An-Yeol Ko

Braking torque control method of IPMSM for electric vehicle using 2D look-up table

This paper presents the control methods of torque when interior mounted permanent magnet synchronous motor (IPMSM) for electric vehicle is in regenerative mode. The current control of IPMSM is generally performed by the Lockup-table to output the most suitable current order which is to make the unit torque like maximum torque per ampere (MTPA). At the electric vehicle system, the regenerative control should generate the braking torque according to the drivers brake control and save the regenerative power to the battery. It is necessary to generate the braking torque for the brake of the electric vehicle during the driving, so the spinning speed of the generator should be considered and it should be differently controlled according to the characteristics at the constant torque and flux-weakening areas. Thus, 2D Lookup-Table should be made considering the speed. This paper presents how to make the 2D Lookup-Table of IPMSM for the electric vehicle, the control methods of brake torque control, voltage, current control of the battery at the regenerative operation and verifies the validity of the regenerative control method through the simulation and experiment.

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.

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.

Control method of propulsion control device for AC railway vehicle

Railway vehicle is classified into the AC and DC railway vehicle according to the distribution of the local environment. DC railway vehicle is directly supplied to the DC power from the power line to drive the inverter but AC railway vehicle is complicated to control and drive sequence as compared to DC vehicle because of the structure for controlling the inverter and converter at the same time. In this paper we describe the sequence and method for controlling a railway driving vehicle on AC power line and confirm the analysis and control performance through computer simulation.

The EV charging system using module balancing method in V2G system

This paper presents the electric vehicle(EV) system using module balancing method in vehicle-to-grid(V2G) system. Since there are intrinsic discrepancies among batteries, the state of charge(SOC) of each battery after charging or discharging may not be the same. Consequently, the batteries are with different voltages during the charging and discharging process. As a result, over-charging or over-discharging may be happened to some of the batteries. To find a solution to this problem, this paper proposes EV charge system using module balancing method in V2G system. To confirm the validity of the proposed system, the simulation and experiment is performed by consist of three modules and dual active bridge(DAB) DC-DC converters.

The Prediction of Total Revenue of V2G System Considering Battery Wear Cost

Recently, research on the smart grid that combines ICT(Information & Communication technology) to the power system has been actively progressed. If the occupancy of the EV(Electric vehicle) is increased. the V2G(Vehicle to grid) system is available which constitutes the micro-grid through battery of EV. V2G system performs load leveling and efficient energy consumption by battery operation considering load condition. But, if the battery is used only depending on the electricity rates, it doses not consider the life of the battery. The ACC(Achievable cycle) and the total transferable energy of battery varies corresponding to the selected DOD(Depth of discharge). In this paper, the optimal DOD selection method of V2G system considering battery wear cost and average driving distance of EV. Also, the total revenue prediction of various nation is presented considering the actual electricity costs per hour.

Interpolation error compensation method for look-up table based IPMSM drive

In this paper, interpolation error compensation method for look-up table(LUT) based IPMSM(Interior Permanent Magnet Synchronous Motor) drive is proposed. Generally, the LUT based IPMSM drive is widely used on automotive application because of its reliable current control. However, the LUT data is memorized discreetly, so the linear interpolation method is used for the absent data condition. Because this interpolation method does not follow the PMSM operation trace, the error is unavoidable between the capable operation point and the interpolated output. This paper proposes the compensation method for this interpolation error. Simulation and Experiment are performed for verify the reliability of the proposed control method.

Regenerative control method without DC-DC converter for electric vehicle application

In the EV system operating regenerative mode without bi-directional DC-DC converter, 3-phase PWM inverter should charge the battery. At this time, regenerative torque reference for braking has to output torque reference in order to charge the battery. This paper proposed the regenerative control method controlling the voltage and current of battery through the regenerative power control at regenerative braking torque corresponding to the drivers brake control.

Reduction of Current Distortion in PWM Inverter by Variable DC-link Voltage of DC-DC Converter for FCEV

A design and control method of DC/DC converter, which can control variable DC-link voltage to drive a fuel cell electric vehicle (FCEV), is proposed in this study. Given that a fuel cell has low-voltage and high-current characteristics, the required voltage for operating motor must be output through the DC/DC boost converter in the system to drive an FCEV. The proposed converter can choose the output voltage of battery or fuel cell in consideration of the driving mode, as well as control DC-link voltage in accordance with the back electromotive force. The switching lag-time to prevent shortage of pulse-width modulation inverter arms makes distorted current waveform caused by voltage distortion. Through this control method, the proposed converter can reduce the output voltage distortion and current ripple of the inverter, thereby reducing the distorted torque. Simulations and experimental results are presented to verify the reliability of the proposed DC/DC converter.

Regenerative control of bi-directional DC-DC converter controlling variable DC-link for FCEV

FCEV (Fuel cell electric vehicle) is provided with energy for operating the motor from the fuel cell. But fuel cell is impossible to be charged at the regenerative mode and also, it has slow dynamic characteristics. So, additional battery is essential as an auxiliary power source in FCEV system. The output current of the VSI (Voltage Source Inverter) is distorted due to the dead-time and the delay time of switching devices [1]. The ripple of the output current is proportional to the DC-link voltage. So, variable DC-Link control is required to alleviate this problem. In this paper, the bi-directional DC-DC converter controlling variable DC-link is proposed. The proposed converter controls DC-link both motoring and regenerative mode. Also, it chooses the source from among the battery and fuel cell corresponding to the motor speed. The operating modes of converter at motoring and regeneration are presented. Finally, simulation results are presented to verify the reliability of proposed bi-directional converter.