JP2015100196A - Permanent magnet synchronous motor driving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To uniformly heat equipment and a device without causing torque to be applied to a rotor and without temperature deviation.SOLUTION: A permanent magnet synchronous motor driving device is provided with heating control means causing a current to flow through a winding of each phase of a permanent magnet synchronous motor and heating equipment and a device prior to a start of rotational driving of the permanent magnet synchronous motor. The heating control means combines a current-carrying period when turning on a switching element of at least one phase out of upper arms and a switching element of at least the other one phase out of lower arms of a voltage inverter and a current-carrying period when turning on a switching element possessed by an arm making a pair with the arm having the switching element turned on in the current-carrying period and repeatedly executes a current-carrying process for causing an alternating current to flow through the winding of the permanent magnet synchronous motor while sequentially changing a current-carrying phase for all phases as objects.

Description

  Embodiments described herein relate generally to a sensorless drive permanent magnet synchronous motor drive device.

  2. Description of the Related Art A variable speed motor driving device that drives an electric motor at a variable speed using an inverter is applied to various fields. Among the electric motors, the permanent magnet synchronous motor has been widely adopted because it has a permanent magnet in the rotor and is more efficient than the induction motor. Further, position / speed sensorless control without using a speed sensor or position sensor is useful in terms of improving reliability and improving constraints on the installation environment.

  The sensorless drive motor driving device is also suitable for driving a compressor (equipment device) in which the motor is integrated. The compressor has a characteristic that the starting load increases when the refrigerant temperature is low. For this reason, if the electric motor is started when the compressor is in a low temperature state, an excessive load is applied to the compressor, a large starting current flows, and an emergency stop function such as overload protection may be activated and cannot be started. Therefore, as a general measure, while the compressor is stopped, the compressor is heated with a heater at all times or intermittently, or a current is passed through the windings of the motor to heat the compressor (patent). References 1 and 2).

  If a method of heating by energizing the windings of the electric motor is adopted, it is not necessary to provide a heater, so that the compressor can be miniaturized and there is no fear of disconnection failure of the heater. On the other hand, when a permanent magnet synchronous motor is used as the electric motor, torque is generated in the rotor depending on the positional relationship between the current flowing through the stator winding and the magnetic flux generated by the permanent magnet of the rotor. In order not to generate torque, it is conceivable that the current of the stator windings flows in a phase direction parallel to the magnetic flux generated by the permanent magnet. However, this causes a difference in the amplitude of the current flowing through each phase winding and the effective value, and the compressor cannot be heated uniformly.

Japanese Patent No. 3831852 Japanese Patent Laid-Open No. 11-324934

  Therefore, a permanent magnet synchronous motor drive device that can uniformly heat an apparatus without causing a rotational force in the rotor and without temperature deviation is provided.

  The permanent magnet synchronous motor drive device according to the embodiment drives a permanent magnet synchronous motor that is configured integrally with an apparatus device without using a sensor that detects a magnetic pole position. This drive device includes a bridge circuit composed of a pair of an upper arm and a lower arm having switching elements for three phases, a voltage source inverter for supplying a voltage to the windings of each phase of the permanent magnet synchronous motor, and a permanent magnet synchronous motor Current detecting means for detecting the phase current of the permanent magnet synchronous motor, and heating control means for heating the device device by passing a current through the windings of each phase of the permanent magnet synchronous motor before starting to rotate the permanent magnet synchronous motor. Yes.

  The heating control means includes an energization period for turning on a switching element of one phase of the upper arm of the voltage source inverter and a switching element of at least one other phase of the lower arm, and a switching element turned on in this energization period. Combined with the energization period to turn on the switching element of the arm that makes a pair with the arm, the energization process of passing an alternating current through the windings of the permanent magnet synchronous motor is repeatedly executed while changing the energized phase in order for all phases To do.

