WO2021214878A1 - Electric motor control device and air conditioning device having same - Google Patents

Abstract

This electric motor control device includes: an electric power conversion device that supplies alternating current voltage corresponding to a voltage instruction value to an electric motor; an electric current detecting device that detects an electric current flowing at the electric motor; and a control device that outputs, to the electric power conversion device, the voltage instruction value calculated in accordance with a speed instruction value and information of the electric current detected by the electric current detecting device. The control device includes: rotations estimating means that calculate estimated rotations of the electric motor using an electric current detection value that is the electric current detected by the electric current detecting device; electric current estimating means that estimate the electric current flowing at the electric motor using the voltage instruction value, the estimated rotations, and a parameter of the electric motor; and compensation amount calculating means that calculate a compensation amount for compensating for voltage error that is an error between output voltage of the electric power conversion device and the voltage instruction value, on the basis of an electric current difference that is a value obtained by subtracting the electric current detection value from an electric current estimation value that is an electric current estimated by the electric current estimating means.

Description

Motor control device and air conditioner equipped with it

The present disclosure relates to an electric motor control device that controls the rotation of a motor using a power conversion device and an air conditioner provided with the electric motor control device.

Motors such as brushless DC motors are used for various purposes such as driving fans of air conditioners. As a power conversion device that supplies electric power to an electric motor, for example, there is an inverter. The inverter has a configuration in which three sets of two switching elements connected in series between the high voltage line and the low voltage line of the DC power supply are provided. Of the two switching elements in each set, the switching element connected to the high voltage line is referred to as the upper switching element, and the switching element connected to the low voltage line side is referred to as the lower switching element.

Each switching element requires a time of several hundred ns to several μs for the switching operation. Therefore, in one set of switching elements, while the upper switching element switches from the on state to the off state and the lower switching element switches from the off state to the on state, the upper and lower switching elements temporarily simultaneously move at the same time. It may be turned on. If the upper and lower switching elements are turned on at the same time, the primary side of the inverter is short-circuited and the switching element is destroyed. In order to prevent this short circuit, a period is provided in which the upper and lower switching elements are simultaneously turned off. This period is called dead time. However, due to the dead time, a voltage error may occur between the output voltage of the inverter and the voltage command value, and the control accuracy may decrease.

As a method of compensating for the voltage error caused by the dead time, a control method is known in which the magnitude of the voltage error caused by the dead time is estimated in advance and the voltage error amount is added to the voltage command value (for example, Patent Document 1). reference). In Patent Document 1, current control is performed so that a constant DC current flows through the motor for each frequency of the two types of switching frequencies, and the difference in output voltage corresponding to the two types of switching frequencies is used to determine the voltage error. A method of estimating the size is disclosed.

International Publication No. 98/042067

In the control method disclosed in Patent Document 1, it is necessary to pass a constant direct current through the motor for each of the two types of switching frequencies. When the motor to be controlled is an electric motor that rotates the blower fan, the control device drives the electric motor by passing an alternating current, so that the method disclosed in Patent Document 1 cannot be applied while the blower fan is being driven.

The present disclosure has been made to solve the above-mentioned problems, and is an electric motor control device for calculating a compensation amount for compensating for a voltage error due to a dead time while driving an electric motor, and an air conditioner equipped with the electric motor control device. Is to provide.

The electric motor control device according to the present disclosure includes a power conversion device that supplies an AC voltage corresponding to a voltage command value, which is a command value of a voltage applied to the electric motor, to the electric motor, and a current detection device that detects a current flowing through the electric motor. A control device that calculates the voltage command value corresponding to the speed command value, which is the command value of the rotation speed of the electric motor, and the current information detected by the current detection device, and outputs the voltage command value to the power conversion device. The control device includes a rotation speed estimation means for calculating an estimated rotation speed, which is an estimated value of the rotation speed of the electric motor, using a current detection value, which is a current detected by the current detection device, and the voltage. A current estimation means for estimating the current flowing through the electric motor using a command value, the estimated rotation speed, and a parameter of the electric motor stored in advance, and a current estimation value which is a current estimated by the current estimation means. A compensation amount calculation means for calculating a compensation amount for compensating for a voltage error which is an error between the output voltage of the power converter and the voltage command value based on the current difference which is a value obtained by subtracting the current detection value from the current detection value. It has.

The air conditioner according to the present disclosure is connected to the motor control device, a heat exchanger for heat exchange between the refrigerant and air, a fan provided corresponding to the heat exchanger, and the fan. It has an electric motor to be controlled by the electric motor control device.

According to the present disclosure, the output of the power converter is based on the current difference obtained by subtracting the current value detected by the current detector from the current estimated value estimated using the voltage command value, the estimated rotation speed and the parameters of the electric motor. The compensation amount for compensating for the voltage error between the voltage and the voltage command value is calculated. Therefore, the voltage error due to the dead time can be appropriately compensated even while the motor is being driven.

It is a refrigerant circuit diagram which shows an example of the air conditioner including the motor control device which concerns on Embodiment 1. FIG. It is a block diagram which shows one configuration example of the motor control device shown in FIG. It is a figure which shows one configuration example when the power conversion apparatus shown in FIG. 2 is an inverter. It is a functional block diagram which shows one configuration example of the control device shown in FIG. It is a hardware configuration diagram which shows one configuration example of the control device shown in FIG. It is a hardware configuration diagram which shows another configuration example of the control device shown in FIG. It is a flowchart which shows an example of the operation procedure of the control device in the motor control device which concerns on Embodiment 1. FIG. It is a flowchart which shows an example of the procedure which the compensation amount calculation means updates a compensation amount in the motor control device which concerns on Embodiment 1. FIG. It is a flowchart which shows a part of the processing after activation of the current estimation means in the electric motor control device which concerns on Embodiment 1. FIG. It is a flowchart which shows an example of the operation procedure of the compensation amount calculation means in the motor control device which concerns on Embodiment 2. FIG. It is a flowchart which shows an example of the operation procedure of the compensation amount calculation means in the motor control device which concerns on Embodiment 3. FIG. It is a flowchart which shows an example of the operation procedure of the compensation amount calculation means in the motor control device which concerns on Embodiment 3. FIG. It is a graph which shows an example of the update result of the compensation amount in the motor control device which concerns on Embodiment 3. FIG. It is a graph which shows another example of the update result of the compensation amount in the motor control device which concerns on Embodiment 3. FIG. It is a figure which shows an example of the command value which changes the compensation amount in the electric motor control device which concerns on Embodiment 4. FIG. It is a flowchart which shows an example of the operation procedure of the compensation amount calculation means in the electric motor control device which concerns on Embodiment 4. FIG.

Embodiment 1.
The configuration of the air conditioner including the motor control device of the first embodiment will be described. FIG. 1 is a refrigerant circuit diagram showing an example of an air conditioner including the motor control device according to the first embodiment. As shown in FIG. 1, the air conditioner 1 has a heat source side unit 2 and a load side unit 3.

