Young-Real Kim

Fast charging technique for EV battery charger using three-phase AC-DC boost converter

This paper presents the battery charging algorithm for electric vehicle. In order to charge the main battery bank for EV, the safety and charging time must be contemplated. The battery charger also requires that it is a capable of the high power capacity. Therefore, three-phase AC-DC boost converter is suitable for the battery charger for EV. For applications above several kilowatts system LCL-filter is more attractive than the L-filter. This paper presents the filter design, contemplating the minimum value of filter reactor. In conjunction with the hardware of the charger, battery charging algorithm is important for the development of the battery charger. The battery charging algorithm is required to reduce the charging time and preserve the battery from overcharging. In this paper, Constant Current-Constant Voltage charging method is adapted for safely charging battery. However, it takes a long time for fully charging the battery, so improved CC-CV charging method is presented. It helps reducing the total charging time. It is described by comparison of conventional CC-CV method and verified through the experimental results.

Analysis of a new PWM method for conducted EMI reduction in a field oriented controlled induction motor

The prevalence of EMI noise problems has been considered many times over the past few years, in inverter fed motor control systems. The advent of high speed power devices, and the high dv/dt of switching devices, has resulted in EMI problems and leakage current. This paper describes the application of the newly developed EMI reduction technique of SVPWM in induction motor drives. This newly developed common mode voltage reduction SVPWM technique does not use any zero-voltage vector states for inverter control, hence can restrict the common mode voltage more efficiently than the conventional PWM technique. The validity of the proposed technique is verified through simulation and experimental results. In this paper, by applying the vector control system, the proposed technique is presented as superior in reducing EMI and equal control performance, compared to the conventional space-vector PWM technique.

Single-phase Active Power Filter based on Rotating Reference Frame Method

This paper presents a new control method of the single-phase active power filter (APF) for the compensation of harmonic current components in nonlinear loads. In order to use a new transformation theory, the two-phase system by constructing a imaginary second-phase is formed. In the conventional method, an imaginary-phase lagged to the load current T/4(here T is the fundamental cycle) is made. But in this proposed method, the new signal as the second phase is the delayed through the filter. As this control method is applied to the system of single-phase, an instantaneous calculation was developed rather by using the rotating reference frames synchronized with source-frequency than by applying instantaneous reactive power theory that uses the conventional fixed reference frames. The control scheme of single-phase APF is analyzed with the experimental results in a laboratory prototype to verify the validities of the proposed control methods

Control method for reduction circulating current in parallel operation of DC distribution system for building applications

In the large system such DC distribution for building, the method that a number of modules converters operation in parallel is commonly used. When parallel operation, circulating current is directly related to the loss of the entire system. Accordingly, each module to share the same current is the most important for the safety of the power system. In this paper, control method for reduction circulating current in parallel operation is proposed. Thus, Response and operation of steady-state with parallel system was verified by simulation and experiment.

Optimal washing time control algorithm for the drum washing machine using an inertia estimator

Generally, operating efficiency of drum washing machine is mostly affected by the washing time. The washing time is determined by the quantity and the type of the laundry. Although the type of the laundry is easily inputted by the user, however the quantity of the laundry can net be easily. Therefore, this paper suggests that the washing time is adjusted by the inertia estimator which can estimate the quantity of the laundry. The proposed algorithm is implemented on the PMSM drive using the low cost position sensor for practical washing machine application. And the experiment is performed by the motor of drum washing machine for the practical load condition.

The Voltage-doubler Rectifier type Full-bridge converter built in voltage-balancing circuit for bipolar LVDC distribution system

This paper proposes Voltage-doubler Rectifier type Full-bridge converter for bipolar LVDC distribution system. This converter is possible of bi-directional power flow and perform DC_link voltage balancing operation. System of bipolar structure has neutral-point unlike unipolar structure. But, this neutral point is incur DC_Link voltage unbalance between top and bottom capacitor. Thus, bipolar structure need voltage balancing-circuit for voltage unbalance compensation. In Voltage-doubler Rectifier type Full-bridge converter to proposes, secondary side diodes of transformer are replaced to power transistors. And perform voltage balancing control using secondary side circuit without additional balancing-circuit. Also, primary side circuit of Full-bridge type can perform ZVS by phase-shift. And last, step-up and step-down operation also can. Such validity of converter is verified by simulation and experimental results.

The configuration of electric vehicle system using isolated DC-DC converter for a low-voltage and high-current type battery

In this paper, electric vehicle (EV) system using bi-directional DC-DC converter which can control the type of low-voltage and high-current battery is proposed. Proposed system uses isolated DC-DC converter for voltage compensation. The proposed topology has a form in which the inputs are connected in parallel and the outputs are connected in series in battery and isolated converters. The basic concept of dc-dc converter is integrated boost-flyback converter. This converter has the advantage of high step-up voltage by boost converter and system isolation by flyback converter. The motor driving mode for the EV can be divided into two such as motoring mode and regenerative braking mode. In the EV system, the regenerative braking control is used during deceleration. The simulation of motoring and regenerative braking mode using proposed system is performed and the result, verify the proposed control method.

The current dynamic improving method of IPMSM using predictive current control for EV

In Electric Vehicle (EV) application, a torque reference of IPMSM (Interior Permanent Magnet Synchronous Motor) depends on accelerator operation. As a torque reference changes instantaneously, IPMSM drive system requires fast current response to track a torque reference. General PI control which is used in industrial application causes time delay in transient state. To improve the performance of control, this paper discusses predictive current control and proposes IPMSM control method using predictive current control and PI control. the proposed control method is experimentally verified. The Experimental results show that low current ripple and reduced time delay by using the proposed control method.

High voltage battery simulator based on Lithium Ion battery

This paper proposed lithium-ion based high-voltage battery simulator. Matlab based battery parameters and modeling were implemented, and the characteristics of the modeled batteries were output by using three-phase grid-connected AC / DC PWM converters. The proposed methods were verified by PSIM.

Three phase current reconstruction method using predictive current in three shunt sensing PWM inverter

When the vector control is performed using PWM three phase inverter in AC motor drive system, three phase current are obtained by measuring voltage between shunt resistors. The PWM inverter obtaining three phase current by shunt resistor is comparatively cheaper than the method that measures three phase current by Current Sensor. And it reduces the size of AC motor drive system. However, the method sensing the phase current using shunt resistor cannot perform the vector control in high motor speed since there is the area that cannot measure three phase current. In this paper, the boundary where phase currents cannot be obtained is defined and the method reconstructing the phase current is proposed by predicting phase current through load modeling in the area which phase current measurement is impossible. The proposed method can restore phase current up to maximum output voltage of SVPWM inverter in linear area and validity of proposed method is proved through simulation.