JP2012161213A - Motor driving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the rotation number of a motor before activation by using a simple method.SOLUTION: A motor driving device 20 comprises: an inverter 25; a voltage detection part 23; and a rotation number estimation circuit 28. The inverter 25 generates driving voltages SU, SV, SW for driving a fan motor 51 by using a post-smoothing voltage Vfl, which is a voltage smoothed by a smoothing capacitor 22, to output the driving voltages SU, SV, SW to the fan motor 51. The voltage detection part 23 detects a value of the post-smoothing voltage Vfl before activating the fan motor 51. The rotation number estimation circuit 28 estimates the rotation number of the fan motor 51 before activation based on the detection result of the voltage detection part 23.

Description

  The present invention relates to a motor drive device.

  The outdoor unit of the heat pump apparatus includes various devices such as a compressor, a fan, and a heat exchanger. As a driving source for the compressor and the fan, for example, a brushless DC motor is used. In order to perform heat exchange in the outdoor unit, the outdoor unit has a structure in which air is sent to the heat exchanger by rotation of the fan.

  By the way, the fan of the outdoor unit may have already been rotated by the influence of wind or the like before the motor is started. If the fan is rotating before the motor is started, air may be sent to the heat exchanger inside the outdoor unit, and it may not be necessary to drive the motor. Therefore, it is desirable to know the number of rotations of the motor before startup.

  As a method for grasping the rotational speed of the motor before starting, for example, there is one disclosed in Patent Document 1 (Japanese Patent Laid-Open No. 7-337080).

  In the method according to Patent Document 1, the rotational speed of the fan before startup is detected based on the induced voltage generated by the rotation of the motor composed of a plurality of phases, that is, the inter-terminal voltage. However, the method according to Patent Document 1 requires a detection circuit for detecting the voltage between the terminals of the motor.

  The signal format of the detection result output from the detection circuit is generally an analog signal. Therefore, a detection result input terminal capable of corresponding to the signal format of the result is required on the control unit side such as a CPU that controls the drive of the motor using the detection result from the circuit. In addition, if the detection result input terminal is not provided on the control unit side, an A / D converter for converting the detection result into a signal format that can be used by the control unit for calculation is provided in the control unit. It will be necessary separately.

  Therefore, an object of the present invention is to grasp the number of rotations of the motor before starting by a simple method.

  A motor drive device according to a first aspect of the present invention includes a first inverter, a voltage detection unit, and a rotation speed estimation unit. A 1st inverter produces | generates the 1st drive voltage for driving a motor using the voltage after smoothing which is the voltage smoothed by the 1st smoothing capacitor, and outputs it to a motor. The voltage detector detects the value of the smoothed voltage before starting the motor. A rotation speed estimation part estimates the rotation speed of the motor before starting based on the detection result by a voltage detection part.

  When the motor is a fan motor of a brushless DC motor, if a motor that has not been started is already rotating under the influence of wind or the like, an induced voltage is generated from the motor, and this induced voltage is first smoothed. Applied to the capacitor. Therefore, this motor drive device estimates the rotation speed of the motor on the basis of the value of the voltage after the smoothing by the first smoothing capacitor before starting the motor. Therefore, it is not necessary to directly detect the rotational speed of the motor itself, and it is possible to know the rotational speed of the motor before starting by monitoring only the smoothed voltage. Therefore, the rotational speed of the motor before start-up can be grasped by a simple method, and high-performance motor drive control according to the rotational state can be performed using the grasped rotational speed.

  In the motor drive device according to the second aspect of the present invention, in the motor drive device according to the first aspect, the first smoothing capacitor smoothes the DC power supplied from the DC power supply unit. And a motor drive device is further provided with the 1st interception part. The first blocking unit blocks the supply of DC power from the DC power supply unit to the first smoothing capacitor before starting the motor.

  According to this motor drive device, the DC power is not supplied to the first smoothing capacitor by the first cutoff unit before the motor is started. In this state, the voltage after smoothing by the first smoothing capacitor is detected, and the rotational speed of the motor before starting is estimated. Therefore, only the induced voltage generated by the motor is applied to the first smoothing capacitor, and the smoothed voltage is a value that purely reflects the rotational speed of the motor before startup. Therefore, the rotational speed of the motor can be directly estimated from the smoothed voltage.

  The motor drive device according to a third aspect of the present invention is the motor drive device according to the second aspect, wherein the first interrupting portion has an inrush current suppressing portion. The inrush current suppression unit suppresses the inrush current from flowing through the first smoothing capacitor immediately after the DC power source starts to be supplied to the first smoothing capacitor.

  Immediately after the DC power supply is supplied to the first smoothing capacitor, no electric charge is stored in the capacitor. Therefore, an inrush current flows through the first smoothing capacitor, and the first smoothing capacitor may be damaged. However, according to the motor drive device, since the first interrupting unit has the inrush current suppressing unit for suppressing such inrush current, the first smoothing capacitor is prevented from being damaged by the inrush current. be able to.

  A motor drive device according to a fourth aspect of the present invention is the motor drive device according to any one of the second to fourth aspects, wherein the DC power supply unit uses an AC voltage output from a commercial power supply. It generates a DC power supply. And a 1st interruption | blocking part isolate | separates a commercial power supply and a 1st inverter by interrupting | blocking supply to the 1st smoothing capacitor of DC power supply further, when abnormality generate | occur | produces in an apparatus.

  According to this motor drive device, the first shut-off unit shuts off the DC power supply from the DC power supply unit to the first smoothing capacitor not only before the motor is started but also when an abnormality occurs in the outdoor unit. Therefore, it is not necessary to provide a switch for shutting off the supply of direct-current power when the device malfunctions, separately from the first shut-off unit.

  A motor drive device according to a fifth aspect of the present invention is the motor drive device according to any one of the first and fourth aspects, wherein the motor is a drive source of the fan. The fan is one of the devices included in the outdoor unit of the heat pump device.

  This motor drive device can easily grasp the number of rotations when the fan is rotating from the start-up due to the influence of wind or the like.

  A motor drive device according to a sixth aspect of the present invention is the motor drive device according to any one of the first to fifth aspects, further comprising a first determination unit. The first determination unit determines whether or not the rotation speed of the motor before startup estimated by the rotation speed estimation unit is greater than or equal to a first predetermined rotation speed. And a 1st inverter outputs a 1st drive voltage to a motor, when the rotation speed of the motor before starting is less than a 1st predetermined rotation speed. The first inverter does not output the first drive voltage to the motor when the rotational speed of the motor before startup is equal to or higher than the first predetermined rotational speed.

  In a state where the motor before starting is already rotating due to the influence of wind or the like, if the rotation speed is equal to or higher than the first predetermined rotation speed, sufficient air has already been sent to the heat exchanger in the outdoor unit. Therefore, since the function as a heat exchanger of the heat pump device can be sufficiently obtained, the motor drive device does not intentionally start the motor. On the other hand, if the rotational speed is less than the first predetermined rotational speed, the motor drive device assumes that the amount of air sent to the heat exchanger in the outdoor unit is insufficient even if the motor is rotating. Activates the motor. As described above, since the start of the motor is controlled in accordance with the number of rotations of the motor before the start, the amount of power consumed by the start of the motor can be minimized.

  A motor drive device according to a seventh aspect of the present invention is the motor drive device according to the first aspect, wherein the motor is a fan motor which is a fan drive source in an outdoor unit of a heat pump device including a compressor and a fan. And this motor drive device is further provided with the 2nd inverter and the 2nd interception part. The second inverter generates a second drive voltage for driving a compressor motor that is a drive source of the compressor based on the voltage from the second smoothing capacitor, and outputs the second drive voltage to the compressor motor. Here, the second smoothing capacitor is a capacitor connected in parallel to the first smoothing capacitor and the first inverter. The 2nd interruption | blocking part is connected between the 2nd smoothing capacitor and the 1st smoothing capacitor, and can interrupt the application of the voltage from the 2nd smoothing capacitor side to the 1st smoothing capacitor side. And a 2nd interruption | blocking part interrupts | blocks between a 2nd smoothing capacitor and a 1st smoothing capacitor, when a voltage detection part detects the voltage after smoothing before starting of a fan motor.

  Here, for example, it is assumed that a configuration in which DC power is supplied to the second smoothing capacitor on the compressor side is adopted. In a circuit configuration in which the drive system of the fan motor and the drive system of the compressor motor are connected in parallel, when the rotation speed of the fan motor before startup is estimated from the smoothed voltage of the first smoothing capacitor, the compressor motor The second smoothing capacitor on the side and the first smoothing capacitor on the fan motor side are blocked by the second blocking unit. Therefore, when estimating the rotation speed of the fan motor, only the induced voltage generated by the fan motor is applied to the first smoothing capacitor, and the DC power source or the compressor connected to the second smoothing capacitor is applied. The induced voltage generated by the motor is not further applied to the first smoothing capacitor. Therefore, the smoothed voltage of the first smoothing capacitor is a value that corresponds purely to the rotational speed of the fan motor before startup, and the rotational speed of the fan motor can be accurately estimated.