The heat source side unit 2 includes a compressor 4 that compresses and discharges the refrigerant, a four-way valve 5 that switches the flow direction of the refrigerant, a heat source side heat exchanger 6 that exchanges heat with the outside air, and expands by reducing the pressure of the refrigerant. It has an electromagnetic valve 7 for causing the refrigerant to operate, and a host control device 9. Further, the heat source side unit 2 includes a fan 10 that supplies outside air to the heat source side heat exchanger 6, an electric motor 11 that drives the fan 10, and an electric motor control device 12 that supplies a three-phase voltage to the electric motor 11. The load-side unit 3 includes a load-side heat exchanger 13 that exchanges heat with the air in the space to be air-conditioned, and an electromagnetic valve 8 that depressurizes and expands the refrigerant.

Although not shown in FIG. 1, the upper control device 9 is connected to the four-way valve 5, the compressor 4, the solenoid valves 7 and 8, and the motor control device 12 via a signal line. The compressor 4, the heat source side heat exchanger 6, the solenoid valves 7 and 8, and the load side heat exchanger 13 are connected by a refrigerant pipe 14, and a refrigerant circuit 15 through which the refrigerant circulates is configured. The upper control device 9 is a control device that controls the air conditioner 1. The upper control device 9 controls the refrigeration cycle of the refrigerant circulating in the refrigerant circuit 15. When the air conditioner 1 performs the cooling operation, the heat source side heat exchanger 6 functions as a condenser, and the load side heat exchanger 13 functions as an evaporator. When the air conditioner 1 performs the heating operation, the heat source side heat exchanger 6 functions as an evaporator, and the load side heat exchanger 13 functions as a condenser.

In the configuration example shown in FIG. 1, the air conditioner 1 is provided with the solenoid valves 7 and 8, but one of the solenoid valves 7 and 8 may be provided. Further, in the configuration example shown in FIG. 1, the configuration when the fan 10, the motor 11 and the motor control device 12 are provided in the heat source side unit 2 is shown, but the configuration is not limited to this case. The fan 10, the motor 11, and the motor control device 12 may be provided on either one or both of the heat source side unit 2 and the load side unit 3.

FIG. 2 is a block diagram showing a configuration example of the motor control device shown in FIG. FIG. 3 is a diagram showing a configuration example when the power conversion device shown in FIG. 2 is an inverter. The electric motor control device 12 includes a power conversion device 17 connected to the power supply 16, a control device 18 for controlling the operation of the power conversion device 17, and a current detection device 19. The power supply 16 is a DC voltage power supply that supplies electric power to the electric motor 11 via the power conversion device 17. In the first embodiment, the case where the power supply 16 is a DC voltage power supply will be described, but the power supply may be an AC voltage power supply. When an AC voltage is supplied to the electric motor control device 12 from an external single-phase power supply (not shown) or a three-phase power supply (not shown), the AC voltage is converted into a DC voltage to the power converter 17. An output rectifying circuit (not shown) is provided in the electric motor control device 12.

The motor 11 is, for example, a brushless DC motor. The motor 11 has a rotor and a stator not shown in the figure. The stator has a U-phase, V-phase and W-phase three-phase winding. A permanent magnet is provided on the rotor. A current flows through the windings in response to the three-phase voltage applied from the power converter 17 to the motor 11, so that the stator generates a rotating magnetic field around the rotor.

The brushless DC motor applies a three-phase AC voltage of appropriate phase and frequency to the stator according to the position of the rotor, generates a rotating magnetic field around the rotor, and attracts and repels the rotating magnetic field and the rotor. Is used to rotate the rotor at a desired rotation speed. At that time, it is necessary to detect the position of the rotor. As a method of detecting the position of the rotor, for example, there are a method of detecting by a hall sensor installed in the motor and a method of calculating by calculation from the three-phase current flowing in the motor. In the first embodiment, the motor control device 12 estimates the position of the rotor by calculation from the three-phase current flowing through the motor.

The current detection device 19 detects the three-phase current Iuvw flowing through the motor 11. In the configuration shown in FIG. 2, the current detection device 19 includes a current detector 19a that detects currents flowing in the U phase and the W phase. The current detector 19a is, for example, a current transformer. The current flowing in the V phase is calculated by the control device 18 from the current values flowing in the U phase and the W phase.

The position where the current is detected is not limited to the position shown in FIG. Instead of providing the current detection device 19, a current detection unit using a shunt resistor may be provided in the inverter 20. The phase detected by the current detection device 19 is not limited to the phase shown in FIG. For example, the current detector 19a may detect the U-phase and V-phase currents.

The upper control device 9 is, for example, a microcomputer. The host control device 9 has a memory 72 for storing a program and a CPU (Central Processing Unit) 62 for executing processing according to the program. The upper control device 9 is located on the upstream side of the control device 18 in the signal system. The upper control device 9 is a control device that issues a command to the control device 18. The commands include, for example, a speed command value ω_ref, which is a command value for the rotation speed of the motor 11, and a stop command for instructing the stop of rotation of the motor 11. Although not shown in the figure, a remote controller for the user to input an instruction to the air conditioner 1 may be connected to the host controller 9.

Next, the configuration of the inverter 20 will be described with reference to FIG. The inverter 20 has a switching element 21 connected to the positive electrode side of the power supply 16 and a switching element 22 connected to the negative electrode side of the power supply 16 with respect to the U phase. The backflow prevention element 31 is connected in parallel to the switching element 21, and the backflow prevention element 32 is connected in parallel to the switching element 22. Further, the inverter 20 has a switching element 23 connected to the positive electrode side of the power supply 16 and a switching element 24 connected to the negative electrode side of the power supply 16 with respect to the V phase. The backflow prevention element 33 is connected in parallel to the switching element 23, and the backflow prevention element 34 is connected in parallel to the switching element 24. The inverter 20 has a switching element 25 connected to the positive electrode side of the power supply 16 and a switching element 26 connected to the negative electrode side of the power supply 16 with respect to the W phase. The backflow prevention element 35 is connected in parallel to the switching element 25, and the backflow prevention element 36 is connected in parallel to the switching element 26.

The switching elements 21 to 26 are, for example, IGBTs (Insulated Gate Bipolar Transistors). The backflow prevention elements 31 to 36 are, for example, diodes.

The three-phase voltage command value Vuvw_ref is input to the inverter 20 from the control device 18. The inverter 20 compares the waveform of the three-phase voltage command value Vuvw_ref with the carrier wave, and performs power conversion by PWM (Pulse Width Modulation) control. The inverter 20 PWM-controls the DC voltage of the power supply 16 in response to the three-phase voltage command value Vuvw_ref received from the control device 18, converts the DC voltage into a three-phase voltage, and supplies the DC voltage to the motor 11.

