WO2021210129A1 - 駆動装置及び空気調和装置 - Google Patents

駆動装置及び空気調和装置 Download PDF

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Publication number
WO2021210129A1
WO2021210129A1 PCT/JP2020/016722 JP2020016722W WO2021210129A1 WO 2021210129 A1 WO2021210129 A1 WO 2021210129A1 JP 2020016722 W JP2020016722 W JP 2020016722W WO 2021210129 A1 WO2021210129 A1 WO 2021210129A1
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WIPO (PCT)
Prior art keywords
motor
speed
current
zero
switching
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Ceased
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PCT/JP2020/016722
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English (en)
French (fr)
Japanese (ja)
Inventor
貴彦 小林
和徳 畠山
慎也 豊留
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Mitsubishi Electric Corp
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Mitsubishi Electric Corp
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Priority to CN202080099611.XA priority Critical patent/CN115398796A/zh
Priority to PCT/JP2020/016722 priority patent/WO2021210129A1/ja
Priority to JP2022514949A priority patent/JP7258235B2/ja
Publication of WO2021210129A1 publication Critical patent/WO2021210129A1/ja
Anticipated expiration legal-status Critical
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P25/00—Arrangements or methods for the control of AC motors characterised by the kind of AC motor or by structural details
    • H02P25/16—Arrangements or methods for the control of AC motors characterised by the kind of AC motor or by structural details characterised by the circuit arrangement or by the kind of wiring
    • H02P25/18—Arrangements or methods for the control of AC motors characterised by the kind of AC motor or by structural details characterised by the circuit arrangement or by the kind of wiring with arrangements for switching the windings, e.g. with mechanical switches or relays
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P27/00—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage
    • H02P27/04—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage
    • H02P27/06—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage using DC to AC converters or inverters

Definitions

  • This disclosure relates to a drive device and an air conditioner.
  • the present disclosure particularly relates to a drive device for driving a motor whose connection state can be switched by an inverter and an air conditioner provided with this drive device.
  • connection state of the stator winding (hereinafter simply referred to as "winding") of the motor is a star connection (hereinafter referred to as Y connection) and a delta connection. It is known to switch between (hereinafter referred to as ⁇ connection).
  • the present disclosure is a drive device in which a motor capable of switching the connection state by the connection switching device is driven by an inverter, and the step-out, stop, etc. due to a decrease in the speed of the motor without damaging the connection switching device, etc. It is an object of the present invention to provide a drive device capable of preventing the above.
  • the drive device is In a drive device including a connection switching device that switches the connection state of a motor connected to a load and an inverter that is connected to a power source and outputs an AC voltage to the motor.
  • the connection state is switched during the period of zero current control for controlling the current of the motor to zero, and the speed of the motor at the start of the zero current control is equal to or higher than the threshold value.
  • FIG. (A) and (b) are schematic views showing different configuration examples of the power source of FIG. It is a circuit diagram which shows the connection switching device of FIG. 1 in more detail. It is a circuit diagram which shows the modification of the connection switching device of FIG. It is a circuit diagram which shows the detail of the inverter of FIG. It is a wiring diagram which shows the computer which realizes the function of the control part of FIG. 1 together with the current detecting means, the inverter and the connection switching device. It is a time chart which shows an example of the operation of the switching control sequence in the drive device of Embodiment 1.
  • FIG. It is a flowchart which shows the operation of the control part when the switching control sequence is performed by the drive device of Embodiment 1.
  • FIG. It is a flowchart which shows the operation of the control part when the switching control sequence is performed by the drive device of Embodiment 2.
  • It is a time chart which shows an example of the operation of the switching control sequence performed by the drive device of Embodiment 3.
  • It is a flowchart which shows the operation of the control part when the switching control sequence is performed by the drive device of Embodiment 3.
  • It is the schematic which shows the structural example of the air conditioner which concerns on Embodiment 5.
  • FIG. 1 is a circuit diagram showing a configuration of a drive device 1 according to a first embodiment.
  • the illustrated drive device 1 is for driving a motor 3 connected to a load 2, and includes an inverter 4, a connection switching device 5, a current detecting means 6, and a control unit 7.
  • the inverter 4 receives power from the power source 8 and outputs a three-phase AC voltage having a variable frequency and a variable voltage to the motor 3.
  • the frequency of the AC voltage is controlled so that the speed of the motor 3 becomes a desired value.
  • the connection switching device 5 switches the connection state of the motor 3.
  • the current detecting means 6 detects the output phase current of the inverter 4.
  • the current detecting means 6 is composed of, for example, a current sensor such as ACCT or DCCT provided on the wiring connecting the inverter 4 and the motor 3.
  • ACCT Alternating Currant Transducer
  • DCCT Direct Current Transducer.
  • the control unit 7 controls the inverter 4 and the connection switching device 5 based on the detection result of the current detecting means 6.
  • the motor 3 is connected to the load 2 via the motor shaft.
  • the load 2 is, for example, a compression element of a compressor of an air conditioner.
  • the motor 3 is, for example, a three-phase permanent magnet synchronous motor, and both ends of the windings 3u, 3v, and 3w of the three phases u, v, and w are drawn out to the outside of the motor 3, and the Y connection and the ⁇ connection are made. It is possible to switch the connection state between and. The switching is performed by the connection switching device 5.