  A motor driving device according to an eighth aspect of the present invention is the motor driving device according to the seventh aspect, further comprising a second determination unit. The second determination unit determines whether or not the rotation number of the motor before startup estimated by the rotation number estimation unit is equal to or greater than a second predetermined rotation number. And when the rotation speed of the fan motor before starting is less than a 2nd predetermined rotation speed, a 2nd interruption | blocking part connects between a 2nd smoothing capacitor and a 1st smoothing capacitor. In this case, the first inverter outputs the first drive voltage to the fan motor. On the other hand, when the rotation speed of the fan motor before activation is equal to or higher than the second predetermined rotation speed, the second blocking unit maintains a state where the second smoothing capacitor and the second smoothing capacitor are blocked. In this case, the first inverter does not output the first drive voltage to the fan motor.

  In the state where the fan motor before starting is already rotating due to the influence of wind or the like, if the rotation speed is equal to or higher than the second predetermined rotation speed, sufficient air has already been sent to the heat exchanger in the outdoor unit. Therefore, the motor driving device keeps the first smoothing capacitor and the second smoothing capacitor in a disconnected state and does not dare to start the fan motor. Conversely, if the rotational speed is less than the second predetermined rotational speed, even if the fan motor is rotating, it is assumed that the amount of air sent to the heat exchanger in the outdoor unit is insufficient and the motor is driven. The apparatus places the first smoothing capacitor and the second smoothing capacitor in a connected state and starts the fan motor. As described above, the fan motor start-up control and the connection / disconnection state between the first smoothing capacitor and the second smoothing capacitor are controlled according to the rotation speed of the fan motor before the start-up. The amount of power consumed by starting up can be kept to a minimum.

  A motor drive device according to a ninth aspect of the present invention is the motor drive device according to the first aspect, wherein the first smoothing capacitor smoothes the DC power supplied from the DC power supply unit for generating the DC power. It is. The voltage detection unit detects the value of the smoothed voltage in a state where the DC power is supplied to the first smoothing capacitor.

  In this motor drive device, unlike the motor drive device according to the second aspect described above, the rotational speed of the motor before start-up is estimated from the smoothed voltage in a state where DC power is supplied to the first smoothing capacitor. . In this case, when the post-smoothing voltage is detected, a DC power source is applied to the first smoothing capacitor, and if the motor rotates to some extent, an induced voltage associated with the number of rotations is applied. That is, the voltage across the first smoothing capacitor increases by the induced voltage of the motor. Therefore, when the motor before starting is rotating to some extent, the rotational speed of the motor before starting can be grasped by the smoothed voltage.

  A motor drive device according to a tenth aspect of the present invention is the motor drive device according to the ninth aspect, wherein the DC power supply unit generates a DC power supply using an AC voltage output from a commercial power supply. When the detection result of the voltage detection unit is greater than the estimated voltage that is a smoothed voltage obtained by estimation from the value of the AC voltage, the rotation number estimation unit sets the rotation number of the motor before startup to the third predetermined rotation. It is determined that the rotation speed is higher than the number.

  From the value of the AC voltage output from the commercial power supply, it can be estimated how much the voltage after smoothing is. However, if the pre-starting motor has already rotated, the estimated voltage generated by the motor is added to the estimated smoothed voltage (that is, the estimated voltage). The actual value of the smoothed voltage increases. Therefore, this motor drive device can determine that the motor is in a high rotation state when the actual smoothed voltage is relatively large. Therefore, the rotational state of the motor can be grasped by the actual magnitude of the smoothed voltage.

  A motor driving device according to an eleventh aspect of the present invention is the motor driving device according to any of the seventh to tenth aspects, further comprising an energization limiting unit. The energization limiting unit performs only energization in one direction from the second smoothing capacitor to the first smoothing capacitor.

  Here, examples of the current limiting unit include a diode. As described above, in this motor drive device, by providing the energization limiting unit, the influence on the first smoothing capacitor side such as load fluctuation on the second inverter side, which is an inverter for the compressor, is reduced, and voltage detection is performed. The accuracy of detecting the rotation speed of the fan motor by the unit can be improved.

  A motor drive device according to a twelfth aspect of the present invention is the motor drive device according to any one of the first to eleventh aspects, wherein the motor is a brushless DC fan motor.

  According to this motor drive device, it is possible to easily grasp the rotational speed of the brushless DC fan motor before starting.

  A motor driving device according to a thirteenth aspect of the present invention is the motor driving device according to any one of the first to twelfth aspects, wherein the motor is driven without a rotor position sensor after activation.

  Even in this configuration, the motor after startup is normally driven by the rotor position sensorless.

  According to the motor drive device of the first aspect of the present invention, the rotation speed of the motor before start-up can be grasped by a simple method, and the high-performance motor according to the rotation state can be obtained using the grasped rotation speed. Drive control can be performed.

  According to the motor drive device of the second aspect of the present invention, the rotational speed of the motor can be directly estimated from the smoothed voltage.

  According to the motor drive device of the third aspect of the present invention, it is possible to prevent the first smoothing capacitor from being damaged by the inrush current.

  According to the motor drive device of the fourth aspect of the present invention, it is not necessary to provide a switch for shutting off the supply of direct-current power itself when an abnormality occurs in the device, separately from the first shut-off unit.

  According to the motor drive device of the fifth aspect of the present invention, when the fan is rotating from before the start due to the influence of wind or the like, the number of rotations can be easily grasped.

  According to the motor drive device of the sixth aspect of the present invention, since the start of the motor is controlled according to the number of rotations of the motor before the start, the amount of power consumption due to the start of the motor can be minimized. .

  According to the motor drive device of the seventh aspect of the present invention, the smoothed voltage of the first smoothing capacitor is a value that corresponds purely to the rotational speed of the fan motor before startup, and the rotational speed of the fan motor is It can be estimated with high accuracy.

  According to the motor drive device of the eighth aspect of the present invention, the start control of the fan motor and the connection / disconnection of the first smoothing capacitor and the second smoothing capacitor according to the rotational speed of the fan motor before the start. Since the state is controlled, the amount of power consumed by starting the fan motor can be minimized.

  According to the motor drive device of the ninth aspect of the present invention, when the motor before starting is rotating to some extent, the rotational speed of the motor before starting can be grasped by the smoothed voltage.

  According to the motor drive device of the tenth aspect of the present invention, the rotational state of the motor can be grasped from the actual magnitude of the smoothed voltage.

  According to the motor drive device of the eleventh aspect of the present invention, by providing the energization limiting unit, the influence on the first smoothing capacitor side, such as load fluctuation on the second inverter side, which is an inverter for the compressor, is reduced. The accuracy of detecting the rotation speed of the fan motor by the voltage detection unit can be improved.

  According to the motor drive device of the twelfth aspect of the present invention, the rotational speed of the brushless DC fan motor before starting can be easily grasped.

  Also in the configuration of the motor drive device according to the thirteenth aspect of the present invention, the motor after startup is normally driven by the rotor position sensorless.

The block diagram which showed the structure of the whole system by which the motor drive device which concerns on 1st Embodiment was employ | adopted, and the internal structure of a motor drive device. The figure which shows simply the structure of the outdoor unit which concerns on a heat pump apparatus. The conceptual diagram showing the relationship between the rotation speed of the motor before a start which concerns on 1st Embodiment, and the smoothed voltage. The figure which shows an example of a structure of a sensorless control circuit simply. The flowchart which shows the operation | movement which the motor drive device which concerns on 1st Embodiment performs. The flowchart which shows the operation | movement which the motor drive device which concerns on 1st Embodiment performs. It is a figure showing a part of motor drive unit concerning modification 1A of a 1st embodiment, and is a figure showing the case where the position of the interception part is different from Drawing 1. The block diagram which showed the whole structure of the system by which the motor drive device which concerns on the modification 1B of 1st Embodiment was employ | adopted, and the internal structure of a motor drive device. (A) The block diagram showing the function part in the drive IC by the side of the fan motor which concerns on the modification 1B of 1st Embodiment. (B) The block diagram showing the function part in the drive IC by the side of the motor for compressors concerning the modification 1C of 1st Embodiment. It is a figure showing a part of motor drive unit concerning modification 1C of a 1st embodiment, and is a figure showing the case where the interception part concerning Drawing 8 comprises an energization regulation part. The block diagram which showed the whole structure of the system by which the motor drive device which concerns on 2nd Embodiment was employ | adopted, and the internal structure of a motor drive device. The conceptual diagram showing the relationship between the rotation speed of the motor before starting which concerns on 2nd Embodiment, and the smoothed voltage. The flowchart which shows the operation | movement which the motor drive device which concerns on 2nd Embodiment performs.

Hereinafter, a motor drive device according to the present invention will be described in detail with reference to the drawings.
<First Embodiment>
(1) Outline FIG. 1 is a configuration diagram of an entire motor drive system 100 including a brushless DC motor 51 and a motor drive device 20 according to the present embodiment for driving the brushless DC motor 51. The brushless DC motor 51 is a fan motor used as a drive source of the outdoor fan 15 that is one of the devices included in the outdoor unit 10 (see FIG. 2) of the heat pump device. The motor drive device 20 is mounted in the outdoor unit 10.

