JP2009195065A - Power calculation device, air-conditioning device, and power calculation method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power calculation device that highly accurately calculates motor power, an air-conditioning device equipped with the same, and a power calculation method. <P>SOLUTION: Each of first and second power calculation devices 9a, 9b includes a DC power calculation part 91, a loss-power calculation part 92, and a motor-power calculation part 93. The DC power calculation part 91 calculates a DC power Wdc on the basis of a DC voltage Vdc applied to an inverter 84 and a DC current Idc conducted to the inverter 84 during operation of the inverter 84. The loss-power calculation part 92 calculates a loss power Wls lost in the inverter 84. The motor-power calculation part 93 calculates a motor power Wmt in each of first/second fan motors 7a, 7b by subtracting the loss power Wls calculated by the loss-power calculation part 92 from the DC power Wdc calculated by the DC-power calculation part 91. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a power calculation device, and more particularly to a power calculation device for a motor driven by AC power from a conversion unit that converts DC power to AC power. The present invention relates to an air conditioner including this power calculation device. Furthermore, the present invention relates to a power calculation method for calculating motor power in a motor in a motor drive system including a conversion unit that converts DC power into AC power and a motor that is driven based on AC power from the conversion unit.

The air conditioner includes various devices such as a compressor and a fan. As a power source for these devices, for example, as shown in Patent Document 1, a motor is often used. The motor is connected to an inverter composed of a plurality of power modules. The inverter converts DC power into AC power by turning on and off each power module, and supplies the converted AC power to the motor. As a result, the motor can rotate.
JP 2004-364492 A

  However, when the inverter converts DC power to AC power, not all DC power is converted to AC power and supplied to the motor, but power loss may occur due to the inverter. That is, the desired power is not necessarily supplied to the motor.

  In addition, power supplied to the motor (hereinafter referred to as motor power) may be used for controlling the motor, for example. In such a case, when the desired motor power is not supplied to the motor, the motor may not be properly controlled.

  Then, an object of this invention is to provide the electric power calculation apparatus which can obtain | require motor electric power accurately, an air conditioning apparatus provided with the same, and an electric power calculation method.

  The power calculation device according to the first aspect of the present invention is a power calculation device for a motor driven by AC power from a conversion unit that converts DC power to AC power. The power calculation device includes a DC power calculation unit, a loss power calculation unit, and a motor power calculation unit. The direct-current power calculation unit calculates direct-current power based on the direct-current voltage applied to the conversion unit and the direct-current supplied to the conversion unit during the operation of the conversion unit. The loss power calculation unit calculates the loss power lost in the conversion unit. The motor power calculation unit calculates motor power in the motor by subtracting the loss power calculated by the loss power calculation unit from the DC power calculated by the DC power calculation unit.

  According to this power calculation device, the motor power can be obtained by subtracting the loss power in the conversion unit from the DC power obtained during operation of the conversion unit. As a result, the motor power can be obtained with high accuracy in consideration of the power loss in the converter.

  A power calculation apparatus according to a second aspect of the present invention is the power calculation apparatus according to the first aspect of the present invention, wherein the loss power calculation unit calculates the loss power during the operation of the conversion unit.

  According to this power calculation device, since the power loss is calculated during the operation of the conversion unit, the power loss at that time can be obtained. Therefore, more accurate motor power is calculated.

  A power calculation device according to a third aspect of the present invention is the power calculation device according to the second aspect of the present invention, wherein the conversion unit has a plurality of switching elements. The switching element is turned on or off to convert DC power into AC power. Then, the power loss calculation unit calculates power loss using at least one of the duty of the direct current that is passed through the conversion unit and the carrier frequency at which the switching element is turned on and off.

  According to this power calculation device, the power loss is calculated using at least one of the duty of the direct current and the carrier frequency of the switching element. Therefore, the loss power is calculated with higher accuracy.

  A power calculation device according to a fourth aspect of the present invention is the power calculation device according to any one of the first to third aspects, wherein an actuator using the motor as a drive source is connected to the motor. The power calculation device further includes a first control unit. The first control unit feedback-controls the motor based on the calculated motor power during the operation of the actuator.

  According to this power calculation device, the motor is feedback-controlled based on the calculated motor power. Therefore, the motor is more appropriately controlled based on the motor power at that time.

  The air conditioning apparatus according to a fifth aspect includes an electric power calculation device, a conversion unit, a fan motor, a fan, and a second control unit. The power calculation device is a power calculation device according to any one of the first to third aspects. The conversion unit converts DC power into AC power. The fan motor is supplied with AC power from the converter. The fan uses a fan motor as a drive source. The second control unit controls the amount of air sent from the fan to the room based on the motor power calculated by the motor power calculation unit of the power calculation device.

  The air conditioner can rotate the fan based on the calculated motor power at that time. Therefore, the air conditioner can perform control so that the amount of air sent to the room is constant.