FIG. 4 is a functional block diagram showing a configuration example of the control device shown in FIG. As shown in FIG. 4, the control device 18 includes a power control means 51, a current estimation means 52, a rotation speed estimation means 53, and a compensation amount calculation means 54. Various functions of the control device 18 are realized by executing software by an arithmetic unit such as a microcomputer. Further, the control device 18 may be composed of hardware such as a circuit device that realizes various functions.

When a start command for the electric motor 11 is input from the upper control device 9 to the control device 18, the control device 18 causes the power control means 51, the current estimation means 52, and the rotation speed estimation means 53 at predetermined timings. To start. For example, the control device 18 is activated in the order of the power control means 51, the current estimation means 52, and the rotation speed estimation means 53. In this case, after the electric motor 11 is activated by the activation of the power control means 51, the current estimation means 52 and the rotation speed estimation means 53 are activated.

Further, when the control device 18 determines that it is necessary to compensate for the voltage error Verr, which is an error between the output voltage of the inverter 20 and the three-phase voltage command value Vuvw_ref, the control device 18 activates the compensation amount calculation means 54. However, since the compensation amount calculation means 54 uses the result of the arithmetic processing by the current estimation means 52, the activation timing of the compensation amount calculation means 54 is later than the activation timing of the current estimation means 52. Therefore, after the current estimation means 52 is started, it may be determined whether or not compensation for the voltage error Verr is necessary, and if it is determined that compensation is necessary, the compensation amount calculation means 54 may be instructed to start. The timing of starting the compensation amount calculation means 54 may be the timing at which the current estimation means 52 calculates the current value by arithmetic processing and outputs the calculated current value to the compensation amount calculation means 54. Further, when a stop command for the electric motor 11 is input from the upper control device 9 to the control device 18, the control device 18 operates the power control means 51, the current estimation means 52, the rotation speed estimation means 53, and the compensation amount calculation means 54. To stop.

The power control means 51 performs vector control based on the speed command value ω_ref input from the host control device 9 and the three-phase current Iuvw detected by the current detection device 19, and the command value of the voltage applied to the motor 11. The three-phase voltage command value Vuvw_ref is generated. The power control means 51 outputs the generated three-phase voltage command value Vuvw_ref to the inverter 20 and the current estimation means 52. When the compensation amount information is input from the compensation amount calculation means 54, the power control means 51 finely adjusts the three-phase voltage command value Vuvw_ref according to the compensation amount. The rotation speed estimation means 53 calculates the estimated rotation speed R, which is an estimated value of the rotation speed of the electric motor 11, by using the three-phase current Iuvw flowing through the electric motor 11.

The current estimating means 52 estimates each of the d-axis current and the q-axis current flowing through the motor 11 when the three-phase voltage command value Vuvw_ref is input to the inverter 20. Specifically, the current estimation means 52 flows through the electric motor 11 using the three-phase voltage command value Vuvw_ref input from the power control means 51, the parameters of the electric motor 11 stored in advance, and the estimated rotation speed R. Calculate the estimated values of the shaft current and the q-axis current. The parameter of the motor 11 is, for example, the winding resistance of the motor 11. In the first embodiment, the case where the current to be subjected to the arithmetic processing is the d-axis current obtained by coordinate-transforming the current flowing through the motor 11 will be described, but it may be the q-axis current.

Further, the configuration of the current estimation means 52 will be described in detail. When the current estimation means 52 is activated by itself, the d-axis current is calculated by converting the coordinates of the three-phase current Iuvw detected by the current detection device 19. This d-axis current is referred to as a d-axis current detection value Idr. The current estimation means 52 uses the three-phase voltage command value Vuvw_ref, the parameters of the motor 11, and the estimated rotation speed R to calculate the d-axis current estimated value Idp, which is an estimated value of the d-axis current flowing through the motor 11. .. When the time measured from the start of its own startup reaches a predetermined waiting time twa, the current estimation means 52 compensates for the calculated d-axis current estimated value Idp when compensation for the voltage error Verr is required. It is output to the calculation means 54. At that time, the current estimation means 52 may output not only the d-axis current estimation value Idp but also the d-axis current detection value Idr to the compensation amount calculation means 54.

The waiting time Twa uses the current estimated value calculated by the current estimating means 52 when a predetermined time elapses from the time when the current estimating means 52 is activated to determine whether or not it is necessary to calculate the compensation amount described later. Is set for. This is because the current estimated value calculated immediately after the activation of the current estimating means 52 is not used for determining whether or not the compensation amount calculation, which will be described later, is necessary. The waiting time twa is, for example, 100 times the sampling time, which is the time interval in which the current detection device 19 detects the current of the electric motor 11.

The compensation amount calculation means 54 calculates the compensation amount Comk that compensates for the voltage error Verr caused by the dead time. Specifically, the compensation amount calculation means 54 uses the three-phase current Iuvw detected by the current detection device 19 and the estimated current calculated by the current estimation means 52 to compensate the voltage error Verr. Is calculated. k is an arbitrary integer of 0 or more, and indicates the number of times the compensation amount is updated. For example, the initial value of the compensation amount Comk is expressed as Com0.

Further, the configuration of the compensation amount calculation means 54 will be described in detail. The compensation amount calculation means 54 uses the d-axis current estimated value Idp and the d-axis current detected value Idr to calculate the value obtained by subtracting the d-axis current detected value Idr from the d-axis current estimated value Idp as the current difference ΔId. That is, the compensation amount calculation means 54 calculates the current difference ΔId according to the equation (Idp-Idr) = ΔId. When the current difference ΔId is a positive value, the detected current value is smaller than the estimated current value. Therefore, the compensation amount calculation means 54 determines that the compensation is insufficient, and determines a predetermined reference compensation amount. Set a compensation amount larger than Clef. For example, the compensation amount calculation means 54 sets the compensation amount Comk as a value obtained by adding a predetermined adjustment value w to the reference compensation amount Clef.

On the other hand, when the current difference ΔId is a negative value, the detected current value is larger than the estimated current value. Therefore, the compensation amount calculation means 54 determines that the compensation amount is overcompensation, and the compensation amount is smaller than the reference compensation amount Clef. Set the amount. For example, the compensation amount calculation means 54 sets the compensation amount Comk as a value obtained by subtracting the adjustment value w from the reference compensation amount Clef. In this way, the compensation amount calculation means 54 calculates the compensation amount Comk so that the voltage error Verr approaches zero. The compensation amount calculation means 54 outputs the calculated compensation amount Comk to the power control means 51.