(1-1) Outdoor Unit Here, the outdoor unit 10 will be briefly described with reference to FIG. Here, as an example of the heat pump apparatus, an outdoor unit of a heat pump hot water heater will be described. The outdoor unit 10 mainly includes various devices such as a compressor 11, a water heat exchanger 12, an expansion valve 13, an evaporator 14, and an outdoor fan 15. The compressor 11, the water heat exchanger 12, the expansion valve 13 and the evaporator 14 are sequentially connected to constitute a refrigeration cycle. The compressor 11 compresses the refrigerant circulating in the refrigeration cycle. The water heat exchanger 12 is provided with a heat exchange water channel 16 through which water sent from a hot water storage tank unit (not shown) connected to the outdoor unit 10 passes, and water flowing through the heat exchange water channel 16 and Heat exchange can be performed with the refrigerant. The expansion valve 13 is an electrically controlled valve that depressurizes the refrigerant circulating in the refrigeration cycle. The evaporator 14 is for causing heat exchange between the refrigerant in the refrigerant cycle and the air to evaporate the refrigerant. The outdoor fan 15 is a propeller fan, for example, and guides air from the outside of the outdoor unit 10 to the evaporator 14 by rotation.

  In such an outdoor unit 10, by driving the compressor 11 and circulating the refrigerant, the water heat exchanger 12 can function as a condenser, and the water passing through the heat exchange channel 16 can be heated.

(1-2) Motor Next, the brushless DC motor 51 will be described. The brushless DC motor 51 according to the present embodiment is a three-phase motor, and includes a stator 52 and a rotor 53. The stator 52 includes U-phase, V-phase, and W-phase drive coils Lu, Lv, and Lw that are star-connected. One ends of the drive coils Lu, Lv, and Lw are connected to drive coil terminals TU, TV, and TW of U-phase, V-phase, and W-phase wirings extending from the inverter 25, respectively. The other ends of the drive coils Lu, Lv, and Lw are connected to each other as a terminal TN. These three-phase drive coils Lu, Lv, and Lw generate an induced voltage according to the rotational speed and the position of the rotor 53 as the rotor 53 rotates.

  The rotor 53 includes a plurality of permanent magnets including N poles and S poles, and rotates about the rotation axis with respect to the stator 52. The rotation of the rotor 53 is output to the outdoor fan 15 via an output shaft (not shown) that is on the same axis as the rotation shaft.

  Hereinafter, the brushless DC motor 51 is referred to as a fan motor 51.

(2) Configuration of Motor Drive Device Next, the configuration of the motor drive device 20 according to the present embodiment will be described. As shown in FIG. 1, the motor drive device 20 according to the present embodiment includes a rectification unit 21 (corresponding to a DC power supply unit), a smoothing capacitor 22 (corresponding to a first smoothing capacitor), a voltage detection unit 23, Current detector 24, inverter 25 (corresponding to the first inverter), gate drive circuit 26, interrupting unit 27 (corresponding to the first interrupting unit), rotation speed detecting circuit 28, sensorless control circuit 29, micro And a computer 30. Each of these functional units constituting the motor control device 20 is mounted on, for example, one printed board.

(2-1) Rectifier The rectifier 21 is configured in a bridge shape by four diodes D1a, D1b, D2a, and D2b. Specifically, the diodes D1a and D1b and D2a and D2b are respectively connected in series. The cathode terminals of the diodes D1a and D2a are both connected to the plus side terminal of the smoothing capacitor 22 and function as the positive side output terminal of the rectifying unit 21. The anode terminals of the diodes D1b and D2b are both connected to the negative side terminal of the smoothing capacitor 22 and function as the negative side output terminal of the rectifying unit 21. A connection point between the diodes D1a and D1b is connected to a commercial power supply 91 via a blocking unit 27 described later. The connection point between the diodes D2a and D2b is directly connected to the commercial power supply 91. That is, the connection point between the diodes D1a and D1b and the connection point between the diodes D2a and D2b each serve as an input to the rectifying unit 21.

  The rectifying unit 21 having such a configuration generates a DC power by rectifying the AC voltage output from the commercial power supply 91 and supplies the DC power to the smoothing capacitor 22.

(2-2) Smoothing Capacitor The smoothing capacitor 22 has one end connected to the positive output terminal of the rectifying unit 21 and the other end connected to the negative output terminal of the rectifying unit 21. The smoothing capacitor 22 smoothes the DC power supplied from the rectifying unit 21, that is, the voltage rectified by the rectifying unit 21. Hereinafter, for the convenience of explanation, the voltage after smoothing by the smoothing capacitor 22 is referred to as “smoothed voltage Vfl”. The smoothed voltage Vfl is a voltage with a ripple lower than that of the voltage related to the DC power supply, and is applied to the inverter 25 connected to the subsequent stage of the smoothing capacitor 22, that is, the output side.

  In addition, as a kind of capacitor | condenser, although an electrolytic capacitor, a ceramic capacitor, a tantalum capacitor, etc. are mentioned, in this embodiment, the case where an electrolytic capacitor is employ | adopted as the smoothing capacitor 22 is taken as an example.

(2-3) Voltage Detection Unit The voltage detection unit 23 is connected to the output side of the smoothing capacitor 22 and detects the voltage across the smoothing capacitor 22, that is, the value of the smoothed voltage Vfl. In particular, the voltage detection unit 23 according to the present embodiment performs the voltage detection operation not only after the fan motor 51 is started but also before the fan motor 51 is started.

  Although not shown, such a voltage detector 23 is configured by, for example, connecting two resistors connected in series to each other in parallel to the smoothing capacitor 22 and dividing the smoothed voltage Vfl. The voltage value at the connection point between the two resistors is input to the rotation speed estimation circuit 28 and the sensorless control circuit 29.

(2-4) Current Detection Unit The current detection unit 24 is connected between the smoothing capacitor 22 and the inverter 25 and connected to the negative output terminal side of the smoothing capacitor 22. The current detection unit 24 detects the motor current Im flowing through the fan motor 51 after the fan motor 51 is started.

  Although not shown, the current detection unit 24 is configured by an amplifier circuit using, for example, a shunt resistor and an operational amplifier that amplifies the voltage across the resistor. The motor current detected by the current detection unit 24 is input to the sensorless control circuit 29.

(2-5) Inverter The inverter 25 is connected to the output side of the smoothing capacitor 22. As shown in FIG. 1, the inverter 25 includes a plurality of insulated gate bipolar transistors (hereinafter simply referred to as transistors) Q3a, Q3b, Q4a, Q4b, Q5a, Q5b and a plurality of freewheeling diodes D3a, D3b, D4a, D4b, D5a and D5b are included. Transistors Q3a and Q3b, Q4a and Q4b, Q5a and Q5b are connected to each other in series. Each diode D3a to D5b has a transistor collector terminal and a diode cathode terminal, The transistors are connected in parallel so that the emitter terminal of the transistor and the anode terminal of the diode are connected. The inverter 26 is configured to drive the fan motor 51 by applying the smoothed voltage Vfl from the smoothing capacitor 22 and turning on and off each of the transistors Q3a to Q5b at a timing instructed by the gate drive circuit 26. Drive voltages SU, SV, and SW (corresponding to the first drive voltage) are generated. The drive voltages SU, SV, SW are output to the fan motor 51 from the connection points NU, NV, NW of the transistors Q3a and Q3b, Q4a and Q4b, and Q5a and Q5b.

  In particular, the inverter 25 according to the present embodiment activates the fan motor 51 in accordance with a signal from the rotational speed estimation circuit 28 that indicates what rotational speed of the fan motor 51 before activation is. Forgive startup. Specifically, when the signal relating to the activation acquired from the rotation speed estimation circuit 28 indicates that the rotation speed of the fan motor 51 before the activation is less than a predetermined rotation speed (corresponding to the first predetermined rotation speed), the inverter 25 The drive voltages SU, SV, and SW are output to the fan motor 51. As a result, the fan motor 51 starts. However, when the number of rotations of the fan motor 51 before activation is equal to or higher than the predetermined number of rotations, the inverter 25 does not output the drive voltages SU, SV, SW to the fan motor 51. As a result, the fan motor 51 remains in a state where it is not activated.

  If the outdoor fan 15 is affected by wind or the like and the fan motor 51 is already rotating at a sufficient number of revolutions before the start-up, the rotation of the outdoor fan 15 causes the evaporator 14 to rotate. It is assumed that sufficient air is being sent. In such a case, since the function as the evaporator 14 of the heat pump device is not impaired, the inverter 25 does not have to output the drive signals SU, SV, SW to the fan motor 51. However, if the rotation speed of the fan motor 51 before startup is not sufficient (including the case where the fan motor 51 before startup is not rotating), sufficient air is not sent to the evaporator 14. . That is, since there is a possibility that the evaporator 14 cannot function sufficiently, the inverter 25 outputs the drive signals SU, SV, SW to the fan motor 51 to start the fan motor 51.

(2-6) Gate Drive Circuit The gate drive circuit 26 changes the on and off states of the transistors Q3a to Q5b of the inverter 26 based on the start command Vpwm from the sensorless control circuit 29. Specifically, the gate drive circuit 26 is configured so that the drive voltages SU, SV, SW having the duty determined by the sensorless control circuit 29 are output from the inverter 25 to the fan motor 51, so that the gates of the transistors Q3a to Q5b. The gate control voltages Gu, Gx, Gv, Gy, Gw, and Gz to be applied to are generated. The generated gate control voltages Gu, Gx, Gv, Gy, Gw, Gz are applied to the gate terminals of the respective transistors Q3a to Q5b.

(2-7) Blocking Unit The blocking unit 27 is located between the commercial power supply 91 and the rectifying unit 21, and turns on or off the application of the AC voltage output from the commercial power supply 91 to the rectifying unit 21. You can do it. In particular, the blocking unit 27 according to the present embodiment blocks the supply of DC power from the rectifying unit 21 to the smoothing capacitor 22 before the fan motor 51 is started. Further, the shut-off unit 27 cuts off the supply of the DC power to the smoothing capacitor 22 when an abnormality occurs in the equipment included in the outdoor unit 10 (for example, the compressor 11 and the expansion valve 13), thereby The power supply 91 and the inverter 25 are disconnected.