The block diagram of the electric motor drive device which shows 1st Embodiment The figure which shows the processing sequence when driving a compressor Diagram showing voltage vector The figure which shows the relationship between a voltage vector and the on-off state of IGBT. (A) is voltage vector V1, (b) is a figure which shows the electric current path when the voltage vector V4 is output. Waveform diagram of the first energization sequence Waveform diagram of phase current during energization sequence A diagram schematically showing the spatial distribution of the reciprocal of motor reactance Adjustment sequence flowchart Flowchart of process A according to the first energization sequence Flowchart of process B according to the second energization sequence Flowchart of process C according to the third energization sequence Waveform diagram of phase current during execution of adjustment sequence (1) Waveform diagram of phase current during execution of adjustment sequence (part 2) Waveform diagram of phase current during execution of adjustment sequence (part 3) Measured waveform diagram of phase current in adjustment sequence and start judgment sequence FIG. 1 equivalent diagram showing the second embodiment

(First embodiment)
A first embodiment will be described with reference to FIGS. FIG. 1 shows the configuration of an electric motor drive device that drives a permanent magnet synchronous motor. The electric motor drive device 1 drives a permanent magnet synchronous motor 3 (hereinafter referred to as the electric motor 3) incorporated in the compressor 2 (equipment device) without using a sensor for detecting a magnetic pole position, so-called sensorless. When the electric motor 3 configured integrally with the compressor 2 rotates, the compression mechanism 4 compresses the refrigerant gas, and the refrigerant gas having a high temperature and a high pressure is guided to a condenser (not shown). In the electric motor 3, three-phase windings 3u, 3v, 3w are wound around a stator 3s, and a rotor 3r is provided with a permanent magnet.

  The main circuit of the motor drive device 1 includes a converter 7 that rectifies an AC voltage input from the commercial power supply PS and outputs the rectified voltage between the DC power supply lines 5 and 6, a smoothing capacitor 8, a voltage source inverter 9, and current sensors 10 and 11. Etc. The voltage source inverter 9 includes a bridge circuit 14u including a pair of an upper arm 13up having an IGBT 12up and a lower arm 13un having an IGBT 12un, a bridge circuit 14v having a pair of an upper arm 13vp having an IGBT 12vp and a lower arm 13vn having an IGBT 12vn, and an IGBT 12wp. A three-phase bridge comprising a bridge circuit 14w comprising a pair of an upper arm 13wp having a lower arm and a lower arm 13wn having an IGBT 12wn. These IGBTs 12up to 12wn (switching elements) are driven by a drive circuit 15.

  The winding terminals of the motor 3 as a load are connected to the output terminals of the bridge circuits 14u, 14v, 14w. The current sensors 10 and 11 are current detection means composed of Hall elements and the like. The phase sensors Iu flowing from the output terminal of the bridge circuit 14u to the winding 3u and the phases flowing from the output terminal of the bridge circuit 14w to the winding 3w, respectively. The current Iw is detected.

  The control means 16 is mainly composed of a microcomputer having a CPU, RAM, ROM, EEPROM, input / output port, A / D converter 17, timer, PWM signal forming circuit, communication means, and the like. The ROM stores a heating control program for heating the compressor 2 by passing a current through the windings 3u, 3v, and 3w of the electric motor 3 as well as a rotational driving program for the electric motor 3 by vector control and V / F constant control. ing.

  The control means 16 functions as a heating control means. Each block (excluding the A / D converter 17) described in the control means 16 in FIG. 1 represents a processing function related to heating control that is executed by the CPU of the microcomputer according to the heating control program stored in the ROM. Yes. Processing functions executed in accordance with other processing programs such as a rotation driving program are not shown.

  The A / D converter 17 converts the signal voltages output from the current sensors 10 and 11 into U-phase and W-phase detection currents Iu and Iw, which are digital values. The energization control means 18 applies an energization period corresponding to the voltage vector output from the voltage source inverter 9 in order to allow the alternating current necessary for heating the compressor 2 to flow evenly through the windings 3 u, 3 v, 3 w of the motor 3. The energization sequence that sequentially sets and outputs the drive command signals of the IGBTs 12up to 12wn according to the voltage vector is executed.

  The energization time adjusting means 19 executes an adjustment sequence for adjusting the time Δtu, Δtv, Δtw of each energization period so that the magnitude of the phase current flowing during execution of the energization sequence becomes equal to the specified current value Iamp. In this adjustment sequence, the current amplitude detection means 20 detects the amplitudes (positive and negative peak values) of the phase currents Iu, Iv, Iw based on the detection currents Iu, Iw, and the specified current value setting means 21 Determine the value Iamp.