  • the power source 8 shown in FIG. 2A is an AC / DC power converter 82a having a converter 82aa that converts AC power supplied from a three-phase AC power supply 81a into DC power, a reactor 82ab, and a capacitor 82ac. It is configured.
  • the power source 8 shown in FIG. 2B is an AC / DC power converter having a well-known converter 82ba that converts AC power supplied from a single-phase AC power supply 81b into DC power, a reactor 82bb, and a capacitor 82bc. It is composed of 82b.
  • a booster circuit for boosting the DC voltage may be inserted on the output side of the AC / DC power converters 82a and 82b.
  • the booster circuit may be, for example, a DC-DC converter.
  • the power source 8 may be a battery that directly supplies DC power instead of the configuration shown in FIGS. 2 (a) and 2 (b). Even when the power source 8 is composed of a battery, a booster circuit may be provided on the output side thereof. The booster circuit may be configured as a part of the drive device 1. Further, the AC / DC power converter 82a or 82b, or the above-mentioned battery may also be configured as a part of the drive device 1.
  • the output terminals 4u, 4v, and 4w of the inverter 4 are connected to the first ends 3ua, 3va, and 3wa of the corresponding windings 3u, 3v, and 3w, respectively.
  • the connection switching device 5 has switching devices 51u, 51v, 51w.
  • the switching devices 51u, 51v, 51w for example, an electromagnetic contactor whose contacts are opened and closed electromagnetically, for example, a relay, a contactor, or the like is used.
  • the magnetic contactor is also called a mechanical relay.
  • each of the switches 51u, 51v, and 51w may be configured by, for example, a c (switching) contact relay having a function of selecting one of two states.
  • the switching devices 51u, 51v, 51w are controlled by the switching control signal Sc output from the control unit 7.
  • the switching control signal Sc is, for example, a signal that takes either a first state or a second state, and when one connection state, for example, a Y connection state should be selected, it becomes the first state, for example, the L state. When another connection state, for example, a ⁇ connection state should be selected, a second state, for example, an H state is obtained.
  • the switches 51u, 51v, and 51w composed of c (switching) contact relays have three terminals, a common terminal COM, a normally closed terminal NC, and a normally open terminal NO.
  • the switches 51u, 51v, and 51w are provided corresponding to the windings 3u, 3v, and 3w, respectively, and the common terminal COM of each switch is connected to the second end of the corresponding winding and is normally closed.
  • the terminal NC is connected to the neutral node 52, and the normally open terminal NO is connected to the first end of the winding in the next phase of the corresponding winding.
  • the phase order is u, v, w.
  • the phases following the u phase, v phase, and w phase are v phase, w phase, and u phase, respectively.
  • each of the windings 3u, 3v, and 3w is the first end 3ua, 3va, 3wa. Is connected to the output terminals 4u, 4v, 4w of the corresponding phase of the inverter 4, and the second end 3ub, 3vb, 3wb is connected to the output terminals 4v, 4w, 4u of the next phase of the corresponding phase of the inverter 4. Then, the motor 3 is in the ⁇ connection state.
  • the normally open terminal NO of each switch is connected to the first end of the winding of the next phase of the corresponding winding, and the normally closed terminal NC is connected to the neutral point node 52.
  • the configuration is such that the normally open terminal NO of each switch is connected to the neutral point node 52, and the normally closed terminal NC is connected to the first end of the winding in the next phase of the corresponding winding. Is also good.
  • connection configuration of the connection switching device 5 may be determined based on which of the time of operation in the Y connection state and the time of operation in the ⁇ connection state is longer. For example, if the operation time in the Y connection state is longer, it is preferable to set the motor 3 in the Y connection state when the connection switching device 5 is in the off state.
  • each switch may be configured by a combination of a normally closed switch and a normally opened switch.
  • FIG. 4 shows a configuration example of the connection switching device in that case.
  • a combination of a normally open switch 51ua and a normally closed switch 51ub is used as the switch 51u, and a combination of the normally open switch 51va and the normally closed switch 51vb is used as the switch 51v, as the switch 51w.
  • a combination of a normally open switch 51wa and a normally closed switch 51wb is used.
  • one terminal of the normally closed switches 51ub, 51vb, and 51wb is connected to the neutral point node 52.
  • the wiring may be such that the motor 3 is in the Y-connected state when the motor 3 is in the ⁇ -connected state, the normally closed switches 51ub, 51vb, 51wb are opened, and the normally-open switches 51ua, 51va, 51wa are closed.
  • an electromagnetic contactor can be used as each switch.
  • An electromagnetic contactor is suitable because it has a small conduction loss when it is turned on.
  • a semiconductor switch may be used as each switch.
  • the semiconductor switch may be made of a wide bandgap semiconductor (WBG semiconductor).
  • the wide bandgap semiconductor (WBG semiconductor) may be silicon carbide (SiC), gallium nitride (GaN), gallium oxide (Ga 2 O 3 ), diamond or the like.
  • a semiconductor switch composed of a wide bandgap semiconductor (WBG semiconductor) has a small on-resistance, low loss, and low element heat generation. These can also perform the switching operation quickly.
  • connection switching device By using the connection switching device as described above, it is possible to switch the connection state of the motor 3 between the Y connection and the ⁇ connection.
