JP2010124584A - Motor control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem, wherein in a motor control device in which the motor drive is executed by directly switching an AC voltage, when motor start-up is to be executed, since an applied voltage always varies, the motor start-up fails due to inappropriate start-up timing. <P>SOLUTION: A motor control device includes at least either one of a voltage detecting part 10 for detecting a voltage value applied to an inverter main circuit 3 and a phase calculating part 11 for calculating an AC power-supply phase; and a start-up timing determination part 12, that determines the timing for starting up a motor 7 by a start-up part 9 while using a calculation result or a detection result of at least either one of a detected value from the voltage detecting part 10 and a calculated value from the phase calculating part 11. Consequently, it is possible to realize sure motor start-up in the motor control device, in which an applied voltage to the inverter main circuit 3 always varies. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to starting a motor in a motor control device capable of driving a three-phase motor at a variable speed from a single-phase AC power source.

  Conventionally, since this type of motor activation does not cause a start-up failure, motor driving is started after positioning processing (see, for example, Patent Document 1).

  FIG. 6 is a block diagram of a conventional motor control device described in Patent Document 1.

  As shown in FIG. 6, a conventional motor control device includes an AC power source 1, a rectifier circuit 2 for converting AC voltage to DC voltage, a capacitor 4 for smoothing the output of the rectifier circuit, and a brushless sensorless DC motor. 7, an inverter circuit 3 that bridges a plurality of semiconductor switches and diodes and converts a DC voltage into an AC voltage, a position detection means 13 that detects the magnetic pole position of the rotor, and a commutation means 14 that drives the inverter circuit. The brushless / sensorless DC motor is controlled by the starter 15 for starting the brushless / sensorless DC motor and the energization control of the AC power source or the inverter circuit based on the signals from the position detection unit and the starter. Or it is comprised from the control means 16 which controls a rotation speed.

  Hereinafter, the starting operation will be described with reference to FIG.

When starting the brushless / sensorless DC motor, if the motor controller is energized, a positioning current is applied between the two Y-connected phases of the brushless / sensorless DC motor, and then a different Y-shape from the energized two-phase A motor is started by applying a positioning current between the connected two phases.
JP 2004-328850 A

  However, when the voltage applied to the inverter circuit fluctuates in the motor start-up with the conventional configuration, the start-up failure is caused by starting the motor below the voltage required to obtain the torque required for motor start-up. It had the problem of generating.

  The present invention solves the above-described conventional problems, and even when the voltage applied to the inverter circuit fluctuates, stable start-up can be achieved by adjusting the start-up timing according to the voltage value applied to the inverter circuit and the power supply phase. An object is to provide a motor control device to be realized.

In order to solve the above-mentioned conventional problems, the motor control device of the present invention includes a bidirectional switching element capable of bidirectionally controlling an AC power supply output from a single-phase AC power supply, and directly switches bidirectionally. The inverter main circuit that drives the motor by the AC output of the variable voltage / variable frequency obtained in this way, the drive control unit that performs on / off control of the switching element of the inverter main circuit, and the motor is stopped by the drive control unit In a motor control device including an activation unit that is driven from a state, at least one of a voltage detection unit that detects a voltage value applied to the inverter main circuit, a phase calculation unit that calculates an AC power supply phase, and the voltage detection unit Detection value of at least one of the detection value of the phase calculation unit and the detection result of the phase calculation unit. Those having a start timing determination unit for determining a ring.

  As a result, in the motor control device to which a varying voltage is applied to the inverter main circuit, it is possible to suppress the occurrence of starting failure due to voltage shortage and torque abnormality.

  The motor control device of the present invention can suppress the occurrence of starting failure due to voltage shortage and torque abnormality even when AC power is directly input to the inverter main circuit.