  A power calculation method according to a sixth aspect of the present invention is a method for calculating motor power in a motor in a motor drive system having a converter that converts DC power into AC power and a motor that is driven based on AC power from the converter. is there. This power calculation method includes the following first step, second step, and third step. In the first step, during operation of the conversion unit, DC power is calculated based on the DC voltage applied to the conversion unit and the DC current supplied to the conversion unit. In the second step, the power loss lost in the converter is calculated. In the third step, the motor power is calculated by subtracting the loss power calculated in the second step from the DC power calculated in the first step.

  According to this power calculation method, the motor power is obtained by subtracting the loss power in the conversion unit from the DC power obtained during operation of the conversion unit. As a result, the motor power can be obtained with high accuracy in consideration of the power loss in the converter.

  A power calculation method according to a seventh aspect is the power calculation method according to the sixth aspect, wherein the second step is performed during the operation of the conversion unit.

  According to this power calculation method, since the loss power is calculated during the operation of the conversion unit, the loss power at that time can be obtained. Therefore, more accurate motor power is calculated.

  An electric power calculation method according to an eighth aspect is the electric power calculation method according to the seventh aspect, wherein the conversion unit includes a plurality of switching elements. The switching element is turned on or off to convert DC power into AC power. In the second step, the loss power is calculated using at least one of the duty of the direct current that is passed through the converter and the carrier frequency at which the switching element is turned on and off.

  According to this power calculation method, the power loss is calculated using at least one of the duty of the direct current and the carrier frequency of the switching element. Therefore, the loss power is calculated with higher accuracy.

  A power calculation method according to a ninth aspect of the present invention is the power calculation method according to any of the sixth to eighth aspects, wherein an actuator using the motor as a drive source is connected to the motor. The power calculation method further includes a fourth step. In the fourth step, during the operation of the actuator, feedback control of the motor is performed based on the motor power calculated in the third step.

  According to this power calculation method, the motor is feedback-controlled based on the calculated motor power. Therefore, the motor is more appropriately controlled based on the motor power at that time.

  According to the power calculation apparatus according to the first aspect of the present invention, the motor power is obtained with high accuracy in consideration of the power loss in the conversion unit.

  According to the power calculation device according to the second aspect of the present invention, since the power loss is calculated during the operation of the conversion unit, the power loss at that time can be obtained. Therefore, more accurate motor power is calculated.

  According to the power calculation device of the third aspect, the loss power is calculated using at least one of the duty of the direct current and the carrier frequency of the switching element. Therefore, the loss power is calculated with higher accuracy.

  According to the power calculation device according to the fourth aspect of the present invention, the motor is feedback-controlled based on the calculated motor power. Therefore, the motor is more appropriately controlled based on the motor power at that time.

  The air conditioning apparatus according to the fifth aspect of the present invention can rotate the fan based on the calculated motor power at that time. Therefore, the air conditioner can perform control so that the amount of air sent to the room is constant.

  According to the power calculation method according to the sixth aspect of the invention, the motor power can be obtained with high accuracy in consideration of the power loss in the conversion unit.

  According to the power calculation method according to the seventh aspect of the present invention, since the loss power is calculated during the operation of the conversion unit, the loss power at that time can be obtained. Therefore, more accurate motor power is calculated.

  According to the power calculation method according to the eighth aspect of the present invention, the loss power is calculated using at least one of the duty of the direct current and the carrier frequency of the switching element. Therefore, the loss power is calculated with higher accuracy.

  According to the power calculation method according to the ninth aspect of the invention, the motor is feedback-controlled based on the calculated motor power. Therefore, the motor is more appropriately controlled based on the motor power at that time.

  Hereinafter, a power calculation device for motor power according to the present invention, an air conditioner including the motor power calculation method, and a power calculation method for motor power will be described with reference to the drawings.

(1) Configuration of Air Conditioner FIG. 1 is a schematic plan view showing the configuration of an air conditioner 1 according to an embodiment of the present invention. An air conditioner 1 in FIG. 1 is a desiccant type external air conditioner in which an adsorbent such as silica gel is supported on the surface of a heat exchanger, and performs a cooling / dehumidifying operation or a heating / humidifying operation on air supplied to an indoor space. Do the driving.

  As shown in FIGS. 1 to 4 and 6, such an air conditioner 1 mainly includes a casing 2, first and second heat exchangers 3 a and 3 b, a compressor 4, a compressor motor 5, 1 and second fans 6a and 6b (corresponding to actuators), first and second fan motors 7a and 7b (corresponding to motors), first and second motor driving units 8a and 8b, first and second power calculating devices 9a, 9b and an air conditioning control unit 10 (corresponding to a second control unit). And the 1st heat exchanger 3a, the 2nd heat exchanger 3b, and the compressor 4 comprise the refrigerant circuit as shown in FIG.