  • the motor at the time of Y connection and the time of ⁇ connection have the relationship of the equations (1) and (2), the motor at the time of Y connection and the time of ⁇ connection
  • the power supplied to 3 is equal to each other. That is, when the electric power supplied to the motor 3 is equal to each other, the current is larger in the ⁇ connection and the voltage required for driving is lower. Utilizing this property, it is conceivable to select the connection state according to the load conditions and the like. For example, when the load is low, the Y connection may be used for low-speed operation, and when the load is high, the ⁇ connection may be used for high-speed operation. In this way, the efficiency at low load can be improved, and the output at high load can be increased.
  • a three-phase permanent magnet synchronous motor is widely used. Further, in recent air conditioners, when the difference between the room temperature and the set temperature is large, the room temperature is brought closer to the set temperature by high-speed operation of the motor 3, and when the room temperature is close to the set temperature, the motor 3 is operated at low speed. I try to maintain the room temperature. When controlled in this way, the ratio of the low-speed operation time to the total operation time is large.
  • the counter electromotive force increases as the number of revolutions increases, and the voltage value required for driving increases.
  • This counter electromotive force is higher in the Y connection than in the ⁇ connection as described above.
  • the current for obtaining the same output torque increases, so that the current flowing through the motor 3 and the inverter 4 increases, and the efficiency decreases.
  • connection state it is conceivable to switch the connection state according to the number of rotations. For example, when high-speed operation is required, a ⁇ connection state is set. In this case, the voltage required for driving can be set to 1 / ⁇ 3 compared to the Y connection state, there is no need to reduce the number of winding turns, and the motor voltage rise is suppressed in the three-phase permanent magnet synchronous motor. It is no longer necessary to use the well-known weakening magnetic flux control for this purpose.
  • the current value can be reduced to 1 / ⁇ 3 compared to the ⁇ connection by setting the Y connection state.
  • the winding can be designed to be suitable for driving at a low speed in the Y connection state, and the current value can be reduced as compared with the case where the Y connection is used over the entire speed range. ..
  • the loss of the inverter 4 can be reduced and the efficiency can be improved.
  • connection state of the motor 3 is switched by the connection switching device 5.
  • the inverter 4 has an inverter main circuit 41 and a drive circuit 45, and the input terminal of the inverter main circuit 41 is an output terminal 8a of the power source 8 via the DC bus 4a and 4b. It is connected to 8b.
  • the inverter main circuit 41 has six arms including switching elements 411 to 416, respectively. Rectifying elements 421 to 426 for reflux are connected in antiparallel to the switching elements 411 to 416.
  • the drive circuit 45 generates drive signals Sr1 to Sr6 based on the PWM signals Sm1 to Sm6 output from the control unit 7, and controls on / off of the switching elements 411 to 416 by the drive signals Sr1 to Sr6. Therefore, a three-phase AC voltage having a variable frequency and a variable voltage is applied to the motor 3 from the output terminals 4u, 4v, and 4w.
  • the switching elements 411 to 416 and the rectifying elements 421 to 426 for reflux are silicon carbide SiC, gallium nitride GaN, and diamond, which are wide bandgap semiconductors capable of high withstand voltage and high temperature operation even if the elements are made of silicon Si. An element composed of such as may be used.
  • the control unit 7 may be composed of a part or all of the processing circuit.
  • the various functions of the control unit 7 may be realized by separate processing circuits, or a plurality of functions may be collectively realized by one processing circuit.
  • the processing circuit may be composed of hardware or software, that is, a programmed computer. Of the various functions of the control unit 7, a part may be realized by hardware and the other part may be realized by software.
  • FIG. 6 shows a computer 9 that realizes all the functions of the control unit 7, together with a current detecting means 6, an inverter 4, and a connection switching device 5.
  • the computer 9 has a processor 91 and a memory 92.
  • the memory 92 stores programs for realizing various functions of the control unit 7.
  • the processor 91 uses, for example, a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), a microprocessor, a microcontroller, a DSP (Digital Signal Processor), or the like.
  • a CPU Central Processing Unit
  • GPU Graphics Processing Unit
  • microprocessor a microcontroller
  • DSP Digital Signal Processor
  • the memory 92 includes, for example, a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory, an EPROM (Erasable Programmable Lead Only Memory), an EEPROM (Electrically Memory Memory, etc.) Alternatively, a photomagnetic disk or the like is used.
  • the processor 91 realizes the function of the control unit 7 by executing the program stored in the memory 92.
  • the function of the control unit 7 includes a function of controlling the inverter 4 and the connection switching device 5 based on the detection result of the current detecting means 6.
  • the computer of FIG. 6 includes a single processor, but may include two or more processors.
  • the control unit 7 calculates the voltage to be applied to the motor 3, generates a voltage command value, generates PWM signals Sm1 to Sm6 based on the voltage command value, and turns on and off each switching element of the inverter 4. To control.
  • the control unit 7 also generates a switching control signal Sc for selecting the connection state of the motor 3 and controls the on / off operation of the switches 51u, 51v, 51w of the connection switching device 5, whereby the motor 3 Is switched between the Y connection and the ⁇ connection.
  • connection switching is performed in response to the wiring switching request.
  • the connection switching request may be generated as a result of internal processing of the control unit 7, or may be generated by an external higher-level control unit (not shown) and transmitted to the control unit 7.
  • the connection switching is performed when it is determined that switching is possible in the switching control sequence described below.
  • the connection switching is executed. If the speed of the motor 3 is less than the threshold value, the connection switching is not executed.
