JP5353073B2 - Motor drive control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor drive controller capable of safely rotatingly driving a motor. <P>SOLUTION: The motor drive controller 1 includes a converter 3, an inverter 4, an inverter micro-computer 7 and a converter micro-computer 8. The converter 3 converts power supply current Im to direct current. The inverter 4 is supplied with the direct current from the converter 3 and supplies drive voltages SU, SV, SW to a motor 51. The inverter micro-computer 7 drive-controls the inverter 4. The converter micro-computer 8 drive-controls the converter 3, and when an abnormal condition is satisfied for determining that the output of the drive voltages SU, SV, SW in the inverter 4 should be forcibly stopped, the converter micro-computer outputs to the inverter micro-computer 7 a second output forcible stop signal SG to stop the output of the drive voltages SU, SV, SW. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

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, when the motor is normally driven, a current more than the normal rotation of the motor may suddenly flow to the inverter or the motor due to a power failure or the like. In particular, if this current is higher than the rated current of the power transistor or motor constituting the inverter, the power transistor may ignite or the motor may fail.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a motor drive control device that can safely rotate a motor.

A motor drive control device according to a first aspect includes a converter, an inverter, an inverter drive control unit, and a converter 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 inverter drive control unit performs drive control of the inverter. The converter drive control unit controls the drive of the converter and outputs an output stop signal for stopping the output of the drive voltage when an abnormal condition for determining that the output of the drive voltage in the inverter should be forcibly stopped is satisfied. Is output to the inverter drive control unit. The converter drive control unit stops driving the converter when the power supply current becomes equal to or lower than the first lower limit value, and then drives the converter when the power supply current becomes equal to or higher than the second lower limit value. Is further performed. The first lower limit value and the second lower limit value are different from each other.

  The abnormal condition is a condition for determining that the inverter must be stopped suddenly, and includes, for example, a condition where the power supply current is equal to or higher than that during normal operation of the motor. According to this motor drive control device, when the abnormal condition occurs, the converter drive control unit outputs an output stop signal to the inverter drive control unit. Accordingly, the inverter drive control unit performs control to forcibly stop the output of the drive voltage to the inverter, and the inverter stops generating the drive voltage. Therefore, the motor drive control device can drive the motor to rotate safely.

  The motor drive control device according to a second aspect is the motor drive control device according to the first aspect, wherein the abnormal condition includes at least one of a first condition, a second condition, and a third condition. The first condition is a condition where the power supply current is equal to or greater than the first predetermined value. The second condition is a condition in which the current supplied to the inverter is equal to or greater than a second predetermined value. The third condition is a condition in which the voltage applied to the inverter is equal to or higher than a third predetermined value.

  Here, examples of the first predetermined value include the maximum value of the power supply current during the normal operation of the motor. Examples of the second predetermined value and the third predetermined value include an allowable maximum value of a current supplied to the inverter during normal operation of the motor and an allowable maximum value of a voltage applied to the inverter. The converter drive control unit in this motor drive control device determines that some abnormality has occurred in the power supply, for example, when the power supply current increases to a first predetermined value or more (ie, the first condition). Can do. Further, the converter drive control unit is configured such that the current supplied to the inverter is equal to or higher than a second predetermined value (that is, the second condition), or the voltage applied to the inverter is equal to or higher than the third predetermined value (that is, the third condition). In such a case, for example, it can be determined that some abnormality has occurred on the main circuit including the converter and the inverter. The converter drive control unit can cause the inverter drive control unit to perform control for forcibly stopping the output of the drive voltage when at least one of the first to third conditions is satisfied. Can be rotated more safely.

  A motor drive control device according to a third aspect is the motor drive control device according to the second aspect, wherein the inverter drive control unit outputs the drive voltage by the inverter when the current passed through the inverter is equal to or greater than a fourth predetermined value. The instruction to stop is output to the inverter.