  Here, as an abnormality that may occur in the equipment included in the outdoor unit 10, the refrigerant pressure after being compressed by the compressor 11 is out of the normal pressure range due to some cause related to the compressor 11. In addition to the case where the high pressure side of the pressure range is higher than a predetermined value, the expansion valve 13 may be broken.

  The blocking unit 27 that performs the above-described operation is mainly configured by a relay 27a. The relay 27a is connected in series on the wiring connecting the output of the commercial power supply 91 and the connection point of the diodes D1a and D1b in the rectifying unit 21. That is, the blocking unit 27 according to the present embodiment is configured to turn on / off the application of DC power from the rectifying unit 21 to the smoothing capacitor 22 by turning on / off the input side of the rectifying unit 21. Here, the relay 27a is turned off before the fan motor 51 is activated and when the equipment of the outdoor unit 10 is abnormal. However, the relay 27a is turned on when the fan motor 51 is activated or during steady rotation, or when the equipment of the outdoor unit 10 is normal. Take.

  Furthermore, the interruption | blocking part 27 which concerns on this embodiment has the inrush current suppression part 27b. The inrush current suppression unit 27 b suppresses the inrush current from flowing through the smoothing capacitor 22 immediately after the DC power supply starts to be supplied to the smoothing capacitor 22. Such an inrush current suppression unit 27b is connected in parallel to the relay 27a, and includes a resistor R27 and a relay 27c. The resistor R27 and the relay 27c are connected in series with each other. When supplying DC power, the relay 27c takes a state complementary to the relay 27a in synchronization with the relay 27a. When the relay 27c changes from the OFF state to the ON state at the start of the supply of the DC power supply, an AC voltage is applied from the commercial power supply 91 to the rectifying unit 21, so the DC power supply is supplied to the smoothing capacitor 22. Will be supplied. At this time, the resistor R27 connected in series with the relay 27c makes it difficult to instantaneously flow an excessive current from the commercial power supply 91 to the rectifying unit 21, so that an inrush current to the smoothing capacitor 22 is suppressed. After the voltage smoothed by the smoothing capacitor 22 becomes a predetermined voltage, the relay 27c is turned off and the relay 27a is turned on. When the relay 27c is turned on and the power from the commercial power supply 91 is supplied to the rectifying unit 21 via the resistor R27, a loss due to the resistor R27 occurs. However, when the relay 27a is turned on, power can be supplied without causing this loss.

  The relays 27a and 27c are turned on and off by a microcomputer 30 described later.

(2-8) Rotational Speed Estimation Circuit The rotational speed estimation circuit 28 is connected to the output terminal of the voltage detector 23 and the input terminal of the microcomputer 23. The rotation speed estimation circuit 28 is a circuit that estimates the rotation speed of the fan motor 51 before activation based on the detection result of the voltage detection unit 23.

  Before the fan motor 51 is started, the relays 27a and 27c in the shut-off unit 27 are turned off, so that the DC power is not supplied from the rectifying unit 21 to the smoothing capacitor 22. In this state, an induced voltage is generated in the rotating fan motor 51 due to the influence of wind or the like. This voltage is rectified by the respective return diodes D3a to D5b in the inverter 25 and applied to the smoothing capacitor 22. Is done. Therefore, the smoothed voltage Vfl, which is the detection result of the voltage detector 23, is a value that directly represents the rotational speed of the fan motor 51, and as shown in FIG. 3, the rotational speed of the fan motor 51 before startup. Increases, the post-smoothing voltage Vfl, that is, the voltage across the smoothing capacitor 22 also increases. Therefore, the rotational speed estimation circuit 28 starts from the magnitude of the smoothed voltage Vfl by grasping in advance the relationship between the magnitude of the smoothed voltage Vfl and the rotational speed of the fan motor 51 before startup (FIG. 3). It becomes possible to estimate the rotation speed of the previous fan motor 51.

  As shown in FIG. 3, the relationship between the magnitude of the smoothed voltage Vfl and the rotation speed of the fan motor 51 before startup is based on the characteristics of the fan motor 51, the capacity of the smoothing capacitor 22, etc. It has been guided in advance by experiments. The rotation speed estimation circuit 28 is configured based on the relationship.

  Further, in the present embodiment, the rotation speed estimation circuit 28 is configured to only estimate the rotation speed regardless of whether the rotation direction of the fan motor 51 before startup is the forward direction or the reverse direction.

(2-9) Sensorless Control Circuit The sensorless control circuit 29 is connected to the voltage detection unit 23, the current detection unit 24, the gate drive circuit 26, and the microcomputer 30. The sensorless control circuit 29 is a circuit that drives the fan motor 51 in a rotor position sensorless system based on an operation command including the rotation speed command Vfg sent from the microcomputer 30.

  Here, the rotor position sensorless system refers to various parameters indicating the characteristics of the fan motor 51, the smoothed voltage Vfl after the fan motor 51 is started (that is, the detection result of the voltage detection unit 23), the motor current Im of the fan motor 51 ( That is, by using a predetermined mathematical model related to the control of the fan motor 51), the rotor position and the rotational speed are estimated, the rotational speed is PI controlled, the motor current is PI controlled, and the like. is there. Examples of various parameters indicating the characteristics of the fan motor 51 include the winding resistance, inductance component, induced voltage, and number of poles of the fan motor 51 used.

  FIG. 4 simply shows an example of the configuration of the sensorless control circuit 29 that performs the rotor position sensorless control in consideration of the mathematical model. The sensorless control circuit 29 in FIG. 4 mainly includes a motor model calculation unit 29a, a rotor position estimation unit 29b, a rotation speed estimation unit 29c, an LPF 29d, a rotation speed control unit 29e, and a current control unit 29f. The motor model calculation unit 29a calculates the ideal value of the motor current from the command voltage to the motor 51, the estimated rotor position, and the estimated rotation speed, using various parameters indicating the characteristics of the fan motor 51 as a motor model. The rotor position estimator 29b estimates the current rotor position using the result obtained by subtracting the ideal value from the motor current Im actually detected by the current detector 24 as an input. The rotation speed estimation unit 29c estimates the rotation speed of the fan motor 51 at the current time using the estimated rotor position. The estimation results in the respective estimation units 29b and 29c are corrected so that the difference between the ideal value of the motor current and the actual motor current Im is “0”, and the motor model is corrected. The LPF 29d removes noise components and harmonic components from the estimated rotation speed. The rotation speed of the fan motor 51 output from the LPF 29d becomes a desired rotation speed signal FG by the waveform shaping section 29g and is output to the microcomputer 30.

  The rotation speed of the fan motor 51 output from the LPF 29d is subtracted from the rotation speed command Vfg included in the operation command sent from the microcomputer 30. When the result of the subtraction process is input, the rotation speed control unit 29e performs PI control on the rotation speed. The current control unit 29f detects the voltage of the d-axis torque current command Id *, which is the control result of the rotation speed control unit 29e, and the command “Iq * = 0” such that the q-axis current command Iq becomes “0”. Current control is performed on the basis of the smoothed voltage Vfl detected by the unit 23, and a command voltage Vpwm that produces a current based on these commands is generated. By such control of the current control unit 29f, the command voltage Vpwm including the duty of the drive voltages SU, SV, SW is generated and input to the gate drive circuit 26. The command voltage Vpwm is input to the motor model calculation unit 29a, and further correction of the motor model is performed.

  It can be said that the sensorless control circuit 29 having such a configuration estimates the rotor position only when the inverter 25 is controlled by the microcomputer 30 and the gate drive circuit 26. The case where the control of the inverter 25 is performed corresponds to the fact that the fan motor 51 is activated by the activation command and is being driven. In other words, the sensorless control circuit 29 cannot estimate the rotational speed of the fan motor 51 before the fan motor 51 is started. This is because, as described above, in the rotor position sensorless system, the estimated rotor position is used for estimating the rotation speed, and therefore the rotor position cannot be estimated in the fan motor 51 before starting.

(2-10) Microcomputer The microcomputer 30 is mainly connected to the rotation speed estimation circuit 28, the sensorless control circuit 29, and the blocking unit 27. Although not shown, the microcomputer 30 is also connected to an outdoor unit side control unit that controls each device of the outdoor unit 10 in an integrated manner. The microcomputer 30 performs drive control of the fan motor 51 by controlling each functional unit of the connected motor drive device 20. Further, the microcomputer 28 controls the driving of the fan motor 51 in accordance with the presence / absence of an abnormality in the devices constituting the outdoor unit 10. In order to perform such operations, the microcomputer 30 functions as a determination unit 30a (corresponding to a first determination unit) and a relay control unit 30b.

  Although not shown, the microcomputer 30 has a power source different from the various circuits 26, 28, 29 and the inverter 25 constituting the motor driving device 20 regardless of the driving state of the fan motor 51. Suppose that it is supplied.