  • the threshold value is a positive value, and the determination of whether or not the speed of the motor 3 is equal to or greater than the threshold value means the determination of whether or not the absolute value of the speed is equal to or greater than the threshold value.
  • the connection switching is performed in a state where zero current control is performed.
  • the zero current control is a control that makes the current flowing between the inverter 4 and the motor 3 zero.
  • zero is not limited to the state of being exactly zero, but also includes the case of being close to zero so that it can be regarded as substantially zero.
  • a current control system is inserted in front of the voltage command value generation unit so that zero can be selected as the current command value, and when the current zero control is performed, the current zero control is performed. Zero may be selected as the current command value. If zero is selected as the current command value of the current control system, a voltage command value for matching the current of the motor 3 to zero is generated. By generating PWM signals Sm1 to Sm6 based on this voltage command value and controlling the on / off operation of the switching elements 411 to 416 of the inverter 4, the current of the motor 3 can be converged to zero.
  • the above current control system can be realized by, for example, a well-known PI (proportional integration) control system.
  • the current zero control is performed for the following reasons.
  • the connection of the common terminal COM of the switches 51u, 51v, 51w is switched from the normally open terminal NO to the normally closed terminal NC, or from the normally closed terminal NC to the normally open terminal NO.
  • this switching operation is performed in a state where a current is flowing between the inverter 4 and the motor 3, and therefore a current is flowing in the switches 51u, 51v, 51w, the contacts of the switches 51u, 51v, 51w. An arc discharge occurs between them, which may cause a failure such as contact welding.
  • zero current control is performed for a certain period (zero current control period) T0, the current flowing between the inverter 4 and the motor 3 is maintained at zero, and in that state, the connection is switched.
  • the device 5 is switched. By doing so, switching can be performed without generating an arc discharge between the contacts of the switches 51u, 51v, and 51w.
  • the speed of the motor 3 prior to the start of the zero current control, it is determined whether the speed of the motor 3 is equal to or higher than the threshold value, and if the speed of the motor 3 is equal to or higher than the threshold value, the zero current control and the connection switching are executed. However, if the speed of the motor 3 is less than the threshold value, the current zero control and the connection switching are not executed.
  • the speed of the motor 3 may be simply referred to as the motor speed.
  • the time is when the motor 3 is in normal operation, that is, when the motor 3 is controlled to a desired speed and the output torque of the motor 3 is in balance with the load torque of the load 2. It is assumed that a switching request is generated at t1 and a switching control sequence is performed under the control of the control unit 7 in response to the request. In FIG. 7, it is assumed that the motor 3 is normally operating at a constant speed until the time t1 when the switching request is generated, and the motor speed ⁇ 1 at the time t1 is equal to or higher than the threshold value ⁇ 0. The period of normal operation is indicated by Tn.
  • the current zero control is started at time t2, the current converges to zero at time t3, and the current converges to zero at time t4.
  • the switching control signal Sc indicates switching of the connection switching device 5 (the switching control signal Sc changes from a state in which one connection state is specified to a state in which another connection state is specified), and the connection switching device 5 is instructed to switch.
  • the switching is performed according to the above time, the switching is completed at time t5, the current zero control is completed at time t6, and the state of normal operation is restored.
  • the period from the start (t2) to the end (t6) of the zero current control is the zero current control period T0.
  • FIG. 7 also shows that the speed decreases from ⁇ 1 to ⁇ n during the zero current control period T0, and the restart for returning to the normal operation state is performed with ⁇ n as the initial value.
  • FIG. 7 shows a case where the motor speed ⁇ 1 at the start of the switching control sequence is equal to or higher than the threshold value ⁇ 0, but when the motor speed ⁇ 1 at the start of the switching control sequence is less than the threshold value ⁇ 0, the current zero control is performed. And the connection is not switched.
  • the reason why the motor speed ⁇ 1 is restricted in this way is to prevent step-out, stop, etc. due to a decrease in the motor speed during the period T0 of the current zero control.
  • the length of the above zero current control period T0 is the time from when the control unit 7 is instructed to start the zero current control until the current between the inverter 4 and the motor 3 actually converges to zero.
  • the current convergence time Ta depends on the responsiveness of the control system of the control unit 7. Generally, the control system is designed so that the current convergence time is about several hundred micro [s] to several millimeters [s].
  • a predetermined length of time may be used. That is, it may be considered that the current has converged to zero when a predetermined time has elapsed since the current zero control was started.
  • the switching instruction by the switching control signal Sc is given when the above time Te has elapsed from the time t1.
  • the switching operation time Tb differs depending on the type of the switch 51u, 51v, 51w.
  • the time required for switching is several hundred milliseconds [s]
  • the switches 51u, 51v, 51w are composed of semiconductor switches
  • the time required for switching is several hundred milliseconds. Is a few milliseconds [s].
  • the length of the current zero control period T0 may be set to the sum (Te + Tf) of the time Te obtained by adding the margin Tc to the current convergence time Ta and the time Tf obtained by adding the margin Td to the switching operation time Tb. ..
  • the length of the current zero control period T0 can also be set to the predetermined values.
  • control is performed so as to suppress step-out and stop due to a decrease in the motor speed.
  • the speed reduction amount ⁇ during the current zero control period is estimated, and the value obtained by adding the margin ⁇ ⁇ to the estimated speed reduction amount (estimated value of the reduction amount) ⁇ is set as the threshold value ⁇ 0 at the start of the switching control sequence. After confirming that the motor speed ⁇ 1 of the above is equal to or higher than the threshold value ⁇ 0, the current zero control is started.