  Here, as the fourth predetermined value, the maximum value of the current supplied to the inverter during the normal operation of the motor can be cited as in the second predetermined value. According to this motor drive control device, the inverter drive control unit has determined by itself that it should be forcibly stopped not only when the output stop signal is output from the converter drive control unit, but also based on the value of the current supplied to the inverter. Even in this case, an instruction to forcibly stop the output of the drive voltage by the inverter can be output to the inverter. Therefore, when a large amount of current is supplied to the inverter, the output of the drive voltage by the inverter can be stopped more reliably.

  A motor drive control device according to a fourth aspect is the motor drive control device according to the third aspect, further comprising a first wiring, a second wiring, a capacitor, a first shunt resistor, and a second shunt resistor. The first wiring is a wiring for flowing a direct current converted by the converter to the inverter. The second wiring is a wiring for allowing the current supplied to the inverter to flow through the converter. The capacitor is located between the converter and the inverter, and both ends are connected to the first wiring and the second wiring, respectively. The first shunt resistor is connected in series on the second wiring on the converter side with respect to the capacitor. The second shunt resistor is connected in series on the second wiring on the inverter side with respect to the capacitor. The converter drive control unit monitors the current flowing through the first shunt resistor. The inverter drive control unit monitors the current flowing through the second shunt resistor.

  Usually, a capacitor is connected between the converter and the inverter for the purpose of smoothing the direct current converted by the converter. However, this capacitor divides the main circuit including the converter and the inverter into a primary side circuit that is closer to the converter than the capacitor and a secondary side circuit that is closer to the inverter than the capacitor. However, in the motor drive control device according to the present invention, the converter drive control unit monitors the current supplied to the inverter using the first shunt resistor located on the primary circuit, and the inverter drive control unit A current supplied to the inverter is monitored using a second shunt resistor located on the secondary circuit. As a result, even if the main circuit is divided into a primary side circuit and a secondary side circuit, the converter drive control unit and the inverter drive control unit may cause an abnormality in the inverter based on the current supplied to the inverter. Can be reliably determined.

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

  By using the motor drive control device according to the present invention for drive control of a compressor motor, the compressor motor can be safely rotated. Therefore, a compressor using a compressor motor as a drive source can be operated normally and safely.

  The motor drive control device according to the first aspect of the present invention can safely rotate the motor.

  According to the motor drive control device of the second aspect of the invention, when at least one of the first to third conditions is satisfied, the inverter drive control unit can be controlled to forcibly stop the output of the drive voltage. The motor can be driven to rotate more safely.

  According to the motor drive control device pertaining to the third aspect of the present invention, when a large amount of current is supplied to the inverter, the output of the drive voltage by the inverter can be stopped more reliably.

  According to the motor drive control device of the fourth aspect of the present invention, the converter drive control unit and the inverter drive control unit are energized to the inverter even when the main circuit is divided into the primary side circuit and the secondary side circuit. Based on the current, it can be reliably determined that an abnormality has occurred in the inverter.

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

  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. The motor drive control device 1 mainly includes a current sensor 2, a converter 3, wirings L4 and L5 (first wiring and second wiring, respectively). ), Inverter 4, smoothing unit 5 (corresponding to a capacitor), voltage detection unit 6, primary shunt resistor Rs1 (corresponding to the first shunt resistor), secondary shunt resistor Rs2 (corresponding to the second shunt resistor) Inverter microcomputer 7 and converter microcomputer 8 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 and wiring L4, L5]
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.

  As described above, the inverter 4 is supplied with the power supply current Im converted into a direct current by the converter 3 via 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 and the like which are insulating bipolar transistors and the like, like 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.

  Further, the inverter 4 according to the present embodiment forcibly stops the output of the drive voltages SU, SV, SW based on the output of the operational amplifier OP2, which will be described later, and outputs the first output forced stop signal SF to the inverter microcomputer 7. It is the composition which can do. The first output forced stop signal SF is a signal for forcibly stopping the output of the drive control signal SB by forcibly stopping the PWM waveform output in the inverter microcomputer 7. The forced stop instruction by the first output forced stop signal SF and the forced stop of the output of the drive voltages SU, SV, SW are performed when the output of the operational amplifier OP2 satisfies a predetermined condition, which will be described later.

