Il-Kuen Won

Performance improvement of IPMSM using finite predictive current control for EV

PMSM (Permanent Magnet Synchronous Motor) is mainly used in electric vehicle because of its high efficiency. Among them, IPMSM (Interior Permanent Magnet Synchronous Motor) has more wide speed range in flux-weakening region than that of SPMSM (Surface Mounted Permanent Magnet Synchronous Motor) because of torque efficiency per unit volume and wide torque out range of IPMSM. Therefore, IPMSM is the most commonly used in the automotive industry as a motor for EV driving. In electric vehicle, the torque output is determined variably and instantly corresponding to the operation of the accelerator and the brake of driver. So, the torque transient periods whose torque reference is variable are generated very frequently in accordance with a variable speed. Therefore, in this paper, improving method of torque response in a transient period for electric vehicle is explained. The current reference of IPMSM is output using 2D-LUT. Also, in order to complement the disadvantages of PI controller of conventional field oriented control, the predictive current control is used, improving torque response at torque transient period.

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.

Position sensorless control method of IPMSM applying three shunt sensing PWM inverter using predictive current

In this paper, position sensorless control method of IPMSM applying three shunt sensing PWM inverter using predictive current for phase current reconstruction and EMF calculation is proposed. Considering the price and volume of the system, a motor drive system applied with shunt and sensorless has been recently studied. However, there is some area that cannot measure three phase current especially in high-speed motor operation where the MI (Modulation index) is increased. It deteriorates the control stability because of the phase current distortion in motor control. In this paper, the boundary where phase currents cannot be obtained is defined and the method for reconstructing the phases current are proposed by predicting phase current in the area which phase current measurement is impossible. Also, the EMF observer and synchronous voltage recalculation method are applied for sensorless control considering both linear area and over-modulated area.

Novel DC-link voltage variation method for interior permanent magnet synchronous motor drive system with high-efficient DC-DC converter

In this paper, a novel DC-link voltage variation method using a high-efficiency dc-dc converter for the three-phase-inverter of IPMSM(Interior Permanent Magnet Synchronous Motor) is proposed. The proper variation method of DC-link voltage is needed to reduce the torque ripple of IPMSM and, switching loss of the inverter. Also, to meet the high-efficiency requirement of the DC-DC converter with the proposed method and, regenerative operation requirements of the motor-driver, a novel DC-DC converter is proposed. Simulation results are given to verify the reliability of the proposed DC-link variation method and DC-DC converter.

Three Phase Current Reconstruction Method of Three Shunt Sensing 3-Phase Inverter by Predictive Current Technique

The measurement of three-phase current is important to control the instantaneous torque of a interior permanent magnet synchronous motor(IPMSM) using a three-phase inverter. Therefore, shunt resistors are used in low-cost motor-driving systems to measure three-phase current instead of additional current sensors that are too expensive for these systems. However, in certain regions of a space vector plane, shunt resistors cannot reconstruct three-phase current in high-speed driving mode. In this paper, predictive current control is used to compensate for the three-phase current in those regions, which results in a reduction of current ripple in a three-shunt sensing inverter(TSSI) and torque ripple in IPMSM.

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.

Design and control of power conversion system for ISG

In this paper, design and control method of power conversion system for the 48[V] ISG system is proposed. Proposed ISG system is consist of bi-directional DC/DC converter, bi-directional DC/AC inverter, ISG motor, and 48 [V] and 12[V] batteries. There are three modes of integrated operation including initial start-up and 48[V] and 12[V] battery. Simulation and experimental results are given to verify the reliability of proposed ISG system.

Lifetime management method of Lithium-ion battery for energy storage system

Recently, the mass production of Energy storage system (ESS) is actively perform around world. Energy storage system is a technique that stores power to energy storage device to supply energy into grid and load at peak-load. Therefore, the efficient energy management is available by using ESS system. The life of Lithium-ion battery is varied corresponding to the power usage, especially selected depth of discharge (DOD). The lifetime of battery is the one of the most issue of the ESS system because of its stability and reliability. Therefore, lifetime management of battery and power converter of ESS module is required. In this paper, the battery lifetime management method estimating residual power and lifetime of lithium ion battery of ESS system is proposed. Also, total avenue prediction of ESS system is simulated considering the total lifetime of battery.

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.