  • the motor speed ⁇ 1 at the start of the switching control sequence and the motor speed ⁇ 2 at the start of the zero current control are equal. Therefore, when the current zero control is started after confirming that the motor speed ⁇ 1 at the start of the switching control sequence is equal to or higher than the threshold value ⁇ 0, it can be said that the motor speed ⁇ 2 at the start of the current zero control is equal to or higher than the threshold value ⁇ 0.
  • the motor speed may be regarded as equal to the speed command value ⁇ * used in the speed control of the motor 3.
  • a speed command value a value calculated inside the control unit 7 or a value given by an external upper control unit (not shown) may be used.
  • the motor speed is controlled so as to follow the speed command value ⁇ *. That is, a voltage command value is generated using a well-known PI (proportional integration) control or the like so that the motor speed follows the speed command value ⁇ *, and PWM signals Sm1 to Sm6 are generated based on this voltage command value. , Controls the on / off operation of the switching elements 411 to 416 of the inverter 4. Therefore, it can be seen that the motor speed matches the speed command value ⁇ * during stable operation.
  • PI proportional integration
  • the control unit 7 controls the torque of the motor 3 (not the speed control)
  • the motor speed itself is not directly controlled.
  • the speed command value ⁇ * cannot be used.
  • the estimated value ⁇ ⁇ of the motor speed may be used.
  • the speed estimation value ⁇ ⁇ is obtained based on, for example, a voltage command value or a current detected by the current detecting means 6.
  • the speed reduction amount ⁇ during the current zero control period T0 is estimated.
  • the motor 3 is controlled at a desired speed, and the motor 3 is operated in a state in which the output torque of the motor 3 is balanced with the load torque of the load 2.
  • TL [Nm] the change in load torque TL [Nm] is sufficiently small.
  • T0 represents the length of the current zero control period T0.
  • Jm represents the shaft inertia (moment of inertia) [kg ⁇ m 2 ] of the motor 3.
  • the value of the shaft inertia Jm of the motor 3 is known in advance by actual measurement or the like. Since the value of the load torque TL changes depending on the state of the load 2 and is difficult to measure, it is assumed that the load torque at the start of the switching control sequence is balanced with the output torque of the motor 3 as described below. Estimate by equation (4). TL ⁇ I1 ⁇ Kt (4)
  • I1 is the output current of the inverter 4.
  • Kt is a torque constant Kt [Nm / A].
  • the output current I1 of the inverter 4 corresponds to ⁇ 3 times the effective value Irms [A] of the output phase current of the inverter 4, and the motor torque current (q) when the current is represented by the well-known dq-axis rotating coordinate system.
  • the torque constant Kt differs depending on whether the connection state is Y connection or ⁇ connection. For the calculation (calculation expressed by the formula (4) or the formula (4) described later), a value corresponding to the connection state at the time of performing the calculation is used. Since the calculation is performed before the connection is switched, the torque constant in the connection state before the connection is used.
  • the value of the torque constant Kt is generally known and is stored in advance in the control unit 7.
  • the torque constant Kt is the magnetic flux ⁇ m of the permanent magnet represented by the well-known dq-axis rotational coordinate system and the number of pole pairs of the motor 3 when the motor 3 is a three-phase permanent magnet synchronous motor that obtains rotational force mainly by magnet torque. Corresponds to the product of.
  • the above magnetic flux ⁇ m corresponds to ⁇ (2/3) times the maximum value of the armature interlinkage magnetic flux per phase.
  • the threshold value ⁇ 0 is set to a value equal to or greater than the speed reduction amount ⁇ obtained by the equation (5). That is, ⁇ 0 ⁇ I1, Kt, T0 / Jm (6) It is determined to meet.
  • the threshold value ⁇ 0 ⁇ + ⁇ ⁇ (7)
  • the output current I1 at the time of performing the calculation is used as the output current I1. Since the above calculation is performed immediately after the start of the switching control sequence, it can be said that the output current I1 at the time of the above calculation is the output current I1 at the start of the switching control sequence.
  • the load 2 applied to the motor 3 is, for example, a compression element of a compressor of an air conditioner
  • the internal temperature of the compressor becomes high, so that it is difficult to attach a sensor for detecting the motor speed or the magnetic pole position. Is. Therefore, it is necessary to obtain information indicating the motor speed at the time of restart by a method other than the method using the sensor.
  • the speed is reduced by the speed reduction amount ⁇ in the current zero control period T0 from the motor speed ⁇ 2 at the start of the current zero control (t2) described above, and the value obtained by subtracting ⁇ from ⁇ 2 is the time tun.
  • the estimated speed of ⁇ ⁇ n is set, and restart is performed with ⁇ ⁇ n as the initial speed.
  • the magnetic pole position at the start of restart can be estimated by also calculating the amount of change in the magnetic pole position (phase) of the motor 3 that changes according to the amount of speed decrease ⁇ .
  • FIG. 8 shows a processing procedure. The process of FIG. 8 is performed in the normal operating state of the motor 3.
  • the control unit 7 determines whether or not the switching control sequence needs to be started. It is necessary to start the switching control sequence when a switching request occurs.