[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 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 on the converter 3 side with respect to the smoothing unit 5, that is, between the connection point between the smoothing unit 5 and the wiring L5 and the converter 3. The secondary shunt resistor Rs2 is provided on the inverter 4 side with respect to the smoothing unit 5, that is, between the connection point between the smoothing unit 5 and the wiring L5 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 output to the inverter 4 and the inverter microcomputer 7. Is done.

[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 state of the air conditioner, the value of a power supply current Im described later, and the like, and is merely for instructing generation and stoppage of the drive voltages SU, SV, and SW. Instead, it also serves as a signal for controlling the duty of the drive voltages SU, SV, SW and the rotation speed of the motor 51.

  In particular, the inverter microcomputer 7 according to the present embodiment can acquire the first output forced stop signal SF from the inverter 4. When acquiring the first output forced stop signal SF, the inverter microcomputer 7 forcibly stops the internal PWM waveform output as described above, and stops the output of the drive control signal SB. Here, the condition when the inverter microcomputer 7 acquires the first output forced stop signal SF is the output of the operational amplifier OP2, that is, the current flowing on the secondary shunt resistor Rs2 (specifically, the inverter 4 is energized). And the output of the drive voltages SU, SV, SW of the inverter 4 is forcibly stopped. Examples of the threshold value include an allowable maximum value of a current that is supplied to the inverter 4 during normal operation of the motor 51, and is set to a rated current of each power transistor or the motor 51 in the inverter 4, for example. As shown in FIG. 3, the inverter microcomputer 7 obtains the first output forced stop signal SF when the current flowing on the wiring L <b> 5 is greater than or equal to the threshold value, thereby stopping the output of the drive control signal SB to the inverter 4. Thus, the stop control of the output of the drive voltages SU, SV, SW by the inverter 4 can be performed more reliably.

  Further, 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 by the operational amplifier OP2 (specifically, the current is supplied to the inverter 4). Current flowing in the secondary shunt resistor) can be calculated. The inverter microcomputer 7 can continue to monitor the calculation result and output a drive control signal SB corresponding to the calculation result to the inverter 4. For example, if the calculated current value on the wiring L5 is equal to or greater than the threshold value, the inverter microcomputer 7 stops generating the drive voltages SU, SV, SW without waiting for the output of the first output forced stop signal SF from the inverter 4. The instructing drive control signal SB is output to the inverter 4. As a result, even when the current value on the wiring L5 is equal to or greater than the threshold value, some abnormality occurs in the inverter 4 and the inverter 4 itself cannot immediately stop generating the drive voltages SU, SV, SW. Since the outputs of the voltages SU, SV, and SW can be forcibly stopped, it is possible to further prevent the inverter 4 and the motor 51 from igniting.

  In addition to the above, the inverter microcomputer 7 is also connected to the converter microcomputer 8 and outputs an operation permission signal SC to the converter microcomputer 8. The operation permission signal SC is a signal for permitting 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, the first output forced stop signal SF, the calculation result, and the like. . 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. If the current value on the wiring L5 is equal to or greater than the threshold value, the inverter microcomputer 7 outputs an operation permission signal SC to the converter microcomputer 8 indicating that the drive control of the converter microcomputer 8 is not permitted, as shown in FIG. If the current value on the wiring L5 is less than the predetermined value, an operation permission signal SC for permitting the drive control of the converter microcomputer 8 is output to the converter microcomputer 8.

  Here, the operation permission signal SC according to the present embodiment is “H” when the inverter 4 is driven, that is, when the drive control of the converter 3 is permitted, and the inverter 4 is not driven. In other words, that is, when the drive control of the converter 3 is not permitted, the logic of “L” is assumed. The first output forced stop signal SF has a logic of “L” when the inverter 4 outputs the drive control signal SB and “H” when the output of the drive control signal SB to the inverter 4 is stopped. Shall have.

  Furthermore, 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 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, and a second output forced stop signal SG (corresponding to an output stop signal). 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. Similar to the first output forced stop signal SF, the second output forced stop signal SG is a signal for forcibly stopping the output of the drive control signal SB by forcibly stopping the PWM waveform output in the inverter microcomputer 7. is there. The inverter microcomputer 7 has a plurality of input / output ports for outputting and acquiring various signals as described above, but the first output forced stop signal SF and the second output forced stop signal according to the present embodiment. SG is input to the same input port.