A first invention includes a single-phase AC power supply and a bidirectional switching element capable of bidirectionally controlling the AC power supply output in a bidirectional manner, and a variable voltage / variable frequency alternating current obtained by direct bidirectional switching. An inverter main circuit for driving a motor by an output; a filter unit installed between the inverter main circuit and the single-phase AC power supply; a drive control unit for performing on / off control of a switching element of the inverter main circuit; In a motor control device comprising an activation unit that drives the motor from a stopped state by a drive control unit,
Timing at which the motor is activated by the activation unit using at least one of a voltage detection unit for detecting a voltage value applied to the inverter main circuit and a phase calculation unit for calculating an AC power supply phase using the detection and calculation results By providing the start timing determining unit for determining the motor, even when the voltage applied to the inverter main circuit pulsates in a half cycle of the AC power source, the motor can be started at a timing that does not cause the motor start failure.

  According to a second aspect of the present invention, in the motor control device according to the first aspect, the phase calculation unit includes a zero voltage to zero voltage, a zero voltage and a maximum voltage value or a minimum voltage value, and a maximum voltage value to a maximum in the AC power supply output. Power supply due to AC power supply voltage distortion by performing AC power supply phase calculation using at least one of the average times between the voltage values, between the minimum voltage value and the minimum voltage value, and between the maximum voltage value and the minimum voltage value. The influence on the phase calculation can be suppressed.

  According to a third aspect of the present invention, in the motor control device according to the first aspect, the start timing determining unit is configured such that the absolute value of the voltage value detected by the voltage detection unit is within a preset voltage value range. By setting the timing to start the motor, it is possible to start the motor in a state where the minimum voltage required for starting the motor is applied to the inverter main circuit.

  According to a fourth aspect of the present invention, in the motor control device of the first aspect, the activation timing determination unit is configured to activate the motor when the power supply phase detected by the phase detection unit is within a preset range. As a result, in the state where the voltage detection period by the voltage detection unit is long and the voltage applied to the inverter main circuit is constantly fluctuating, even if it is not possible to detect within the predetermined voltage range, the most torque is given to the motor. The motor can be started at the timing.

  According to a fifth aspect of the present invention, in the motor control device of the first aspect, the start timing determination unit is a voltage detected by the voltage detection unit within a range in which the power supply phase calculated by the phase calculation unit is set in advance. Even when the voltage applied to the inverter main circuit constantly fluctuates by using the timing for starting the motor when the absolute value of the value is within a preset voltage value range, the voltage detector is used. The motor can be started in a state where the minimum voltage necessary for starting the motor is applied to the inverter main circuit with a smaller number of voltage detections.

According to a sixth aspect of the present invention, in any one of the first to fifth motor control devices, the starter starts driving the motor at a timing determined by the start timing determining unit after positioning. A reliable motor start can be realized.

  According to a seventh invention, in any one of the first to sixth motor control devices, the bidirectional switching element provided in the inverter main circuit is made of GaN having at least one of a normally-off type and a double gate type. Therefore, it is possible to reduce conduction loss in the inverter main circuit, increase efficiency by high-speed switching, and improve device reliability.

  According to an eighth invention, in any one of the first to seventh motor control devices, the filter unit is connected in series to at least one line between the AC power source and the inverter main circuit, and an inverter of the reactor It is composed of capacitors connected in parallel between the main circuit side lines, and the capacitance value and reactance value are determined so that the resonance frequency is 40 times or more of the AC power supply frequency, thereby improving the power supply harmonic characteristics of the input current. Performance can be realized.

  According to a ninth aspect of the present invention, by providing any one of the first to eighth motor control devices in the air conditioner, high reliability without starting failure is realized in an inexpensive and high-efficiency device having no rectifier circuit. be able to.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 shows a configuration diagram of a motor control device according to an embodiment of the present invention.

  The motor control device of FIG. 1 is supplied with electric power from a single-phase AC power source 1 and has a bidirectional switching without directly passing the supplied AC voltage through a rectifier circuit 2 composed of a diode bridge. An inverter main circuit 3 for converting the frequency into AC output, a filter unit 6 including a capacitor 4 and a reactor 5 installed between the inverter main circuit 3 and the single-phase AC power source 1, and the inverter main circuit 3. A motor 7 driven by output, a drive control unit 8 composed of a microcomputer or the like that performs on / off control of the bidirectional switching element of the inverter main circuit 3, and the motor from the stop state by the drive control unit 8 A starting unit 9 to be driven, a voltage detecting unit 10 for detecting a voltage value applied to the inverter main circuit 3, and a phase calculating unit 11 for calculating an AC power supply phase. , The detection, and a start timing determination section 12 for determining the timing for starting the motor 7 by the starting unit 9 by using an arithmetic result.