  • step ST1 If it is determined in step ST1 that it is necessary to start the switching control sequence (if YES), the control unit 7 starts the switching control sequence in step ST2. In the following description, this start time is t1.
  • the control unit 7 also acquires the motor speed at time t1 at the start of the switching control sequence. For example, at time t1, the speed command value ⁇ * used in the speed control of the motor 3 is acquired as the motor speed ⁇ 1 at the start of the switching control sequence.
  • step ST1 If it is determined in step ST1 that the start of the switching control sequence is unnecessary (NO), the control unit 7 maintains the normal operating state of the motor 3. That is, the process of step ST1 is repeated.
  • the control unit 7 After the start of the switching control sequence, the control unit 7 first determines the threshold value ⁇ 0 in step ST3.
  • the threshold value ⁇ 0 serves as a reference for determining whether or not zero current control should be started.
  • the threshold value ⁇ 0 is set to a value that is larger than the speed reduction amount ⁇ obtained by the calculation of the equation (5) by a predetermined margin ⁇ ⁇ , that is, a value represented by the equation (7).
  • step ST3 when calculating the equations (5) and (7) to obtain the threshold value ⁇ 0, the output current I1 at the time when the threshold value ⁇ 0 is calculated in step ST3 is used as the output current I1. Since the processing of step ST3 is performed immediately after the start of the switching control sequence in step ST2, the output current I1 at the time of performing the processing of step ST3 is the output current I1 at the time of starting the switching control sequence. I can say.
  • control unit 7 compares the motor speed ⁇ 1 acquired in step ST2 with the threshold value ⁇ 0 determined in step ST3 in step ST4, and determines whether or not ⁇ 1 ⁇ ⁇ 0. ..
  • control unit 7 If it is determined that ⁇ 1 ⁇ ⁇ 0 (if YES), the control unit 7 starts the current zero control in step ST5. The control unit 7 also acquires the time at this time as the start time t2 of the current zero control, and acquires the motor speed at this time as the motor speed ⁇ 2 at the start of the current zero control (t2).
  • step ST4 If it is determined that ⁇ 1 ⁇ 0 (NO in ST4), the process returns to step ST1. That is, the control unit 7 does not switch the connection state of the motor 3, and maintains the normal operation state of the motor 3.
  • step ST4 the process may return to step ST2 as shown by the dotted line in FIG. That is, when it is determined that ⁇ 1 ⁇ 0, the acquisition of the motor speed ⁇ 1, the determination of the threshold value ⁇ 0, and the determination of whether or not ⁇ 1 ⁇ ⁇ 0 (ST2, ST3, and ST4) may be repeated.
  • step ST4 If YES in step ST4, the time difference between the start time t1 of the switching control sequence in step ST2 immediately before that and the start time t2 of the current zero control in step ST5 is small, so that there is no such difference. You may consider it. Therefore, in step ST5, it may be regarded as t2 ⁇ t1. Further, the speed change during this period is also minute and can be ignored. That is, it may be regarded as ⁇ 2 ⁇ ⁇ 1. Therefore, ⁇ 1 acquired in the process of step ST2 immediately before the result of YES in step ST4 may be used as it is as ⁇ 2.
  • step ST7 the control unit 7 instructs the switching operation by the switching control signal Sc.
  • the switching operation is performed by operating the switching devices 51u, 51v, 51w of the connection switching device 5.
  • the control unit 7 also acquires the time t4 of the switching operation instruction.
  • Tf time
  • Tb + Td time
  • step ST9 the control unit 7 ends the zero current control and estimates the motor speed at the end of the zero current control.
  • the estimated value is represented by ⁇ ⁇ n.
  • the speed has decreased by the amount of speed reduction ⁇ in the period T0, and the speed has decreased during zero current control, and the value obtained by subtracting ⁇ from ⁇ 2 is the time tn. It may be the estimated speed of ( ⁇ ⁇ n).
  • step ST10 the control unit 7 returns to the normal operation with the estimated value ⁇ ⁇ n as the initial value.
  • the life or reliability of the connection switching device 5 can be improved, and the step-out due to a decrease in the motor speed can be achieved. And there is an effect that can prevent the stop.
  • the value obtained by subtracting the speed decrease amount ⁇ during the current zero control period from the motor speed ⁇ 2 at the start of the current zero control is the value of the motor at the time of restarting. Since the initial speed is 3, there is an effect that the return can be performed more reliably and quickly.
  • the current detecting means 6 is a current sensor such as ACCT or DCCT provided on the wiring connecting the inverter 4 and the motor 3 in FIG. 1, but the DC bus 4a and 4b Alternatively, a well-known shunt resistor for phase current detection, which is inserted in series with the switching elements 414, 415, and 416 on the negative side of the inverter 4, may be used. Even when these current detecting means 6 are used, the current flowing from the inverter 4 to the motor 3 can be obtained by a well-known method.
  • the current of the motor 3 is converged to zero by controlling the on / off operation of the switching elements 411 to 416 of the inverter 4.
  • all the switching elements 411 to 416 of the inverter 4 may be turned off. When all the switching elements 411 to 416 of the inverter 4 are turned off, the current between the motor 3 and the inverter 4 is cut off, and the current of the motor 3 converges to zero.
  • Embodiment 2 when a predetermined length of time has elapsed from the start of the zero current control, it is considered that the current has converged to zero, and the switching operation is started.