Next, the operation of this embodiment will be described with reference to FIGS.
FIG. 2 shows a flow of processing executed when the control means 16 stops driving the compressor 2 and receives a drive command for the compressor 2 from the host device. First, the energization time adjustment means 19 executes an adjustment sequence, and stores the obtained times Δtu, Δtv, Δtw in the RAM. Subsequently, the energization control means 18 measures the winding resistance of the electric motor 3, and executes a start determination sequence for determining the necessity of heating by comparing the measured resistance value with a reference resistance value.

  As described above, if the refrigerant temperature of the compressor 2 is low, the starting load of the compressor 2 becomes large. Therefore, before starting, the windings 3u, 3v, and 3w of the electric motor 3 are energized to heat (preheat) the compressor 2 )There is a need to. When the measured resistance value is smaller than the reference resistance value, it is estimated that the refrigerant temperature of the compressor 2 is a low temperature that requires heating. Simply referred to as an energization sequence). On the other hand, when the winding resistance value is greater than or equal to the reference resistance value, the energization control means 18 immediately shifts to the rotation drive sequence of the electric motor 3 without executing the energization sequence.

  In the process of heating the compressor 2, the energization control means 18 temporarily stops heating every time the energization sequence is executed for a predetermined time. Then, the winding resistance of the electric motor 3 is measured, and the end determination sequence for determining the continuation / end of heating is executed by comparing the measured resistance value with the reference resistance value. When the measured resistance value is smaller than the reference resistance value, the energization sequence is continued, and when the measured resistance value is greater than or equal to the reference resistance value, the energization sequence is terminated and the process proceeds to the rotation drive sequence of the electric motor 3.

  The voltage vector used in the energization sequence for heating the compressor 2 is determined so that the rotor 3r does not rotate and the compressor 2 can be heated uniformly. The voltage source inverter 9 includes a bridge circuit 14x (x is u, v, w) including a pair of an upper arm 13xp having an IGBT 12xp and a lower arm 13xn having an IGBT 12xn. When the IGBT 12xp of the upper arm 13xp is turned on, 1 is set when the IGBT 12xn of the lower arm 13xn is turned on, and these are combined in the order of (U phase V phase W phase), and voltage vectors V0 to V7 shown in FIG. can get.

  In the vector diagram shown in FIG. 3, the directions of V1 (100), V3 (010), and V5 (001) coincide with the directions of the U-phase, V-phase, and W-phase axes, respectively. The α axis and β axis are two-phase coordinate axes obtained by three-phase to two-phase conversion. FIG. 4 shows the correspondence between the voltage vector and the on / off states of the IGBTs 12up to 12wn.

  The energization control means 18 turns on the IGBT 12xp of one phase of the upper arm 13up, 13vp, 13wp of the voltage source inverter 9 and the other two-phase IGBT 12yn, 12zn of the lower arm 13un, 13vn, 13wn in the energization sequence. An energizing period is provided. Here, x, y, and z correspond to u, v, and w in no particular order. Further, an energization period is provided in which the IGBTs 12xn, 12yp, and 12zp of the arms 13xn, 13yp, and 13zp that are paired with the arms 13xp, 13yn, and 13zn having the IGBTs 12xp, 12yn, and 12zn that are turned on in the energization period are turned on. The energization control means 18 repeatedly executes an energization sequence combining these two energization periods while sequentially changing the energized phases for all phases.

  Specifically, the first energization sequence for switching the voltage vector in the order of V1, V4, V4, V1 or the order of V4, V1, V1, V4 for each energization period having the width of time Δtu, and the width of time Δtv. A second energization sequence for switching voltage vectors in the order of V3, V6, V6, V3 or V6, V3, V3, V6 for each energization period, and V5, V2, V2, V5 for each energization period having a width of time Δtw. Or the third energization sequence for switching the voltage vectors in the order of V2, V5, V5, and V2 is sequentially executed. When the same voltage vector lasts for the time 2Δtu, 2Δtv or 2Δtw, switching between them is not necessary. In FIGS. 5A and 5B, the current paths when the voltages of the voltage vectors V1 (100) and V4 (011) are output are indicated by thick lines.