[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

  Further, the converter microcomputer 8 detects the power supply current Im detected by the current sensor 2, the output of the operational amplifier OP1 (that is, the current that flows through the first shunt resistor Rs1 through the inverter 4), the output of the voltage detector 6, and the inverter The operation permission signal SC output from the microcomputer 7 is monitored. The converter microcomputer 8 determines the drive control signal SA, the abnormality signal SD, and the warning signal SE based on the monitored various information. For example, when the value of the power supply current Im is a predetermined value or more, or when the operation permission signal SC is “H”, the converter microcomputer 8 outputs a drive control signal SA for driving the converter 3. . Conversely, when the value of the power supply current Im is less than a predetermined value or when the operation permission signal SC is “L”, the converter microcomputer 8 drives the drive control signal SA for stopping the drive of the converter 3. Or an operation permission signal SC indicating that drive control of the inverter microcomputer 7 is not permitted. Here, the predetermined value can be, for example, the value of the power supply current Im that is at least necessary for normal rotation of the motor 51. If the detected value of the power supply current Im becomes lower than this value, the motor 51 It is a value that hinders the rotation of. 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. The power supply current Im is less than a predetermined value, for example, when there is some abnormality in the power supply 61. In such a case, the converter microcomputer 8 determines that the motor 51 cannot be driven, and the converter 3 is stopped.

  In the present invention, in consideration of the influence of harmonics in the power source current Im, as shown in FIG. 4, different values “predetermined value A” and “predetermined value B” are provided as 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, as shown in FIGS. 5 to 7, when an abnormal condition for determining that the output of the drive voltages SU, SV, SW in the inverter 4 should be forcibly stopped is satisfied. In addition, the output of the drive voltages SU, SV, SW is forcibly stopped by outputting a second output forced stop signal SG for forcibly stopping the output of the drive voltages SU, SV, SW to the inverter microcomputer 7.

Here, the abnormal condition will be described. The abnormal condition according to the present embodiment is a condition that the inverter 4 must be stopped suddenly, and specifically includes the following conditions.
First condition: When the power supply current Im detected by the current sensor 2 is greater than or equal to a first predetermined value (FIG. 5)
Second condition: When the result calculated based on the output of the operational amplifier OP1 (that is, the current that flows through the inverter 4 and flows on the primary shunt resistor Rs1) is equal to or greater than the second predetermined value (FIG. 6).
Third condition: When the result calculated based on the output of the voltage detector 6 (that is, the voltage applied to the inverter 4) is equal to or greater than a third predetermined value (FIG. 7).

  Examples of the first predetermined value include an allowable maximum value of the power supply current Im when the motor 51 performs normal rotation. As the second predetermined value, the allowable maximum value of the current supplied to the inverter 4 during normal rotation of the motor 51 can be cited as in the case of the threshold value. Examples of the third predetermined value include an allowable maximum value of the voltage applied to the inverter 4 during normal rotation of the motor 51. In particular, the first condition is a condition regarding an abnormality in the power supply 61 in the main circuit including the converter 3 and the inverter 4, and the third condition is a condition regarding whether or not the voltage applied to the inverter 4 is an overvoltage. is there. Further, since the second condition is a condition based on the current value on the wiring L5 in the primary side portion of the main circuit, it can be said that the second condition is a condition for detecting an abnormality on the converter 3 side with respect to the smoothing unit 5. When at least one of the first to third conditions is satisfied, the converter microcomputer 8 determines that some abnormality has occurred on the power supply 61 or the main circuit, and outputs the second output forced stop signal SG. Thus, the inverter microcomputer 7 can be forcibly stopped. Therefore, the converter microcomputer 8 can stop the drive of the motor 51 by immediately stopping the drive of the inverter microcomputer 7 when the abnormality which should stop the drive of the motor 51 immediately is detected.

  The second output forced stop signal SG according to the present embodiment is “L” when the inverter microcomputer 7 outputs the drive control signal SB, similarly to the first output forced stop signal SF, and the output of the drive control signal SB. It is assumed that the logic of “H” is used when stopping.