(1-1) Casing The casing 2 has a substantially rectangular parallelepiped shape, and the first and second heat exchangers 3a and 3b, the compressor 4, the first and second fans 6a and 6b, and the like are included therein. Is stored. In FIG. 1, a first suction port 22 for sucking outdoor air OA into the casing 2 and a second suction port 23 for sucking indoor air RA into the casing 2 are formed in the left side plate 21 a of the casing 2. Has been. On the other hand, the right side plate 21b of the casing 2 is formed with a first air outlet 24 for exhausting the exhaust air EA to the outside and a second air outlet 25 for supplying the air SA after humidity adjustment to the room. ing. Note that a pipe extending into the room is connected to the second air outlet 25, and the air SA after being conditioned is supplied to the room through this pipe.

  A partition plate 26 that partitions the inside of the casing 2 is provided inside the casing 2. By the partition plate 26, the inside of the casing 2 is divided into an air chamber S1 and a machine chamber S2. The air chamber S1 is provided with first and second heat exchangers 3a and 3b and partition members for the heat exchangers 3a and 3b. The machine chamber S2 includes first and second heat exchangers 3a. , 3b other devices (specifically, the compressor 4, the first and second fans 6a, 6b, etc.) are arranged.

(1-2) Heat Exchanger The first heat exchanger 3a and the second heat exchanger 3b are cross fin type fin-and-tube heat exchangers as shown in FIG. A large number of aluminum fins 31 formed in a plate shape and a copper heat transfer tube 32 penetrating the fins 31 are provided. On the outer surfaces of the fins 31 and the heat transfer tubes 32, an adsorbent that adsorbs moisture contained in the air passing through the heat exchangers 3a and 3b is supported by dip molding (dip molding) or the like. Here, examples of the adsorbent include zeolite, silica gel, activated carbon, hydrophilic or water-absorbing organic polymer material, ion-exchange resin material having carboxylic acid group or sulfonic acid group, and temperature-sensitive polymer. A functional polymer material or the like can be used.

  Such first and second heat exchangers 3a and 3b are connected to each other via an expansion valve 13, as shown in FIG. For example, the first heat exchanger 3a exchanges heat with the indoor air RA sucked from the second suction port 23, and the second heat exchanger 3b heats the outdoor air OA sucked from the first suction port 22 and heat Exchange. The indoor air RA after the heat exchange is discharged outside as the exhaust air EA, and the outdoor air OA after the heat exchange is supplied indoors as the air SA after humidity adjustment.

  The first and second heat exchangers 3a and 3b include a first state where the first heat exchanger 3a functions as a condenser and the second heat exchanger 3b functions as an evaporator, and the first heat exchanger 3a includes It is controlled by the air conditioning control unit 10 so that the evaporator and the second heat exchanger 3b can take either the second state functioning as a condenser. In the first state, the adsorbent regeneration operation that desorbs moisture from the adsorbent when the first heat exchanger 3a functions as a condenser, and the adsorbent when the second heat exchanger 3b functions as an evaporator. An adsorbing operation for adsorbing moisture on the surface is performed. Further, in the second state, an adsorption operation for adsorbing moisture to the adsorbent when the first heat exchanger 3a functions as an evaporator, and moisture from the adsorbent when the second heat exchanger 3b functions as a condenser. An adsorbent regeneration operation for desorbing is performed. As described above, the adsorption operation and the regeneration operation are alternately performed, and the flow paths of the air EA and SA that pass through the heat exchangers 3a and 3b and are supplied indoors and outdoors are switched. Moisture adsorption and release (ie desorption) can be performed continuously. Therefore, the air conditioning apparatus 1 can perform various operations while maintaining the dehumidifying performance or the humidifying performance.

  Here, the flow path switching of the air EA, SA that passes through the heat exchangers 3a, 3b and is supplied indoors and outdoors is performed by a switching damper (not shown). The switching damper is blown out from the first outlet 24 or the first outlet 25 after the outdoor air OA and the indoor air RA have passed through either the first heat exchanger 3a or the second heat exchanger 3b. The air flow path is switched.

(1-3) Compressor and Compressor Motor The compressor 4 is connected to the first heat exchanger 3a and the second heat exchanger 3b via the four-way switching valve 12, as shown in FIG. . The compressor 4 compresses the refrigerant from the first heat exchanger 3a or the second heat exchanger 3b that functions as an evaporator. The compressor 4 that performs the compression operation is driven by a compressor motor 5.

  The compressor motor 5 is connected to the compressor 4. Such a compressor motor 5 is, for example, a three-phase brushless DC motor, and is rotationally driven by a compressor motor drive unit 51 (FIG. 6).

(1-4) Fan and fan motor [Fan]
As shown in FIG. 1, the first fan 6 a is provided at a position corresponding to the first air outlet 24, and exhaust air EA is supplied to the outside of the casing 2 (specifically, outdoors) via the first air outlet 24. To send. The 2nd fan 6b is provided in the position corresponding to the 2nd blower outlet 25, and sends out the air SA after humidity control outside the casing 2 (specifically indoors) through the 2nd blower outlet 25. As shown in FIG. The first fan 6a and the second fan 6b are, for example, crossflow fans, and rotate using the first fan motor 7a and the second fan motor 7b as drive sources, respectively.