Note that the standard compensation amount Clef is not limited to a predetermined value. The finally calculated compensation amount Com (k-1) may be the reference compensation amount Cref of the compensation amount Comk first calculated when the motor 11 is started next time. Further, the compensation amount calculation means 54 may calculate the d-axis current detection value Idr by coordinate-converting the three-phase current Iuvw detected by the current detection device 19, and the d-axis current detection value Idr may be calculated from the current estimation means 52. Idr may be acquired. Further, a calculation formula for calculating the compensation amount Comk from the current difference ΔId may be stored in the control device 18 in advance.

Here, an example of the hardware of the control device 18 shown in FIG. 4 will be described. FIG. 5 is a hardware configuration diagram showing a configuration example of the control device shown in FIG. When various functions of the control device 18 are executed by hardware, the control device 18 shown in FIG. 4 is composed of a processing circuit 80 as shown in FIG. Each function of the power control means 51, the current estimation means 52, the rotation speed estimation means 53, and the compensation amount calculation means 54 shown in FIG. 4 is realized by the processing circuit 80.

When each function is executed by hardware, the processing circuit 80 may be, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), or an FPGA (Field-Programmable Gate). It corresponds to Array) or a combination of these. The functions of the power control means 51, the current estimation means 52, the rotation speed estimation means 53, and the compensation amount calculation means 54 may be realized by separate processing circuits 80. Further, the functions of the power control means 51, the current estimation means 52, the rotation speed estimation means 53, and the compensation amount calculation means 54 may be realized by one processing circuit 80.

Further, an example of another hardware of the control device 18 shown in FIG. 4 will be described. FIG. 6 is a hardware configuration diagram showing another configuration example of the control device shown in FIG. When various functions of the control device 18 are executed by software, the control device 18 shown in FIG. 4 is composed of a processor 61 such as a CPU and a memory 71 as shown in FIG. The functions of the power control means 51, the current estimation means 52, the rotation speed estimation means 53, and the compensation amount calculation means 54 are realized by the processor 61 and the memory 71. FIG. 6 shows that the processor 61 and the memory 71 are communicably connected to each other. Hereinafter, the case where the hardware configuration of the control device 18 is the configuration shown in FIG. 6 will be described. The memory 71 stores information such as the parameters of the motor 11 and the waiting time twa.

When each function is executed by software, the functions of the power control means 51, the current estimation means 52, the rotation speed estimation means 53, and the compensation amount calculation means 54 are realized by software, firmware, or a combination of software and firmware. .. The software and firmware are written as a program and stored in the memory 71. The processor 61 realizes the function of each means by reading and executing the program stored in the memory 71.

As the memory 71, for example, a non-volatile semiconductor memory such as a ROM (Read Only Memory), a flash memory, an EPROM (Erasable and Programmable ROM) and an EEPROM (Electrically Erasable and Programmable ROM) is used. Further, as the memory 71, a volatile semiconductor memory of RAM (Random Access Memory) may be used. Further, as the memory 71, a detachable recording medium such as a magnetic disk, a flexible disk, an optical disk, a CD (Compact Disc), an MD (Mini Disc), and a DVD (Digital Versaille Disc) may be used.

Next, the operation of the motor control device 12 according to the first embodiment will be described. FIG. 7 is a flowchart showing an example of the operation procedure of the control device in the motor control device according to the first embodiment.

After the electric motor 11 is started, the current estimation means 52 coordinates the three-phase current detected by the current detection device 19 to calculate the d-axis current detection value Idr (step S11). Further, the current estimating means 52 calculates the d-axis current estimated value Idp by using the three-phase voltage command value Vuvw_ref, the parameters of the motor 11, and the estimated rotation speed R calculated by the rotation speed estimating means 53 (the d-axis current estimated value Idp). Step S12). Then, the current estimation means 52 outputs the d-axis current estimation value Idp and the d-axis current detection value Idr to the compensation amount calculation means 54.

When the d-axis current estimated value Idp and the d-axis current detected value Idr are input from the current estimating means 52, the compensation amount calculating means 54 subtracts the d-axis current detected value Idr from the d-axis current estimated value Idp to obtain a current difference. Calculate ΔId (step S13). The compensation amount calculation means 54 calculates the compensation amount Comk based on the current difference ΔId (step S14). For example, when the current difference ΔId is a positive value, the compensation amount calculation means 54 sets the value obtained by adding the adjustment value w to the reference compensation amount Clef as the compensation amount Comk. Here, the compensation amount Comk is an initial value Com0. The compensation amount calculation means 54 outputs the calculated compensation amount Comk to the power control means 51.

Next, the operation of the motor control device 12 according to the first embodiment will be described. FIG. 8 is a flowchart showing an example of a procedure in which the compensation amount calculation means updates the compensation amount in the motor control device according to the first embodiment. As an initial state, the case where the last calculated compensation amount Com (k-1) is stored in the memory 71 as the current compensation amount will be described.

When the d-axis current estimated value Idp and the d-axis current detected value Idr are input from the current estimating means 52, the compensation amount calculating means 54 subtracts the d-axis current detected value Idr from the d-axis current estimated value Idp to obtain a current difference. Calculate ΔId (step S101). The compensation amount calculating means 54 determines whether or not the current difference ΔId is larger than 0 (step S102). When the current difference ΔId is larger than 0, the compensation amount calculation means 54 determines that the current compensation amount Com (k-1) is insufficient compensation. Then, the compensation amount calculation means 54 updates the value obtained by adding the adjustment value w to the current compensation amount Com (k-1) to a new compensation amount Comk (step S103).

If the current difference ΔId is 0 or less as a result of the determination in step S102, the compensation amount calculation means 54 determines whether or not the current difference ΔId is smaller than 0 (step S104). When the current difference ΔId is smaller than 0, the compensation amount calculation means 54 determines that the current compensation amount Com (k-1) is overcompensation. Then, the compensation amount calculation means 54 updates the value obtained by subtracting the adjustment value w from the current compensation amount Com (k-1) to a new compensation amount Comk (step S105).

On the other hand, when the current difference ΔId is 0 as a result of the determination in step S104, the compensation amount calculation means 54 determines that the voltage error Verr is appropriately compensated by the current compensation amount Com (k-1). The compensation amount is not changed (step S106).

The adjustment value w added to the compensation amount Com (k-1) in step S103 of FIG. 8 and the adjustment value w subtracted from the compensation amount Com (k-1) in step S105 are fixed values. The adjustment value w is, for example, 10% of the theoretical value of the voltage error Verr under the rated condition represented by the product of the switching frequency, the rated output voltage of the DC voltage power supply, and the dead time set value. Although the case where the adjustment value w in step S103 and the adjustment value w in step S105 are equivalent values has been described, these values may be different values.