-Judgment part-
The determination unit 30a compares the rotational speed of the fan motor 51 before startup estimated by the rotational speed estimation circuit 28 with a predetermined rotational speed (corresponding to the first predetermined rotational speed), and the rotational speed of the fan motor 51 before startup. Is determined to be greater than or equal to a predetermined rotational speed. If the rotation speed of the fan motor 51 before the start is greater than or equal to the predetermined rotation speed, the fan motor 51 has already been rotated at a sufficient rotation speed due to the influence of wind or the like. Since sufficient air is being sent to and sufficient heat exchange is possible, the determination unit 30a determines that the fan motor 51 is not started. In this case, since the startup command for the fan motor 51 is not sent from the microcomputer 30 to the sensorless control circuit 29, the transistors Q3a to Q5b of the inverter 25 remain off. Conversely, if the rotational speed of the fan motor 51 before activation is less than the predetermined rotational speed, sufficient air has not been sent to the evaporator 14 at the present time. Is determined to activate. In this case, an activation command for the fan motor 51 is sent from the microcomputer 30 to the sensorless control circuit 29, and the transistors Q3a to Q5b of the inverter 25 are turned on and off at different timings.

  It is assumed that the above-described predetermined rotational speed is set to an appropriate value in advance by desktop calculation, simulation, experiment, or the like based on the characteristics of the fan motor 51, the outdoor fan 15, and the evaporator 14.

-Relay control unit-
The relay control unit 30 b controls on and off of the relays 27 a and 27 c configuring the blocking unit 27. Specifically, the relay control unit 30b turns off the relays 27a and 27c before the fan motor 51 is started. When an abnormality occurs in the equipment included in the outdoor unit 10, the relay control unit 30b turns off the relays 27a and 27c. When the determination unit 30a determines that the fan motor 51 is to be activated, the relay control unit 30b switches the relays 27a and 27c in a complementary manner to OFF and ON, respectively. While the fan motor 51 is being driven, the relay control unit 30b keeps the relay 27a in an on state unless there is an abnormality in the equipment included in the outdoor unit 10.

(3) Operation Next, the operation of the motor drive device 20 of this embodiment will be described with reference to FIGS. 5 and 6 are flowcharts showing operations performed by the motor drive device 20.

  Steps S1 to S4: When the operation start instruction for the outdoor fan 15 is acquired from the outdoor unit side control unit of the outdoor unit 10 (Yes in Step S1), the microcomputer 30 functioning as the relay control unit 30b 27a and 27c are turned off (step S2). After the relays 27a and 27c are turned off, the voltage detection unit 23 detects the voltage across the smoothing capacitor 22, that is, the smoothed voltage Vfl (step S3). The number of rotations of the fan motor 51 is estimated (step S4).

  Steps S5 to S6: The microcomputer 28 functioning as the determination unit 30a compares the rotational speed of the fan motor 51 before startup estimated in Step S4 with a predetermined rotational speed (Step S5). If the rotation speed of fan motor 51 before activation is equal to or higher than the predetermined rotation speed (Yes in step S5), determination unit 30a determines that fan motor 51 is not activated at the present time (step S6). In this case, the drive voltage SU, SV, SW is not output from the inverter 25 to the fan motor 51.

  Step S7: Every time a predetermined time elapses from the operation of Step S3, the operations after Step S3 are repeated. That is, if it is determined in step S6 that the fan motor 51 is not started, the detection operation of the smoothed voltage Vfl is retried.

  Steps S8 to S9: If the current rotation speed of the fan motor 51 before the start is less than the predetermined rotation speed in Step S5 (No in Step S5), the determination unit 30a determines to start the fan motor 51. . In this case, the microcomputer 30 functioning as the relay control unit 30b turns on the relay 27c in the blocking unit 27 from OFF (step S8).

  Steps S9 to S11: After step S8, when the voltage across the smoothing capacitor 22, that is, the smoothed voltage Vfl rises to a predetermined voltage (Yes in step S9), the microcomputer 30 functioning as the relay control unit 30b is turned off. The relay 27c in the unit 27 is turned off from on and the relay 27a is turned on from off (step S10). Thereafter, the drive voltage SU, SV, SW is output from the inverter 25 to the fan motor 51 (step S11), and the fan motor 51 is started.

  Step S <b> 12: The fan motor 51 started in Step S <b> 11 is driven by the sensorless control circuit 29 without the rotor position sensor.

  Steps S13 to S15: When the fact that an abnormality has occurred in the equipment included in the outdoor unit 10 is acquired from the outdoor unit control unit while the fan motor 51 is being driven (Yes in step S13), the relay control unit 30b The microcomputer 30 that functions as turns off the relays 27a and 27c in the blocking unit 27 (step S14). As a result, the supply of DC power to the smoothing capacitor 22 is stopped, so that the output of the drive voltages SU, SV, SW to the fan motor 51 by the inverter 25 is stopped, and the fan motor 51 stops driving (step S15). .

  Step S16: In step S13, while the fan motor 51 is being driven, an instruction to stop driving the outdoor fan 15 is acquired without acquiring from the outdoor unit side control unit that an abnormality has occurred in the equipment included in the outdoor unit 10. In the case (No in Step S13, Yes in Step S16), the output of the drive voltages SU, SV, SW to the fan motor 51 by the inverter 25 is stopped, and the fan motor 51 stops driving.

(4) Features (4-1)
If the fan motor 51 that has not yet started is already rotating due to the influence of wind or the like, for example, an induced voltage is generated from the fan motor 51, and the induced voltage is generated by each of the return diodes D 3 a to D 5 b in the inverter 25. And is applied to the smoothing capacitor 22. Therefore, the motor drive device 20 according to the present embodiment estimates the rotational speed of the fan motor 51 based on the value of the smoothed voltage Vfl by the smoothing capacitor 22 before the fan motor 51 is started. Therefore, it is not necessary to directly detect the rotational speed of the fan motor 51, and the rotational speed of the fan motor 51 before starting can be known by monitoring only the smoothed voltage Vfl. Therefore, it is possible to grasp the rotational speed of the fan motor 51 before starting by a simple method, and to perform drive control of the high-performance fan motor 51 according to the rotational state using the grasped rotational speed. Become.

(4-2)
Further, according to the motor drive device 20 according to the present embodiment, before the fan motor 51 is started, the smoothing capacitor 22 is not supplied with the rectified voltage (that is, DC power supply) by the blocking unit 27. In this state, the voltage Vfl after smoothing by the smoothing capacitor 22 is detected, and the rotational speed of the fan motor 51 before starting is estimated. Therefore, only the induced voltage generated in the fan motor 51 is applied to the smoothing capacitor 22, and the smoothed voltage Vfl is a value that purely reflects the rotational speed of the fan motor 51 before starting. Therefore, the rotational speed of the fan motor 51 can be directly estimated from the smoothed voltage Vfl.

(4-3)
Immediately after the DC power supply starts to be supplied to the smoothing capacitor 22, a current exceeding the allowable current of the capacitor 22 flows through the smoothing capacitor 22 as an inrush current, and the smoothing capacitor 22 may be damaged. However, since the interruption | blocking part 27 which concerns on this embodiment has the inrush current suppression part 27b for suppressing such an inrush current, it can prevent that the smoothing capacitor 22 is damaged by the inrush current. it can.

(4-4)
Further, according to the motor drive device 20 according to the present embodiment, the blocking unit 27 is not only from the start of the fan motor 51 but also from the rectifying unit 21 to the smoothing capacitor 22 not only when an abnormality of the equipment included in the outdoor unit 10 occurs. Shut off the DC power supply. Therefore, it is not necessary to provide a switch for shutting off the supply of the DC power supply when the device malfunctions, separately from the shut-off unit 27.

(4-5)
Here, the motor 51 of the present embodiment is a drive source of the outdoor fan 15. The outdoor fan 15 is one of the devices included in the outdoor unit 10 of the heat pump device. Therefore, the motor drive device 20 according to the present embodiment can easily grasp the number of rotations when the outdoor fan 15 is rotating from the start-up due to the influence of wind or the like.

(4-6)
In a state where the fan motor 51 before starting is already rotating due to the influence of wind or the like, if the rotation speed is equal to or higher than a predetermined rotation speed, sufficient air has already been sent to the evaporator 14 in the outdoor unit 10. Therefore, the motor driving device 20 according to the present embodiment does not intentionally start the fan motor 51. Conversely, if the rotation speed of the fan motor 51 is less than the predetermined rotation speed, the amount of air sent to the evaporator 14 in the outdoor unit 10 is insufficient even if the fan motor 51 is rotating. Assuming that there is a motor drive device 20, the fan motor 51 is activated. As described above, since the start execution of the fan motor 51 is controlled according to the rotational speed of the fan motor 51 before the start, the amount of power consumption due to the start of the fan motor 51 can be minimized.

(4-7)
Moreover, according to the motor drive device 20 according to the present embodiment, the rotational speed before the brushless DC fan motor 51 is started can be easily grasped.

(4-8)
Further, according to the motor drive device 20 according to the present embodiment, the fan motor 51 is normally driven by the rotor position sensorless drive after being started.

(5) Modification (5-1) Modification 1A
In the above embodiment, the case where the position of the blocking unit 27 is between the commercial power supply 91 and the rectifying unit 21 as illustrated in FIG. 1 has been described. However, the blocking unit 27 only needs to block the supply of the DC power to the smoothing capacitor 22, and the position of the blocking unit 27 is not limited to the position shown in FIG.

  For example, as shown in FIG. 7, the blocking unit 27 may be between the rectifying unit 21 and the smoothing capacitor 22. In FIG. 7, only the part including the commercial power supply 91, the rectifying unit 21, the smoothing capacitor 22, the voltage detecting unit 23, and the blocking unit 27 is extracted from the configuration illustrated in FIG. 1.