  • the current detecting means 6 may detect the current flowing between the inverter 4 and the motor 3, confirm that the detected current has converged to zero, and then start the switching operation after confirmation.
  • the processing procedure in this case is as shown in FIG.
  • step ST11 is provided instead of step ST6.
  • step ST11 it waits for the detected current to converge to zero.
  • the term "zero" here is not limited to the state of being exactly zero, but also includes the case of being close to zero so that it can be regarded as substantially zero.
  • the current can be detected by, for example, the current detecting means 6. If YES in step ST11, the process proceeds to step ST7.
  • Embodiment 3 In the first embodiment, at the start of the switching control sequence (t1), after confirming that the motor speed ⁇ 1 is equal to or higher than the threshold value ⁇ 0, the connection switching is executed, while at the start of the switching control sequence. In (t1), when the motor speed ⁇ 1 is less than the threshold value ⁇ 0, the connection is not switched and the motor speed ⁇ 1 is waited to reach the threshold value or more.
  • the connection switching is immediately executed as in the first embodiment, while the connection switching is immediately performed.
  • the motor speed ⁇ 1 is less than the threshold value ⁇ 0, the motor 3 is accelerated to increase the speed to the threshold value ⁇ 0 or more, and then the connection is switched.
  • the acceleration of the motor 3 is performed as follows. For example, when the control unit 7 controls the speed of the motor 3, acceleration can be performed by changing the speed command value ⁇ *.
  • the speed command value ⁇ * may be switched to a value equal to or higher than the threshold value ⁇ 0 at once, that is, in a stepped manner.
  • the speed command value ⁇ * may be gradually increased over time. When it is gradually increased, it may be continuously increased or gradually increased. When increasing in stages, for example, a constant increment may be repeatedly added.
  • the speed command value ⁇ * or the estimated value ⁇ ⁇ may be used to determine whether or not the motor speed during acceleration has reached the threshold value ⁇ 0 or higher.
  • the speed estimation value ⁇ ⁇ is obtained based on the voltage command value or the current detected by the current detecting means 6.
  • FIG. 10 shows an example of the operation when the switching control sequence is performed by the drive device of the third embodiment.
  • the motor 3 is normally operating at a constant speed until the time t1 when the switching request occurs, and the motor speed ⁇ 1 at the time t1 is less than the threshold value ⁇ 0.
  • Zero current control is started as soon as the acceleration is completed.
  • the time point at which the zero current control starts coincides with the time point t2b at the end of acceleration.
  • the current converges to zero after the time Ta elapses (t3) from the start of the current zero control (t2b), and the switching operation ends after the time Tb elapses (t5) from the switching instruction (t4).
  • FIG. 10 shows that the speed decreases from ⁇ 2 to ⁇ n during the zero current control period T0, and the restart for returning to the normal operation state is performed with ⁇ n as the initial value.
  • FIG. 11 shows the processing procedure according to the third embodiment.
  • the procedure shown in FIG. 11 is generally the same as in FIG. However, steps ST5 and ST6 are replaced by steps ST5b and ST6b, and steps ST21 and ST22 are added.
  • step ST21 the control unit 7 controls for accelerating the motor 3.
  • the control unit 7 also acquires the motor speed ⁇ 1'during acceleration.
  • the acceleration of the motor 3 may be performed by switching the speed command value ⁇ * to a value equal to or higher than the threshold value ⁇ 0 at once, or by gradually increasing the speed command value ⁇ * with the passage of time.
  • the amount of increase in one process of step ST21 may be predetermined.
  • the speed command value ⁇ * is changed slowly, the motor speed ⁇ 1'during acceleration can be regarded as equal to the speed command value ⁇ *. If they cannot be regarded as equal, the estimated value ⁇ ⁇ of the motor speed is obtained, and the estimated value is used as the motor speed ⁇ 1'.
  • step ST22 the control unit 7 determines whether or not the motor speed ⁇ 1'during acceleration is equal to or greater than the threshold value ⁇ 0.
  • step ST22 If YES in step ST22, the process proceeds to step ST5b. If NO in step ST22, the process returns to step ST21, and the acceleration in step ST21 and the determination in step ST22 are repeated.
  • step ST5b the control unit 7 starts the current zero control, acquires the time at this time as the start time t2b of the current zero control, and acquires the motor speed at this time as the motor speed ⁇ 2 at the start of the current zero control. ..
  • step ST22 the time t21 at which the processing of step ST21 immediately before the step ST22 for which the determination is YES and the time t2b at the start of the zero current control are performed is in step ST22.
  • t2b-t21 the time difference for the time required for the processing and the calculation processing (step ST22) of the control unit 7, but since this time difference is small, it may be considered that there is no speed change during this time. That is, it may be regarded as ⁇ 1' ⁇ 2.
  • the threshold value ⁇ 0 determined in step ST3 is also used in step ST22.
  • the threshold ⁇ 0 may be redetermined after the acceleration in step ST21. In this case, the same calculation as in step ST3 is performed using the output current I1 after acceleration in step ST21.
  • FIG. 12 shows the processing procedure according to the fourth embodiment.
  • the processing procedure of FIG. 12 is generally the same as the processing procedure of FIG. 11, but step ST23 is added.
  • step ST23 the control unit 7 redetermines the threshold value ⁇ 0. In re-determining, equations (5) and (7) are calculated. However, as the output current I1, the output current I1 in the state after the acceleration in the immediately preceding step ST22 is used.