[Fan motor]
The first fan motor 7a and the second fan motor 7b are connected to the first fan 6a and the second fan 6b, respectively. Like the compressor motor 5, the first fan motor 7a and the second fan motor 7b are, for example, three-phase brushless DC motors, specifically, a rotor composed of permanent magnets having a plurality of magnetic poles, and a drive coil. And a stator having. The first fan motor 7a and the second fan motor 7b are driven by the first motor driving unit 8a and the second motor driving unit 8b.

(1-5) Motor Drive Unit The first and second motor drive units 8a and 8b supply AC power to the first and second fan motors 7a and 7b, respectively, and the first and second fan motors 7a and 7b. It is for driving. As a drive control method of the first and second fan motors 7a and 7b in the first and second motor drive units 8a and 8b, PWM (Plus-Width-Modulation) drive control and PAM (Plus-Amplitude-Modulation) drive are used. Control, drive control by a combination of PWM drive control and PAM drive control, and the like. Here, since the first and second motor drive units 8a and 8b have the same configuration, the configuration of the first motor drive unit 8a will be described below as an example.

  As shown in FIG. 4, the first motor drive unit 8 a includes a power supply unit 81, a voltage detection unit 82, a current detection unit 83, an inverter 84 (corresponding to a conversion unit), and a gate driver 85.

〔Power supply part〕
The power supply unit 81 generates a power supply voltage and supplies it to the inverter 84 via the power supply line L1. Here, examples of the type of the power supply unit 81 include a dropper type power supply and a switching power supply.

(Voltage detector)
Voltage detector 82 detects a power supply voltage (hereinafter referred to as DC voltage Vdc) applied to inverter 84. Such a voltage detection part 82 is comprised by resistance, an operational amplifier, etc. The resistor is connected between the power supply line L 1 and the GND line L 2 of the inverter 84. Two input terminals of the operational amplifier are respectively connected to both ends of the resistor, and an output terminal is connected to a first power calculation device 9a described later. The result (that is, the DC voltage Vdc) detected by the voltage detector 82 having such a configuration is output to the first power calculation device 9a.

[Current detector]
The current detection unit 83 detects a direct current Idc that flows on the GND wiring L <b> 2 of the inverter 84. Like the voltage detection unit 82, the current detection unit 83 includes a resistor connected in series on the GND wiring L1, an operational amplifier in which two input terminals are connected to both ends of the resistor, and the like. . The detection result (that is, the direct current Idc) by the current detection unit 83 is output to the first power calculation device 9a.

[Inverter]
The inverter 84 is for converting DC power into AC power and supplying it to the first fan motor 7a, and includes a plurality of power modules Q1 to Q6 and a plurality of reflux diodes D1 to D6. The power modules Q1 to Q6 are, for example, insulated gate bipolar transistors (hereinafter simply referred to as transistors). The transistors Q1 and Q2, Q3 and Q4, and Q5 and Q6 are connected in series between the power supply line L1 and the GND line L2. It is connected to the. The connection points NU, NV, NW between the transistors Q1 and Q2, Q3 and Q4, Q5 and Q6 are respectively connected to U-phase, V-phase and W-phase drive coils (not shown) of the first fan motor 7a. It is connected. The diodes D1 to D6 have such characteristics that they are turned on when a reverse voltage is applied to the transistors Q1 to Q6, and are connected in parallel to the transistors Q1 to Q6.

  In the inverter 84 having such a configuration, the gate signals Gu, Gx, Gv, Gy, Gw, and Gz output from the gate driver 85 are applied to the gate terminals of the transistors Q1 to Q6, so that the transistors Q1 to Q6. Turns on and off. Thereby, direct-current power is converted into alternating current power. Then, the drive signals SU, SV, SW based on the AC power are applied to the first fan motor 7a.

[Gate driver]
The gate driver 85 is configured by a microcomputer including a CPU and a memory, for example. The gate driver 85 uses the gate signals Gu, Gx so that the drive signals SU, SV, SW instructed by the feedback control unit 94 or the air conditioning control unit 10 of the first power calculating device 9a are applied to the first fan motor 7a. , Gv, Gy, Gw, Gz are generated and output to the inverter 84.

(1-6) Power Calculation Device The first and second power calculation devices 9a and 9b are devices that calculate the motor power Wmt of the fan motors 7a and 7b. The first and second power calculating devices 9a and 9b according to the present embodiment are configured by a microcomputer including a CPU and a memory, respectively, and are configured by a microcomputer different from the gate driver 85 described above. Here, since the first and second power calculation devices 9a and 9b have the same configuration, the configuration of the first power calculation device 9a will be described below as an example.

  As shown in FIG. 4, the first power calculation device 9a is mounted on the printed circuit board P1 together with the first motor drive unit 8a, and is connected to the voltage detection unit 82, the current detection unit 83, the inverter 84, and the gate driver 85. Has been. Such a first power calculation device 9a includes a DC power calculation unit 91, a loss power calculation unit 92, a motor power calculation unit 93, and a feedback control unit 94 (corresponding to the first control unit).