(5-2) Modification 1B
In the above embodiment, the case where the motor driving device 20 drives only the fan motor 51 has been described. However, the motor driving device described above can also be applied to the case where the motors 51 and 61 are driven in a configuration in which the fan motor 51 is connected in parallel to the compressor motor 61.

  FIG. 8 is a configuration diagram of the system 200 including the motor driving device 120 when the fan motor 51 and the compressor motor 61 are connected in parallel. In FIG. 8, in order to simplify the configuration, the detailed configuration inside the rectifying unit 131 and each of the inverters 125 and 133 is omitted, but the internal configuration of the rectifying unit 131 and each of the inverters 125 and 133 is as follows. The same as FIG.

  The motor driving device 120 includes a first smoothing capacitor 122, a voltage detection unit 123, a current detection unit 124, a fan inverter 125 (corresponding to the first inverter and the DC power supply unit), and a fan motor side. Driving IC 126 and a relay 127 (corresponding to a second blocking section). The motor drive device 120 includes a compressor inverter 133 (corresponding to a second inverter) and a drive IC 136 on the compressor motor 61 side as a configuration on the compressor motor 61 side that is a drive source of the compressor 11. And the motor drive device 120 has the rectification | straightening part 131 connected to the commercial power source 91, and the 2nd smoothing capacitor 132 as a structure common to the compressor 11 and the outdoor fan 15. FIG.

  As shown in FIG. 9A, the driving IC 126 on the fan motor 51 side includes a gate driving circuit 126a, a rotation speed estimation circuit 126b, and a sensorless control circuit 126c. As shown in FIG. 9B, the driving IC 136 on the compressor motor 61 side includes a gate driving circuit 136a and a sensorless control circuit 136b.

  The first smoothing capacitor 122, the voltage detection unit 123, the current detection unit 124, the fan inverter 125, the gate drive circuit 126a, the rotation speed estimation circuit 126b, and the sensorless control circuit 126c are the same as the smoothing capacitor 22 according to the first embodiment described above. This is the same as the voltage detector 23, current detector 24, inverter 25, gate drive circuit 26, rotation speed estimation circuit 28, and sensorless control circuit 29. That is, the first smoothing capacitor 122 smoothes the DC power supplied from the rectifying unit 131, and the voltage detection unit 123 detects the value of the smoothed voltage Vfl in the first smoothing capacitor 122. The current detection unit 124 detects the motor current Im of the fan motor 51 after startup. The fan inverter 125 generates drive voltages SU 1, SV 1, SW 1 (corresponding to the first drive voltage) for driving the fan motor 51, and outputs them to the fan motor 51. The gate drive circuit 126 a outputs a gate control voltage to the fan inverter 125. The rotation speed estimation circuit 126b estimates the rotation speed of the fan motor 51 before startup based on the smoothed voltage Vfl that is the detection result of the voltage detection unit 123. The sensorless control circuit 126c drives and controls the fan motor 51 after startup by a rotor position sensorless system.

  The rectifying unit 131 is connected to the commercial power supply 91 and rectifies the AC voltage from the commercial power supply 91. The second smoothing capacitor 132 is connected in parallel to the first smoothing capacitor 122 and the fan inverter 125, and smoothes the DC power supplied from the rectifying unit 131. The voltage smoothed by the second smoothing capacitor 132 is supplied to the compressor inverter 133 and is also supplied to the first smoothing capacitor 122 side which is the fan side. The capacitance value of the second smoothing capacitor 132 is generally larger than the capacitance value of the first smoothing capacitor 122, but this method is useful regardless of the magnitude relationship of the capacitance. The compressor inverter 133 generates drive voltages SU <b> 2, SV <b> 2, and SW <b> 2 (corresponding to the second drive voltage) for driving the compressor motor 61, and outputs them to the motor 61. The gate drive circuit 136a outputs a gate control voltage to the compressor inverter 133. The sensorless control circuit 136c drives and controls the compressor motor 61 by a rotor position sensorless system.

  The relay 127 is connected between the first smoothing capacitor 122 and the second smoothing capacitor 132. In other words, the relay 127 is located after the second smoothing capacitor 132 and before the first smoothing capacitor 122. The relay 127 can cut off the application of voltage from the second smoothing capacitor 132 side to the first smoothing capacitor 122 side. Specifically, the relay 127 is in an OFF state before the fan motor 51 is started and when the voltage detection unit 123 detects the voltage across the first smoothing capacitor 122, that is, the smoothed voltage Vfl. Thus, the second smoothing capacitor 132 and the first smoothing capacitor 122 are disconnected from each other.

  This is because when the voltage detection unit 123 detects the voltage across the first smoothing capacitor 122, the first smoothing capacitor 122 is connected between the second smoothing capacitor 132 and the first smoothing capacitor 122. In addition, not only the induced voltage accompanying the rotation of the fan motor 51 but also the induced voltage accompanying the rotation of the compressor motor 61 and the DC power from the rectifying unit 131 side are applied. For this reason, even if the voltage across the first smoothing capacitor 122 is detected, it is difficult to accurately estimate the rotational speed of the fan motor 51. In particular, such a problem may occur when the compressor motor 61 is activated but the fan motor 51 is not activated. Therefore, when the voltage detection unit 123 detects the voltage across the first smoothing capacitor 122, the relay 127 is turned off, so that the induced voltage generated by the rotation of the fan motor 51 before starting (specifically, the fan Only the induced voltage after being rectified by the freewheeling diode in the inverter 125 is applied to the first smoothing capacitor 122. Therefore, the smoothed voltage Vfl of the first smoothing capacitor 122 is a value that corresponds purely to the rotational speed of the fan motor 51 before startup, and the rotational speed of the fan motor 51 can be accurately estimated.

  The motor driving device 120 includes a microcomputer 130 that controls the fan motor 51 and the compressor motor 61 in an integrated manner. As shown in FIG. 8, the microcomputer 130 includes a determination unit 130aa (corresponding to a second determination unit) as a fan motor control system 130a and a relay control unit 130ab.

  The determination unit 130aa determines whether or not the estimated rotation speed of the fan motor 51 before startup is equal to or higher than a predetermined rotation speed (corresponding to the second rotation speed). When the estimated number of rotations of the fan motor 51 before activation is greater than or equal to the predetermined number of rotations, the determination unit 130aa determines that the fan motor 51 is not activated. When the estimated number of rotations of the fan motor 51 before activation is less than the predetermined number of rotations, the determination unit 130aa determines to activate the fan motor 51. When the determination unit 130aa determines that the fan motor 51 is to be activated, the relay control unit 130ab changes the relay 127 from off to on and connects the second smoothing capacitor 132 and the first smoothing capacitor 122. To do. In this case, when the fan inverter 125 outputs the drive voltages SU1, SV1, and SW1 to the fan motor 51, the fan motor 51 starts. Conversely, when the determination unit 130aa determines that the fan motor 51 is not activated, the relay control unit 130ab keeps the relay 127 off, so that the second smoothing capacitor 132 and the first smoothing capacitor 122 Keep the state between the two. In this case, since the fan inverter 125 does not output the drive voltages SU1, SV1, and SW1 to the fan motor 51, the fan motor 51 does not start and is kept rotating under the influence of wind or the like. .

  Thus, in a state where the fan motor 51 before starting is already rotating due to the influence of wind or the like, if the rotation speed is equal to or higher than the predetermined rotation speed, sufficient air is already in the evaporator 14 in the outdoor unit 10. Therefore, the motor driving device 120 brings the first smoothing capacitor 122 and the second smoothing capacitor 132 into a disconnected state and does not intentionally start the fan motor 51. On the other hand, if the rotational speed is less than the predetermined rotational speed, even if the fan motor 51 is rotating, the amount of air sent to the evaporator 14 in the outdoor unit 10 is considered to be insufficient. The driving device 120 connects the first smoothing capacitor 122 and the second smoothing capacitor 132 to start the fan motor 51. As described above, the start execution control of the fan motor 51 and the connection / non-connection state between the first smoothing capacitor 122 and the second smoothing capacitor 132 are controlled according to the rotation speed of the fan motor 51 before the start. Therefore, the amount of power consumed by starting the fan motor 51 can be minimized.

  It is assumed that the above-described predetermined rotational speed is set to an appropriate value in advance by desktop calculation, simulation, experiment, or the like based on the characteristics of the fan motor 51, the outdoor fan 15, and the evaporator 14.

  Further, as shown in FIG. 8, the microcomputer 130 functions as an operation control unit 130ba as a compressor motor control system 130b. The operation control unit 130ba controls the start and stop of driving of the compressor motor 61.

  Further, here, the case where the second blocking unit is configured by one relay 127 has been described. However, the 2nd interruption | blocking part may have a structure which suppresses an inrush current like the said 1st Embodiment.

(5-3) Modification 1C
In the modification 1B, the case where the second blocking unit that blocks between the first smoothing capacitor 122 and the second smoothing capacitor 132 is configured by only the relay 127 has been described. However, the 2nd interruption | blocking part may be comprised by the series circuit of the relay 127 and electricity supply restriction | limiting part 127 '. FIG. 10 shows a part of the motor driving device in which the second blocking unit is configured by the relay 127 and the energization limiting unit 127 ′.