  FIG. 6 shows waveforms of the voltage vector, the voltage Vu-vw between the output terminal of the bridge circuit 14u and the output terminals of the bridge circuits 14v and 14w, and the U-phase current Iu in the first energization sequence. In FIG. 6, the current change rate during the positive period and the current change rate during the negative period, that is, the peak current value | Iu2 + | during the positive period and the peak current value | Iu2- | during the negative period are slightly different. Yes.

  This is because the saturation characteristic of the inductance changes according to the magnetic pole position of the rotor 3r due to the saliency of the electric motor 3. For example, when the direction of the magnetic pole is close to the direction of the U-phase, if the voltage vector V1 is output and a current is passed through the U-phase, the magnetic flux in the U-phase direction increases and the inductance decreases due to saturation. As a result, the current change rate increases and the peak current value | Iu2 + | increases. Conversely, when the voltage vector V4 is output and a current is passed through the U-phase, the magnetic flux in the U-phase direction is reduced, so that saturation is reduced and inductance is increased. As a result, the rate of change in current decreases and the peak current value | Iu2- | becomes smaller.

  In each of the first to third energization sequences, an alternating current flows through the windings 3u to 3w, so that the generated torque cancels out with positive and negative values in the energization sequence. However, when the current close to the magnetic pole direction is energized due to the change in saturation characteristics described above, there is a possibility that a deviation occurs between the positive generated torque and the negative generated torque due to the difference between the positive and negative peak current values. There is. As shown in FIG. 7, the energization control means 18 sequentially executes the first to third energization sequences having different energization phases, so that the time during which positive torque is generated and the negative torque regardless of the saturation characteristics. The generated torque is averaged by the time when the occurrence of As a result, the positive and negative torques cancel each other, and the generated torque is effectively zero.

  By the way, it is required that the time from when the drive command for the compressor 2 is received to when the compressor 2 is started is short. In order to heat the compressor 2 without bias in a short time, the magnitude of the U-phase current flowing during the execution of the first energization sequence, the magnitude of the V-phase current flowing during the execution of the second energization sequence, and the third energization It is preferable to adjust the times Δtu, Δtv, and Δtw so that the magnitude of the W-phase current that flows during the execution of the sequence is equal to the specified current value Iamp. The energization sequence shown in FIG. 7 is a waveform after adjustment.

  As a result, the specified current value setting unit 21 sets the specified current value Iamp to be relatively large, and a phase current equal to the specified current value Iamp can be made to flow evenly through the windings 3u, 3v, 3w. The compressor 2 can be heated evenly in a short time according to Iamp. Further, since the bias of the magnitude of the phase current flowing in the first to third energization sequences is eliminated, the action of canceling the alternating torque as the entire energization sequence is further enhanced, and the rotor 3r rotates even when a relatively large current flows. Can be prevented.

  Hereinafter, the adjustment sequence will be specifically described. FIG. 8 schematically shows a spatial distribution of the reciprocal 1 / (ωL) of the reactance of the electric motor 3. In a permanent magnet synchronous motor designed to actively use reluctance torque, the difference between the Q-axis inductance and the D-axis inductance is large, and the Q-axis inductance is larger than the D-axis inductance where the magnetic flux exists. Is common. Accordingly, the spatial distribution curve of the reciprocal of the reactance has the long axis in the D-axis direction.

  Intersection points 1 / Xu (= 1 / ωLu), 1 / Xv (= 1 / ωLv), 1 / Xw (= 1 / ωLw) and the origin O of each axis (U, V, W) in this distribution curve The distance is proportional to the reciprocal of the reactance in each phase. This distance changes according to the stop position of the rotor 3r. The longer the distance from the origin, the smaller the reactance, and the current reaches the specified current value Iamp in a shorter energization time. Therefore, when the electric motor 3 having saliency is used, if the energization times Δtu, Δtv, and Δtw of the first, second, and third energization sequences are equal, the magnitude of the current varies from phase to phase.

  Therefore, prior to the energization sequence, the energization time adjusting means 19 sets the time (phase of positive or negative peak) flowing in the first to third energization sequences to be equal to the specified current value Iamp. An adjustment sequence for adjusting Δtu, Δtv, Δtw is executed. FIG. 9 is a flowchart of the entire adjustment sequence, and FIGS. 10 to 12 show processes A, B, and B related to the first, second, and third energization sequences for detecting voltage vector switching and phase current positive and negative peak values. 5 is a flowchart showing C. 13 to 15 continuously show the waveforms of the phase currents Iu, Iv, and Iw during the adjustment sequence.