Further, with reference to FIG. 8, the case where the compensation amount is updated so that the current difference ΔId becomes 0 has been described, but the value that serves as a criterion for determining whether or not the compensation amount needs to be updated is not limited to 0. For example, the memory 71 stores a positive threshold value + Is and a negative threshold value-Ith as a criterion for determining whether or not to update the compensation amount. In this case, a positive threshold value + Is is used instead of 0 as the determination criterion in step S102, and a negative threshold value -Ith is used instead of 0 as the determination criterion in step S104. When the current difference ΔId belongs to the range between the positive threshold value + Is and the negative threshold value-Ith, the compensation amount calculation means 54 does not change the compensation amount in step S106.

Next, another operation of the motor control device 12 according to the first embodiment will be described. FIG. 9 is a flowchart showing a part of the processing after the activation of the current estimation means in the motor control device according to the first embodiment.

The current estimation means 52 determines whether or not the measurement time t from the start of activation has reached the waiting time twa (step S111). When the measurement time t reaches the waiting time twa, the current estimation means 52 determines whether or not the update end condition, which is the condition for ending the update of the compensation amount, is satisfied (step S112). When the update end condition is satisfied, the current estimation means 52 does not activate the compensation amount calculation means 54 (step S113). On the other hand, if the update end condition is not satisfied as a result of the determination in step S112, the current estimation means 52 activates the compensation amount calculation means 54 (step S114). After the compensation amount calculation means 54 is activated, the current estimation means 52 outputs the d-axis current estimation value Idp and the d-axis current detection value Idr to the compensation amount calculation means 54. Since the subsequent processing executed by the compensation amount calculating means 54 is the same as the processing described with reference to FIG. 7 or FIG. 8, detailed description thereof will be omitted.

The update end condition is, for example, that the absolute value of the current difference ΔId when the measurement time t from the start of the current estimation means 52 reaches the waiting time twa is equal to or less than a predetermined threshold value Is.

The timing for determining whether or not the update end condition is satisfied is not limited to the position shown in FIG. Before starting the current estimation means 52, it may be determined whether or not the control device 18 satisfies the update end condition.

The motor control device 12 of the first embodiment includes a power conversion device 17 that supplies an AC voltage corresponding to a voltage command value to the motor 11, a current detection device 19 that detects a current flowing through the motor 11, and a control device 18. Has. The control device 18 calculates a voltage command value corresponding to the speed command value and the current information detected by the current detection device 19, and outputs the voltage command value to the power conversion device 17. The control device 18 includes a rotation speed estimation means 53, a current estimation means 52, and a compensation amount calculation means 54. The rotation speed estimation means 53 calculates the estimated rotation speed, which is an estimated value of the rotation speed of the electric motor 11, using the current detection value detected by the current detection device 19. The current estimation means 52 estimates the current flowing through the motor 11 by using the voltage command value, the estimated rotation speed, and the parameters of the motor 11 stored in advance. The compensation amount calculating means 54 sets the output voltage and the voltage command value of the power conversion device 17 based on the current difference ΔId which is a value obtained by subtracting the current detection value from the current estimated value which is the current estimated by the current estimating means 52. The compensation amount for compensating for the voltage error Verr, which is the error of the above, is calculated.

The operation and effect of the first embodiment will be described. According to the first embodiment, based on the current difference obtained by subtracting the current value detected by the current detection device 19 from the current estimated value estimated using the voltage command value, the estimated rotation speed R, and the parameters of the motor 11. , The compensation amount for compensating for the voltage error Verr is calculated. Therefore, even while the motor 11 is being driven, the voltage error Verr due to the dead time can be appropriately compensated. As a result, the control stability of the motor 11 can be improved.

In the air conditioner 1 of the first embodiment, the electric motor 11 that drives the fan 10 can be stably driven. Therefore, it is possible to prevent the electric motor 11 from abnormally stopping and prevent the heat exchange capacity of the heat source side heat exchanger 6 from being lowered.

In the first embodiment, when the compensation is insufficient with the current compensation amount, the current difference ΔId calculated immediately after the activation of the current estimation means 52 becomes larger than 0. Further, when the current compensation amount is overcompensation, the current difference ΔId calculated immediately after the activation of the current estimation means 52 becomes smaller than 0. This principle can be used to determine the validity of the current amount of compensation.

Further, in the first embodiment, if the current compensation amount is insufficient, the compensation amount is updated so as to increase the compensation amount. If the current compensation amount is overcompensated, the compensation amount is updated to reduce the compensation amount. The motor control device 12 can bring the compensation amount closer to the value required for the compensation of the voltage error Verr by repeating the update of the compensation amount until the update end condition is satisfied. As a result, the control accuracy of the electric motor 11 is improved, and the electric motor 11 can be stably driven without being abnormally stopped.

If the method disclosed in Patent Document 1 is executed before starting the fan 10, a process of passing a direct current to estimate the voltage error is required, so that it takes a long time to start the fan 10. On the other hand, in the air conditioner 1 provided with the motor control device 12, since the compensation amount calculating means 54 operates while the fan 10 is being driven, the compensation amount can be calculated in parallel with the driving process of the fan 10. can. As a result, the compensation amount can be calculated without affecting the drive sequence of the fan 10, and it is possible to prevent the start time and stop time of the fan 10 from becoming long.

As an application example of the motor control device 12 of the first embodiment, there is a blower device (not shown) mounted on the air conditioner 1. The blower has a plurality of motors and a fan attached to each motor. The blower selectively rotates some fans or all fans at the same time according to the required air volume. By applying the motor control device 12 to such a blower, the motor attached to each fan can be stably driven.

Embodiment 2.
The motor control device of the second embodiment is different from the first embodiment in the method of setting the adjustment value to be added to or subtracted from the compensation amount. In the second embodiment, the same components as those described in the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

The configuration of the motor control device 12 of the second embodiment will be described. In the second embodiment, the differences from the first embodiment will be described, and detailed description of the same configuration as that of the first embodiment will be omitted. The compensation amount calculation means 54 changes the adjustment value w according to the absolute value of the current difference ΔId, which is the value obtained by subtracting the d-axis current detection value Idr from the d-axis current estimated value Idp. The compensation amount calculating means 54 sets the adjustment value w to a larger value as the absolute value of the current difference ΔId is larger. The compensation amount calculating means 54 sets the adjustment value w to a smaller value as the absolute value of the current difference ΔId becomes smaller.

The method of obtaining the adjustment value w from the absolute value of the current difference ΔId is not limited to the case where the compensation amount calculating means 54 calculates using the absolute value of the current difference ΔId. For example, an adjustment value table in which the absolute values of the plurality of current differences ΔId and the plurality of adjustment values w are associated with each other is created in advance, and the adjustment value table is stored in the memory 71. After calculating the absolute value of the current difference ΔId, the compensation amount calculating means 54 refers to the adjustment value table and reads out the adjustment value w corresponding to the calculated absolute value of the current difference ΔId from the adjustment value table.