  Here, the filter unit 6 connected between the AC power supply 1 and the inverter main circuit 3 is a switching noise generated from the inverter main circuit 3 set so that the resonance frequency is 40 times or more of the AC power supply frequency. Are connected in series as a snubber for the inverter main circuit 3 and a reactor 5 connected in series to prevent the leakage to the input side (AC power supply 1). The capacitor 4 is connected to the inverter main circuit 3 side from the reactor 5.

  About the motor control apparatus comprised as mentioned above, the operation | movement and an effect | action are demonstrated below. FIG. 4 and FIG. 5 are operation waveforms of each part in the present embodiment.

  First, when a commercial power supply with an AC power supply frequency fac = 50 Hz or 60 Hz is used as the AC power supply 1, the output voltage waveform is a sinusoidal waveform with a period Tac = 20 msec or 16.7 msec as shown in FIG. Become. Reactor 5 and capacitor 4 (resonance value 0.5 mH, capacitance value 10 μF, resonance frequency fc = 1 / (2π * √ (LC) = 2250 Hz> 40 * fac (= 50 Hz)) to be supplied to the inverter main circuit 3.

  Here, the input current waveform to the inverter main circuit 3 is a current waveform in which the switching waveform is superimposed as shown in FIG. Therefore, by connecting the reactor 5 in series between the AC power source 1 and the inverter main circuit 3, the current waveform on the AC power source 1 (input) side becomes a current waveform from which the switching component is removed as shown in FIG. Further, by setting the resonance frequency with the capacitor 4 to be 40 times or more of the AC power supply frequency, it is possible to realize high performance of the input current with respect to the international standard of power supply harmonic current regulation.

  Further, the parasitic capacitance of the inverter main circuit 3 is C0, and the capacitor 4 having the capacitance C (C >> C0) is compared with the inverter when an abnormal voltage surge having a peak value V0 is applied (FIG. 5A). By connecting in parallel to the main circuit 3, a steep voltage surge can be absorbed and reduced to V0 * C0 / C (FIG. 5B), and the inverter main circuit 3 can be prevented from being broken as a snubber.

  Next, the start to drive from the motor stop state will be described with reference to FIGS. When the motor is driven by directly switching the voltage supplied from the AC power source 1 without rectifying and smoothing, the voltage applied to the inverter main circuit 3 fluctuates in the AC power source cycle as shown in FIG. Therefore, after starting to energize the motor control device 301, a positioning current is energized 302 between two phases (for example, between U and W) for positioning, and further, a positioning current between two phases (for example, between U and V) different from the two phases. When the motor is started, it is determined 304 whether the power phase θ by the phase calculation unit 11 is within a predetermined power phase range (D1 ≦ θ ≦ D2, D3 ≦ θ ≦ D4).

  If it is out of the predetermined power supply phase range, the positioning operation is continued. If it is within the predetermined power supply phase range, it is determined 305 whether or not the absolute value of the voltage detection value Vrs from the voltage detection unit 10 is within the predetermined range (Va ≦ abs (Vrs) ≦ Vb). If it is outside the predetermined voltage value range, the positioning operation is continued. When it is within the predetermined voltage value range, the start timing determination unit 12 determines that it is time to start the motor 306, and motor start by the start unit 9 and the drive control unit 8 is started.

  That is, when a voltage as shown in FIG. 2 is applied to the inverter main circuit 3, the activation timing determination unit 12 sets the power supply phase D1a ≦ θ ≦ D2a and D3a ≦ θ ≦ D4a as the motor activation start timing.

  Note that the activation timing determined by the activation timing determination unit 12 may be determined only by the AC power supply phase calculated by the phase calculation unit 11 or only by the voltage value detected by the voltage detection unit 10.

  However, when the start timing is determined based on the voltage value detected by the voltage detection unit 10, the motor is not started if a voltage value within a predetermined range cannot be detected for a predetermined period (for example, one cycle of the AC power supply).

