JP5167962B2 - Motor drive control device - Google Patents

Description

  The present invention relates to a motor drive control device.

The air conditioner includes various devices such as a compressor and a fan, and a motor is often used as the power source. The air conditioner further includes a motor drive control device that drives and controls these motors. In the motor drive control device, for example, as disclosed in Patent Document 1, the converter controls the converter in addition to the converter that converts the output from the power source into direct current, the inverter that outputs the drive voltage for driving the motor to the motor. A converter microcomputer and an inverter microcomputer for driving and controlling the inverter are provided.
JP 2007-74810 A

  By the way, in the motor drive control apparatus described above, the inverter microcomputer may run out of control while the inverter outputs a normal drive voltage to the motor. In this case, it becomes difficult for the inverter microcomputer to continuously drive and control the inverter normally.

  Therefore, an object of the present invention is to provide a motor drive control device in which an inverter is normally driven and controlled.

  A motor drive control device according to a first aspect includes a converter, an inverter, a converter drive control unit, and an inverter drive control unit. The converter converts a power supply current output from the power supply into a direct current. The inverter is supplied with a direct current from the converter, generates a drive voltage for driving the motor, and outputs the drive voltage to the motor. The converter drive control unit controls the drive of the converter and monitors the power supply current. The inverter drive control unit performs drive control of the inverter and outputs a drive state signal indicating whether or not the inverter is being driven to the converter drive control unit. And a converter drive control part resets an inverter drive control part, when the drive state signal which shows that an inverter is a drive stop state is acquired from the said inverter drive control part, and a power supply current is more than predetermined value.

  Here, the predetermined value includes, for example, the value of the power supply current that is minimum required when the motor rotates normally. If the power supply current is greater than or equal to a predetermined value, it can be seen that the inverter is in a driving state. Therefore, in this motor drive control device, if the power supply current is equal to or greater than a predetermined value, but the drive state signal acquired from the inverter drive control unit indicates that the inverter is stopped, the inverter drive control unit is in a runaway state. And the inverter drive control unit is reset. As a result, it is possible to avoid that the inverter is not normally driven and controlled and adversely affects the rotational drive of the motor.

  A motor drive control device according to a second aspect is the motor drive control device according to the first aspect, further comprising a reset unit. The reset unit is connected to the inverter drive control unit and the converter drive control unit, and resets the inverter drive control unit. The converter drive control unit acquires a drive state signal indicating that the inverter is in a drive stop state from the inverter drive control unit, and resets the inverter drive control unit to the reset unit when the power supply current is equal to or greater than a predetermined value. A reset instruction signal for outputting the signal is output to the reset unit.

  According to this motor drive control device, the reset unit resets the inverter drive control unit when a reset instruction signal for resetting the inverter drive control unit is acquired from the converter drive control unit. Therefore, the inverter drive control unit is not reset directly by the converter drive control unit, but is reset by the reset unit.

  A motor drive control device according to a third aspect is the motor drive control device according to the second aspect, wherein the reset unit resets the inverter drive control unit at a predetermined timing when the reset instruction signal is acquired from the converter drive control unit. Do.

  When the converter drive control unit is configured to directly reset the inverter drive control unit, in some cases, the current drive state of the inverter drive control unit and the start of the reset operation cannot be synchronized, and as a result, the inverter drive control There is a risk that the inverter drive control unit may malfunction without being reset normally. However, according to the motor drive control device of the present invention, the reset unit resets the inverter drive control unit at a predetermined timing, which may occur when the converter drive control unit directly resets the inverter drive control unit. Malfunctions are less likely to occur.

  A motor drive control device according to a fourth aspect of the present invention is the motor drive control device according to any of the first through third aspects, wherein the motor is a compressor motor.

  According to this motor drive control device, since the runaway in the drive control unit for the inverter that outputs the drive voltage to the compressor motor is avoided, the compressor motor is normally driven to rotate. Therefore, the compressor using the compressor motor as a drive source can be operated normally.

  According to the motor drive control device according to the first aspect of the present invention, it is possible to avoid that the inverter drive control unit does not normally drive and control the inverter and adversely affects the rotational drive of the motor.