  • the threshold value ⁇ 0 By using the output current I1 after acceleration, a more appropriate value can be obtained as the threshold value ⁇ 0, and it is possible to more appropriately determine whether or not the motor speed ⁇ 1'after acceleration is equal to or higher than the threshold value ⁇ 0.
  • FIG. 13 shows the air conditioner 100 according to the fifth embodiment together with the electric power source 8.
  • the illustrated air conditioner includes an outdoor unit 101, an indoor unit 102, and an air conditioning controller 103.
  • the outdoor unit 101 has a drive device 1 and a compressor 110.
  • the compressor 110 has a motor 3 and a compression element 111 as a load 2 of the motor 3.
  • the outdoor unit 101 further includes a four-way valve 121, a heat source side heat exchanger 122, and a heat source side expansion valve 123.
  • the drive device 1 and the motor 3 may be those described in the first to fourth embodiments.
  • the drive device 1 is connected to the power source 8.
  • the power source 8 may supply DC power or AC power as shown in FIG. 2A or 2B.
  • the drive device 1 may be provided with an AC / DC power converter.
  • the indoor unit 102 has a load-side expansion valve 131 and a load-side heat exchanger 132.
  • the four-way valve 121 and the heat source side expansion valve 123 are controlled by the air conditioning controller 103.
  • the compression element 111 of the compressor 110 is a refrigerant circuit connected to each other by a refrigerant pipe 141 together with a four-way valve 121, a heat source side heat exchanger 122, a heat source side expansion valve 123, a load side expansion valve 131, and a load side heat exchanger 132.
  • the refrigeration cycle is established by the flow of the refrigerant through the refrigerant circuit.
  • the four-way valve 121 makes the refrigerant discharged from the compressor 110 go to the heat source side heat exchanger 122, and the refrigerant flowing out from the load side heat exchanger 132 goes to the compressor 110.
  • the flow path can be switched.
  • an accumulator for storing excess refrigerant may be provided on the suction side of the compression element 111 of the compressor 110.
  • the cooling plate may be brought into contact with the power module which is a component of the inverter 4, and the refrigerant pipe 141 described above may be further brought into contact with the cooling plate. Then, the refrigerant flowing through the refrigerant pipe 141 can absorb the heat generated in the inverter 4, and the temperature rise of the inverter 4 can be efficiently suppressed.
  • the indoor unit 102 and the outdoor unit 101 are provided with expansion valves 123 and 131, respectively.
  • the cooling capacity of the air conditioner can be controlled independently by the two expansion valves 123 and 131, the refrigerant can be finely and efficiently controlled.
  • one of the expansion valves 123 and 131 may be omitted. That is, the expansion valves 123 and 131 may be provided on either the indoor unit side or the outdoor unit side.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Control Of Ac Motors In General (AREA)
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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPWO2023214453A1 (https=) * 2022-05-02 2023-11-09
WO2024075318A1 (ja) * 2022-10-07 2024-04-11 住友電気工業株式会社 車両用モータの巻線切替システム、制御装置、車両用モータの制御方法、及びコンピュータプログラム
WO2024185339A1 (ja) * 2023-03-03 2024-09-12 住友電気工業株式会社 制御装置、巻線切替システム、車両、制御方法、及び制御プログラム

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2019167379A1 (ja) * 2018-03-02 2019-09-06 株式会社日立製作所 回転機駆動システム
WO2020016972A1 (ja) * 2018-07-18 2020-01-23 三菱電機株式会社 回転機制御装置、冷媒圧縮装置、冷凍サイクル装置及び空気調和機
WO2020021681A1 (ja) * 2018-07-26 2020-01-30 三菱電機株式会社 電動機駆動装置及び冷凍サイクル適用機器

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP6717695B2 (ja) * 2016-07-21 2020-07-01 株式会社Ｓｏｋｅｎ 電力変換装置
JP6721476B2 (ja) * 2016-09-28 2020-07-15 シャープ株式会社 モータ駆動システムおよび空気調和機
WO2019021452A1 (ja) * 2017-07-28 2019-01-31 三菱電機株式会社 駆動装置、圧縮機、及び空気調和機、並びに永久磁石埋込型電動機の駆動方法

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2019167379A1 (ja) * 2018-03-02 2019-09-06 株式会社日立製作所 回転機駆動システム
WO2020016972A1 (ja) * 2018-07-18 2020-01-23 三菱電機株式会社 回転機制御装置、冷媒圧縮装置、冷凍サイクル装置及び空気調和機
WO2020021681A1 (ja) * 2018-07-26 2020-01-30 三菱電機株式会社 電動機駆動装置及び冷凍サイクル適用機器

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPWO2023214453A1 (https=) * 2022-05-02 2023-11-09
WO2023214453A1 (ja) * 2022-05-02 2023-11-09 三菱電機株式会社 駆動装置及び冷凍サイクル装置
JP7603884B2 (ja) 2022-05-02 2024-12-20 三菱電機株式会社 駆動装置及び冷凍サイクル装置
WO2024075318A1 (ja) * 2022-10-07 2024-04-11 住友電気工業株式会社 車両用モータの巻線切替システム、制御装置、車両用モータの制御方法、及びコンピュータプログラム
WO2024185339A1 (ja) * 2023-03-03 2024-09-12 住友電気工業株式会社 制御装置、巻線切替システム、車両、制御方法、及び制御プログラム

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