Next, the operation of the motor control device 12 according to the second embodiment will be described. FIG. 10 is a flowchart showing an example of an operation procedure of the compensation amount calculation means in the motor control device according to the second embodiment. Steps S201 and S203 to S207 shown in FIG. 10 are the same processes as steps S101 to S106 shown in FIG. 8, and in the second embodiment, the process of step S202 is added. Therefore, here, the detailed description of steps S201 and S203 to S207 will be omitted, and the process of step S202 will be described.

In step S201, the compensation amount calculating means 54 calculates the current difference ΔId by subtracting the d-axis current detection value Idr from the d-axis current estimated value Idp. Then, the compensation amount calculation means 54 calculates the adjustment value w corresponding to the absolute value of the current difference ΔId (step S202).

The operation and effect of the second embodiment will be described. The larger the absolute value of the current difference ΔId, which is the value obtained by subtracting the d-axis current detection value Idr from the d-axis current estimated value Idp, the larger the voltage error Verr. The smaller the absolute value of the current difference ΔId, the smaller the voltage error Verr. Therefore, in the second embodiment, the compensation amount calculating means 54 sets the adjustment value w large when the absolute value of the current difference ΔId is large, and sets the adjustment value w small when the absolute value of the current difference ΔId is small. do. Therefore, the compensation amount can be increased when the voltage error Verr is large, and the compensation amount can be decreased when the voltage error Verr is small. Since the compensation amount is set according to the magnitude of the voltage error Verr, the number of times the compensation amount is updated can be reduced.

Embodiment 3.
The motor control device of the third embodiment is different from the first embodiment in the method of updating the compensation amount and the condition for ending the update. In the third embodiment, the same components as those described in the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

The configuration of the motor control device 12 of the third embodiment will be described. In the third embodiment, the differences from the first embodiment will be described, and detailed description of the same configuration as that of the first embodiment will be omitted. The compensation amount calculation means 54 stores the initial value Com0 of the compensation amount and the compensation amount Com (k-1) finally calculated in the memory 71.

The compensation amount calculation means 54 compares the sign of the current difference ΔId (k-1) when the compensation amount Com (k-1) is calculated with the sign of the latest current difference ΔIdk which is the newly calculated current difference ΔId. do. When the sign of the current difference ΔId (k-1) and the sign of the latest current difference ΔIdk are different, the compensation amount calculation means 54 updates the value obtained by adding or subtracting the adjustment value w to the initial value Com to the compensation amount Comk. Specifically, the compensation amount calculating means 54 adjusts to the initial value Com0 when the sign of the current difference ΔId (k-1) and the sign of the latest current difference ΔIdk are different and the sign of the latest current difference ΔIdk is positive. The value obtained by adding the value w is updated to a new compensation amount Comk. Further, when the sign of the current difference ΔId (k-1) and the sign of the latest current difference ΔIdk are different from each other and the sign of the latest current difference ΔIdk is negative, the compensation amount calculating means 54 sets the adjustment value w from the initial value Com. The subtracted value is updated to a new compensation amount Comk.

Next, the operation of the motor control device 12 according to the third embodiment will be described. 11 and 12 are flowcharts showing an example of the operation procedure of the compensation amount calculation means in the motor control device according to the third embodiment. Here, the last calculated compensation amount is the current compensation amount Com (k-1), the newly calculated compensation amount is Comk, and the initial value of the compensation amount is Com0.

When the d-axis current estimated value Idp and the d-axis current detected value Idr are input from the current estimating means 52, the compensation amount calculating means 54 calculates the current difference ΔIdk between the d-axis current estimated value Idp and the d-axis current detected value Idr. Calculate (step S301). The compensation amount calculating means 54 determines whether or not the current difference ΔIdk is larger than 0 (step S302). When the current difference ΔIdk is larger than 0, the compensation amount calculating means 54 determines whether or not the previously calculated current difference ΔId (k-1) is larger than 0 (step S303).

As a result of the determination in step S303, when the current difference ΔId (k-1) is larger than 0, the compensation amount calculation means 54 determines that the current compensation amount Com (k-1) is insufficient compensation, and the current compensation amount Com. The value obtained by adding the adjustment value w to (k-1) is updated to the compensation amount Comk (step S304). As a result of the determination in step S303, when the current difference ΔId (k-1) is 0 or less, the compensation amount calculation means 54 updates the value obtained by adding the adjustment value w to the initial value Com0 to the compensation amount Comk (step S305). ).

On the other hand, if the current difference ΔIdk is 0 or less as a result of the determination in step S302, the compensation amount calculation means 54 determines whether or not the current difference ΔIdk is smaller than 0 (step S306). When the current difference ΔIdk is smaller than 0, the compensation amount calculating means 54 determines whether or not the previously calculated current difference ΔId (k-1) is smaller than 0 (step S307). When the current difference ΔId (k-1) is smaller than 0, the compensation amount calculation means 54 determines that the current compensation amount Com (k-1) is overcompensation and adjusts from the current compensation amount Com (k-1). The value obtained by subtracting the value w is updated to the compensation amount Comk (step S308).

As a result of the determination in step S307, when the current difference ΔId (k-1) is 0 or more, the compensation amount calculation means 54 updates the value obtained by subtracting the adjustment value w from the initial value Com0 to the compensation amount Comk (step S309). ). On the other hand, when the current difference ΔIdk is 0 as a result of the determination in step S306, the compensation amount calculation means 54 can appropriately compensate the voltage error Verr due to the dead time by the current compensation amount Com (k-1). It is determined that the compensation amount is not changed (step S310). After steps S304, S305 and S308 to S310, the compensation amount calculating means 54 stores the current difference ΔIdk in the memory 71 as the final value of the current difference ΔId (step S311). Further, after steps S304, S305, S308 and S309, the compensation amount calculation means 54 outputs the calculated compensation amount to the power control means 51.

In the third embodiment, the update end condition is that the control stability of the motor 11 is ensured. The update end condition is, for example, that the motor 11 does not stop abnormally. In the third embodiment as well, as in the first embodiment, a positive threshold value + Is and a negative threshold value-Ith may be used instead of 0 as the criterion for updating the compensation amount.

Next, in the third embodiment, the change in the update of the compensation amount when the compensation amount calculation means 54 repeats the procedures shown in FIGS. 11 and 12 will be described. FIG. 13 is a graph showing an example of the update result of the compensation amount in the motor control device according to the third embodiment. Specifically, FIG. 13 shows an example of the update result of the compensation amount when the current difference ΔId calculated after the activation of the current estimation means 52 is smaller than 0, although the compensation is insufficient with the current compensation amount. show. The vertical axis of FIG. 13 is the compensation amount, and the horizontal axis is the number of updates of the compensation amount.