  According to the motor drive control device pertaining to the second aspect of the invention, the inverter drive control unit is not reset directly by the converter drive control unit, but is reset by the reset unit.

  According to the motor drive control device pertaining to the third aspect of the present invention, malfunction that may occur when the converter drive control unit directly resets the inverter drive control unit is less likely to occur.

  According to the motor drive control device pertaining to the fourth aspect of the present invention, the compressor that uses the compressor motor as the drive source can operate normally.

  Hereinafter, a motor drive control device according to the present invention will be described in detail with reference to the drawings.

(1) Configuration FIG. 1 is an overall configuration diagram of a motor drive control system 100 including a motor 51 and a motor drive control device 1 that controls the drive of the motor 51. In this embodiment, the case where the motor 51 is a motor for a compressor mounted on the outdoor unit of the air conditioner is taken as an example. The compressor motor 51 is a compressor drive source for compressing the refrigerant flowing on the refrigerant circuit included in the air conditioner, and may be, for example, a three-phase brushless DC motor. Specifically, the compressor motor 51 includes a rotor made of a permanent magnet having a plurality of magnetic poles, a stator having a three-phase drive coil, and the like.

  The motor drive control device 1 supplies AC power to the motor 51 to drive the motor 51, and includes a current sensor 2, a converter 3, an inverter 4, a smoothing unit 5, a voltage detection unit 6, and a primary side. A shunt resistor Rs1, a secondary shunt resistor Rs2, an inverter microcomputer 7, a converter microcomputer 8, and a reset IC 9 are provided.

[Current sensor]
The current sensor 2 is for detecting the power source current Im output from the three-phase power source 61, and one power source wire L1 among the three power source wires L1, L2, and L3 extending from the power source 61. Only provided. The value of the power supply current Im detected by the current sensor 2 is taken into the converter microcomputer 8.

〔converter〕
The converter 3 is composed of a plurality of power transistors such as insulated bipolar transistors, and is connected to three power supply lines L1, L2, and L3. The output of the converter 3 is connected to the inverter 4 through the wiring L4, and the GND of the converter 3 is connected to the GND of the inverter 4 through the wiring L5. The converter 3 having such a wiring configuration converts a power supply current Im, which is an alternating current output from the power supply 61, into a direct current based on a drive control signal SA (described later) sent from the converter microcomputer 8. This is converted and output to the inverter 4 via the wiring L4.

  Note that, as described above, the inverter 4 is supplied with the power supply current Im converted into a direct current through the wiring L4. Therefore, the wiring L4 can be called a “power supply wiring” for the inverter 4. On the other hand, the wiring L5 can be said to be a “GND wiring” for the inverter 4, and a current supplied to the inverter 4 flows on the wiring L5. The current supplied to the inverter 4 is specifically a current that flows through the power transistor again through the power transistor of the inverter 4 and the drive coil of the motor 51. The current that flows on the wiring L5 flows to the GND of the converter 3.

[Inverter]
The inverter 4 is connected to the wiring L4 and the wiring L5, and is composed of a plurality of power transistors such as an insulated bipolar transistor as in the converter 3. Three wires L 7, L 8, L 9 extend from the output of the inverter 4, and each of the wires L 7, L 8, L 9 is connected to one end of three drive coils included in the motor 51. When the inverter 4 is supplied with the direct current from the converter 3 via the wiring L4, the inverter 4 generates drive voltages SU, SV, SW based on a drive control signal SB (described later) sent from the inverter microcomputer 7, This is output to the motor 51 via each wiring L7, L8, L9. Here, the drive voltages SU, SV, and SW are voltages for driving the motor 51, and are generated by turning on and off each power transistor based on the drive control signal SB.

[Smooth part]
The smoothing unit 5 is for smoothing the output from the converter 3 (specifically, the power supply current Im converted into direct current), and is located between the converter 3 and the inverter 4. Specifically, the smoothing unit 5 has a configuration in which two capacitors c1 and c2 are connected in series, and both ends of the smoothing unit 5 are connected to the output and GND of the converter 3, that is, the wiring L4 and the wiring L5, respectively. It is connected.

