance of the CL-TCM converter is measured and compared to the performance of the converter operated in TCM mode. The measurements show that the CL-TCM converter offers similar performance compared to the TCM operation at lower inductor power density, but has the advantage of a significantly reduced switching frequency variation. In applications, where a very high power density is needed, the TCM converter outperforms the CL-TCM converter in terms of efficiency.

This paper proposes a hybrid current mode between Triangular current mode (TCM) and Discontinuous current mode (DCM) in order to achieve Zero-voltage switching (ZVS) for a bidirectional buck/boost DC-DC converter. In the proposed Hybrid Discontinuous Current Mode entitled HDCM, the TCM operation is applied during the zero-current interval of DCM. Therefore, both ZVS and the variable current ripple, which result in the high efficiency at wide load range, are achieved. The achievement of ZVS with HDCM is confirmed by a 600-W prototype. Compared to TCM, the Root-Mean-Square current is reduced by 47.2% at most with HDCM, which further contributes to the loss reduction. Moreover, under the condition of the same boost inductor, the efficiency of HDCM at load of 0.2 p.u. is improved by 1.5% compared to TCM.

The demand for highly efficient and dynamic electric vehicles (EVs) has increased dramatically. The traction inverter, a pivotal component in an EV powertrain, plays a crucial role. This study is dedicated to designing a traction inverter with focus on achieving high efficiency and elevated power density and mitigating electromagnetic interference (EMI) issues. To realize these objectives, autonomous gate drivers (AGDs) are proposed and designed using LTspice simulation software. The aim is to achieve zero voltage switching (ZVS) at both turn-on and turn-off through the utilization of triangular current mode (TCM) control on the gate driver. The AGDs implement a current modulation scheme by sensing the current and voltage and generating gate-source voltage signals with minimal delays. The implemented current modulation scheme by the AGDs results in an efficiency exceeding 99% for a 10 kW power rating. The sinusoidal output waveforms not only contribute to extending the motor lifespan by mitigating sharp-edge voltages but also bring advantages such as reduced switch stress, decreased EMI, and simplified thermal management.

The introduction of soft switching features in medium power static converters promises improved semiconductor utilization and higher switching frequencies. In this paper a DC-side commutated zero voltage switching (ZVS) PWM 3-/spl Phi/ VSI topology is discussed. This topology consists of a typical six-switch bridge with the addition of a simple DC bus commutating subcircuit which can provide, on demand, the necessary soft switching zero-volts interval across the inverter DC bus. The objective of this paper is to identify a specific PWM technique which, in combination with the proposed ZVS scheme, can provide optimum overall converter switching performance. Moreover, the combination of the inverter topology and the modulation strategy proposed here yields a soft switching environment at the lowest possible switching frequency. Reduction in switching losses is further enhanced by increasing the effective and reducing the actual switching frequency. Finally, this paper includes a detailed analysis and design procedure for the proposed notch commutated inverter topology. Simulation and experimental results are also presented to verify key predicted results.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

The first electric vehicles (EVs) debuted in the last decades of the nineteenth century when electricity was becoming increasingly popular to power motor vehicles. EVs power the battery packs with electricity rather than petroleum-based energy sources like gasoline or diesel. EV chargers will significantly influence the adoption of EVs. A battery is required to power the EV. Since this battery needs to be charged regularly, the reduced grid-side power factor in existing converters is caused by increased input current harmonics, which occurs only under extreme conditions. The Vienna rectifier is superior to other options for excess power due to its ability to raise the voltage at the output, diminish ripple and enhance efficiency and power factor. The Vienna Rectifier is an excellent front-side converter for applications requiring rapid DC battery charging. Here, the proposed charger charges the batteries using a two-stage conversion system consisting of a Vienna rectifier and buck converter. An EV can be charged using a variety of methods where several complicated parameters are required, as well as AC and DC charging at high power levels. To facilitate this, the Indian government developed Bharat DC 001, the standard for Direct Current (DC) charging and Bharat AC 001, the standard for Alternating Current (AC) charging, for EV chargers. The Bharat EV Charger Protocol was created expressly to regulate India's EV charging ecosystem. Based on the Bharat DC001 standard, this work suggests a two-way DC rapid charger. The Bharat DC001 standards for EV charging stations can simultaneously power two EV batteries with ratings of 72 and 48 volts at charging levels of up to 14.5 kW and 9.6 kW, respectively. The paper provides an analysis of the proposed Vienna rectifier topology and derives the mathematics model from a three-level vector to a two-level vector model. In addition, a well-known SVPWM control technique is implemented to enhance input-side power quality, reduce switching losses and reduce the total harmonic distortion value. Thus, the proposed architecture with its control technique is simulated using MATLAB/SIMULINK to validate the results.