[DC power calculation section]
DC power calculation unit 91 calculates DC power Wdc based on DC voltage Vdc applied to inverter 84 and DC current Idc supplied to inverter 84. Specifically, the DC power calculation unit 91 according to the present embodiment multiplies the DC voltage Vdc detected by the voltage detection unit 82 and the DC current Idc detected by the current detection unit 83 during the operation of the inverter 84. Thus, the DC power Wdc is calculated (the following formula (1)).

Vdc × Idc = Wdc (1)
Note that the DC power calculation unit 91 according to the present embodiment calculates the DC power Wdc every predetermined time. Here, an example of the predetermined time is 3 μsec. In this case, since the DC power Wdc is calculated every 3 μsec, the DC power Wdc with relatively high accuracy can be obtained.

[Power Loss Calculation Unit]
The power loss calculation unit 92 calculates power loss Wls lost in the inverter 84. Here, the loss power Wls means that when the DC power Wdc is converted into AC power by the inverter 84, the DC power Wdc is not converted into AC power in the transistors Q1 to Q6 that are power modules in the inverter 84. The power that is lost. In general, as the motor capacity increases, the motor current Im supplied to the motor increases, and thus the loss power Wls increases. For example, when the first fan motor 7a requires 400 W of motor power Wmt to drive, the loss power Wls in the inverter 84 reaches about 30W. Since such a power loss in the inverter 84 occurs during the operation of the inverter 84, the loss power calculation unit 92 according to the present embodiment performs the calculation operation of the loss power Wls during the operation of the inverter 84.

  Here, how the loss power calculation unit 92 according to the present embodiment calculates the loss power Wls will be described. FIG. 5 shows induced voltages Vun and Vvn generated in the U-phase drive coil and the V-phase drive coil when the drive voltages SU and SV are applied to the U-phase drive coil and the V-phase drive coil of the first fan motor 7a. An example of the direct current Idc is shown. The loss power calculation unit 92 calculates the loss power Wls using at least one of the duty of the direct current Idc in FIG. 5 and the carrier frequency at which the transistors Q1 to Q6 are turned on and off. More specifically, the power loss calculation unit 92 first reads the value of the direct current Idc to obtain the magnitude of the motor current Im that is supplied to the first fan motor 7a. Next, the loss power calculation unit 92 generates a loss based on the motor current Im, the DC voltage Vdc, the duty of the DC current Idc, and the frequencies of the gate signals Gu, Gx, Gv, Gy, Gw, Gz (that is, the carrier frequency). Electric power Wls is calculated. Here, in the present embodiment, in order to calculate the loss power Wls with higher accuracy, not only the DC current Idc and the carrier frequency but also the DC voltage Vdc and the motor current Im are used to calculate the loss power Wls. Take the case as an example.

  The above-described loss power Wls is calculated by the loss power calculation unit 92 every predetermined time, for example, every 3 μsec, like the DC power Wdc. As a result, the loss power Wls with relatively high accuracy can be obtained.

[Motor power calculator]
Motor power calculation unit 93 calculates motor power Wmt using DC power Wdc calculated by DC power calculation unit 91 and loss power Wls calculated by loss power calculation unit 92. More specifically, the motor power calculation unit 93 calculates the motor power Wmt by subtracting the loss power Wls from the DC power Wdc (the following equation (2)).

Wdc-Wls = Wmt (2)
Since DC power Wdc and loss power Wls are both calculated during operation of inverter 84, motor power Wmt is also obtained during operation of inverter 84. Further, similarly to the calculation of the DC power Wdc and the loss power Wls, the calculation operation of the motor power Wmt is also performed every predetermined time such as every 3 μsec. As a result, a relatively accurate motor power Wmt can be obtained.

[Feedback control section]
The feedback control unit 94 feedback-controls the first fan motor 7a based on the motor power Wmt calculated by the motor power calculation unit 93 during the operation of the first fan 6a. For example, when the motor power Wmt becomes extremely low, the feedback control unit 94 estimates that the loss power Wls in the inverter 84 has increased due to some abnormality, and the gate signal that stops the rotation of the first fan motor 7a. An instruction to generate Gu, Gx, Gv, Gy, Gw, and Gz is output to the gate driver 85. Here, as the abnormality that has occurred, there is a problem that any of the transistors Q1 to Q6, which are power modules in the inverter 84, has failed, and the current flowing through the power modules Q1 to Q6 has increased.

(1-7) Air-conditioning control part The air-conditioning control part 10 is a microcomputer comprised by memories, such as RAM and ROM, and CPU. In this embodiment, the case where the air-conditioning control part 10 is provided with the microcomputer different from each electric power calculation apparatus 9a, 9b and the gate driver 85 is taken as an example. As shown in FIG. 6, the air conditioning control unit 10 is connected to and connected to the four-way switching valve 12, the expansion valve 13, the compressor motor driving unit 51, and the first and second motor driving units 8a and 8b. Control each device. For example, the air conditioning control unit 10 performs path switching control of the four-way switching valve 12, driving control of the compressor motor driving unit 51, driving control of the first and second motor driving units 8a and 8b, and the like.