  In the present embodiment, as shown in FIG. 1, the smoothing unit 5 is configured by two capacitors c1 and c2, but the smoothing unit 5 may be configured by one or a plurality of capacitors.

(Voltage detector)
The voltage detection unit 6 is for detecting a voltage applied to the inverter 4 and has a configuration in which two resistors r1 and r2 are connected in series. The voltage detection unit 6 is located between the converter 3 and the inverter 4, and both ends thereof are connected to the output and GND of the converter 3, that is, the wiring L4 and the wiring L5, respectively. That is, the voltage detection unit 6 is connected to the smoothing unit 5 in parallel. More specifically, the voltage detection unit 6 is connected to the inverter 4 side with respect to the smoothing unit 5. That is, the voltage detection unit 6 is connected to the secondary side of the main circuit including the converter 3 and the inverter 4.

  The voltage detected by the voltage detection unit 6 having such a wiring configuration is taken into the converter microcomputer 8. In the present embodiment, as shown in FIG. 1, it is assumed that the voltage value of the portion where the two resistors r 1 and r 2 are connected is taken into the converter microcomputer 8.

[Shunt resistance]
The primary shunt resistor Rs1 and the secondary shunt resistor Rs2 are both connected in series on the wiring L5, and are for detecting the current flowing on the wiring L5. More specifically, the primary shunt resistor Rs1 is provided between a connection point between the smoothing unit 5 and the wiring L5 and the converter 3, and the secondary shunt resistor Rs2 is connected to the voltage detection unit 6 and the wiring L5. Between the inverter 4 and the inverter 4. That is, the primary shunt resistor Rs1 is for detecting the current flowing on the wiring L5 at the primary side portion of the main circuit including the converter 3 and the inverter 4, whereas the secondary shunt resistor Rs2 Can be said to be for detecting the current flowing on the wiring L5 at the secondary side portion of the main circuit including the converter 3 and the inverter 4. Then, both end portions of each shunt resistor Rs1, Rs2 are connected to the inputs of the operational amplifiers OP1, OP2, respectively, and the both end voltages of each shunt resistor Rs1, Rs2 are amplified in each of the operational amplifiers OP1, OP2. The voltage across the primary shunt resistor Rs1 amplified by the operational amplifier OP1 is taken into the converter microcomputer 8, and the voltage across the secondary shunt resistor Rs2 amplified by the operational amplifier OP2 is taken into the inverter microcomputer 7.

[Inverter microcomputer]
The inverter microcomputer 7 is a microcomputer composed of a CPU and a memory, and is connected to the inverter 4 and performs drive control of the inverter 4. Specifically, the inverter microcomputer 7 outputs a drive control signal SB for controlling the drive of the inverter 4 to the inverter 4, thereby causing the inverter 4 to generate or stop generating the drive voltages SU, SV, SW. To do. The drive control signal SB is determined based on the current operating status of the air conditioner, a reset signal SH described later, and the like, and is not only for instructing generation and stop of the drive voltages SU, SV, SW. Also, it plays a role as a signal for controlling the duty of the drive voltages SU, SV, SW and the rotation speed of the motor 51.

  Furthermore, the inverter microcomputer 7 according to the present embodiment is also connected to the converter microcomputer 8 and outputs an operation permission signal SC (corresponding to a drive state signal) to the converter microcomputer 8. Here, the operation permission signal SC is a signal indicating whether or not to permit the drive control of the converter 3 by the converter microcomputer 8, and is determined mainly based on the drive state of the inverter 4. For example, the state in which the motor 51 is rotating corresponds to a state in which the inverter 4 generates the drive voltages SU, SV, SW and outputs them to the motor 51. Thus, if the inverter 4 is in a driving state, the inverter microcomputer 7 outputs an operation permission signal SC for permitting the drive control of the converter 3 to the converter microcomputer 8. On the contrary, the state where the motor 51 stops rotating corresponds to the state where the inverter 4 is not generating the drive voltages SU, SV, SW. Thus, if the inverter 4 is not driven, the inverter microcomputer 7 outputs an operation permission signal SC to the converter microcomputer 8 indicating that the drive control of the converter 3 is not permitted. That is, it can be said that the operation permission signal SC is a signal indicating whether or not the inverter 4 is being driven. The operation permission signal SC according to the present embodiment is “H” when the inverter 4 is being driven, that is, when the drive control of the converter 3 is permitted, while the inverter 4 is not being driven. In some cases, that is, when drive control of the converter 3 is not permitted, the logic of “L” is assumed.

