JP6374891B2 - Motor drive control device and motor drive control method thereof - Google Patents

Description

  The present invention relates to a motor drive control device that drives a motor and a motor drive control method thereof.

  Conventionally, a motor drive control device for driving a motor is known. For example, Patent Document 1 describes a motor drive control device that drives a brushless motor with an electronic commutator. A motor drive control device that drives a motor by receiving a DC power supply as described above includes an inverter circuit composed of a plurality of switching elements such as MOSFETs, and these switching elements are controlled by a PWM (Pulse Width Modulation) signal. The motor is PWM driven by on / off control.

JP 2010-252470 A

  By the way, in the motor drive control device described in Patent Document 1, a switch composed of two MOSFETs is provided between a power source and an inverter circuit. The two MOSFETs are connected in series so that the respective parasitic diodes are opposite to each other, and the switch is controlled to be turned on / off by inputting a switching control signal to the gate terminals of these MOSFETs.

  In addition, in a motor that rotates at high speed, an excessive back electromotive force may be generated by kickback from the motor coil at the time of phase switching or sudden fluctuations in the rotational speed. Such back electromotive force is regenerated to the power supply line to increase the power supply voltage, which may lead to application of an excessive voltage to the components used. For this reason, in the motor drive control device described in Patent Document 1, a Zener diode is connected to the output side of the switch to suppress an increase in power supply voltage. Such a Zener diode limits the regenerative voltage and suppresses sneaking into the power supply voltage. Since the regenerative energy by kickback is pulsed or short-time, a relatively small Zener diode may be used.

  On the other hand, in order to ensure the reliability in the market of equipment equipped with such a motor drive control device, the motor drive control device is broken even if the power supply voltage exceeds the upper limit of the use voltage range within a predetermined range. There is a need for no level of durability. However, if an excessive power supply voltage that exceeds the Zener voltage of the Zener diode that limits the regenerative voltage is input to the motor drive control device, an excessive current may continue to flow through the Zener diode, eventually leading to damage.

Also, it is conceivable to connect a large-capacity electrolytic capacitor to absorb regenerative energy due to kickback, but such an electrolytic capacitor cannot be said to have sufficient durability. In addition, when a large-capacity capacitor is used, there is a concern that a large inrush current flows through the capacitor when the power is turned on, so that the entire inrush current is significantly increased and the MOSFET for the switch is damaged. For this reason, a means for reducing the inrush current, for example, connecting an inductor is added. However, when an inductor is used, a problem of induced voltage of the inductor and a problem of cost increase arise. Therefore, it is not desirable from the viewpoint of reliability and cost increase to use a large-capacitance capacitor in order to absorb the regenerative energy of kickback.
From such a background, the present inventor has recognized that it is a problem to use a Zener diode to limit the regenerative voltage in the motor drive control device and to protect the Zener diode from an excessive power supply voltage.

  An object of the present invention is made in view of such problems, and a technology for a highly reliable motor drive control device in which a Zener diode for limiting a regenerative voltage is protected when a power supply voltage rises excessively. It is to provide.

In order to solve the above problems, a motor drive control device according to an aspect of the present invention includes a voltage supply circuit that supplies a power supply voltage to an inverter circuit connected to the motor. The voltage supply circuit includes a Zener diode that limits a regenerative voltage generated by the motor, a voltage identification circuit that outputs a stop signal when the power supply voltage exceeds a predetermined threshold by superimposing the regenerative voltage on the power supply voltage, and a stop And a cutoff circuit configured to stop energization of the Zener diode in response to the signal.

  According to this aspect, since the voltage supply circuit includes the Zener diode that limits the regenerative voltage generated by the motor, the regenerative voltage that wraps around the power supply voltage is suppressed, and the Zener diode is protected when the power supply voltage rises excessively. be able to.

Another aspect of the present invention is a motor drive control method. This method includes a voltage supply circuit that supplies a power supply voltage to an inverter circuit connected to a motor, and the voltage supply circuit performs motor drive control executed by a motor drive control device that includes a Zener diode that limits a regenerative voltage generated by the motor. A method of outputting a stop signal when the power supply voltage exceeds a predetermined threshold by superimposing the regenerative voltage on the power supply voltage ; and stopping energization to the Zener diode according to the stop signal; including.

  According to this aspect, the power supply voltage has increased excessively because it includes outputting a stop signal when the power supply voltage exceeds a predetermined threshold and stopping energization to the Zener diode in response to the stop signal. Sometimes a Zener diode can be protected.

  Note that any combination of the above-described constituent elements and those obtained by replacing the constituent elements and expressions of the present invention with each other among methods, apparatuses, etc. are also effective as an aspect of the present invention.

  According to the present invention, there is provided a highly reliable motor drive control device and a motor drive control method thereof in which a Zener diode for suppressing the regenerative voltage from entering the power supply voltage is protected when the power supply voltage rises excessively. can do.