(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 with reference to FIGS. FIG. 8 is a flowchart for explaining a flow of a series of operations performed by the motor drive control device 1 according to this embodiment. FIGS. 2 to 7 illustrate the number of rotations of the motor 51, the power supply current Im, It is a figure which shows the time-dependent change of various signals, such as 2nd output forced stop signal SF and SG.

  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. 2, the drive control signal SB “H” and the drive control signal SA “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 first output forced stop signal SF and the second output forced stop signal SG are both kept at the “L” state. Then, the motor 51 eventually reaches a steady rotation state (“steady rotation” in FIG. 2).

  Steps S3 to S8: The converter microcomputer 8 monitors the output of the current sensor 2, the output of the operational amplifier OP1, the output of the voltage detector 6, and the like. As shown in FIG. 5, when the value of the power source current Im that is the output of the current sensor 2 is equal to or greater than the first predetermined value (Yes in S3, first condition), as shown in FIG. When the value of the current flowing on the resistor Rs1 becomes equal to or greater than the second predetermined value (Yes in S4, second condition), the applied voltage to the inverter 4 that is the output of the voltage detector 6 is as shown in FIG. If it is equal to or greater than the third predetermined value (Yes in S5, the third condition), converter microcomputer 8 outputs second output forced stop signal SG “H” (S6). As a result, the inverter microcomputer 7 outputs the drive control signal SB “L” to the inverter 4, so that the inverter 4 stops driving (S7) and the driving of the motor 51 is forcibly stopped (S8). . The converter microcomputer 8 outputs the second output forced stop signal SG “H” and also stops the drive of the converter 3 in order to set the drive control signal SA output to the converter 3 to “L”.

  Steps S9 to S10: In Steps S3 to S5, none of the conditions are satisfied. However, as shown in FIG. 3, the current on the secondary shunt resistor Rs2 becomes equal to or greater than the threshold (Yes in S9), and the inverter 4 When the 1-output forced stop signal SF “H” is output (S10), the inverter microcomputer 7 switches the operation permission signal SC from “H” to “L” and outputs the drive control signal SB “L”. (S7). Thereby, the drive of the inverter 4 is stopped, and the converter microcomputer 8 stops the drive of the converter 3, so that the drive of the motor 51 is completely stopped (S8).

  When none of the above conditions of steps S3 to S5 and S9 is satisfied, the microcomputers 8 and 7 perform drive control of the converter 3 and the inverter 4 so that the motor 51 continues to rotate normally. Continue. Although not shown in FIG. 8, as shown in FIG. 4, when the power supply current Im monitored by the converter microcomputer 8 becomes a predetermined value B or less, the microcomputers 8 and 7 are connected to the converter 3 and The drive of the inverter 4 is stopped and the motor 51 is stopped. Further, when the first output forced stop signal SF is not “H”, but the inverter microcomputer 7 determines that the current on the secondary shunt resistor Rs2 is equal to or greater than the threshold value, the inverter microcomputer 7 The drive is stopped and an operation permission signal SC “L” is output to the converter microcomputer 8. Thereby, the drive of converter 3 is also stopped and motor 51 is stopped.

(3) Effect (A)
According to the motor drive control device 1 according to the present embodiment, the converter microcomputer 8 outputs the second output when an abnormal condition for determining that the output of the drive voltages SU, SV, SW in the inverter 4 should be forcibly stopped occurs. A forced stop signal SG is output to the inverter microcomputer 7. Thereby, the inverter microcomputer 7 performs control to forcibly stop the output of the drive voltages SU, SV, and SW to the inverter 4, and the inverter 4 stops generating the drive voltages SU, SV, and SW. Therefore, the motor drive control device 1 can drive the motor 51 to rotate safely.