  Furthermore, the inverter microcomputer 7 according to the present embodiment is also connected to the reset IC 9 and can be reset based on the reset signal SH output from the reset IC 9. That is, when the inverter microcomputer 7 acquires the reset signal SH to be reset from the reset IC 9, the inverter microcomputer 7 forcibly turns off the operation that has been performed so far, such as stopping the output of the drive control signal SB to the inverter 4. The reset signal SH will be described later.

  In addition to the above, the inverter microcomputer 7 is also connected to the output of the operational amplifier OP2, and the current flowing on the wiring L5 based on the voltage of the secondary shunt resistor Rs2 amplified in the operational amplifier OP2 (specifically, The current supplied to the inverter 4) is calculated, and the content of the drive control signal SB output to the inverter 4 is determined according to the calculation result, or the content of the operation permission signal SC output to the converter microcomputer 8 is determined. . For example, if the calculated current value on the wiring L5 is equal to or higher than the rated current of each power transistor or motor 51 in the inverter 4, the inverter microcomputer 7 may ignite. A drive control signal SB instructing to stop generation of SU, SV, and SW is output to the inverter 4, and an operation permission signal SC “L” is output to the converter microcomputer 8.

  Further, the inverter microcomputer 7 can acquire various signals from the converter microcomputer 8 and can determine the contents of the drive control signal SB and the operation permission signal SC to be output based on the contents of the acquired various signals. . Here, examples of signals acquired by the inverter microcomputer 7 from the converter microcomputer 8 include an abnormal signal SD, a warning signal SE, a waveform output state signal SF, and the like. The abnormality signal SD is a signal indicating whether or not there is any abnormality in the primary side portion of the main circuit including the converter 3 and the inverter 4. The warning signal SE is a signal that indicates that the state is close to an abnormality, although it cannot be determined as abnormal. The waveform output state signal SF is a signal indicating whether or not the converter microcomputer 8 is outputting the drive control signal SA to the converter 3.

[Converter microcomputer]
The converter microcomputer 8 is a microcomputer composed of a CPU and a memory, and controls the drive of the converter 3. Specifically, the converter microcomputer 8 outputs a drive control signal SA for controlling the drive of the converter 3 to the converter 3, thereby causing the converter 3 to convert the power supply current Im to a direct current or to stop the conversion. Or

  Furthermore, the converter microcomputer 8 monitors the power supply current Im detected by the current sensor 2, and determines the content of the drive control signal SA based on the value of the power supply current Im. Specifically, if the value of power supply current Im is equal to or greater than a predetermined value, converter microcomputer 8 outputs drive control signal SA for driving converter 3. Conversely, if the value of the power supply current Im is less than a predetermined value, the converter microcomputer 8 outputs a drive control signal SA for stopping the drive of the converter 3. Here, the predetermined value can be a current value consumed by the main circuit, the motor 51, and the like when the motor 51 rotates, and if the detected power source current Im becomes higher than this value, harmonics are generated. Can be set to a value that becomes remarkable. Further, the predetermined value can be a value of the power supply current Im that is at least necessary for normal rotation of the motor 51. When the detected value of the power supply current Im becomes lower than this value, the rotation of the motor 51 is possible. It can also be set to a value that would hinder the operation. For example, the predetermined value may be a value of a current flowing on the wiring L1 in a state where the motor 51 is not driven, that is, a no-load state. That is, if the power supply current Im is equal to or greater than a predetermined value, the converter microcomputer 8 determines that the motor 51 can be driven without any problem, and drives the converter 3. Moreover, as a case where the power supply current Im is less than a predetermined value, for example, there is a case where some abnormality occurs in the power supply 61. In such a case, the converter microcomputer 8 cannot drive the motor 51. Judgment is made and the drive of the converter 3 is stopped. The value of the power supply current Im is used not only for determining the drive control signal SA but also for determining the abnormal signal SD, the warning signal SE, and the waveform output state signal SF to be output to the inverter microcomputer 7.