It is a block diagram of the motor drive control device concerning an embodiment. It is a block diagram of the motor drive control apparatus which concerns on embodiment. It is explanatory drawing explaining the fluctuation | variation of a power supply voltage. It is explanatory drawing explaining the fluctuation | variation of the smoothed monitoring voltage. It is a flowchart of an overvoltage protection circuit. It is a timing chart of an overvoltage protection circuit.

  The present invention will be described below based on preferred embodiments with reference to the drawings. The same or equivalent components and members shown in the drawings are denoted by the same reference numerals, and repeated descriptions are appropriately omitted. In addition, the dimensions of the members in each drawing are appropriately enlarged or reduced for easy understanding. Also, in the drawings, some of the members that are not important for describing the embodiment are omitted.

  FIG. 1 is a block diagram of a motor drive control device 100 according to the embodiment. The motor drive control device 100 includes a voltage supply circuit 110 that supplies a power supply voltage Vdd to the inverter circuit 2 connected to the motor 20. The voltage supply circuit 110 includes a Zener diode ZD31 that limits a regenerative voltage generated by the motor 20, a voltage identification circuit 8 that outputs a stop signal FD when the power supply voltage Vdd exceeds a predetermined threshold, and a stop signal FD. A blocking circuit 9 configured to stop energization of the Zener diode ZD31 and a reverse connection protection circuit 5 are included. The reverse connection protection circuit 5 will be described later. The voltage identification circuit 8 outputs a drive control signal Sd to the pre-drive circuit 3. The inverter circuit 2 is switching-controlled by the predrive circuit 3.

(Zener diode)
The motor 20 generates back electromotive force due to the inductance of the coil in accordance with load fluctuations and rotation fluctuations. In particular, when the motor 20 is rapidly reduced from high-speed rotation, a large counter electromotive force is generated. Such back electromotive force may be regenerated in the power supply line of the inverter circuit 2 to increase the power supply voltage Vdd. When the power supply voltage Vdd increases, the main device connected to the power supply voltage Vdd is also affected. Therefore, an excessive regenerative voltage superposition may cause a malfunction of the main device.

  FIG. 3 is an explanatory diagram for explaining fluctuations in the power supply voltage Vdd. An ellipse P shows an example in which the power supply voltage Vdd is the rated voltage Vin1, an ellipse S shows an example in which the power supply voltage Vdd is the upper limit voltage Vin2 in the operating range, and an ellipse T shows the overvoltage Vin3 in which the power supply voltage Vdd exceeds the operating range. An example is shown. For example, in the example indicated by the ellipse S, the regenerative voltage k1 due to kickback is superimposed on the power supply voltage Vdd in a pulse shape. When the power supply voltage Vdd increases in this way, an excessive voltage is applied to the components used, and the reliability of the device may be reduced.

  Thus, in the motor drive control device 100 according to the embodiment, the Zener diode ZD31 that limits the regenerative voltage k1 is provided. For example, the Zener diode ZD31 is connected between the power supply line Vp that supplies the power supply voltage Vdd to the inverter 2 and the ground line GND. In particular, the Zener diode ZD31 has a cathode connected to the power supply line Vp on the positive power supply side and an anode connected to the ground line GND. By connecting in this way, the power supply voltage Vdd is clamped by the Zener voltage Vz of the Zener diode ZD31, and the rise exceeding the Zener voltage Vz is limited.

  On the other hand, in order to ensure reliability in the market, the motor drive control device is required to have durability that does not break even if the power supply voltage Vdd exceeds the upper limit of the operating voltage range within a predetermined range. For example, even if an excessive voltage whose power supply voltage Vdd is twice the rated voltage is continuously input for a predetermined time (for example, when the rating is 50 V, 100 V is 2 minutes), it is practical because it has durability that does not break. It is thought that market reliability can be realized. However, as indicated by an ellipse T in FIG. 3, when the power supply voltage Vdd exceeds the operating range, the power supply voltage Vdd exceeds the Zener voltage Vz of the Zener diode ZD31, and an excessive current flows in the Zener diode ZD31. There is a possibility that the temperature of the element continues to rise and eventually breaks.

  Therefore, in the motor drive control device 100 according to the embodiment, the overvoltage protection circuit 6 configured to stop energization of the Zener diode ZD31 and the inverter circuit 2 when the power supply voltage Vdd exceeds the predetermined threshold Vth is provided. Is provided. The overvoltage protection circuit 6 includes a voltage identification circuit 8 and a cutoff circuit 9. The voltage identification circuit 8 monitors the power supply voltage Vdd and outputs a stop signal FD when the power supply voltage Vdd exceeds the threshold value Vth. The cutoff circuit 9 is connected to the power supply voltage Vdd at the previous stage and to the Zener diode ZD31 and the inverter circuit 2 at the subsequent stage. When the stop signal FD becomes active (L level), the cutoff circuit 9 stops energization to the subsequent stage. That is, the cutoff circuit 9 stops energization to the Zener diode ZD31 and the inverter circuit 2 in response to the stop signal FD.