  The energization time adjusting means 19 sequentially repeats the first, second, and third energization sequences described above. Since the inductance value at the start of the adjustment sequence is unknown, the short energization time Δt1 at which the peak current value is sufficiently small is set as the initial times Δtu, Δtv, Δtw. In the process A of step S1, the timer time t is initialized to 0 (step S21), and the output of the voltage vector V1 and the timer time t are added every control cycle Tc until the timer time t becomes Δtu or more (step S21). Steps S22 and S23). When the timer time t becomes Δtu or more, the U-phase current Iu at that time is input from the current amplitude detection means 20 as the peak current value Iu2 + (step S24).

  Subsequently, the output of the voltage vector V4 and the addition of the timer time t are executed every control cycle Tc until the timer time t becomes 3Δtu or more (steps S25 and S26). When the timer time t becomes 3Δtu or more, the U-phase current Iu at that time is input from the current amplitude detection means 20 as the peak current value Iu2- (step S27). Thereafter, the output of the voltage vector V1 and the addition of the timer time t are executed every control cycle Tc until the timer time t becomes 4Δtu or more (steps S28 and S29). Finally, the timer time t is cleared to 0 and the process ends (step S30).

  In step S2, the energization time adjusting means 19 determines whether or not at least one of the absolute values | Iu2 + | and | Iu2- | of the peak current value exceeds the specified current value Iamp (condition A). If it is determined that the value has been exceeded, 1 (adjustment completion) is set in FlagU (step S3). If it is determined that it does not exceed, FlagU is set to 0 (unadjusted), and the time Δtu is increased by the adjustment width Δtadj (step S4).

  Subsequently, the energization time adjusting means 19 executes the process B of the second energization sequence in step S5, and in step S6, at least one of the absolute values | Iv2 + | and | Iv2- | of the peak current value has the specified current value Iamp. It is determined whether or not (Condition B) has been exceeded. If it exceeds, FlagV is set to 1 (step S7), and if not exceeded, FlagV is set to 0 to increase the time Δtv by the adjustment width Δtadj (step S8).

  Further, the energization time adjusting means 19 executes the process C of the third energization sequence in step S9, and in step S10, at least one of the absolute values | Iw2 + | and | Iw2- | of the peak current value exceeds the specified current value Iamp. (Condition C) is determined. If it exceeds, FlagW is set to 1 (step S11), and if not exceeded, FlagW is set to 0 to increase the time Δtw by the adjustment width Δtadj (step S12).

  In step S13, the energization time adjustment unit 19 determines whether or not FlagU, FlagV, and FlagW are all 1 (adjustment complete) (condition D). Here, if it is determined that the adjustment of the time Δtu, Δtv, Δtw of any phase is incomplete (NO), the process proceeds to step S1 and the above-described processing is repeated. If it is determined that the adjustment of the times Δtu, Δtv, Δtw of all phases is completed (YES), the process proceeds to step S14, and the times Δtu, Δtv, Δtw are stored in the RAM. The energization control means 18 executes the energization sequence using the energization times Δtu, Δtv, Δtw stored for each phase.

  13 to 15 show phase current waveforms in the case of Xu <Xw <Xv shown in FIG. The initial values of the times Δtu, Δtv, Δtw are Δt1, Δtadj is added every time the first to third energization sequences are completed, and the U-phase peak current value | Iu2 + in the first energization sequence after increasing to Δt3 Since |, | Iu2- | exceeds the specified current value Iamp, the time Δtu is fixed to Δt3. Thereafter, the first to third energization sequences are executed while increasing the times Δtv and Δtw.

  Since the W-phase peak current values | Iw2 + | and | Iw2- | exceed the specified current value Iamp in the third energization sequence after increasing to Δt5, the time Δtw is fixed to Δt5, and thereafter only the time Δtv is increased. However, the first to third energization sequences are executed. Since the V-phase peak current values | Iv2 + | and | Iv2- | exceed the specified current value Iamp in the second energization sequence after increasing to Δt7, the time Δtv is fixed at Δt7 and the adjustment sequence is completed. . FIG. 7 shows an energization sequence using energization times Δtu (= Δt3), Δtv (= Δt7), and Δtw (= Δt5) determined as described above.