  In particular, the air conditioning control unit 10 according to the present embodiment is also connected to the first and second power calculation devices 9a and 9b, and controls these devices. Specifically, the air conditioning control unit 10 controls the amount of air sent from the second fan 6b to the room based on the motor power Wmt of the fan motors 7a and 7b calculated by the power calculators 9a and 9b. . For example, the air-conditioning control unit 10 calculates the number of rotations of the first and second fan motors 7a and 7b so that the air volume into the room is substantially constant based on the motor power Wmt, and the calculated number of rotations can be obtained. The generation instruction of the gate signals Gu, Gx, Gv, Gy, Gw, Gz is output to the gate driver 85. As a result, gate signals Gu, Gx, Gv, Gy, Gw, and Gz are output from the gate driver 85 to the inverter 84 so as to obtain the rotational speed determined by the air conditioning control unit 10. Then, the transistors Q1 to Q6 of the inverter 84 are turned on and off based on the gate signals Gu, Gx, Gv, Gy, Gw, and Gz, so that the amount of air sent to the fan motors 7a and 7b is constant. Driving voltages SU, SV, and SW based on such AC power are applied.

  As described above, the air-conditioning control unit 10 performs the rotational speed control of the first and second fan motors 7a and 7b using the motor power Wmt, and performs the air volume control into the room, for example, from the second air outlet 25. It is possible to keep the air volume that is easily affected by atmospheric pressure or the like that changes depending on the length of the pipe extending into the room or the size of the room.

  Note that, as described in the present embodiment, the air volume control by the air conditioning control unit 10 and the feedback control by the feedback control unit 94 have different contents, and may be performed individually as independent controls. Further, when the content of the feedback control can be executed simultaneously with the air volume control, the air volume control and the feedback control may be performed simultaneously. Furthermore, when the air volume control and the feedback control are exclusive controls and the content of the feedback control is not executable simultaneously with the air volume control, either the air volume control or the feedback control is preferentially performed. May be.

(2) Operation Next, a series of operations of each of the power calculation devices 9a and 9b and the air conditioning control unit 10 will be described. FIG. 7 shows a motor drive system having first and second fan motors 7a and 7b and first and second motor drive units 8a and 8b. The first and second power calculation devices 9a and 9b and the air conditioning control unit 10 It is a flowchart for demonstrating a series of operation | movement performed. In FIG. 7, for convenience of explanation, the operation of the first power calculation device 9a out of the two power calculation devices 9a and 9b is taken as an example.

  Steps S1 to S3: When the first fan motor 7a is rotating and the inverter 84 and the first fan 6a are operating (Yes in S1), the DC power calculating unit 91 of the first power calculating device 9a DC power Wdc is calculated using current Idc and DC voltage Vdc (S2). Then, the loss power calculation unit 92 calculates the loss power Wls using the motor current Im, the DC voltage Vdc, the duty of the DC current Idc, and the carrier frequency of the transistors Q1 to Q6 obtained from the DC current Idc (S3).

  Step S4: The motor power calculation unit 93 subtracts the loss power Wls in step S3 from the DC power Wdc in step S2 to calculate the motor power Wmt (S4).

  Steps S5 to S6: When an error in the motor power Wmt occurs, such as the motor power Wmt calculated in step S4 is equal to or lower than the predetermined power and is significantly lower than the normal motor power Wmt (Yes in S5) The feedback control unit 94 of the first power calculating device 9a performs feedback control for stopping the rotation of the first fan motor 7a for the first fan motor 7a (S6).

  Step S7: In step S5, if the motor power Wmt error has not occurred (No in S5), the air conditioning control unit 10 performs constant air volume control using the motor power Wmt (S7).

  Step S8: Until the first fan motor 7a stops rotating and the inverter 8 and the first fan 6a stop operating, the first power calculation device 9a and the air conditioning control unit 10 repeatedly perform the operations after Step S2. (No in S8). When the first fan motor 7a stops rotating and the inverter 84 and the first fan 6a stop operating (Yes in S8), the first power calculation device 9a and the air conditioning control unit 10 perform a series of operations. finish.

(3) Effect (A)
According to the first and second power calculating devices 9a and 9b according to the present embodiment, the motor power Wmt is obtained by subtracting the loss power Wls in the inverter 84 from the DC power Wdc obtained during the operation of the inverter 84. . Thereby, the motor power Wmt is obtained with high accuracy in consideration of the power loss in the inverter 84.

(B)
Further, according to the first and second power calculating devices 9a and 9b according to the present embodiment, the loss power Wls is calculated during the operation of the inverter 84, and thus the loss power Wls at that time can be obtained. Therefore, more accurate motor power Wmt is calculated.