  Further, the bidirectional switching element included in the inverter main circuit 3 is composed of GaN having at least one of a normally-off type and a double gate type, thereby reducing conduction loss by reducing operating resistance in the inverter main circuit 3 and by high-speed switching. Switching loss can be reduced and the reliability of the device can be improved.

As described above, in the present embodiment, the phase calculation unit 11 that calculates the phase of the AC voltage applied to the inverter main circuit 3, the voltage detection unit 10 that detects the applied voltage value, and the calculated value and detection By providing the start timing determination unit 12 that determines the timing to start the motor 7 that has stopped based on the value, the rectifier circuit 2 is not provided, thereby realizing downsizing, cost reduction, and high efficiency of the entire apparatus. A reliable motor start-up can be realized.

  As described above, since the motor control device according to the present invention does not require a rectifier circuit, such as a compressor that requires reduction in size, cost, and efficiency of the device and motor start without a sensor. Since the start-up operation can be performed reliably, it can be applied to any device equipped with a compressor such as an air conditioner.

The block block diagram of the motor control apparatus in embodiment of this invention Voltage waveform diagram applied to the inverter main circuit in the embodiment of the present invention Schematic showing the flow of the motor starting in embodiment of this invention Operation waveform diagram of each part of the inverter device in the embodiment of the present invention Operation waveform diagram of each part of the inverter device in the embodiment of the present invention Block diagram of a conventional motor control device Schematic showing the flow of motor startup in a conventional motor control device

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 AC power supply 2 Rectifier circuit 3 Inverter main circuit 4 Capacitor 5 Reactor 6 Filter part 7 Motor 8 Drive control part 9 Start-up part 10 Voltage detection part 11 Phase calculation part 12 Start-up timing determination part 13 Position detection part 14 Commutation means 15 Start-up means 16 Control means

Claims (9)

Inverter with a bi-directional switching element capable of bi-directionally controlling the AC power output from a single-phase AC power source, and driving the motor with AC output of variable voltage and variable frequency obtained by direct bi-directional switching A main circuit; a filter unit installed between the inverter main circuit and the single-phase AC power supply; a drive control unit that performs on / off control of switching elements of the inverter main circuit; and the motor by the drive control unit. A motor control device including an activation unit that is driven from a stopped state,
Timing at which the motor is activated by the activation unit using at least one of a voltage detection unit for detecting a voltage value applied to the inverter main circuit and a phase calculation unit for calculating an AC power supply phase using the detection and calculation results A motor control device comprising a start timing determining unit for determining The phase calculation unit is an AC power supply output between zero voltage and zero voltage, between zero voltage and maximum voltage value or minimum voltage value, between maximum voltage value and maximum voltage value, between minimum voltage value and minimum voltage value, and maximum voltage value. 2. The motor control device according to claim 1, wherein the AC power supply phase calculation is performed using at least one of a plurality of average time values between the first voltage value and the minimum voltage value. The said starting timing determination part is set as the timing which starts the said motor when the absolute value of the voltage value detected by the said voltage detection part is in the preset voltage value range. Motor control device. The motor control device according to claim 1, wherein the start timing determination unit sets a start timing of the motor when a power supply phase calculated by the phase calculation unit is within a preset range. When the absolute value of the voltage value detected by the voltage detector is within a preset voltage value range within the range in which the power supply phase calculated by the phase calculator is preset, The motor control apparatus according to claim 1, wherein the motor control timing is a timing for starting the motor. 6. The motor control device according to claim 1, wherein the starting unit starts motor driving at the timing determined by the starting timing determining unit after positioning. The motor control device according to any one of claims 1 to 6, wherein the bidirectional switching element included in the inverter main circuit is made of GaN having at least one of a normally-off type and a double gate type. The filter unit includes a reactor connected in series to at least one line between the AC power source and the inverter main circuit, and a capacitor connected in parallel between the inverter main circuit side lines of the reactor, and the resonance frequency is AC. The motor control device according to any one of claims 1 to 7, wherein the reactance value and the capacitance value are determined so as to be 40 times or more of a power supply frequency. The motor control device according to at least one of claims 1 to 8, which is provided in an air conditioner.

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