(B)
The abnormal condition includes a first condition in which the power supply current Im is equal to or higher than a first predetermined value, a second condition in which a current supplied to the inverter 4 is equal to or higher than a second predetermined value, and a voltage applied to the inverter 4 3 At least one of the third conditions that is greater than or equal to a predetermined value is included. The first predetermined value, the second predetermined value, and the third predetermined value respectively include an allowable maximum value of the power source current Im during normal rotation of the motor, an allowable maximum value of current that is supplied to the inverter 4 during normal rotation of the motor, and the inverter 4 The allowable maximum value of the energized voltage is mentioned. According to the motor drive control device 1, the converter microcomputer 8 has some abnormality in the power supply 61, for example, when the power supply current Im increases to be equal to or greater than the first predetermined value (that is, the first condition). It can be judged. Further, the converter microcomputer 8 determines that the current supplied to the inverter 4 is equal to or higher than the second predetermined value (that is, the second condition), or the voltage applied to the inverter 4 is equal to or higher than the third predetermined value (that is, the third condition). ), It can be determined that some abnormality has occurred on the main circuit including the converter 3 and the inverter 4. Thus, the converter microcomputer 8 causes the inverter microcomputer 7 to perform control to forcibly stop the output of the drive voltages SU, SV, SW when at least one of the first to third conditions is satisfied. Therefore, the motor 51 can be rotated more safely.

(C)
When the current supplied to the inverter 4 is equal to or greater than the threshold value, the inverter microcomputer 7 outputs an instruction to stop the drive voltage output by the inverter to the inverter. As the threshold value, the allowable maximum value of the current that is supplied to the inverter 4 during normal motor operation can be cited as in the case of the second predetermined value. Therefore, according to this motor drive control device 1, when the inverter microcomputer 7 forcibly stops not only when the converter microcomputer 8 outputs the second output forced stop signal SG but also based on the current supplied to the inverter 4. Even when it is determined by itself, an instruction to forcibly stop the output of the drive voltages SU, SV, SW by the inverter 4 can be output to the inverter 4. Therefore, when a large amount of current is supplied to the inverter 4, the output of the drive voltages SU, SV, SW by the inverter 4 can be stopped more reliably.

(D)
By the way, normally, between the converter 3 and the inverter 4, a smoothing unit 5 composed of capacitors c <b> 1 and c <b> 2 is connected for the purpose of smoothing the direct current (power supply current Im) after being converted by the converter 3. Is done. However, due to the capacitors c1 and c2, the main circuit including the converter 3 and the inverter 4 is a primary side circuit that is closer to the converter 3 than the capacitors c1 and c2, and a secondary side that is closer to the inverter 4 than the capacitors c1 and c2. It will be divided into circuits. However, in the motor drive control device 1 according to the present embodiment, the converter microcomputer 8 monitors the current supplied to the inverter 4 by using the primary shunt resistor Rs1 located on the primary circuit, and the inverter microcomputer 7 Monitors the current supplied to the inverter 4 using the secondary shunt resistor Rs2 located on the secondary circuit. As a result, even if the main circuit is divided into the primary side circuit and the secondary side circuit, the converter microcomputer 8 and the inverter microcomputer 7 are abnormal in the inverter 4 based on the current supplied to the inverter 4. Can be reliably determined.

(E)
The motor drive control device 1 according to the present embodiment is used for drive control of the compressor motor 51. Thereby, since the compressor motor 51 is rotationally driven safely, the compressor using the compressor motor 51 as a drive source can operate normally and safely.

<Other embodiments>
(A)
In addition to the operation shown in FIG. 8, the motor drive control device 1 according to the above embodiment may further perform an operation for forcibly stopping the motor 51 when the inverter microcomputer 7 runs away. The motor drive control device 1 in this case further includes a reset IC 9 as shown in FIG. The reset IC 9 is for resetting the inverter microcomputer 7 and 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 SH output port in the converter microcomputer 8 via wiring, and the output of the reset IC 9 is connected to the reset signal SI input port in the inverter microcomputer 7 via wiring. ing. When the reset IC 9 acquires the reset instruction signal SH for resetting the inverter 4 from the converter microcomputer 8, the reset IC 9 outputs a reset signal SI for resetting the inverter microcomputer 7.