  The energization limiting unit 127 ′ is configured by a diode or the like, for example. The anode side terminal of the energization limiting unit 127 ′ is connected to the second smoothing capacitor 132 side, and the cathode side terminal is connected to the first smoothing capacitor 122 side. The energization limiting unit 127 ′ is turned on when a voltage equal to or higher than a predetermined voltage value is applied to both ends thereof, and only energizes in one direction from the second smoothing capacitor 132 side to the first smoothing capacitor 122 side.

  Thus, by providing the energization limiting unit 127 ′ in addition to the second blocking unit, the influence of the load fluctuation on the compressor inverter 133 side and the like on the first smoothing capacitor 122 side is reduced, and the fan motor 51 The detection accuracy of the number of rotations can be improved.

  In FIG. 10, the number of diodes is one, but the number of diodes may be plural depending on the value of the circuit current.

Second Embodiment
(1) Outline In the first embodiment described above, the case where the smoothed voltage Vfl is detected before the fan motor 51 is started up and the DC power supply to the smoothing capacitor 22 is shut off by the shut-off unit 27 is described. did. In contrast, in the present embodiment, a case where the smoothed voltage Vfl is detected before the fan motor 51 is started and the DC power is supplied to the smoothing capacitor 222 will be described.

(2) Configuration FIG. 11 is a configuration diagram of an entire motor drive system 300 including a fan motor 51 that is a brushless DC motor and a motor drive device 220 according to the present embodiment for driving the fan motor 51. The motor driving device 220 includes a rectifying unit 221 (corresponding to a DC power supply unit), a smoothing capacitor 222 (corresponding to a first smoothing capacitor), a voltage detecting unit 223, a current detecting unit 224, and an inverter 225 (first inverter). ), A gate drive circuit 226, a rotation speed estimation circuit 228, and a sensorless control circuit 229. Further, although not shown, the motor drive device 220 has a microcomputer for outputting an operation command including a rotation speed command and a start command to the sensorless control circuit 229. The rectifying unit 221, the smoothing capacitor 222, the current detecting unit 224, the inverter 225, the gate drive circuit 226, and the sensorless control circuit 229 are the rectifying unit 21, the smoothing capacitor 22, and the current detecting unit according to the first embodiment shown in FIG. 24, the inverter 25, the gate drive circuit 26, and the sensorless control circuit 29. Therefore, below, description of these function parts is abbreviate | omitted, and the voltage detection part 223 and the rotation speed estimation circuit 228 different from the said 1st Embodiment are demonstrated.

(2-1) Voltage Detection Unit The voltage detection unit 223 according to the present embodiment is connected to the output side of the smoothing capacitor 222 in the same manner as the voltage detection unit 23 according to the first embodiment. The voltage detection unit 223 detects the voltage across the smoothing capacitor 222, that is, the smoothed voltage Vfl not only after the fan motor 51 is started but also before the fan motor 51 is started.

  However, the voltage detection unit 223 according to the present embodiment is different from the voltage detection unit 23 according to the first embodiment, after smoothing in a state where the DC power from the rectification unit 221 is supplied to the smoothing capacitor 222. The value of the voltage Vfl is detected. That is, in this embodiment, since the blocking unit 27 according to the first embodiment is not provided, the DC power source is supplied to the smoothing capacitor 222 even during the voltage detection operation by the voltage detection unit 223 before the fan motor 51 is activated. It will remain supplied.

(2-2) Rotational Speed Estimation Circuit The rotational speed estimation circuit 228 performs an operation of estimating the rotational speed of the fan motor 51 before starting from the detection result of the voltage detection unit 223. This is different from the embodiment.

  Hereinafter, the estimation operation of the rotational speed of the fan motor 51 before activation according to the present embodiment will be described. First, the rotation speed estimation circuit 228 estimates the voltage across the smoothing capacitor 222, that is, the value of the smoothed voltage Vfl from the value of the AC voltage output from the commercial power supply 91 before the fan motor 51 is started. Hereinafter, this voltage is referred to as “estimated voltage”. Then, the rotation speed estimation circuit 228 compares the detection result of the voltage detection unit 223 with the estimated voltage, and when the detection result of the voltage detection unit 223 is larger than the estimated voltage, the rotation speed of the fan motor 51 before starting. Is higher than a predetermined rotational speed (corresponding to a third predetermined rotational speed), and is determined to be in a high rotational state.

  In the present embodiment, unlike the first embodiment, since the DC power is still supplied to the smoothing capacitor 222 even during the voltage detection operation by the voltage detection unit 223, the voltage across the smoothing capacitor 222 is used. From the smoothed voltage Vfl, the rotational speed of the fan motor 51 cannot be directly derived. However, if the rotational speed of the fan motor 51 is large to some extent, an induced voltage (specifically, in addition to the direct current power from the rectifier 221 and the rotational speed of the fan motor 51 is applied to the smoothing capacitor 222 to which direct current power is supplied. Is applied with the induced voltage rectified by the freewheeling diodes D3a to D5b of the inverter 225 (see FIG. 12). Therefore, the rotation speed estimation circuit 228 is actually detected from the estimated voltage that is estimated by the AC voltage from the commercial power supply 91 and will be applied to the smoothing capacitor 222 regardless of the rotation of the fan motor 51. If the result is higher (area A in FIG. 12), it is determined that the fan motor 51 is in a high rotation state.

  In the case of the present embodiment, even if the fan motor 51 has been rotated before the start due to the influence of wind or the like, if the rotational speed is equal to or lower than the predetermined rotational speed, the induced voltage associated with the rotational speed is increased. In comparison, the DC power source is sufficiently large, and the DC capacitor is charged in the smoothing capacitor 222 (region B in FIG. 12). In this case, it is difficult to grasp whether or not the fan motor 51 before the rotation is rotating. However, since the method according to the present embodiment can roughly grasp whether or not the rotational speed of the fan motor 51 before activation is high, the operation of step S5 in FIG. 5 of the first embodiment is performed. Is no longer necessary.

  In addition, as described above, when control is performed such that the fan motor 51 is not activated when the rotation speed of the fan motor 51 is equal to or higher than the predetermined rotation speed, the absolute value of the rotation speed is not necessarily required. It is only necessary to know that the rotational speed of the fan motor 51 is equal to or higher than the predetermined rotational speed. Therefore, even with the method of the second embodiment, it is possible to perform drive control of a high-performance motor according to the rotation state.

  The rotation speed estimation circuit 228 can obtain the estimated voltage described above from characteristics such as the capacity of the smoothing capacitor 222 and the magnitude of the AC voltage.

  Also in the present embodiment, as in the first embodiment, the rotation speed estimation circuit 228 merely estimates the rotation speed regardless of whether the rotation direction of the fan motor 51 before startup is the forward direction or the reverse direction. It has become.

(3) Operation Next, the operation of the motor drive device 220 of the present embodiment will be described with reference to FIG. FIG. 13 is a flowchart showing the overall operation of the motor drive device 220.

  Steps S <b> 21 to S <b> 22: When the sensorless control circuit 229 obtains an operation start instruction for the outdoor fan 15 from the outdoor unit side control unit of the outdoor unit 10 (Yes in Step S <b> 21), the voltage detection unit 223 has both ends of the smoothing capacitor 222. The voltage, that is, the smoothed voltage Vfl is detected (step S22).

  Steps S23 to S25: The rotation speed estimation circuit 228 performs an operation for estimating the rotation speed of the fan motor 51 before activation (S23). Then, the rotational speed estimation circuit 228 compares the actual smoothed voltage Vfl in step S22 with the estimated voltage in step S23 (S24). When the actual smoothed voltage Vfl is equal to or higher than the estimated voltage (Yes in S24), the rotation speed estimation circuit 228a determines that the current fan motor 51 is in a high rotation state before startup. At this time, the activation of the fan motor 51 is postponed (S25).

  Step S26: Every time a predetermined time elapses from the operation of Step S22, the operations after Step S22 are repeated. That is, when it is determined in step S25 that the fan motor 51 is not started, the detection operation of the smoothed voltage Vfl is retried.

  Step S27: In step S24, when the actual smoothed voltage Vfl is less than the estimated voltage (No in S24), the rotational speed estimation circuit 228 determines whether the fan motor 51 at the present time before starting is rotating. Or it is determined that the engine is in a low rotation state. At this time, the start-up operation of the fan motor 51 is performed (S27), and the drive voltages SU, SV, SW are output to the fan motor 51 from the inverter 225.

  Step S <b> 28: The fan motor 51 started in Step S <b> 27 is driven by the sensorless control circuit 229 without the rotor position sensor.

  Steps S29 to S30: Until the sensorless control circuit 229 obtains an instruction to stop driving the outdoor fan 15 (No in Step S29), the rotor position sensorless driving according to Step S28 is performed. When the sensorless control circuit 229 receives an instruction to stop driving the outdoor fan 15 (Yes in step S29), the output of the drive voltages SU, SV, SW to the fan motor 51 by the inverter 225 is stopped, and the fan motor 51 is not driven. Stop (S30).

(4) Features (4-1)
In the motor driving device 120, unlike the motor driving device 20 according to the first embodiment described above, the fan motor 51 before starting is activated by the smoothed voltage Vfl in a state where the DC power is supplied to the first smoothing capacitor 122. Is estimated. In this case, when the post-smoothing voltage Vfl is detected, a direct current power source is applied to the first smoothing capacitor 122. In addition, if the fan motor 51 is rotating to some extent, an induced voltage (more specifically, Is applied with the induced voltage after being rectified by the return diodes D3a to D5b of the fan inverter 125. That is, the voltage across the first smoothing capacitor 122 is increased by the induced voltage of the fan motor 51. Therefore, when the fan motor 51 before starting is rotating to some extent, the rotational speed of the fan motor 51 before starting can be grasped by the smoothed voltage Vfl.