(C)
Further, according to the first and second power calculation devices 9a and 9b according to the present embodiment, the loss power Wls is calculated using at least one of the duty of the DC current Idc and the carrier frequency of the transistors Q1 to Q6. . Therefore, the loss power Wls is calculated with higher accuracy.

(D)
Further, according to the first and second power calculating devices 9a and 9b according to the present embodiment, the first and second fan motors 7a and 7b are feedback-controlled by the feedback control unit 94 based on the motor power Wmt. Therefore, the first and second fan motors 7a and 7b are more appropriately controlled based on the motor power Wmt at that time.

(E)
The air conditioner 1 equipped with the first and second power calculating devices 9a and 9b according to the present embodiment is controlled so that the amount of air sent to the room is constant based on the calculated motor power Wmt at that time. It can be performed.

<Other embodiments>
(A)
In the said embodiment, the case where the air conditioning apparatus which concerns on this invention was used for what is called a desiccant external air conditioner was demonstrated as an example, and was demonstrated. However, the air conditioner according to the present invention may be applied to an air conditioner other than a desiccant air conditioner.

(B)
In the above embodiment, the first and second power calculating devices 9a and 9b according to the present invention are motors for the first fan motor 7a and the second fan motor 7b that are the driving sources of the first fan 6a and the second fan 6b. The case where the present invention is applied as a device for calculating the power Wmt has been described. However, the usage of the first and second power calculating devices 9a and 9b according to the present invention is not limited to this, and can be applied when it is necessary to calculate the motor power Wmt with high accuracy. Other application examples of the first and second power calculating devices 9a and 9b of the present invention include use as a device for calculating the motor power mt of the compressor motor 5, for example.

(C)
In the above embodiment, the loss power Wls is based on the duty of the direct current Idc, the frequency of the gate signals Gu, Gx, Gv, Gy, Gw, Gz (that is, the carrier frequency) at a predetermined time such as 3 μsec. The case where it is calculated has been described. However, the loss power Wls may be determined in advance by performing simulation, desktop calculation, experiment, or the like based on the specifications of the inverter 84 and the fan motors 7a and 7b, for example. In this case, the motor power calculation unit 93 of the power calculation devices 9a and 9b can obtain the motor power Wmt by subtracting the predetermined loss power Wls from the DC power Wdc obtained every predetermined time. it can.

  Further, the calculation method of the loss power Wls is not limited to the above embodiment as long as the loss power Wls can be calculated, and any method may be used. For example, when the calculation method of the loss power Wls is described in the specification of the motor drive unit including the inverter, the loss power Wls may be calculated using this calculation method.

(D)
FIG. 7 of the above embodiment represents a case where step S3 for calculating the lost power Wls is performed after step S2 for calculating the DC power Wdc. However, in the power calculation method according to the present invention, the DC power Wdc and the loss power Wls are calculated, and the motor power Wmt may be calculated using these powers Wdc and Wls. Is not limited to FIG. Step S2 and step S3 may be performed simultaneously. Further, step S2 may be performed after step S3.

(E)
In the said embodiment, the 1st and 2nd electric power calculation apparatus 9a, 9b is comprised by the microcomputer different from the microcomputer which comprises the microcomputer which comprises the air-conditioning control part 10, and the gate driver 85. Explained the case. However, the 1st and 2nd electric power calculation apparatus 9a, 9b, the air-conditioning control part 10, and the gate driver 85 may be comprised with one microcomputer. In this case, it is assumed that a motor power calculation program, various device control programs, and a gate signal generation program are stored in the memory of one microcomputer. Such a microcomputer reads and executes any one of the motor power calculation program, the various device control programs, and the gate signal generation program in the memory, thereby executing the first and second power calculation devices 9a and 9b. It can function as either the air conditioning control unit 10 or the gate driver 85.

(F)
In the above embodiment, the feedback control for the first and second fan motors 7a and 7b performed by the feedback control unit 94 of the first and second power calculating devices 9a and 9b is different from the constant air volume control in the air conditioning control unit 10. The case where the control is performed has been described. However, the feedback control according to the present invention may be a constant air volume control instead of the error occurrence control of the motor power Wmt as described in the above embodiment. In this case, the control unit for performing the constant air volume control may be provided as the feedback control unit 94 in the first and second power calculation devices 9a and 9b, or provided as the air conditioning control unit 10 in the air conditioner 1. . In other words, in this case, one of the feedback control unit 94 and the air conditioning control unit 10 may be provided without providing them separately.

  The power calculation device and the power calculation method according to the present invention have an effect that the motor power can be obtained with high accuracy in consideration of the power loss in the conversion unit. Such a power calculation device and a power calculation method can be applied to an air conditioner, for example, as a device for calculating the motor power of a fan motor or a compressor motor.