This paper introduces a novel digital controlled DC-DC converter tailored specifically for electric vehicle (EV) applications. The primary objective of this system is to efficiently convert the high battery voltage characteristic of EVs into a lower voltage suitable for powering the vehicle's electronic subsystems. The core of the proposed converter resides in a meticulously designed power stage, which employs a phase-shifted Zero Voltage Switching (ZVS) full-bridge DC-DC architecture. The system employs a singular one-chip PIC microcomputer to handle both feedback control of output power and the actuation of all switching elements within the converter. This streamlined approach establishes a highly efficient digital control block specifically tailored for this DC-DC converter architecture. To validate the efficacy and performance of the proposed design, a prototype converter with a power rating of 3.0 kW is constructed and subjected to comprehensive testing.

The Dual Active Bridge (DAB) is one of the bidirectional converters in the High frequency Power processing with galvanic isolation, is widely preferred in many industrial applications. Historically, the power flow in the DAB is accomplished by popular phase shift control. The reduction of switching losses in the high voltage (HV) side converter by both Zero Voltage Switching (ZVS) and Zero Current Switching (ZCS) cannot be achieved simultaneously in the phase shift control. In this paper, the limitations of the phase shift control are conquered by the vector control. Vector control technique ascertains active and reactive power flow in a controlled fashion inside the bridge and thus able to position the DAB current in phase with the HV side DAB Voltage for ZVS as well as ZCS of the device. However judicious control of the active and reactive components of the current depends on appropriate current sensing, filtering mechanism and very fast parallel processing of the data. This paper mainly emphasizes on the decoupling of active and reactive currents using digital Band Pass Filter (BPF) followed by Second Order Low Pass Filter (SLPF) and vector control implementation technique in the real time control hardware. The control implementation methodology is discussed with the support of necessary experimental results presented in the paper.

Three-phase AC/DC pulse-width-modulated (PWM) converters have been widely employed in various renewable energy systems and industrial applications, which require a high-efficiency power converter operation. This article proposes a technique to reduce switching loss in AC/DC converters by integrating a voltage vector preselection strategy to model predictive virtual flux control. The voltage vector preselection strategy preselects available voltage vectors corresponding to switching states that lead to minimum switching loss in the phase leg, which conducts the highest current. By using preselected voltage vectors, clamping intervals are generated at every fundamental period to maintain the present switching states of the power switches, resulting in the reduction in switching loss. Additionally, by using virtual flux control, the proposed approach can effectively be used under both ideal and distorted source voltage conditions. The proposed method is compared with the conventional model predictive current control and the conventional model predictive virtual flux control. Both a simulation and experiment are performed to validate the correctness and effectiveness of the proposed method, which has been found to decrease the switching loss of an AC/DC converter by up to 15% compared to conventional control schemes at a negligible increase in the input current total harmonic distortion and DC output voltage ripple.

This paper proposes a new soft switching synchronous Buck converter to provide complete ZVS conditions for both high and low side MOSFETs under the light- or no-load, as well as full load conditions. In the continuous conduction mode (CCM) with a heavy load current condition, the high side MOSFET is generally turned ON while the body diode of low side MOSFET is in the conducting condition in a dead-time region, which causes switching loss in the high side MOSFET. A proposed soft-switching Buck converter consists of the conventional synchronous Buck converter with additional L and C. By using a resonance with the additional L and C, the inductor current in CCM can be effectively commutated from the low side body diode to the high side body diode of the two MOSFETs during the dead time region. The detailed modes of operation with experimental results are provided to verify performance.

This paper presents a new soft switching (SS) multiphase interleaved boost converter (MIBC) consisting of three boost converters (BCs) that operate rapidly and efficiently to charge a lithium-ion battery for photovoltaic (PV) power system applications. This suggested converter can operate both active power switches at zero current switching (ZCS), and when switched off, it works at zero voltage switching (ZVS), which reduces switching losses and increases switching efficiency (SF). An interleaving structure is employed to decrease the conduction losses and reduce the input current ripple (ICR) and output voltage ripple (OVR) to increase the power rating. The suggested converter regulates the input and output power by modulating the phase shift in the pulse width modulation (PWM) technique using the maximum power point tracking (MPPT) algorithm via two closed feedback loops, one for a slower external loop and the other for a faster PWM control internal loop, similar to current mode control. The suggested converter has high voltage (HV) gain due to the coupled inductors (CIs), which act as a transformer. This magnetic design structure in both the steady-state and transient states also decreases the size and enhances the converter’s performance. Finally, the suggested converter was experimentally verified on a 285W prototype, and the maximum efficiency was found to be 98%, based on modeling and experimental data.