(4-2)
In the motor drive device 120 according to the present embodiment, when the actual smoothed voltage Vfl is greater than the smoothed voltage obtained by estimation based on the AC voltage output from the commercial power supply 91 (that is, the estimated voltage). The fan motor 51 is determined to be in a high rotation state. Therefore, the rotational state of the fan motor 51 can be grasped by the actual magnitude of the smoothed voltage Vfl.

(5) Modification (5-1) Modification 2A
In the above embodiment, the case where the motor driving device 220 drives only the fan motor 51 has been described as shown in FIG. However, the motor driving device 220 can also be applied to a configuration in which the fan motor 51 and the compressor motor 61 are connected in parallel, as shown in Modification 1B of the first embodiment. The configuration of the motor driving device in this case employs a configuration without the relay 127 in FIG. Then, the rotation speed estimation circuit 228 determines whether or not the rotation speed of the fan motor 51 before startup is in a high rotation state according to the comparison result between the detection result of the voltage detection unit 223 and the estimated voltage, An operation for estimating the rotational speed of the fan motor 51 before starting from the detection result of the voltage detection unit 223 is performed.

  Further, as in Modification 1C, the motor drive device may further include an energization limiting unit 127 ′ positioned between the first smoothing capacitor 122 and the second smoothing capacitor 132.

  Also in this case, the energization limiting unit 127 ′ is configured by a diode or the like, for example. The anode side terminal of the energization limiting unit 127 ′ is connected to the second smoothing capacitor 132 side, and the cathode side terminal is connected to the first smoothing capacitor 122 side. The energization limiting unit 127 ′ is turned on when a voltage equal to or higher than a predetermined voltage value is applied to both ends thereof, and only energizes in one direction from the second smoothing capacitor 132 side to the first smoothing capacitor 122 side.

  By providing the energization limiting unit 127 ′ in this way, the influence on the first smoothing capacitor 122 side, such as load fluctuation on the compressor inverter 133 side, is reduced, and the detection accuracy of the rotational speed of the fan motor 51 is improved. be able to. Further, as in Modification 1C, the number of diodes may be plural according to the value of the circuit current.

(5-2) Modification 2B
In the above-described embodiment, the case where the rotation speed estimation circuit 228 is configured by hardware has been described. However, as long as the rotation speed estimation unit can perform the operation of estimating the rotation speed of the fan motor 51 before starting as described in the above “(2-2) rotation speed estimation circuit”, any configuration is possible. It may be. Therefore, the rotation speed estimation unit may be constituted by a microcomputer that operates according to the above-described program for the rotation speed estimation operation.

  In the above embodiment, the description has been made assuming that the rotation speed estimation circuit 228 estimates the voltage across the smoothing capacitor 222 from the value of the AC voltage. However, since the AC voltage is normally supplied within a predetermined voltage range, it can be considered that the estimated voltage, which is a value obtained by rectifying the AC voltage, also falls within the predetermined range. That is, in the present embodiment, it is only necessary to know that “the rotational speed of the fan motor 51 is equal to or higher than the predetermined rotational speed”. Therefore, the application that does not require the accuracy of driving the fan motor 51 or the fan motor 51 If the motor drive device according to the present embodiment is used for an application in which the induced voltage is relatively higher than the estimated voltage, the rotation speed estimation circuit 228 can omit the measurement of the AC voltage. Thereby, it can be set as a still cheaper structure.

  As mentioned above, although embodiment of this invention and its modification were demonstrated based on drawing, specific structure is not restricted to these embodiment and its modification, It changes in the range which does not deviate from the summary of invention. Is possible.

DESCRIPTION OF SYMBOLS 10 Outdoor unit 14 Evaporator 15 Outdoor fan 20 Motor drive device 21 Rectification part 22 Smoothing capacitor 23 Voltage detection part 24 Current detection part 25 Inverter 26 Gate drive circuit 27 Blocking part 27c Inrush current suppression part 28 Rotation speed estimation circuit 29 Sensorless control circuit 30 Microcomputer 30a Judgment unit 30b Relay control unit 51 Brushless DC motor (fan motor)
100 Motor drive system 122 First smoothing capacitor 125 Fan inverter 126 Fan motor drive IC
127 Relay 127 ′ Energization limiting unit 132 Second smoothing capacitor 133 Compressor inverter 136 Compressor motor drive IC

JP-A-7-337080

Claims (13)

Generating a first drive voltage (SU to SW, SU1 to SW1) for driving the motor (51) using the smoothed voltage which is a voltage smoothed by the first smoothing capacitor (22, 122, 222); A first inverter (25, 125, 225) that outputs to the motor;
A voltage detector (23, 123, 223) for detecting a value of the smoothed voltage before starting the motor;
A rotational speed estimation unit (28, 126b, 228) for estimating the rotational speed of the motor before startup based on a detection result by the voltage detection unit;
A motor drive device (20, 120, 220). The first smoothing capacitor (22) smoothes the DC power supplied from the DC power supply (21),
A first shut-off unit (27) for shutting off the supply of the DC power from the DC power supply to the first smoothing capacitor before starting the motor;
Further comprising
The motor drive device (20) according to claim 1. The first interrupting unit (27) includes an inrush current suppressing unit (27b) for suppressing an inrush current from flowing through the first smoothing capacitor immediately after the DC power source starts to be supplied to the first smoothing capacitor.
The motor drive device (20) according to claim 2. The DC power supply unit (21) generates the DC power supply using an AC voltage output from a commercial power supply (91),
The first blocking part (27)
Further, when an abnormality occurs in the device, the supply of the DC power supply to the first smoothing capacitor is cut off, thereby disconnecting the commercial power supply (91) and the first inverter (25).
The motor drive device (20) according to any one of claims 2 to 4. The motor is a drive source of a fan that is one of the devices included in the outdoor unit of the heat pump device.
The motor drive device (20) according to any one of claims 1 to 4. A first determination unit (30a) for determining whether the rotation speed of the motor before startup estimated by the rotation speed estimation unit (28) is equal to or higher than a first predetermined rotation speed;
Further comprising
The first inverter (25)
When the rotational speed of the motor before startup is less than the first predetermined rotational speed, the first drive voltage is output to the motor,
When the rotational speed of the motor before activation is equal to or higher than the first predetermined rotational speed, the first drive voltage is not output to the motor.
The motor drive device (20) according to any one of claims 1 to 5. The motor (51) is a fan motor which is a drive source of the fan in an outdoor unit of a heat pump apparatus including a compressor and a fan,
Based on a voltage from a second smoothing capacitor (132) connected in parallel to the first smoothing capacitor (122) and the first inverter (125), a compressor motor (61) as a drive source of the compressor A second inverter (133) for generating a second drive voltage (SU2 to SW2) for driving the compressor motor and outputting it to the compressor motor;
Application of voltage from the second smoothing capacitor (132) side to the first smoothing capacitor (122) side is connected between the second smoothing capacitor (132) and the first smoothing capacitor (122). A second blocking portion (127) capable of blocking
Further comprising
The second shut-off unit (127) is connected to the second smoothing capacitor (132) and the first smoothing unit when the voltage detection unit (123) detects the smoothed voltage before the fan motor (51) is activated. To disconnect from the capacitor (122),
The motor drive device (120) according to claim 1. A second determination unit (130aa) for determining whether the rotation speed of the motor before startup estimated by the rotation speed estimation unit (126b) is equal to or higher than a second predetermined rotation speed;
Further comprising
When the rotational speed of the fan motor (51) before startup is less than the second predetermined rotational speed,
The second blocking part (127) connects between the second smoothing capacitor (132) and the first smoothing capacitor (122),
The first inverter (125) outputs the first drive voltage to the fan motor (51),
When the rotational speed of the fan motor (51) before startup is equal to or higher than the second predetermined rotational speed,
The second blocking unit (127) maintains a state where the second smoothing capacitor (132) and the first smoothing capacitor (122) are blocked,
The first inverter (125) does not output the first drive voltage to the fan motor (51).
The motor drive device (120) according to claim 7. The first smoothing capacitor (222) smoothes the DC power supplied from a DC power supply unit (221) for generating DC power,
The voltage detector (223) detects the value of the smoothed voltage in a state where the DC power supply is supplied to the first smoothing capacitor.
The motor drive device (220) according to claim 1. The DC power supply unit (221) generates the DC power using an AC voltage output from a commercial power supply (91),
The rotation speed estimation unit (228) rotates the motor before starting when the detection result of the voltage detection unit is larger than the estimated voltage that is the smoothed voltage obtained by estimation from the value of the AC voltage. Determining that the number of revolutions is higher than the third predetermined number of revolutions;
The motor drive device (220) according to claim 9. An energization limiting unit (127 ′) that performs energization in only one direction from the second smoothing capacitor (132) to the first smoothing capacitor (122);
In addition,
The motor drive device (120) according to any one of claims 7 to 10. The motor is a brushless DC fan motor.
The motor drive device (20, 120, 220) according to any one of claims 1 to 11. The motor is driven without a rotor position sensor after startup,
The motor drive device (20, 120, 220) according to any one of claims 1 to 12.

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