• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2004년도 전력전자학술대회 논문집(2)
• /
• pp.769-773
• /
• 2004

Conventional SVPWM method has null switching vectors. Null switching vectors cause high common-mode voltage in induction motor drive system. The newly developed common mode voltage reduction PWM technique don't use zero switching state for inverter control. It is realized by changing software without additional hardware. Simulation and experimental results show that proposed method are reduced common mode voltage more than conventional method.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2011년도 제42회 하계학술대회
• /
• pp.1141-1142
• /
• 2011

An electrical vehicle (EV) is a huge issue in the automotive industry. The EV have many electrical units: electric motors, batteries, converters, ets. The DC power distribution system (PDS) is essential for the EV. The DC PDS offers many advantages. However, multiple loads in the DC PDS may affect the severe instability on the DC bus voltage. Therefore, a voltage bus conditioner (VBC) may use the DC PDS. The VBC is used to mitigate the voltage transient on the bus. In this paper, sliding mode controller (SMC) is designed for the VBC of DC PDS in the EV. The simulation results by PISM simulation package are presented for validating the proposed control technique.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2007년도 추계학술대회 논문집
• /
• pp.218-220
• /
• 2007

A new 3-phase voltage disturbance generator is proposed. The voltage drop of the conventional generator in normal mode can be reduced significantly. The output voltage of the proposed generator is constant in normal mode and the efficiency of the series transformer is improved. The proposed generator has good feature of simple structure, cost effective implementation, high reliability, high efficiency, and easy control. The usefulness of the scheme is verified through simulation and experiments.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2004년도 ICEIC The International Conference on Electronics Informations and Communications
• /
• pp.221-224
• /
• 2004

This paper proposed an ultra low-power CMOS exponential voltage-mode circuit using the Pseudo-exponential function for realizing the exponential characteristics. The proposed circuit provides high dB-linear output voltage range at low-voltage applications. In a $0.25\;\mu m$ CMOS process, the simulations show more than 35 dB output voltage range and 26 dB with the linearity error less than $\pm0.5\;dB.$ The average current consumption is less than 80 uA. The proposed circuit can be used for the design of an extremely low-power variable gain amplifier (VGA) and automatic gain control (AGC).

• 조명전기설비학회논문지
• /
• 제30권3호
• /
• pp.65-72
• /
• 2016

This paper discussed the LCL-type & Isolated bidirectional dc-dc converter(BDC) with dual full bridge inverter. In order to verify the analysis of the BDC, Experimental prototype has been designed and implemented to supply constant voltage regardless of loads and proposed a method to select switching frequency that depended on two inductors' inductance ratio and transformer parameters. The proposed converter has been composed of LCL resonant network with unit inductance ratio ($L_r/L_f$=1) and then operated with fixed duty, 50% duty ratio and fixed frequency. There are some characteristics that input voltage and output voltage of the BDC is nearly identical and zero voltage turn-on switching is possible in forward and reverse mode. Finally, it has been showed that BDC is possible to commutate operating mode normally and provide constant output voltage in selected switching frequency.

• 대한기계학회논문집
• /
• 제19권6호
• /
• pp.1371-1381
• /
• 1995

A novel hybrid control scheme to actively control the endpoint position of a very flexible single-link manipulator is proposed. The control scheme consists of a motor mounted at the beam hub and a piezofilm actuator bonded to the surface of the flexible link. The control torque of the motor to produce a desired motion is firstly determined by employing the sliding mode control theory on the equation of motion of the rigid link having the same mass as that of the proposed flexible link. The torque is then applied to the flexible manipulator in order to activate the commanded motion. During the motion, undesirable oscillation is actively suppressed by applying a feedback control voltage to the piezofilm actuator. Consequently, the imposed desired position is accomplished. In order to demonstrate high control performances accrued from the proposed method, computer simulations are undertaken by treating both regulating and tracking control problems.