Referring to FIG. 13, since the current difference ΔId is smaller than 0 when the number of updates is 0 to 2, the processing of step S308 shown in FIG. 12 is repeated, so that the compensation amount is stepped each time it is updated. Becomes smaller. The compensation amount becomes smaller for each update, and when the number of updates reaches the third time, the current difference ΔId becomes larger than 0. In the fourth update, the value obtained by adding the adjustment value w to the initial value Com0 of the compensation amount becomes the compensation amount Comk (see step S305 in FIG. 11). Therefore, as shown in FIG. 13, the compensation amount Comk falls within the range of the compensation amount that satisfies the update end condition. By updating the compensation amount in this way, it is possible to prevent the compensation amount from converging on the compensation amount when the current difference ΔId becomes 0. In the example shown in FIG. 13, the compensation amount indicated by the alternate long and short dash line is the compensation amount when the current difference ΔId becomes 0.

FIG. 14 is a graph showing another example of the update result of the compensation amount in the motor control device according to the third embodiment. Specifically, FIG. 14 shows an example of the update result of the compensation amount when the current difference ΔId calculated after the activation of the current estimation means 52 becomes larger than 0, although the current compensation amount is overcompensation. show. The vertical axis of FIG. 14 is the compensation amount, and the horizontal axis is the number of updates of the compensation amount.

Referring to FIG. 14, since the current difference ΔId is larger than 0 when the number of updates is 0 to 2, the processing of step S304 shown in FIG. 11 is repeated, so that the compensation amount is stepped each time it is updated. Becomes larger. As the compensation amount increases with each update, the current difference ΔId becomes smaller than 0 at some point. In the example shown in FIG. 14, the current difference ΔId becomes smaller than 0 when the number of updates reaches the third time. In the fourth update, the value obtained by subtracting the adjustment value w from the initial value Com0 of the compensation amount becomes the compensation amount Comk (see step S309 in FIG. 12). Therefore, as shown in FIG. 14, the compensation amount Comk falls within the range of the compensation amount that satisfies the update end condition. By updating the compensation amount in this way, it is possible to prevent the compensation amount from converging on the compensation amount when the current difference ΔId becomes 0. In the example shown in FIG. 14, the compensation amount indicated by the alternate long and short dash line is the compensation amount when the current difference ΔId becomes 0.

As described above, the compensation amount satisfying the update end condition can be obtained, and the motor 11 can be stably driven without abnormally stopping.

The operation and effect of the third embodiment will be described. Various influences can be considered as the reason why the compensation amount does not correspond to the voltage error Verr. One of the effects is the effect of variation due to hardware. The variation caused by the hardware is, for example, a variation in the detection accuracy of the current detection device 19 and a variation in the winding resistance of the motor 11. Further, as one of the influences, when the electric motor 11 is a motor for driving the fan 10, there is an influence of disturbance such as an outside wind.

Here, the effect of the outside wind on the compensation amount will be explained. When the heat source side unit 2 shown in FIG. 1 is installed outdoors, the blower device including the fan 10 and the electric motor 11 is also installed outdoors. In this case, the fan 10 may be in a free-run state due to the outside wind. When the fan 10 is in a free-run state due to the outside wind, the load of the motor 11 fluctuates, so that the accuracy of calculating the compensation amount for the voltage error Vref may deteriorate.

Due to the above-mentioned influence, the current difference ΔId calculated immediately after the activation of the current estimation means 52 may be smaller than 0 even though the compensation is insufficient with the current compensation amount. Further, due to the above-mentioned influence, the current difference ΔId calculated immediately after the activation of the current estimation means 52 may be larger than 0 even though the current compensation amount is overcompensated. In the third embodiment, even in such a case, as described with reference to FIGS. 13 and 14, a compensation amount satisfying the update end condition can be obtained.

Embodiment 4.
The motor control device of the fourth embodiment is different in the method of obtaining the compensation amount as compared with the first embodiment. In the fourth embodiment, the same components as those described in the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

The configuration of the motor control device 12 of the fourth embodiment will be described. In the fourth embodiment, the differences from the first embodiment will be described, and detailed description of the same configuration as that of the first embodiment will be omitted. The compensation amount calculation means 54 changes the compensation amount according to a predetermined command value for a predetermined fixed time tset during the normal driving of the electric motor 11. Since these compensation amounts are provisional compensation amounts, they are referred to as candidate compensation amounts Comc. Specifically, the compensation amount calculation means 54 sequentially applies a plurality of candidate compensation amounts Comc as compensation amounts to tset for a certain period of time. The compensation amount calculation means 54 outputs each candidate compensation amount Comc to the power control means 51.

The compensation amount calculation means 54 calculates the effective value ΔIdeff of the current difference ΔId corresponding to the candidate compensation amount Comc in tset for a certain period of time. The compensation amount calculation means 54 stores the compensation amount Comm0 in the memory 71 in association with the effective value ΔIdeff in order to record the correspondence between the effective value ΔIdeff and the candidate compensation amount Comc. The compensation amount calculation means 54 reads from the memory 71 a candidate compensation amount Comc corresponding to the minimum effective value ΔIdeff among the plurality of effective values ΔIdeff collected in the memory 71 for a certain period of time. The compensation amount calculation means 54 updates the read candidate compensation amount Com to the compensation amount Comk.

FIG. 15 is a diagram showing an example of a command value for changing the compensation amount in the motor control device according to the fourth embodiment. The vertical axis of FIG. 15 is the candidate compensation amount, and the horizontal axis is time. In FIG. 15, the fixed time tset is, for example, 2 seconds. The command value shown in FIG. 15 starts from the initial value Com0, linearly increases the candidate compensation amount Comc to Comc1, then linearly decreases the candidate compensation amount Comc to Comc2, and then linearly decreases to Com0, which is the end point. It is to increase to. In the command value shown in FIG. 15, the relationship between the candidate compensation amount Comc and the time is represented by a straight line, but the candidate compensation amount Comc may change stepwise with respect to the time. For example, the command value changes the candidate compensation amount Comc in a fixed time unit. The command value shown in FIG. 15 is an example, and the command value is not limited to the case shown in FIG.

Next, the operation of the motor control device 12 according to the fourth embodiment will be described. FIG. 16 is a flowchart showing an example of an operation procedure of the compensation amount calculation means in the motor control device according to the fourth embodiment. For example, after the motor 11 is started, the compensation amount calculating means 54 executes the procedure shown in FIG. 16 when a start instruction is input from the current estimating means 52. As an initial state, it is assumed that the compensation amount is Com0, which is the initial value.

The compensation amount calculation means 54 calculates the effective value ΔIdeff of the current difference ΔId in a state where the compensation amount is set to the initial value Com0 (step S401). The compensation amount calculation means 54 stores the initial value Com0 in the memory 71 in association with the effective value ΔIdeff in order to record the correspondence between the calculated effective value ΔIdeff and the initial value Com0 of the compensation amount (step S402). The compensation amount calculation means 54 changes the candidate compensation amount Comc according to a predetermined command value (step S403). The compensation amount calculation means 54 outputs the changed candidate compensation amount Comc to the power control means 51. The compensation amount calculation means 54 repeats steps S401 to S403 until the measurement time t after the start instruction is input from the current estimation means 52 elapses for a certain period of time tset.

