Abstract: It is an object of the present invention to provide an excellent method for producing an excellent therapeutic agent. The solution of the present invention is as shown in the following scheme: wherein R1 represents a C1-C6 alkyl group, R2 represents a C1-C6 alkyl group, and R3 represents a C1-C6 alkyl group.

Abstract: It is an object of the present invention to provide an excellent method for producing an excellent therapeutic agent. The solution of the present invention is as shown in the following scheme: wherein R1 represents a C1-C6 alkyl group, R2 represents a C1-C6 alkyl group, and R3 represents a C1-C6 alkyl group.

Abstract: A motor driving apparatus and a refrigerator using the same is provided. The refrigerator may include a compressor, a motor, a driving unit, temperature sensing units sensing the temperatures of storage chambers and an external temperature, and a control unit selecting a driving mode of the driving unit based on the sensing result of the temperature sensing units and controlling the driving unit to drive the motor according to the selected driving mode. In a general operation mode, the control unit controls the driving unit to drive the motor in a 120 degree conduction method, and in a power-saving operation mode, the control unit controls the driving unit to drive the motor in a 90 degree conduction method. The refrigerator increases a pulse width of driving current by converting the conduction method of the motor to drive the motor at a low speed during power-saving operation of the refrigerator.

Abstract: A motor driving apparatus and a refrigerator using the same is provided. The refrigerator may include a compressor, a motor, a driving unit, temperature sensing units sensing the temperatures of storage chambers and an external temperature, and a control unit selecting a driving mode of the driving unit based on the sensing result of the temperature sensing units and controlling the driving unit to drive the motor according to the selected driving mode. In a general operation mode, the control unit controls the driving unit to drive the motor in a 120 degree conduction method, and in a power-saving operation mode, the control unit controls the driving unit to drive the motor in a 90 degree conduction method. The refrigerator increases a pulse width of driving current by converting the conduction method of the motor to drive the motor at a low speed during power-saving operation of the refrigerator.

Abstract: A compressor includes a motor driven by a controller and having a rotor and a stator, a compressing unit driven by the motor in a hermetic container in which refrigerant is filled. Driving the motor at a low rpm, the controller practices a feedback control which determines a timing of turning on/off switching elements based on a signal detecting a position of the rotor, and when the motor is driven at a high rpm, the controller practices an open-loop control which outputs a given frequency and drives the motor synchronizing with the given frequency. This structure achieves a compressor working with a fewer noises in PWM driving.

Abstract: A method of driving a brushless DC motor includes operations of rectifying an AC voltage of an AC power source by a rectifier circuit to which a capacitor is coupled between its output terminals and the AC voltage of the AC power source is input; driving the motor by an inverter coupled to the rectifier circuit; detecting a rotor position of the motor by a position detector based on a motor back electromotive force or a motor current; estimating the rotor position by a position estimator when the rotor position is not detectable by the position detector; and controlling the inverter by a controller based on the rotor position detected by the position detector or the rotor position estimated by the position estimator.

Abstract: A motor system includes a BLDC (brushless direct current) motor; an inverter driving the BLDC motor; a current detector detecting a direct current of the inverter; an induced voltage detector detecting an induced voltage of the BLDC motor; and a controller controlling at least one of an output voltage and an output frequency of the inverter based on the direct current detected by the current detector and the induced voltage detected by the induced voltage detector.

Abstract: A method of driving a brushless DC motor includes operations of rectifying an AC voltage of an AC power source by a rectifier circuit to which a capacitor is coupled between its output terminals and the AC voltage of the AC power source is input; driving the motor by an inverter coupled to the rectifier circuit; detecting a rotor position of the motor by a position detector based on a motor back electromotive force or a motor current; estimating the rotor position by a position estimator when the rotor position is not detectable by the position detector; and controlling the inverter by a controller based on the rotor position detected by the position detector or the rotor position estimated by the position estimator.

Abstract: A BLDC motor phase commutation method is provided, which can correctly detect phase commutation timing and position detection timing of a BLDC motor in a compressor to stabilize rotation and RPM of the compressor, thereby minimizing noise and vibration. When the BLDC motor rotates through a mechanical angle corresponding to one period, the BLDC motor operates according to a first scheme in which operation of the BLDC motor in the first phase commutation section of a period is performed in the same manner as in the last phase commutation section of a period immediately prior to the period. After the BLDC motor switches to sensorless mode, the BLDC motor operates according to a third scheme in which the first phase commutation section of a period has a time interval equal to the average of time intervals of first phase commutation sections of periods prior to the period.

Abstract: A motor drive inverter control apparatus includes a rectifier circuit for rectifying an AC power supply, an inverter circuit driven by an output from the rectifier circuit, a motor driven by an output from the inverter circuit, a first capacitor coupled in parallel to the output of the rectifier circuit, and a second capacitor coupled in parallel to the first capacitor via a diode. The second capacitor has capacitance not less than three times that of the first capacitor. Although the second capacitor shows a ripple content not less than 90% during practical use, it well absorbs regenerative energy produced by the motor. As a result, elements of the apparatus can be prevented from degrading caused by an over-voltage, and the apparatus can be downsized and reduced its cost.

Abstract: A method of controlling the speed of a BLDC (brushless direct current) motor and a method of controlling the cooling speed of a refrigerator using the same. A method of controlling the speed of a BLDC motor includes: inputting a driving signal having a predetermined reference current applying angle to the motor to achieve a predetermined reference speed; measuring a rotating speed of the motor; increasing a current applying angle of the driving signal if the measured rotating speed does not reach the reference speed and the driving signal has reached a maximum input of the motor; and inputting the driving signal having the increased current applying angle to the BLDC motor.

