The paper presents a Switched-Capacitor Boost DC-DC Converter (SC-BC) which can be used in energy harvesting applications using thermoelectric generators (TEGs) with low output voltage, low power and a significant internal resistance. It consists of a switching capacitor circuit, where MOSFETs are used as switches, and a boost stage. The converter is a modification of a previously presented scheme in which diodes are used in the switched capacitor stage. A higher voltage gain and an increased efficiency can thus be achieved. The model of the converter was developed considering the internal resistance of the TEG and boost stage inductor. A comparison with the diode based converter is shown, with consideration of the TEG internal resistance. Calculation is presented of the main passive components. A control algorithm is also proposed and evaluated. It is based on a linearization approach, and designed for output voltage and inductor current control. The operation of both converter and control are verified with the simulation and experimental results.
This study discusses a converter structure appropriate for charging the batteries of an electric vehicle (EV). The structure is obtained by a transformation of a conventional three-phase inverter, which is already present in an EV's power-train system. Since the motor inverter's semiconductor components and the electric motor's windings form the battery charger's circuit, a reduction in the power-train system's size and weight is achievable. The proposed fully integrated battery charger operates alternately in two modes, buck and boost, while providing power factor (PF) correction capability continuously. This study also proposes an input current control strategy that ensures smooth operating mode transitions, which occur during the operation of a battery charger. The control is entirely implemented within a microcontroller and ensures operation with a high PF and low total harmonic distortion of the input current. The performance of the discussed converter using the proposed control scheme was verified experimentally.
This paper investigates a control approach for achieving reliable zero-voltage switching transitions within the entire operating range of a conventional nonisolated bidirectional dc-dc converter that utilizes synchronous rectification. The approach is based on operation in the discontinuous conduction mode with a constant reversed current of sufficient amplitude, which is achieved by load-dependent variation of the switching frequency. This paper focuses on the obtained resonant voltage transitions and provides analytical models for determining the reversed current and timing parameters that would ensure safe, reliable and highly efficient operation of the converter. In addition, the proposed approach solves the synchronous transistor's spurious turn-on and body diode reverse recovery induced issues, does not require any additional components or circuitry for its realization, and can be entirely implemented within a digital signal controller. The effectiveness and performance of the presented control approach was confirmed in a 1-kW experimental bidirectional dc-dc converter that achieved 97% efficiency over a wide range of output powers at switching frequencies above 100 kHz.
Based on the standardization in the automotive industry, systems require extensive testing, which represents significant costs regarding personnel and equipment. The testing systems must be built in such a way that a bidirectional power flow is possible between the power source and the tested system. Additionally, applied testing systems have to possess high disturbance immunity. Classical current programmed control performed using an analogue approach suffers from low disturbance rejection during switching operation. The digital control of DC-DC converter can solve this problem with the use of digital integration in a measurement chain. The integrals of values are obtained by using a Voltage Control Oscillator (VCO) and appropriate counters. Digital control of an interleaving operated bidirectional buck-boost synchronous converter can be applied in the testing system for automotive powertrains. The voltage and current measurements with the application of an integral-measurement principle act as low-pass filters, which remove the disturbances from the measured values. The digital implementation of a compensation ramp (current mode control) and method for choice of control parameters are described. All the tasks for measurements, as well as current and voltage control, were implemented within the FPGA (Field Programmable Gate Array). The presented converter can operate as a close to ideal voltage or current source, and satisfies the requirements of testing electric motor drive-trains with bidirectional DC-AC converters that are applied in automotive applications. The proposed system was verified by simulation and experiments.
A pulse-density-modulated (PDM) flyback-based microinverter with a high-frequency AC (HFAC) link and an active decoupling circuit is proposed. The converter's structure and basic operating principle are analysed. The advantages of utilising an active decoupling circuit and the demand for using pulse-density modulation are explained. The operation of the proposed microinverter has been verified by experiment.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.