FIG. 2 is a schematic plan view showing the configuration of the air conditioning apparatus according to the present embodiment. The refrigerant circuit figure of the air conditioning apparatus in this embodiment. The perspective view of the 1st and 2nd heat exchanger with which an air harmony device is provided. The figure which shows the circuit structure inside the printed circuit board with which the 1st and 2nd motor drive part and 1st and 2nd electric power calculation apparatus which concern on this embodiment are mounted together. When the drive voltages SU and SV are applied to the U-phase drive coil and the V-phase drive coil of the first fan motor, induced voltages Vun and Vvn and DC current Idc generated in the U-phase drive coil and the V-phase drive coil One case. The block diagram which shows typically the structure of the air conditioning apparatus which concerns on this embodiment. In the motor drive system which concerns on this embodiment, the flowchart for demonstrating a series of operation | movement performed by an electric power calculation apparatus and an air-conditioning control part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Air conditioning apparatus 2 Casing 3a 1st heat exchanger 3b 2nd heat exchanger 4 Compressor 5 Motor 6a, 6b for compressors Fan 7a, 7b 1st fan motor, 2nd fan motor 8a, 8b 1st motor drive part , Second motor drive unit 81 power supply unit 82 voltage detection unit 83 current detection unit 84 inverter 85 gate drivers 9a, 9b first power calculation device, second power calculation device 91 DC power calculation unit 92 loss power calculation unit 93 motor power calculation Unit 94 feedback control unit 10 air conditioning control unit L1 power supply wiring L2 GND wiring Vdc direct current voltage Idc direct current Wdc direct current power Wls loss power Wmt motor power Q1 to Q6 transistors D1 to D6 diode

Claims (9)

A power calculation device (9a, 9b) of a motor (7a, 7b) driven by the AC power from the converter (84) that converts DC power (Wdc) into AC power,
During the operation of the conversion unit (84), the direct current power (Idc) applied to the conversion unit (84) and the direct current power (Idc) applied to the conversion unit (84) are used to determine the DC power ( DC power calculation unit (91) for calculating (Wdc);
A power loss calculation unit (92) for calculating power loss (Wls) lost in the conversion unit (84);
The motor (7a, 7b) is obtained by subtracting the loss power (Wls) calculated by the loss power calculation unit (92) from the DC power (Wdc) calculated by the DC power calculation unit (91). A motor power calculation unit (93) for calculating motor power (Wmt) at
A power calculation device (9a, 9b). The power loss calculation unit (92) calculates the power loss (Wls) during operation of the conversion unit (84).
The power calculation device (9a, 9b) according to claim 1. The converter (84) has a plurality of switching elements (Q1 to Q6) that are turned on or off to convert the DC power into the AC power,
The loss power calculation unit (92) uses at least one of a duty of a direct current (Idc) passed through the conversion unit (84) and a carrier frequency at which the switching elements (Q1 to Q6) are turned on and off. To calculate the power loss (Wls).
The power calculation device (9a, 9b) according to claim 2. Actuators (6a, 6b) using the motors (7a, 7b) as drive sources are connected to the motors (7a, 7b),
A first control unit (94) that feedback-controls the motor (7a, 7b) based on the calculated motor power (Wmt) during the operation of the actuator (6a, 6b) is further provided.
The electric power calculation apparatus (9a, 9b) according to any one of claims 1 to 3. The power calculation device (9a, 9b) according to any one of claims 1 to 3,
A converter (84) for converting the DC power (Wds) into the AC power;
Fan motors (7a, 7b) to which the AC power is supplied from the converter (84);
Fans (6a, 6b) using the fan motors (7a, 7b) as drive sources;
Based on the motor power (Wmt) calculated by the motor power calculation unit (93) of the power calculation device (9a, 9b), the amount of air sent from the fans (6a, 6b) to the room is controlled. 2 control unit (10);
An air conditioner (1) comprising: In the motor drive system, comprising: a converter (84) that converts DC power (Wdc) into AC power; and a motor (7a, 7b) that is driven based on the AC power from the converter (84). A power calculation method for calculating motor power (Wmt) in (7a, 7b),
During the operation of the conversion unit (84), the direct current power (Idc) applied to the conversion unit (84) and the direct current power (Idc) applied to the conversion unit (84) are used to determine the DC power ( A first step of calculating Wdc);
A second step of calculating the power loss (Wls) lost in the converter (84);
A third step of calculating the motor power (Wmt) by subtracting the loss power (Wls) calculated in the second step from the DC power (Wdc) calculated in the first step;
A power calculation method comprising: The second step is performed during the operation of the conversion unit (84).
The power calculation method according to claim 6. The converter (84) has a plurality of switching elements (Q1 to Q6) that are turned on or off to convert the DC power into the AC power,
In the second step, the power loss (at least one of the duty of the direct current (Idc) passed through the converter (84) and the carrier frequency at which the switching elements (Q1 to Q6) are turned on and off is used. Wls) is calculated,
The power calculation method according to claim 7. Actuators (6a, 6b) using the motors (7a, 7b) as drive sources are connected to the motors (7a, 7b),
During the operation of the actuators (6a, 6b), the method further includes a fourth step of feedback-controlling the motors (7a, 7b) based on the motor power (Wmt) calculated in the third step.
The electric power calculation method in any one of Claims 6-8.

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