  In this adjustment sequence, the energization control means 18 detects the position of the rotor 3r based on the change rate of the phase current when the times Δtu, Δtv, Δtw are set to the initial value Δt1. Specifically, in the first energization sequence, as shown in FIG. 6, the difference | δIu + | between the peak current value δIu2 + and the current value Iu1 + that is a predetermined time (for example, Δtu / 2) before that time, and the peak current The difference | δIu− | between the value δIu2− and the current value Iu1− that is a predetermined time before the time is obtained. Then, the difference | δIu + | − | δIu− | between the difference | δIu + | and the difference | δIu− | Similarly in the second and third energization sequences, the differences | δIv + | − | δIv− | and | δIw + | − | δIw− |

  As described above, when the electric motor 3 having saliency is used, the influence of saturation appears greatly in the D-axis direction, and the difference between the current change rates when the current increases and when the current decreases increases. On the other hand, the influence of saturation is reduced in the Q-axis direction, and the current change rate when the current increases and when the current decreases is substantially equal. The position of the rotor 3r can be detected by such a change in saturation characteristics according to the stop position of the rotor 3r.

  In the start determination sequence and the end determination sequence, the energization control means 18 measures the winding resistance without rotating the rotor 3r by applying a DC voltage in the direction of the detected magnet magnetic flux position and causing a DC current to flow. . The reference resistance value to be compared with the winding resistance value is measured in advance and written in the EEPROM. FIG. 16 shows measured waveforms of the phase currents Iu, Iv, and Iw in the adjustment sequence and the start determination sequence.

  As described above, the electric motor drive device 1 according to the present embodiment includes the energization period corresponding to the voltage vector in the direction of the U phase, the V phase, or the W phase and the energization period corresponding to the voltage vector in the opposite phase. The compressor 2 is heated by repeatedly executing the combined energization sequence while sequentially changing the energized phases for all phases. Thereby, the compressor 2 can be heated uniformly without generating a rotational force in the rotor 3r and without temperature deviation.

  Before starting energization for heating, the electric motor drive device 1 adjusts the energization times Δtu, Δtv, and Δtw so that the magnitudes of the phase currents flowing in the first to third energization sequences are equal. By executing the energization sequence using the adjusted times Δtu, Δtv, and Δtw, there is no bias in the magnitude of the phase current flowing in the first to third energization sequences, and a relatively large current is supplied for heating. Even in this case, the generated torque is effectively zero, and the rotor 3r can be prevented from rotating.

  The electric motor drive device 1 measures the winding resistance value of the electric motor 3 before starting heating, and starts heating when the measured resistance value is smaller than the reference resistance value. Therefore, when the starting load of the compressor 2 is small, such as a period from when the compressor 2 stops until the refrigerant temperature decreases, the compressor 2 can be started immediately without performing unnecessary heat treatment. Moreover, the electric motor drive device 1 measures the winding resistance value of the electric motor 3 every time a predetermined time elapses in the heating process of the compressor 2, and heats the heating when the measured resistance value exceeds the reference resistance value. Stop and start the compressor 2. Thereby, it can prevent that the compressor 2 is heated too much.

(Second Embodiment)
A second embodiment will be described with reference to FIG. The electric motor drive device 31 includes temperature detection means 32 that detects the internal temperature of the device. The internal temperature of the apparatus is, for example, the temperature of a heat sink of IGBT 12up to 12 wn. When the energization control means 18 receives the drive command for the compressor 2, the energization control means 18 inputs the detected temperature from the temperature detecting means, and starts heating the compressor 2 when the detected temperature is lower than the reference temperature. When the detected temperature is equal to or higher than the reference temperature, the compressor 2 is started without heating. This determination process is an alternative to the start determination sequence shown in FIG.