DC-DC converters are extensively used for switched mode power supplies. Hence, this chapter presents a design, modelling and hardware implementation of a digitally controlled system and its application to DC-DC buck converter being interfaced with Texas Instruments DSP TMS320F2812 controller for voltage control mode. ADC, compensator and digital PWM are the main building blocks that appears in digital controller design. Conventionally, analog controller is popular to get the desired output voltage in DC-DC converters, whereas, digital controllers offer high speed arithmetic and high resolution. Analog PI controller design approach is reviewed and the digital PI controller design is being implemented in this chapter. Digital control has been applied using standard frequency responses with design by emulation approach. Modulation delay in digital control is very critical while designing for fast control loops. Therefore, this chapter also introduces discrete time modelling of synchronous buck converter from practical standpoint considering feedback loop delays. Whereas, this chapter illustrates PI digital controller design methodology, hardware implementation and experimental verification. Experimental results have been taken from a closed loop 18W buck converter. The transient and steady state performance of the converter using PI controller are also presented with appropriate simulation and hardware results.

The buck converter, a type of DC-DC converter, plays a crucial role in modern electronic systems by efficiently stepping down voltage levels. This process is essential for devices that require stable and lower voltage inputs from a higher voltage source, such as batteries or power supplies. The buck converter operates through a combination of switching elements, typically a transistor and a diode, and energy storage components like inductors and capacitors. By rapidly switching the transistor on and off, the converter regulates the voltage output, minimizing energy loss and enhancing efficiency. This capability is pivotal in various applications, including portable electronics, electric vehicles, and renewable energy systems, where efficient power management is critical. The buck converter's ability to maintain high efficiency, compact size, and reliable performance makes it a fundamental component in the design of power supplies for a wide range of electronic devices, contributing to energy conservation and system optimization.

This paper presents a novel single-stage AC-DC drive circuit for powering LED projection lamps, which combines a modified stacked boost converter with a half-bridge LLC resonant converter into a single-stage power converter with power-factor correction (PFC) and soft switching. The PFC functionality is realized by designing the inductor in the modified stacked boost converter subcircuit in discontinuous-conduction-mode (DCM). Besides, the power switch features zero-voltage switching (ZVS), which reduces switching losses and improves the efficiency of the proposed driver circuit.This paper has completed the development of a 100W (36V/2.77A) prototype driver circuit, and tested the experimental results when the input mains line voltage is 110 V. According to the test results of the single-stage AC-DC driver circuit, the power factor is greater than 0.99, the total harmonic distortion factor of the input current is less than 6%, and the circuit efficiency is greater than 89%. Therefore, satisfactory experimental results demonstrate the functionality of the proposed driver circuit for powering the LED projection lamp.

This article introduces a three-mode variable-frequency zero-voltage switching (ZVS) modulation method for the four-switch buck+boost converter. This method makes this circuit concept well suited for applications, such as wireless power charging of electric vehicles, where this circuit operates as a power buffer between the resonant converter and the battery with the function to implement the required charging profile. Herein, the buck+boost converter operation is subdivided into three operating regions according to the converter static voltage gain, i.e., buck-, buck-boost- and boost-type modes. A ZVS turn- <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">on</small> triangular current mode (TCM) control is adopted for buck-type and boost-type modes. In the buck-boost-type mode when the input-to-output voltage gain is close to unit, all the possible modulation cases are studied thoroughly based on the phase shift of the two half bridges in a full switching period. The selection of the most suitable modulation scheme is performed to minimize the rms value of the inductor current while taking into account the simplification of the practical implementation. Closed-form equations are derived, which makes it easy to implement in practice. The proposed strategy is described, analyzed, and finally verified through a 3 kW surface mounted device (SMD) silicon carbide (SiC) <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">mosfet</small> -based laboratory prototype with designed input voltage of 300–600 V and the typical output voltage of 400 V class battery. The efficiency from the measured results is remarkably high, i.e., between 99.2% and 99.6% in a power range from 1 to 3 kW. Finally, tests for the operating mode transitions demonstrated the feasibility of the proposed modulation method. The power density of this converter is 4.86 kW/L.

Electric vehicles (EVs) have emerged as the best alternative to conventional fossil fuel-based vehicles due to their lower emission rate and operating cost. The escalating growth of EVs has increased the necessity for distributed charging stations. On the other hand, the fast charging of EVs can be improved by the use of efficient converters. Hence, the fractional order proportional resonant (FOPR) controller-based current-fed bidirectional DC-DC converter is proposed in this work for EV charging applications. The output capacitance of the switches is utilized to achieve the resonance condition for zero voltage switching (ZVS) and zero current switching (ZCS). The proposed converter topology is implemented using the MATLAB Simulink tool. The result analysis verified that the proposed converter topology provides better switching characteristics for different operating modes, which is necessary for a high-voltage EV charger. Hence, it is proved that the proposed converter is more efficient for battery charging in EVs.