Current-driven Rectifier Research Articles

A 10-MHz Resonant Converter With a Synchronous Rectifier for Low-Voltage Applications

This paper proposes a high-frequency dc–dc converter with a synchronous rectifier (SR), which is suitable for the low-voltage output application. The proposed topology consisting of a Class Φ2 inverter and a synchronous Class E current-driven rectifier features low switch voltage stress, fast transient response, and high efficiency. First, the analysis and design method of the converter are presented. Concerning the coupling of amplitude and phase of the fundamental voltage and current in the rectifier stage, the duty cycle of the switch is considered in the proposed design method. For the design of the inverter stage, the impedance of the resonant tank across the main mosfet is utilized in the design process. Second, a self-oscillating resonant driver with dc bias voltage is proposed for the SR switch and features low component count and low driving power loss. A prototype with 12 V input and 5 V/10 W output was built to verify the theoretical analysis.

Analysis and design of a class E current-driven rectifier for 1 MHz wireless power transfer system

Abstract The paper presents the design of the class E current-driven rectifier, which is intended for operation in the wireless power transmission system, as well as the concept of selection of the rectifier parameters which allows the operation with high efficiency. The selection of the rectifier parameters was performed with a view to the use of the existing wireless power transmission (WPT) system. The procedure for selection of the rectifier parameters has been proposed to enable its optimal use in reference to the system parameters given already at the design stage, ie; load resistance and the coil magnetic coupling factor (distance between coils). In order to verify the correctness of the procedure for selection of the parameters, the numerical model of the system which consists of the class E resonance inverter, the air-core transformer and the designed E class rectifier system was developed in the LTspice environment. Simulation tests and analysis of the obtained calculation results were performed. Based on the simulation results, a prototype of the class E rectifier system which cooperates with the existing wireless power transmission system supplied from the class E inverter was developed. The obtained results of laboratory measurements demonstrated a high compliance with the simulation results, thus, confirming the correctness of the proposed design procedure and the high operating efficiency of the rectifier system.

A Single-Stage LED Driver Based on ZCDS Class-E Current-Driven Rectifier as a PFC for Street-Lighting Applications

This paper presents a light-emitting diode (LED) driver for street-lighting applications that uses a resonant rectifier as a power-factor corrector (PFC). The PFC semistage is based on a zero-current and zero-derivative-switching (ZCDS) Class-E current-driven rectifier, and the LED driver semistage is based on a zero-voltage-switching (ZVS) Class-D LLC resonant converter that is integrated into a single-stage topology. To increase the conduction angle of the bridge-rectifier diodes current and to decrease the current harmonics that are injected in the utility line, the ZCDS Class-E rectifier is placed between the bridge-rectifier and a dc-link capacitor. The ZCDS Class-E rectifier is driven by a high-frequency current source, which is obtained from a square-wave output voltage of the ZVS Class-D LLC resonant converter using a matching network. Additionally, the proposed converter has a soft-switching characteristic that reduces switching losses and switching noise. A prototype for a 150-W LED street light has been developed and tested to evaluate the performance of the proposed approach. The proposed LED driver had a high efficiency (>91%), a high PF (>0.99), and a low total harmonic distortion (THD $_{i}$ ${{V}}_{{\rm{rms}}}$ . These experimental results demonstrate the feasibility of the proposed LED scheme.

Design of a Class-DE Rectifier with Shunt Inductance and Nonlinear Capacitance for High-Voltage Conversion

This paper presents a design method for a resonant class-DE rectifier with a shunt inductance input network. The cass-DE resonant rectifier offers numerous advantages at high operating frequencies and high output voltages. For a high-voltage design, the limiting factor has been the absence of a design process incorporating shunt inductance for low-to-high impedance matching as well as nonlinear capacitance from semiconductor devices. To design a rectifier with a specific input impedance at the fundamental frequency of operation, designers have been relying on either parametric variation in iterative simulations that often takes a long time to complete, or simple equations without considering nonlinear capacitances that renders the analysis inaccurate at high frequencies. In this paper, we propose a design procedure that begins with universal design curves that are applicable regardless of the capacitance nonlinearity. This is followed by parameter selection and a convergence check to ensure the rectifier operates at the desired output voltage. Based on the outlined procedure, we design and experimentally verify a 27-MHz 350-V current-driven rectifier, a 25-MHz 500-V voltage-driven rectifier, and a 27.12-MHz 2-kV four-stage rectifier, all of which the resonant capacitor is nonlinear and the input impedance is resistive at the switching frequency.

Class-E Half-Wave Zero dv/dt Rectifiers for Inductive Power Transfer

This paper analyses and compares candidate zero dv / dt half-wave Class-E rectifier topologies for integration into multi-MHz inductive power transfer (IPT) systems. Furthermore, a hybrid Class-E topology comprising advantageous properties from all existing Class-E half-wave zero dv / dt rectifiers is analyzed for the first time. From the analysis, it is shown that the hybrid Class-E rectifier provides an extra degree of design freedom that enables optimal IPT operation over a wider range of operating conditions. Furthermore, it is shown that by designing both the hybrid and the current-driven rectifiers to operate below resonance provides a low deviation input reactance and inherent output voltage regulation with duty cycle allowing efficient IPT operation over wider dc load range than would otherwise be achieved. A set of case studies demonstrated the following performances: First, for a constant dc load resistance, a receiving end efficiency of 95% was achieved when utilizing the hybrid rectifier, with a tolerance in required input resistance of 2.4% over the tested output power range (50–200 W). Second, for a variable dc load in the range of 100–10%, the hybrid and current-driven rectifiers presented an input reactance deviation less than 2% of the impedance of the magnetizing inductance of the inductive link respectively and receiving end efficiencies greater than 90%. Third, for a constant current in the receiving coil, both the hybrid and the current-driven rectifier achieve inherent output voltage regulation in the order of 3% and 8% of the nominal value, respectively, for a variable dc load range from 100% to 10%.