• Journal of Power Electronics
• /
• 제15권6호
• /
• pp.1601-1608
• /
• 2015

This paper presents a PQ control strategy for micro grid inverters with axial voltage regulators. The inverter works in the voltage-controlled mode and can help improve the terminal power quality. The inverter has two axial voltage regulators. The 1st regulator involves the output voltage amplitude and output impedance, while the 2nd regulator controls the output frequency. The inverter system is equivalent to a controllable voltage source with a controllable inner output impedance. The basic PQ control for micro grid inverters is easy to accomplish. The output active and reactive powers can be decoupled well by controlling the two axial voltages. The 1st axial voltage regulator controls the reactive power, while the 2nd regulator controls the active power. The paper analyses the axial voltage regulation mechanism, and evaluates the PQ decoupling effect mathematically. The effectiveness of the proposed control strategy is validated by simulation and experimental results.

• Journal of Electrical Engineering and Technology
• /
• 제10권5호
• /
• pp.1989-2000
• /
• 2015

In this paper, digital peak current mode control for single phase H-bridge inverters is developed and implemented. The digital peak current mode control is achieved by directly controlling the PWM signals by cycle-by-cycle current limitation. Unlike the DC-DC converter where the output voltage always remains in the positive region, the output of DC-AC inverter flips from positive to negative region continuously. Therefore, when the inverter operates in negative region, the control should be changed to valley current mode control. Thus, a novel control logic circuit is required for the function and need to be analyzed for the hardware to track the sinusoidal reference in both regions. The problem of sub-harmonic instability which is inherent with peak current mode control is also addressed, and then proposes the digital slope compensation in constant-sloped external ramp to suppress the oscillation. For unipolar PWM switching method, an adaptive slope compensation in digital manner is also proposed. In this paper, the operating principles and design guidelines of the proposed scheme are presented, along with the performance analysis and numerical simulation. Also, a 200W inverter hardware prototype has been implemented for experimental verification of the proposed controller scheme.

• Journal of Power Electronics
• /
• 제15권1호
• /
• pp.54-64
• /
• 2015

This paper presents a current sensorless maximum power point tracking (MPPT) control method for dual-mode photovoltaic (PV) module-type interleaved flyback inverters (ILFIs). This system, called the MIC (Module Integrated Converter), has been recently studied in small PV power generation systems. Because the MIC is an inverter connected to one or two PV arrays, the power system is not affected by problems with other inverters. However, since the each PV array requires an inverter, there is a disadvantage that the initial installation cost is increased. To overcome this disadvantage, this paper uses a flyback inverter topology. A flyback inverter topology has an advantage in terms of cost because it uses fewer parts than the other transformer inverter topologies. The MPPT control method is essential in PV power generation systems. For the MPPT control method, expensive dc voltage and current sensors are used in the MIC system. In this paper, a MPPT control method without current sensor where the input current is calculated by a simple equation is proposed. This paper also deals with dual-mode control. Simulations and experiments are carried out to verify the performance and effectiveness of the proposed current sensorless MPPT control method on a 110 [W] prototype.

• Journal of Power Electronics
• /
• 제9권4호
• /
• pp.553-566
• /
• 2009

In-phase control and energy-optimized control are the two major control strategies proposed for series power quality controllers (SPQC). However quantitative analysis and comparison between these two control strategies is quite limited in previous publications. In this paper, an extensive quantitative analysis is carried out on these two control strategies through phasor diagram approach, and a detailed quantitative comparison is conducted accordingly. The load current is used as the reference phasor, and this leads to a simpler and clearer phasor diagram for the quantitative relationship. Subsequently detailed analysis of SPQC using in-phase control and energy-optimized control are provided respectively, under different modes both for under voltage/voltage sag and for over voltage/voltage swell. The closed form analytic expressions and the curves describing SPQC compensation characteristics are obtained. The detailed system power flow is figured out for each mode, and the detailed quantitative comparison between the two control strategies is then carried out. The comparison covers several aspects of SPQC, such as required compensating voltage magnitude, required capacity of energy storage component, and maximal ride-through time. In the end, computer simulation and prototype experimental results are shown to verify the validity of all the analysis and the result of the comparison.