Power Electronics for Household Appliance Revolution

Jih-Sheng (Jason) Lai 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6

Cascaded Dual-Buck Inverter With Reduced Number of Inductors

Institute of Electrical and Electronics Engineers 2018 IEEE transactions on power electronics Vol.33 No.4

<P>A dual-buck inverter (DBI) possesses no shoot-through worries and can boost efficiency by using power <SMALL>mosfet</SMALL> s. The main drawback of a DBI is the use of more inductors than in a traditional full-bridge inverter. This greater number of inductors decreases the power density and increases system cost. In this paper, a modified cascaded full-bridge DBI is proposed. It retains all the advantages of the conventional cascaded full-bridge DBI, possesses no shoot-through issues, and can be operated with no pulse-width-modulation dead-times. It can be implemented with power <SMALL>mosfet</SMALL> without reverse recovery issues of a body diode to boost efficiency. The cascaded modules in the proposed inverter share current limiting inductors. Therefore, the number of inductors and inductor footprints, the complexity of the circuit layout, required inductance, and magnetic volume can all be decreased. To show the advantages of the proposed inverter, detailed theoretical analysis and experimental results are provided.</P>

DSP-Based Switched Reluctance Motor Incremental Inductance Measurement through Current Loop

Jongwan Kim,Jih-Sheng Lai 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5

Switched reluctance motor (SRM) has double saliency structure and operates under the saturated condition to achieve high energy conversion ratio. Therefore, the magnetic characteristics of switched reluctance motor is highly non-linear that the actual inductance profile can not be simply obtained by the inductance measurement instrument. As the control performance of SRM drive is highly dependent on a priori knowledge of magnetic characteristics, the accurate measurement is important. This paper presents the incremental inductance measurement method through closed loop current control. The rate of change of the phase current is captured by additional sampling instant. The effects of phase resistance variation, core loss, and power device voltage drop are considered to minimize the measurement error. The measurement results are verified with LCR meter and torque transducer measurement.

A Transformer-Coupled, Series-Resonant Topology for the Induction Heating of Aluminum Cookware

Andrew Amrhein,Jih-Sheng (Jason) Lai 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6

Induction heating of aluminum cookware is difficult due to its low resistivity and lack of ferromagnetic properties. Both of these factors result in an effective impedance reflected through the work coil that is too low for practical inverter design and makes efficient coil design difficult. This paper presents a transformer-coupled topology as a means of efficiently delivering the desired amount of power into such low-impedance induction heating loads while keeping the inverter design within practical constraints. This topology consists of a conventional series-load-resonant coil/capacitor circuit. A high-frequency transformer is then used to the couple the series-resonant load to a full-bridge inverter, removing the constraint between load impedance and inverter design. The proposed circuit is built and its operation is experimentally verified.

Dynamic Modeling and Controller Design of Dual-Mode Cuk Inverter in Grid-Connected PV/TE Applications

Han, Byeongcheol,Lai, Jih-Sheng,Kim, Minsung Institute of Electrical and Electronics Engineers 2018 IEEE transactions on power electronics Vol.33 No.10

<P>This paper presents a dual-mode Cuk inverter for photovoltaic/thermoelectric power applications. A dual-mode Cuk inverter operates in both discontinuous conduction mode (DCM) and continuous conduction mode (CCM), and has the advantages of low ripples of voltage and current at the input and output, medium power density, and step-up/step-down ability, but is difficult to control because DCM and CCM have distinct system dynamics. To overcome this control problem, we propose to use a repetitive controller (RC) with a multiple phase-lead compensator for the dual-mode Cuk inverter. If the RC is applied by itself, the distinct system dynamics may severely degrade its system performance. Thus, in the proposed RC, we mainly use a multiple phase-lead compensator to compensate for the different phase lags of the dual-mode Cuk inverter. To reduce the burden from the RC, we use the dual-mode nominal duty ratio as feedforward control input. We also analyze the boundary of operation modes in the dual-mode Cuk inverter, then provide detailed and practical guidelines to design the control parameters. Experimental results obtained on a 500-W digitally controlled module integrated converter prototype confirmed the effectiveness of the control approach.</P>

A Digital Single-loop Control of Multi-phase dc-dc Converter for Fuel Cell Powered Truck Auxiliary Power Unit

Younghoon Cho,Hidekazu Miwa,Jih-Sheng Lai 전력전자학회 2011 ICPE(ISPE)논문집 Vol.2011 No.5