  In this case, the converter microcomputer 8 not only simply switches the drive control signal SA based on the operation permission signal SC sent from the inverter microcomputer 7 but also determines whether or not the inverter microcomputer 7 is in a runaway state. Specifically, the power supply current Im is a value at the time of normal rotation of the motor 51, but the operation permission signal SC is a content indicating the drive stop state of the inverter 4 (specifically, the operation permission signal SC “L”). If there is, the converter microcomputer 8 determines that the motor 51 is rotating normally but the inverter microcomputer 7 is in a runaway state. In this case, the converter microcomputer 8 outputs a reset instruction signal SH for resetting the inverter 4 to the reset IC 9. When the inverter microcomputer 7 acquires the reset signal SI having the contents 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 IC 9 may be a so-called synchronous reset IC that resets the inverter microcomputer 7 at a predetermined timing based on the reference clock CLK.

(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.

  The motor drive control device according to the present invention has an effect that the motor can be rotationally driven safely, and can be applied as a device for driving and controlling the compressor motor.

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 figure which shows the time-dependent change of the rotation speed of a motor, a power supply current, and various signals 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, when the electric current which flows on a secondary side shunt resistance becomes more than a threshold value. The figure which shows the rotation speed of a motor, and a time-dependent change of various signals when a power supply current temporarily becomes the predetermined value B or less while the motor is performing steady rotation. The figure which shows the time-dependent change of the rotation speed of a motor and various signals when the 1st condition is satisfy | filled. The figure which shows the time-dependent change of the rotation speed of a motor and various signals when 2nd conditions are satisfy | filled. The figure which shows the time-dependent change of the rotation speed of a motor and various signals when 3rd conditions are satisfy | filled. 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 conceptual diagram of the schematic structure of the motor control apparatus which concerns on other embodiment (a), and the system provided with this motor drive control apparatus and a motor.

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 51 Motor 61 Power supply 100 Motor drive control systems L1-L9 Various wiring SA, SB Drive control signal SC Operation permission signal SD Abnormal signal SE Warning signal SF First output forced stop signal SG Second output forced stop 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 (5)

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);
An inverter drive controller (7) for controlling the drive of the inverter (4);
When the abnormal condition for performing the drive control of the converter (3) and determining that the output of the drive voltage (SU, SV, SW) in the inverter (4) should be forcibly stopped is satisfied, the drive A converter drive control unit (8) for outputting an output stop signal (SG) for stopping output of the voltages (SU, SV, SW) to the inverter drive control unit (7);
Equipped with a,
The converter drive control unit (8) stops driving the converter (3) when the power supply current (Im) is equal to or lower than a first lower limit value, and then the power supply current (Im) is second. When the lower limit value is exceeded, further control for driving the converter (3) is performed,
The first lower limit value and the second lower limit value are different from each other.
Motor drive control device (1). The abnormal condition includes a first condition in which the power supply current (Im) is equal to or higher than a first predetermined value, a second condition in which a current supplied to the inverter (3) is equal to or higher than a second predetermined value, and the inverter ( 4) includes at least one of the third conditions in which the voltage applied is equal to or greater than a third predetermined value.
The motor drive control device (1) according to claim 1. The inverter drive control unit (7) stops the output of the drive voltage (SU, SV, SW) by the inverter (4) when the current supplied to the inverter (4) is a fourth predetermined value or more. An instruction to output to the inverter (4),
The motor drive control device (1) according to claim 2. A first wiring (L4) for flowing the DC current converted by the converter (3) to the inverter (4);
A second wiring (L5) for passing a current passed through the inverter (4) to the converter (3);
A capacitor (5) positioned between the converter (3) and the inverter (4) and having both ends connected to the first wiring (L4) and the second wiring (L5),
A first shunt resistor (Rs1) connected in series on the second wiring (L5) on the converter (3) side with respect to the capacitor (5);
A second shunt resistor (Rs2) connected in series on the second wiring (L5) on the inverter (4) side with respect to the capacitor (5);
Further comprising
The converter drive control unit (8) monitors a current flowing through the first shunt resistor (Rs1),
The inverter drive controller (7) monitors a current flowing through the second shunt resistor (Rs2);
The motor drive control device (1) according to claim 3. The motor (51) is a compressor motor.
The motor drive control device (1) according to any one of claims 1 to 4.

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