  The compressor 2 is driven by energizing the electric motor 3 by the electric motor driving device 31 using the voltage source inverter 9. During driving, the refrigerant temperature of the compressor 2 is increased, and the temperature of the IGBTs 12up to 12wn and thus the temperature of the heat sink is increased. When stopped, the refrigerant temperature of the compressor 2 is lowered, and the temperatures of the IGBTs 12up to 12wn and the temperature of the heat sink are also lowered. Therefore, the temperature detected by the temperature detecting means 32 has a high correlation with the refrigerant temperature of the compressor 2.

  According to the present embodiment, when the temperature of the heat sink is equal to or higher than the reference temperature, it is estimated that the refrigerant temperature of the compressor 2 is high and the start-up load of the compressor 2 is small, so unnecessary heat treatment is performed. The compressor 2 can be started immediately.

(Other embodiments)
In addition to the plurality of embodiments described above, the following configuration may be adopted.
Current sensors may be provided for all three phases.

  Instead of the current sensors 10 and 11, a phase current may be detected by providing a shunt resistor (current detection means) between the IGBTs 12un, 12vn and 12wn on the lower arm side and the DC power supply line 6. For example, during the period when the first voltage vector V1 of the first energization sequence is output, current does not flow through the U-phase shunt resistor as shown in FIG. The U-phase detection current is obtained from the detection current. In the period during which the voltage vector V4 is output, the detection current is obtained from the U-phase shunt resistor as shown in FIG.

  A shunt resistor that detects a direct current input to the voltage source inverter 9 may be provided as a current detection unit that replaces the current sensors 10 and 11. This is because the phase current can be detected based on this direct current. For example, the shunt resistor may be provided on the DC power supply line 6 between the capacitor 8 and the voltage source inverter 9.

  In the first to third energization sequences, an alternating current with an average current of zero is obtained by combining an energization period corresponding to a predetermined voltage vector and an energization period corresponding to a voltage vector having an opposite phase to the voltage vector. Just flow away. Therefore, for example, in the case of the first energization sequence, two periods such as V1, V4, V4, V1, V1, V4, V4, V1,... Or V4, V1, V1, V4, V4, V1, V1, V4,. You may repeat above.

  The energization control means 18 includes an energization period in which the IGBT 12xp of one phase of the upper arm 13up, 13vp, 13wp of the voltage source inverter 9 and the IGBT 12yn of any one of the lower arms 13un, 13vn, 13wn are turned on, A voltage is output in accordance with an energization process (energization sequence) that combines the energization periods of turning on the IGBTs 12xn and 12yp of the arms 13xn and 13yp that are paired with the arms 13xp and 13yn having the IGBTs 12xp and 12yn that are turned on in the energization period, An alternating current may flow. Here, x and y correspond to different phases of u, v, and w. Also in this case, the process is repeatedly executed while sequentially changing the energized phases for all phases.

  Specifically, in the first energization sequence, with the IGBTs 12wp and 12wn turned off, the IGBTs 12up and 12vn are turned on for the time Δtu, the IGBTs 12un and 12vp are turned on for the time 2Δtu, and the IGBTs 12up and 12vn are turned on for the time Δtu. In the second energization sequence, with the IGBTs 12up and 12un turned off, the IGBTs 12vp and 12wn are turned on for a time Δtv, the IGBTs 12vn and 12wp are turned on for a time 2Δtv, and the IGBTs 12vp and 12wn are turned on for a time Δtv. In the third energization sequence, with the IGBTs 12vp and 12vn turned off, the IGBTs 12wp and 12un are turned on for the time Δtw, the IGBTs 12wn and 12up are turned on for the time 2Δtw, and the IGBTs 12wp and 12un are turned on for the time Δtw. Even if such an energization sequence is used, the compressor 2 can be uniformly heated without generating a rotational force in the rotor 3r.

  The energization control means 18 inputs a temperature signal indicating the temperature of the compressor 2 from a sensor provided outside the motor drive devices 1 and 31, and heats the compressor 2 when the detected temperature is lower than the reference temperature. The compressor 2 may be started without heating when the detected temperature is equal to or higher than the reference temperature. Further, in the heating process of the compressor 2, the energization control means 18 inputs a temperature signal indicating the temperature of the compressor 2 from an external sensor, and when the detected temperature exceeds the reference temperature, the heating is stopped and the compressor 2 is turned off. It may be configured to start. These replace the above-described start determination sequence and end determination sequence. The sensor is formed of, for example, a thermistor, and the temperature signal of the compressor 2 is preferably a signal indicating the refrigerant temperature.