Abstract: The invention provides a refrigerator having a compressor, the refrigerator including: a motor driving the compressor; a motor driver supplying power to the motor; and a controller outputting a control signal corresponding to a second command speed to the motor driver, and outputting a control signal corresponding to a first command speed which is higher than the second command speed to the motor driver when a driving on/off ratio of the motor driver is maintained below a given reference driving on/off ratio for a given reference period. Accordingly, it is an aspect of the present invention to provide a refrigerator to operate a compressor stably and easily under overload or low voltage conditions, and a method for controlling the same.

Abstract: A Brushless Direct Current (BLDC) motor starting method and device are provided. With the method and/or device, startup noise and vibration and startup failure rate can be reduced using a constant low-speed startup scheme when the BLDC motor is in startup mode. Additionally, Pulse Width Modulation (PWM) duty is also maintained at low level when the BLDC motor starts up, thereby preventing excessive current from occurring due to desynchronization of the motor at startup, so that it is possible to optimize specifications of an inverter in the BLDC motor. The BLDC motor starts up with a synchronous speed and a PWM duty of a rotor of the BLDC motor being kept constant, and the BLDC motor switches to sensorless mode if a position of the rotor is detected a predetermined number of times or more during a specific time period.

Abstract: A motor controller, including: a power supply which supplies DC power; an inverter which converts the DC power into AC power to be supplied to a motor; a shunt resistor which connects the power supply and the inverter; and a controller which supplies a control signal to the inverter to drive the motor and determines an error of the inverter when it is determined that a size of voltage between both ends of the shunt resistor is less than a predetermined first reference value. Thus, a motor controller is provided which detects an error of an inverter more easily and precisely, and a control method thereof and an error detecting apparatus of an inverter.

Abstract: A method of controlling a three-phase brushless direct current (BLDC) motor, including (a) arranging a rotor of the three-phase BLDC motor by making a current flow to two of the three phases; (b) rotating the rotor through a phase shift; (c) detecting a position detecting point of time where a sign of an inductive electromotive voltage generated by a rotation of the rotor in a non-exciting phase is initially changed; and (d) calculating a rotation speed of the rotor based on a size of the inductive electromotive voltage of the non-exciting phase detected at the position detecting point of time. Thus, provided is a brushless direct current (BLDC) motor controller and a control method thereof which precisely detects a position detecting point of time of a rotor to determine a rotation speed of a rotor and minimizes noise and vibration during an initial drive of the three-phase BLDC motor.

Abstract: A motor drive inverter control apparatus includes a rectifier circuit for rectifying an AC power supply, an inverter circuit driven by an output from the rectifier circuit, a motor driven by an output from the inverter circuit, a first capacitor coupled in parallel to the output of the rectifier circuit, and a second capacitor coupled in parallel to the first capacitor via a diode. The second capacitor has capacitance not less than three times that of the first capacitor. Although the second capacitor shows a ripple content not less than 90% during practical use, it well absorbs regenerative energy produced by the motor. As a result, elements of the apparatus can be prevented from degrading caused by an over-voltage, and the apparatus can be downsized and reduced its cost.

Abstract: A rectangular wave or a waveform similar to the rectangular wave is output with an conductive angle no less than 120° but no more than 150° during low-speed operation, but output a rectangular wave, a sine wave or a waveform similar to them with an conductive angle no less than 130° but under 180° by changing the frequency only while maintaining the PWM duty constant at high-speed operation, making it possible to realize high-efficiency and low-noise operation at low-speed operation, secure stable high speed, and prevent peak current of effective current because the current waveform also comes closer to sine wave.

Abstract: A BLDC motor phase commutation method is provided, which can correctly detect phase commutation timing and position detection timing of a BLDC motor in a compressor to stabilize rotation and RPM of the compressor, thereby minimizing noise and vibration. When the BLDC motor rotates through a mechanical angle corresponding to one period, the BLDC motor operates according to a first scheme in which operation of the BLDC motor in the first phase commutation section of a period is performed in the same manner as in the last phase commutation section of a period immediately prior to the period. After the BLDC motor switches to sensorless mode, the BLDC motor operates according to a third scheme in which the first phase commutation section of a period has a time interval equal to the average of time intervals of first phase commutation sections of periods prior to the period.

Abstract: A Brushless Direct Current (BLDC) motor starting method and device are provided, in which startup noise and vibration and startup failure rate can be reduced using a constant low-speed startup scheme when the BLDC motor is in sensorless startup mode, and PWM duty is also maintained at low level when the BLDC motor starts up, thereby preventing an excessive current from occurring due to desynchronization of the motor at startup, so that it is possible to optimize specifications of an inverter in the BLDC motor. The BLDC motor starts up with a startup speed and a PWM duty of a rotor of the BLDC motor being kept constant, and the BLDC motor switches to sensorless mode if a position of the rotor is detected a predetermined number of times or more during a specific time.

Abstract: A rectangular wave or a waveform similar to the rectangular wave is output with an conductive angle no less than 120° but no more than 150° during low-speed operation, but output a rectangular wave, a sine wave or a waveform similar to them with an conductive angle no less than 130° but under 180° by changing the frequency only while maintaining the PWM duty constant at high-speed operation, making it possible to realize high-efficiency and low-noise operation at low-speed operation, secure stable high speed, and prevent peak current of effective current because the current waveform also comes closer to sine wave.