• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.15 no.7
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• pp.551-556
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• 2003

The present study concerns an experiment on the heating characteristics of a system air-conditioner (A/C) using PWM method or inverter method at low temperature con-ditions. The compressors used are digital scroll type and BLDC inverter type. Under the low outside temperature condition, -5$^{\circ}C$, -1$0^{\circ}C$, -15$^{\circ}C$, heating capacities and COPs are mea-sured by the psychometric calorimeter using air enthalpy method. Also, outlet air temperatures at heating operation mode are measured at -5$^{\circ}C$, -1$0^{\circ}C$ and -15$^{\circ}C$. Experimental results show that COPs of the system A/C using a PWM method are more effective than those of the inverter method at heating operation mode. Although the heater is on, COPs of PWM method are similar to those of BLDC inverter method. Moreover, the heating capacities of PWM method at -5$^{\circ}C$, -1$0^{\circ}C$ and -15$^{\circ}C$ are larger about 10~20% and outlet air tempe-rature at -15$^{\circ}C$ is larger about 10%, compared to the inverter method.

• Journal of Electrical Engineering and Technology
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• v.9 no.6
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• pp.1914-1920
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• 2014

In this paper, characteristics of blushless direct current (BLDC) motor including core loss are analyzed considering pulse width modulation (PWM) of inverter. Input voltage of BLDC motor due to PWM is calculated considering duty ratio and carrier frequency of inverter in order to control torque or speed of BLDC motor. For the calculation of core loss, the input current with harmonics due to PWM voltage is calculated by using equivalent circuit model of BLDC motor according to switching pattern and carrier frequency. Next, core loss is analyzed by inputting the currents as a source of BLDC motor for FEM. Characteristics including core loss are compared with ones without PWM waveform according to reference speed.

• Journal of IKEEE
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• v.23 no.4
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• pp.1182-1186
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• 2019

This paper discussed the research results on the development and output characteristics of single-phase direct drive 20W BLDC motor with ADC converter. It is designed to drive the rotor through PWM inverter switching and position the back electromotive force of the motor electrically 30° ahead of the hall sensor phase angle signal to ensure optimum switching time. As a major result of the characteristics evaluation, the maximum inverter efficiency was 92[%], the system efficiency was 53.34[%,] and the motor efficiency was 57.85[%].

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.58 no.4
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• pp.391-396
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• 2009

In this paper, a control algorithm for DC-Link voltage unbalancing compensation of a four-switch inverter for a three-phase BLDC motor drive is proposed. Compared with a conventional six-switch inverter, the split source of the four-switch inverter can be obtained by splitting DC-link capacitor into two capacitors to drive the three phase BLDC motor. The voltages across each of two capacitors are not always equal in steady state because of the unbalance in the impedance of the DC-link capacitors $C_1$ and $C_2$ or the variable current flowed into the capacitor's neutral point in motor control. Despite the unbalance, if the BLDC motor may be run for a long time the voltage across one of the capacitors is more increased. So the unbalance in the capacitors voltages will be accelerated. As a result, The current ripple and torque ripple is increased due to the fluctuation of input current which flows into 3-phase BLDC motor. According to that, the vibration of motor will be increased and the whole system will be instable. This paper presents a control algorithm for DC-Link voltage unbalancing compensation. The sampling from the voltages across each of two capacitors is used to perform the voltage control of DC-Link by using the feedforward controller.

• Journal of Electrical Engineering and Technology
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• v.8 no.2
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• pp.295-303
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• 2013

This paper reports an investigation of pulse width modulation (PWM) techniques for two-phase brushless DC (BLDC) motors fed by a two-phase eight-switch inverter in a fan application. The three-phase BLDC motor is widely applied in industry; however, a lower-cost two-phase BLDC motor and drive circuit has been greatly in demand in recent years. In this paper, we introduce a mathematical model of the two-phase BLDC motor with sinusoidal back electromotive forces (EMFs) based on traditional three-phase BLDC motors. To simplify the drive algorithm and speed up its application, we analyze the principle of block commutation for a two-phase BLDC motor drive in the 180-electrical-degree conduction mode, and we further propose five PWM schemes to improve the commutation performance of the two-phase BLDC drive. The effectiveness of the proposed PWM methods is verified through experiments.

• Proceedings of the KIPE Conference
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• 2014.11a
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• pp.33-34
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• 2014

In this paper, the inverter switch losses of BLDC motor for three types of PWM method and power devices was analyzed. When BLDC motor is driven at low currents, inverter switch losses for MOSFET is low because MOSFET operates like resistance. But, inverter switch losses for IGBT is higher than MOSFET due to its large turn-off losses. For low power inverter with MOSFET, the power losses of unified PWM is lower than that of unipolar and bipolar PWM.

• The Transactions of the Korean Institute of Power Electronics
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• v.11 no.2
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• pp.164-171
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• 2006

In this paper, the fault tolerant system for BLDC motor has been proposed to maintain control performance under an open switch fault of inverter. The fault identification is proposed to two methods, which are using the difference between reference and actual current, and adding voltage sensors across lower legs of inverter. The reconfiguration scheme is achieved by the four-switch topology connecting a faulty leg to the middle point of DC-link using bidirectional switches. The proposed fault tolerant system quickly recovers control performance by short fault detecting time and reconfiguration of system topology. Therefore, continuous free operation of the BLDC motor drive system after faults is available. The superior performance of the proposed fault tolerant system is proved by simulation.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.5
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• pp.139-144
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• 2023

In order to obtain the maximum characteristics of motors such as torque and efficiency, all motors basically use universal inverters designed for each motor's characteristics. However, if you look at the recent research results, you can see cases of SRM(Switched Reluctance Motor) driving studies using 6-switch inverters, which are BLDC(Brushless DC Motor) universal inverters, and research cases of driving 3-phase BLDC motors using 4-switch inverters. Therefore, it is possible to search for research methods by approaching various methods of driving and control that can drive each motor apart from the existing universal inverter. In line with this research trend, in this paper, a C-dump type converter, which is an SRM drive converter, was applied as a drive driver for a BLDC motor, and its characteristics and possibilities were studied.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.15 no.9
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• pp.738-743
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• 2003

In the present study, the heating and cooling characteristics of system air-conditioner using a PWM compressor or a BLDC inverter compressor are investigated by the psychometric calorimeter using air enthalpy method. Cooling and heating capacities, power inputs and COPs are measured at the low, moderate, high loads under the cooling and heating standard conditions. At cooling conditions, the capacity of the PWM system is larger than that of the inverter case. Due to large power input, however, low COPs are measured under total load ranges. At heating conditions, the capacity of the PWM method is a little larger than that of the inverter case, except high load range. Since power input is low, large COPs are measured at moderate and high load ranges, which are different from cooling data. This shows that the PW system compared with the inverter case has good energy consumption efficiency at moderate and high load ranges except low load range. And when the system A/C is operated under the cooling and heating standard conditions, COPs are nearly uniform at total load ranges.

• Proceedings of the KIPE Conference
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• 2008.06a
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• pp.598-600
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• 2008

On this paper, digitally controlled flyback dc-dc converter and dc-ac inverter for bldc motor control are presented, which is used one processor. This system has 12V battery input for the flyback-converter, and the flyback-converter generates 30V output for BLDC motor inverter input. In order to compensate the flyback-converter, the transfer function of flyback converter is derived and digital PI compensator is adapted. Through bode diagram, stability of digital flyback-converter is analyzed. To verify the proposed system, digital simulation of the bldc motor drive using digital flyback-converter are performed.