According to the embodiment described above, it is possible to uniformly heat the device without causing a rotational force in the rotor and without temperature deviation.
Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the invention described in the claims and equivalents thereof in the same manner as included in the scope and gist of the invention.

  In the drawings, 1 and 31 are motor drive devices (permanent magnet synchronous motor drive devices), 2 is a compressor (equipment device), 3 is permanent magnet synchronous motors, 3u, 3v and 3w are windings, 9 is a voltage source inverter, 10 and 11 are current sensors (current detection means), 12up to 12wn are IGBTs (switching elements), 13up to 13wp are upper arms, 13un to 13wn are lower arms, 14u to 14w are bridge circuits, and 16 is control means (heating control) Means) and 32 are temperature detecting means.

Claims (6)

In a permanent magnet synchronous motor driving device that drives a permanent magnet synchronous motor configured integrally with an apparatus without using a sensor that detects a magnetic pole position,
A voltage-type inverter that includes a bridge circuit composed of a pair of an upper arm and a lower arm having a switching element for three phases, and supplies a voltage to windings of each phase of the permanent magnet synchronous motor;
Current detecting means for detecting a phase current of the permanent magnet synchronous motor;
Heating control means for heating the device device by causing a current to flow through the windings of each phase of the permanent magnet synchronous motor before starting to rotate the permanent magnet synchronous motor;
The heating control means includes an energization period for turning on a switching element for one phase of the upper arm of the voltage source inverter and a switching element for at least one other phase of the lower arm, and a switching element that is turned on in this energization period. The energization process in which an alternating current is passed through the windings of the permanent magnet synchronous motor in combination with the energization period during which the switching element of the arm paired with the arm having a pair is turned on, the energized phases are sequentially changed for all phases. The permanent magnet synchronous motor driving device is characterized by being repeatedly executed. When the switching element of the upper arm of the bridge circuit is on, it is 1 when the switching element of the lower arm is on, and it is expressed by combining them in the order of (U phase V phase W phase), and the voltage source inverter outputs If the possible voltage vectors are defined as V1 (100), V2 (110), V3 (010), V4 (011), V5 (001), V6 (101),
The heating control means has a first energization sequence for switching voltage vectors in the order of V1, V4, V4, V1 or V4, V1, V1, V4 for each energization period having a width of time Δtu, and a width of time Δtv. A second energization sequence for switching voltage vectors in the order of V3, V6, V6, V3 or the order of V6, V3, V3, V6 for each energization period, and V5, V2, V2, The permanent magnet synchronous motor drive device according to claim 1, wherein a third energization sequence for switching voltage vectors in order of V5 or V2, V5, V5, and V2 is sequentially repeated.   The heating control means includes a magnitude of a U-phase current flowing during execution of the first energization sequence, a magnitude of a V-phase current flowing during execution of the second energization sequence, and during execution of the third energization sequence. 3. The permanent magnet synchronous motor drive device according to claim 2, wherein the time Δtu, Δtv, Δtw is adjusted so that the magnitude of the flowing W-phase current becomes equal to a predetermined specified current value.   The heating control means measures the resistance value of the winding of the permanent magnet synchronous motor before starting the heating of the device apparatus, and the measurement resistance value is smaller than a reference resistance value on the condition that the measurement value of the device apparatus is The permanent magnet synchronous motor drive device according to any one of claims 1 to 3, wherein heating is started. Temperature detecting means for detecting the internal temperature of the permanent magnet synchronous motor driving device,
The heating control means inputs the detected temperature from the temperature detecting means before starting the heating of the equipment device, and starts heating the equipment device on condition that the detected temperature is lower than a reference temperature. The permanent magnet synchronous motor drive device according to any one of claims 1 to 3, wherein the drive device is a permanent magnet synchronous motor drive device.   The heating control means measures the resistance value of the winding of the permanent magnet synchronous motor in the process of heating the device apparatus, and continues heating the device apparatus until the measured resistance value exceeds a reference resistance value. The permanent magnet synchronous motor drive device according to any one of claims 1 to 5, wherein the permanent magnet synchronous motor drive device is provided.

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