  Here, in the present invention, the influence of the harmonics on the power supply current Im is further considered, and as shown in FIG. 4, different values “predetermined value A” and “predetermined value B” are provided as the predetermined values. The predetermined value A is a predetermined value when the converter 3 is driven, and the predetermined value B is a predetermined value when the drive of the converter 3 is stopped. Specifically, when the power supply current Im can take a value in the range of about 0A to 12A, the predetermined value A is determined to be 3.5A and the predetermined value B is determined to be 2.0A. The predetermined value A that is a threshold value of the power supply current Im for driving the converter 3 is higher than the predetermined value B that is a threshold value of the power supply current Im for stopping the converter 3. In this way, by providing a difference between the predetermined value A and the predetermined value B so as to give a so-called hysteresis characteristic in the operation of driving and stopping the converter 3, a harmonic converter in the power supply current Im is provided. The influence on the microcomputer 8 and the like can be suppressed.

  In particular, the converter microcomputer 8 according to the present embodiment has the value of the power supply current Im detected by the current sensor 2 when the operation permission signal SC indicating that the inverter 4 is in the drive stop state is acquired from the inverter microcomputer 7. When the value is equal to or greater than the predetermined value A, a signal SG indicating a reset instruction of the inverter microcomputer 7 is output to the reset IC 9. This corresponds to the state where the inverter 4 is not driven when the operation permission signal SC is “L”. Therefore, the power supply current Im should also be a value less than the predetermined value A. . However, the fact that the power supply current Im is equal to or greater than the predetermined value A corresponds to the motor 51 rotating normally. Therefore, when the value of the power supply current Im is equal to or greater than the predetermined value A but the operation permission signal SC is “L”, the converter microcomputer 8 has run out of the inverter microcomputer 7 that is the output source of the operation permission signal SC. Judgment is made and the reset IC 9 is instructed to reset the inverter microcomputer 7 (see FIG. 5).

  The converter microcomputer 8 is also connected to the output of the operational amplifier OP1 and the output of the voltage detector 6. The converter microcomputer 8 calculates the current flowing through the primary side portion of the wiring L5 based on the voltage of the primary side shunt resistor Rs1 amplified by the operational amplifier OP1, and applies it to the inverter 4 based on the output of the voltage detection unit 6. The voltage to be calculated is calculated. Then, the converter microcomputer 8 determines a drive control signal SA according to each calculation result, and outputs various signals (specifically, an abnormal signal SD, a warning signal SE, a waveform output state signal SF) to the inverter microcomputer 7. ).

[Reset IC]
The reset IC 9 has a circuit configuration including, for example, a plurality of flip-flops. The input of the reset IC 9 is connected to the reset instruction signal SG output port in the converter microcomputer 8 via wiring, and the output of the reset IC 9 is connected to the reset signal SH input port in the inverter microcomputer 7 via wiring. ing. When the reset IC 9 acquires a reset instruction signal SG for resetting the inverter microcomputer 7 from the converter microcomputer 8, the reset IC 9 outputs a reset signal SH for resetting the inverter microcomputer 7.

  Here, the reset signal SH has a logic of “H” when the inverter microcomputer 7 is reset and “L” when the inverter microcomputer 7 is not reset (see FIG. 5). That is, the reset IC 9 outputs a reset signal SH of “L” in a normal time when the inverter microcomputer 7 is not reset, and outputs a reset signal SH of “H” when the inverter microcomputer 7 is reset.

  In particular, the reset IC 9 according to this embodiment is a so-called synchronous reset IC that resets the inverter microcomputer 7 at a predetermined timing based on the reference clock CLK, as shown in FIG. For this reason, when the reset IC 9 acquires the reset instruction signal SG for resetting the inverter microcomputer 7 from the converter microcomputer 8, for example, at the next rise of the reference clock CLK, the reset IC 9 outputs the reset signal SH “H” to the inverter microcomputer 7. .