This paper proposes a digital single-loop control method which enables a seamless mode transition between voltage and current control mode and current slew-rate control for a battery connected multi-phase dc-dc converter. The proposed algorithm consists of a current reference generator and a digital average current controller. The current reference generator changes the time constant of the digital integrator to implement ramp-up and ramp?down of the current reference command. The digital average current controller is designed to track the current reference accurately. A small signal model of the current control loop is derived and the control parameters are determined by the small signal analysis. A startup method when the output of the dc-dc converter is connected to a battery is also proposed to prevent reverse current flowing back to the converter input which is connected to the fuel-cell stack in the design. A prototype 5 ㎾ four-phase dc-dc converter serving as an auxiliary power supply in heavy duty trucks has been built and tested to verify the effectiveness of the proposed method.

Analysis of the Admittance Component for Digitally Controlled Single-Phase Bridgeless PFC Converter

Cho, Younghoon,Mok, Hyungsoo,Lai, Jih-Sheng The Korean Institute of Power Electronics 2013 JOURNAL OF POWER ELECTRONICS Vol.13 No.4

This paper analyzes the effect of the admittance component for the digitally controlled single-phase bridgeless power factor correction (PFC) converter. To do this, it is shown how the digital delay effects such as the digital pulse-width modulation (DPWM) and the computation delays restrict the bandwidth of the converter. After that, the admittance effect of the entire digital control system is analyzed when the bridgeless PFC converter which has the limited bandwidth is connected to the grid. From this, the waveform distortion of the input current is explained and the compensation method for the admittance component is suggested to improve the quality of the input current. Both the simulations and the experiments are performed to verify the analyses taken in this paper for the 1 kW bridgeless PFC converter prototype.

Analysis of the Admittance Component for Digitally Controlled Single-Phase Bridgeless PFC Converter

Younghoon Cho,Hyungsoo Mok,Jih-Sheng Lai 전력전자학회 2013 JOURNAL OF POWER ELECTRONICS Vol.13 No.4

This paper analyzes the effect of the admittance component for the digitally controlled single-phase bridgeless power factor correction (PFC) converter. To do this, it is shown how the digital delay effects such as the digital pulse-width modulation (DPWM) and the computation delays restrict the bandwidth of the converter. After that, the admittance effect of the entire digital control system is analyzed when the bridgeless PFC converter which has the limited bandwidth is connected to the grid. From this, the waveform distortion of the input current is explained and the compensation method for the admittance component is suggested to improve the quality of the input current. Both the simulations and the experiments are performed to verify the analyses taken in this paper for the 1 kW bridgeless PFC converter prototype.

A Smooth Transition Method Between Position Sensorless Control Algorithms of PM Machines

Thomas LaBella,Younghoon Cho,Jih-Sheng Lai 전력전자학회 2011 ICPE(ISPE)논문집 Vol.2011 No.5

This paper presents a method of smoothly transitioning between low-speed and high-speed position sensorless control algorithms of permanent magnet synchronous machines (PMSMs). The transition method estimates the load torque, synchronizes the estimated outputs of both algorithms, and then smoothly transitions from one algorithm to the other. This is achieved by commanding a calculated open-loop torque reference while the estimator that is taking over reaches steady-state. The effectiveness of the proposed method has been experimentally verified by transitioning between various low-speed and high-speed control algorithms using an 11-㎾ interior permanent magnet (IPM) motor.

Design Criteria of the Auxiliary Resonant Snubber Inverter Using a Load-Side Circuit for Electric Propulsion Drives

Byeong-Mun song,Jih-Sheng Lai,Soon-Kurl Kwon 전력전자학회 1998 ICPE(ISPE)논문집 Vol.- No.-

The design criteria of the auxiliary resonant snubber inverter (ARSI) using a load-side circuit are discussed in relation to electric propulsion drives. In this regard, this paper attempts to develop a set of design criteria for the ARSI. First, the switching characteristics of IGBTs under soft-switching mainly in terms of dv/dt, dildt and switching losses are discussed and utilized for optimizing the selection of the resonant components in the system. After that, the proper control strategies of ARSIs are analyzed and simulated based on voltage space vector modulations. Later, the design, control and implementation of the auxiliary resonant circuit suitable for industrial products are analyzed and presented. And finally, other factors including power stage layout, packaging and the choice of current sensors are included.<br/> The detailed simulation and experimental results will be included based on a laboratory prototype. The proposed design criteria of the ARSI would help the implementation of an electric propulsion drive system.<br/>