In step S404, the compensation amount calculating means 54 determines whether or not the measurement time t after the start instruction is input from the current estimating means 52 has passed the test for a certain period of time (step S404). If tset has not elapsed for a certain period of time, the compensation amount calculation means 54 returns to step S401. As a result of the determination in step S404, when tset has elapsed for a certain period of time, the compensation amount calculating means 54 obtains the minimum effective value ΔIdeff among the plurality of effective values ΔIdeff stored in the memory 71 (step S405). ). Then, the compensation amount calculation means 54 refers to the information stored in the memory 71, and reads out the candidate compensation amount Comc corresponding to the minimum value of the effective value ΔIdeff from the memory 71 (step S406). The compensation amount calculation means 54 updates the candidate compensation amount Comc obtained in the process of step S406 to the compensation amount Comk (step S407).

In the fourth embodiment, the update end condition is that the control stability of the motor 11 is ensured. The update end condition is, for example, that the motor 11 does not stop abnormally.

In the first embodiment, a method of converging the compensation amount by repeatedly updating the compensation amount has been described, but in the fourth embodiment, as described with reference to FIG. 16, the first embodiment has been described. Different from the method. Therefore, once the compensation amount is updated, the compensation amount calculation means 54 may not be activated thereafter, and the update of the compensation amount may be completed.

The operation and effect of the fourth embodiment will be described. Comparing the case where the voltage error Verr is properly compensated and the case where the compensation is insufficient or overcompensated during the normal driving of the motor 11, the current difference is higher when the voltage error Verr is properly compensated. The effective value ΔIdeff of ΔId becomes smaller. In the fourth embodiment, the compensation amount is intentionally changed, the relationship between the compensation amount and the effective value ΔIdeff of the current difference ΔId is confirmed, and the compensation amount when the effective value ΔIdeff of the current difference ΔId is minimized is determined. I'm looking for. Thereby, the compensation amount required for the compensation of the voltage error Verr can be obtained.

Further, according to the fourth embodiment, if the compensation amount calculation means 54 is activated once, the compensation amount that minimizes the effective value ΔIdeff of the current difference ΔId is obtained. Therefore, it is not necessary to repeatedly update the compensation amount to converge the compensation amount to a value required for compensation of the voltage error Verr. As a result, the number of times the compensation amount is updated can be reduced.

The above-mentioned effect can be obtained by combining any two or more of the above-described embodiments 1 to 4. In the first to fourth embodiments, the control device 18 and the upper control device 9 have been described with separate configurations, but the control device 18 and the upper control device 9 may be integrated.

Further, in the first to fourth embodiments, the load of the motor 11 is described in the case of the fan for the air conditioner, but the load is not limited to the fan for the air conditioner. The compensation amount calculation and compensation amount update described in the first to fourth embodiments can be applied to various loads regardless of the type of load of the motor 11.

1 air conditioner, 2 heat source side unit, 3 load side unit, 4 compressor, 5 four-way valve, 6 heat source side heat exchanger, 7, 8 electromagnetic valve, 9 upper control device, 10 fan, 11 electric power, 12 electric power control Equipment, 13 load side heat exchanger, 14 refrigerant piping, 15 refrigerant circuit, 16 power supply, 17 power conversion device, 18 control device, 19 current detector, 19a current detector, 20 inverter, 21-26 switching element, 31- 36 Backflow prevention element, 51 power control means, 52 current estimation means, 53 rotation speed estimation means, 54 compensation amount calculation means, 61 processor, 62 CPU, 71, 72 memory, 80 processing circuit.

Claims (8)

1. A power converter that supplies an AC voltage corresponding to the voltage command value, which is the command value of the voltage applied to the motor, to the motor, and
   A current detection device that detects the current flowing through the motor, and
   A control device that calculates the voltage command value corresponding to the speed command value, which is the command value of the rotation speed of the motor, and the current information detected by the current detection device, and outputs the voltage command value to the power conversion device.
   Have,
   The control device is
   A rotation speed estimation means for calculating an estimated rotation speed, which is an estimated value of the rotation speed of the motor, using a current detection value which is a current detected by the current detection device.
   A current estimation means for estimating the current flowing through the motor using the voltage command value, the estimated rotation speed, and the parameters of the motor stored in advance.
   A voltage error, which is an error between the output voltage of the power converter and the voltage command value, based on the current difference, which is the value obtained by subtracting the current detection value from the current estimated value, which is the current estimated by the current estimation means. An electric motor control device having a compensation amount calculation means for calculating a compensation amount for compensating for the electric current.
2. The compensation amount calculation means is
   The process of updating the compensation amount based on the current difference is repeated until the update end condition, which is the condition for ending the update of the compensation amount, is satisfied.
   The motor control device according to claim 1.
3. The update end condition is that the absolute value of the current difference is equal to or less than a predetermined threshold value.
   The motor control device according to claim 2.
4. The compensation amount calculation means is
   The compensation amount is calculated after the motor is started, and when the current difference is larger than a predetermined positive threshold value, the value obtained by adding the predetermined adjustment value to the compensation amount is updated to a new compensation amount. When the current difference is smaller than a predetermined negative threshold value, the value obtained by subtracting the adjustment value from the compensation amount is updated with a new compensation amount.
   The motor control device according to claim 1 or 2.
5. The compensation amount calculation means is
   When updating the compensation amount, the adjustment value is changed according to the magnitude of the absolute value of the current difference.
   The motor control device according to claim 4.
6. The compensation amount calculation means is
   When the sign of the current difference when the initial value of the compensation amount is stored in advance and the compensation amount is finally calculated is different from the sign of the latest current difference which is the newly calculated current difference. When the sign of the latest current difference is positive, the value obtained by adding a predetermined adjustment value to the initial value is updated to a new compensation amount, and when the sign of the latest current difference is negative, the initial value is used. The value obtained by subtracting the adjustment value from the above is updated to a new compensation amount.
   The motor control device according to claim 1 or 2.
7. The compensation amount calculation means is
   A plurality of candidate compensation amounts are sequentially applied as the compensation amount during a certain period of time while the motor is being driven, the effective value of the current difference is stored corresponding to each candidate compensation amount, and the effect of the plurality of current differences is obtained. Of the values, the candidate compensation amount that minimizes the effective value of the current difference is updated to the compensation amount.
   The motor control device according to claim 1 or 2.
8. The motor control device according to any one of claims 1 to 7.
   A heat exchanger that exchanges heat between the refrigerant and air,
   With the fan provided corresponding to the heat exchanger,
   An electric motor connected to the fan and controlled by the electric motor control device, and
   Air conditioner with.

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