(2) Operation of Motor Drive Control Device (2-1) Flow of a Series of Operations Next, operations performed by the motor drive control device 1 will be described. FIG. 2 is a flowchart for explaining a flow of a series of operations performed by the motor drive control device 1 according to the present embodiment. 3 to 4 are diagrams showing temporal changes of the rotation speed of the motor 51, the power supply current Im, the drive control signals SA, SB, and the like when the inverter microcomputer 7 functions normally without running away. FIG. 5 is a diagram showing temporal changes in the rotation speed of the motor 51, the power supply current Im, the drive control signals SA, SB, etc. when the inverter microcomputer 7 runs away.

  In the flowchart of FIG. 2, the outputs of the operational amplifiers OP1 and OP2, the output of the voltage detector 6, and various signals output from the converter microcomputer 8 (specifically, the abnormal signal SD, the warning signal SE, and the waveform output) The drive control operation of the motor 51 based on the status signal SF) is omitted. Hereinafter, the drive control operation of the motor 51 based on the value of the power supply current Im and the operation permission signal SC, which are features of the present embodiment, will be described. The drive control signals SA and SB have a logic of “H” when the converter 3 and the inverter 4 are driven, and “L” when the drive is stopped. Further, the reset instruction signal SG has a logic of “H” when instructing reset of the inverter microcomputer 7 and “L” when not instructing reset.

  Steps S1 to S2: When the motor drive control device 1 obtains a drive instruction for the compressor from a control unit (not shown) that controls various devices included in the air conditioner (S1), the motor drive control device 1 controls the drive of the motor 51. Start and drive the motor 51 (S2). Then, as shown in “stop” to “start” in FIG. 3, the drive control signal SA “H” and the drive control signal SB “H” are output from each of the microcomputers 7 and 8, and from the inverter microcomputer 7, An operation permission signal SC “H” indicating a state in which the motor 51 is driven is output. The reset instruction signal SG is in the “L” state. Then, the motor 51 eventually reaches a steady rotation state (“steady rotation” in FIG. 3).

  Steps S3 to S4: The converter microcomputer 8 monitors the operation permission signal SC acquired from the inverter microcomputer 7. As shown in FIG. 5, when the operation permission signal SC changes from “H” to “L” (Yes in S3), the converter microcomputer 8 determines that the value of the power supply current Im that is the output of the current sensor 2 is predetermined. It is confirmed whether or not the value is A or more (in this embodiment, 3.5 A or more) (S4).

  Steps S5 to S6: If the value of the power supply current Im is equal to or greater than the predetermined value A in step S4, the converter microcomputer 8 performs an operation of resetting the inverter microcomputer 7 (S5). Specifically, as shown in FIG. 5, the converter microcomputer 8 changes the drive control signal SA output from the converter microcomputer 8 itself from “H” to “L”, whereby the direct current of the power supply current Im in the converter 3 is changed. Stops conversion to current. Further, the converter microcomputer 8 changes the reset instruction signal SG output to the reset IC 9 from “L” to “H”. The reset IC 9 that has acquired the reset instruction signal SG “H” changes the reset signal SH from “L” to “H” in synchronization with the next rising edge of the reference clock CLK. Due to the change of the reset signal SH, the inverter microcomputer 7 is forcibly reset, and the drive control signal SB output from the inverter microcomputer 7 changes from “H” to “L”. Accordingly, the generation and output operation of the drive voltages SU, SV, SW by the inverter 4 is stopped, and the drive of the motor 51 is completely stopped (S6).

  Step S7: In steps S3 and S4, the operation permission signal SC is “L”, but if the power supply current Im is less than the predetermined value A, the converter microcomputer 8 is in a normal state in which the inverter microcomputer 7 is not running away. The drive control signal SA is switched from “H” to “L”. Thereby, the conversion operation of the power source current Im by the converter 3 to the direct current and the generation and output operations of the drive voltages SU, SV, SW by the inverter 4 are stopped, and the drive of the motor 51 is stopped.