Low-Harmonic-Contents and High-Efficiency Class E Full-Wave Current-Driven Rectifier for Megahertz Wireless Power Transfer Systems

Wireless power transfer (WPT) working at megahertz (MHz) is now being widely considered a promising candidate for the midrange transfer of a medium amount of power. Efforts have been made to build high-efficiency MHz WPT systems via both component- and system-level approaches. However, so far there have been few discussions on high-frequency rectifier for MHz WPT applications. The soft-switching-based rectifiers, such as the Class E rectifiers, are one of the promising candidates for MHz rectification. This paper investigates the application of a Class E full-wave current-driven rectifier, for the first time, in WPT systems. A procedure is also developed to optimize the design of the rectifier and the MHz WPT system. For comparison purposes, the performances of both the Class E rectifier and the conventional full-bridge rectifier are investigated in terms of total harmonic distortion (THD), efficiency, power factor, voltage/current stresses, and voltage/current transfer functions, when being applied in an example 6.78-MHz WPT system. The simulation and experimental results show that the input voltage THD of the Class E full-wave rectifier is reduced to one-fourth of the THD of the full-bridge rectifier. In the optimally designed MHz WPT system, efficiencies of both the rectification (over 91%) and the overall system (around 80%) are obviously improved compared to the system using the conventional full-bridge rectifier.

Parameter Design for a 6.78-MHz Wireless Power Transfer System Based on Analytical Derivation of Class E Current-Driven Rectifier

Magnetic resonance coupling working at megahertz (MHz) is widely considered as a promising technology for the mid-range transfer of a medium amount of power. It is known that the soft-switching-based Class E rectifiers are suitable for high-frequency rectification, and thus potentially improve the overall efficiency of MHz wireless power transfer (WPT) systems. This paper reports new results on optimized parameter design of a MHz WPT system based on the analytical derivation of a Class E current-driven rectifier. The input impedance of the Class E rectifier is accurately derived, for the first time, considering the on-resistance of the diode and the equivalent series resistance of the filter inductor. This derived input impedance is then used to develop and guide design procedures that determine the optimal parameters of the rectifier, coupling coils, and a Class E PA in an example 6.78-MHz WPT system. Furthermore, the efficiencies of these three components and the overall WPT system are also analytically derived for design and evaluation purposes. In the final experiments, the analytical results are found to well match the experimental results. With loosely coupled coils (mutual inductance coefficient $k$ =0.1327), the experimental 6.78-MHz WPT system can achieve 84% efficiency at a power level of 20 Watts.

Single-capacitor phase-controlled series resonant converter

A new phase-controlled series resonant, DC/DC converter is described, analyzed, and experimentally verified. The circuit comprises a phase-controlled inverter and a Class D current-driven rectifier. The phase-controlled inverter consists of two switching legs, two resonant inductors, and a single resonant capacitor connected in series with an AC load. The phase shift between the voltages that drive the MOSFETs is varied to control the AC current of the inverter and thereby regulate the DC output voltage of the converter. A frequency-domain analysis is used to derive basic equations which govern the circuit operation. An important advantage of the converter is that the operating frequency can be maintained constant. For operation at a switching frequency greater than 1.15 resonant frequency, the load of each switching leg is inductive. The proposed converter has an excellent full-load and part-load efficiency. An experimental prototype of the converter with a center-tapped rectifier was built and extensively tested at an output power of 78 W and a switching frequency of 200 kHz. The theoretical and experimental results were in good agreement. >

Frequency-domain analysis of series resonant converter for continuous conduction mode

Most previous analyses of a series resonant DC-DC power converter (SRC) have been performed in the time domain. A comprehensive frequency-domain analysis of the SRC for steady-state operation, along with experimental results is presented. Simple analytical design equations are derived for the basic performance parameters of the converter operating in the continuous conduction mode (CCM) using Fourier series techniques and a high-Q/sub L/ assumption. Three types of class-D current-driven rectifiers are considered. The diode threshold voltage and forward resistance as well as the ESR of the output filter capacitor are taken into account. Experimental results were in good agreement with theoretical predictions. >

Class D current-driven rectifiers for resonant DC/DC converter applications

Analyses and experimental results are given for a family of three Class D current-driven rectifiers. The diode current is half-sine wave and the diode voltage is a square wave. The diode forward voltage and forward resistance are taken into account in the analyses. The basic performance parameters of the rectifiers are determined, such as input resistance, voltage transfer function, efficiency, and power factor. The ripple voltage is estimated, and some effects of the equivalent series resistance and equivalent series inductance of filter capacitors on the ripples are discussed. The experimental results were obtained using IR31DQ06 Schottky diodes at 1 MHz and 16 W output power. >