  Steps S8 to S10: When the operation permission signal SC does not change to “L” and remains in the “H” state in Step S3 (No in S3), the converter microcomputer 8 indicates that the power supply current Im has a predetermined value. It is confirmed whether or not the value is A or more (in this embodiment, 3.5 A or more) and whether or not the value of the power supply current Im is less than a predetermined value B (in this embodiment, less than 2.0 A). (S8, S9). When the power supply current Im is equal to or greater than the predetermined value A (Yes in S8) and when the power supply current Im is not equal to or greater than the predetermined value A but is equal to or greater than the predetermined value B (Bo in S9), the motor drive control device 1 The drive control of the motor 51 is continued (S10). That is, as shown in FIG. 3, the drive control signals SB and SA output from the microcomputers 7 and 8 are “H”, the operation permission signal SC is “H”, and the reset instruction signal SG is “L”. Kept.

  In step S9, when the value of the power supply current Im becomes less than the predetermined value B (Yes in S9, that is, the power supply current Im> 2.0A), as shown in FIG. The control signals SB and SA and the operation permission signal SC change from “H” to “L”, respectively. Thereby, the driving of the motor 51 is completely stopped (S7).

  Step S11: After step S7, when the operation permission signal SC becomes “H” and the value of the power supply current Im is equal to or greater than a predetermined value A (specifically, 3.5 A or greater), FIG. As shown, the drive control signals SB and SA and the operation permission signal SC of the microcomputers 7 and 8 change from “L” to “H”, respectively. Thereby, the motor 51 is restarted, and the motor drive control apparatus 1 repeats the operation | movement after step S2. If the operation permission signal SC remains “L” or the value of the power supply current Im remains below the predetermined value B (specifically, 2.0 A or more), the motor 51 stops driving. It will be in a state as it is.

(3) Effect (A)
According to the motor drive control device 1 according to the present embodiment, the operation permission signal SC indicating that the inverter 4 is in the drive stop state is output from the inverter microcomputer 7, and the power supply current Im that is the output of the current sensor 2 is the motor. If the value is equal to or more than a predetermined value A required at the time of normal rotation 51, the converter microcomputer 8 determines that the inverter microcomputer 7 is in a runaway state even though the inverter 4 is normally driven, and the inverter microcomputer 7 is reset. Thereby, drive control of the inverter 4 is not normally performed, and it is possible to avoid adversely affecting the rotational drive of the motor 51.

(B)
In addition, the motor drive control device 1 according to the present embodiment includes a reset IC 9 for resetting the inverter microcomputer 7. The reset IC 9 resets the inverter microcomputer 7 when the reset instruction signal SG for performing the reset is acquired from the converter microcomputer 8. As a result, the inverter microcomputer 7 is not reset directly by the converter microcomputer 8 but is reset by the reset IC 9.

(C)
By the way, if the converter microcomputer 8 is configured to directly reset the inverter microcomputer 7, in some cases, the current drive state of the inverter microcomputer 7 and the start of the reset operation cannot be properly synchronized. There is a possibility that the inverter microcomputer 7 malfunctions without being reset normally. However, since the reset IC 9 according to the present embodiment resets the inverter microcomputer 7 at a predetermined timing, a malfunction that may occur when the converter microcomputer 8 directly resets the inverter microcomputer 7 is less likely to occur.

(D)
The motor drive control device 1 according to the present embodiment is used for drive control of the compressor motor 51. Thereby, since the runaway of the inverter microcomputer 7 that outputs the drive voltages SU, SV, SW to the compressor motor 51 can be avoided, the compressor motor 51 is normally rotated. Therefore, the compressor using the compressor motor 51 as a drive source can be operated normally.

<Other embodiments>
(A)
In the above-described embodiment, predetermined values such as the predetermined value A that is the threshold value of the power source current Im when the motor 51 is driven and the predetermined value B that is the threshold value of the power source current Im when the driving of the motor 51 is stopped are set. The case where two are provided has been described. However, the predetermined value may be one. The predetermined value may also be determined as appropriate based on the range that the power supply current Im can take, the value of the minimum power supply current Im that can drive the motor 51, and the like.

(B)
In the above embodiment, the case where the motor drive control device 1 drives and controls the compressor motor 51 that is the drive source of the compressor has been described. However, the motor drive control device 1 according to the present invention can also be used when driving a motor other than the compressor motor. Another example other than the compressor motor is a fan motor.

(C)
In the above embodiment, the case where the converter microcomputer 8 does not directly reset the inverter microcomputer 7 but the inverter microcomputer 7 is reset via the reset IC 9 has been described. However, if it is determined that even if the converter microcomputer 8 directly resets the inverter microcomputer 7, problems such as malfunctions are unlikely to occur, the converter microcomputer 8 may directly reset the inverter microcomputer 7 without providing the reset IC 9. .

  The motor drive control device according to the present invention has an effect that it is possible to avoid that the inverter is not normally driven and controlled, and adversely affects the rotational drive of the motor, and the drive motor is controlled for the compressor. It can be applied as a device for

1 is a conceptual diagram of a schematic configuration of a motor drive device according to the present embodiment, and a system including the motor drive control device and a motor. The flowchart for demonstrating the flow of a series of operation | movement which the motor drive control apparatus which concerns on this embodiment performs. The figure which shows the time-dependent change of various signals, such as the rotation speed of a motor and an operation permission signal, when an inverter microcomputer performs drive control of an inverter normally. The figure which shows the time-dependent change of various signals, such as the rotation speed of a motor, and an operation permission signal, when a power supply current becomes temporarily below predetermined value B when the motor is carrying out steady rotation. The figure which shows the time-dependent change of various signals, such as the rotation speed of a motor and an operation permission signal, when an inverter microcomputer runs away while the motor is carrying out steady rotation.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Motor drive control apparatus 2 Current sensor 3 Converter 4 Inverter 5 Smoothing part 6 Current detection part 7 Inverter microcomputer 8 Converter microcomputer 9 Reset IC
51 Motor 61 Power supply 100 Motor drive control system L1 to L9 Various wirings SA, SB Drive control signal SC Operation permission signal SD Abnormal signal SE Warning signal SF Waveform output state signal SG Reset instruction signal SH Reset signal SU, SV, SW Drive voltage Rs1, Rs2 Shunt resistor c1, c2 Capacitor r1, r2 Resistor Im Power supply current OP1, OP2 Operational amplifier

Claims (4)

A converter (3) for converting a power source current (Im) output from the power source (61) into a direct current;
An inverter (4) that is supplied with the DC current from the converter (3), generates a drive voltage (SU, SV, SW) for driving the motor (51), and outputs the drive voltage to the motor (51);
A converter drive control unit (8) for controlling the drive of the converter (3) and monitoring the power supply current (Im);
Inverter drive that controls the drive of the inverter (4) and outputs a drive state signal (SC) indicating whether or not the inverter (4) is being driven to the converter drive control unit (8). A control unit (7);
With
The converter drive control unit (8) acquires the drive state signal (SC) indicating that the inverter (4) is in a drive stop state from the inverter drive control unit (7) and the power supply current (Im ) Is greater than or equal to a predetermined value, the inverter drive control unit (7) is reset.
Motor drive control device (1). A reset unit (9) connected to the inverter drive control unit (7) and the converter drive control unit (8), for resetting the inverter drive control unit (7);
The converter drive control unit (8) acquires the drive state signal (SC) indicating that the inverter (4) is in a drive stop state from the inverter drive control unit (7) and the power supply current (Im ) Is equal to or greater than a predetermined value, a reset instruction signal (SG) for causing the reset unit (9) to reset the inverter drive control unit (7) is output to the reset unit (9).
The motor drive control device (1) according to claim 1. The reset unit (9) resets the inverter drive control unit (7) at a predetermined timing when the reset instruction signal (SG) is acquired from the converter drive control unit (8).
The motor drive control device (1) according to claim 2. The motor (51) is a compressor motor.
The motor drive control device (1) according to any one of claims 1 to 3.

Images