  Next, a specific configuration of the motor drive control device 100 will be described. FIG. 2 is a configuration diagram illustrating an example of a circuit of the motor drive control device 100 according to the embodiment. As shown in FIG. 2, the motor drive control device 100 includes a voltage supply circuit 110, an inverter circuit 2, a predrive circuit 3, and a position detection unit 30. The voltage supply circuit 110 includes a reverse connection protection circuit 5, a regenerative voltage protection circuit 7, a voltage identification circuit 8, and a cutoff circuit 9.

  The motor 20 is a single-phase brushless motor driven by the H-bridge type inverter circuit 2. The inverter circuit 2 has a leg in which transistors Q1 and Q3 which are high-side switching elements and transistors Q2 and Q4 which are low-side switching elements are connected in series, and the leg is a power supply line Vp which is a positive electrode of a DC power supply and a negative electrode The motor 20 is driven by being connected to the ground line GND. The motor 20 is provided with position detecting means 30 for detecting the position of the rotor. The position detection means 30 outputs a position signal Sp to the control circuit unit 4 based on the rotational position of the rotor. The position detection means 30 may include a hall sensor, for example, and the position signal Sp may be a hall signal. The control circuit unit 4 of the voltage identification circuit 8 outputs a drive control signal Sd for rectangular wave driving or sine wave driving to the pre-drive circuit 3 based on the position signal Sp. The pre-drive circuit 3 generates PWM signals H1, L1, H2, and L2 of about 20 kHz to 100 kHz based on the drive control signal Sd and outputs them to the gates of the transistors Q1 to Q4 of the inverter circuit 2. Transistors Q1-Q4 perform switching operation by PWM signals H1, L1, H2, and L2, and output drive signals 2a and 2b to the armature coil of motor 20. The armature coil generates a rotating magnetic field in a space facing the magnet incorporated in the rotor based on the drive signals 2a and 2b. A rotational driving force is generated in the rotor by the interaction between the rotating magnetic field and the magnetic pole of the magnet.

  The Zener diode ZD31 has a cathode connected to the positive power line Vp of the inverter circuit 2 and an anode connected to the negative ground line GND. The cathode of the Zener diode ZD31 is connected to the drain of a transistor Q14, which will be described later, which is a subsequent stage of the cutoff circuit 9. A capacitor C31 for absorbing high frequency ripple is connected in parallel to the Zener diode ZD31. For example, a ceramic capacitor may be used as the capacitor C31. As the Zener diode ZD31, a Zener diode having a Zener voltage Vz that is slightly higher than the upper limit voltage in the voltage range of the power supply voltage Vdd is used. That is, as indicated by an ellipse S in FIG. 3, the upper limit voltage Vin2 (for example, 75v) is set so as not to exceed the Zener voltage Vz (for example, 82v) even when the regenerative voltage k1 is superimposed. As a result, the Zener diode ZD31 does not operate at the upper limit voltage Vin2, and operates when the Zener voltage Vz that is slightly higher than the upper limit voltage Vin2 is exceeded to limit the increase in the power supply voltage Vdd due to kickback.

  However, as indicated by an ellipse T in FIG. 3, when the power supply voltage Vdd exceeds the operation range, the power supply voltage Vdd exceeds the Zener voltage Vz of the Zener diode ZD31. Excessive current continues to flow. For this reason, as shown in FIG. 2, the voltage supply circuit 110 is provided with an overvoltage protection circuit 6 including a voltage identification circuit 8 and a cutoff circuit 9.

  The voltage identification circuit 8 includes a diode D11 and a voltage dividing circuit connected to the diode D11, and the voltage dividing circuit includes resistors R11 and R12. The voltage identification circuit 8 outputs a monitoring voltage Vc obtained by dividing the power supply voltage Vdd by a voltage dividing ratio according to the resistance values of the resistors R11 and R12 to the input terminal 4c of the control circuit unit 4. In the control circuit unit 4, a comparison value Vx based on a value obtained by multiplying the threshold value Vth by the voltage dividing ratio of the resistors R11 and R12 is set. That is, the threshold value Vth is set to a value obtained by dividing the comparison value Vx by the voltage dividing ratio of the resistors R11 and R12. The control circuit unit 4 compares the input monitoring voltage Vc with the comparison value Vx, and outputs a stop signal FD to the output terminal 4a when the monitoring voltage Vc is equal to or higher than the comparison value Vx.

  On the other hand, as shown in FIG. 3, a pulsed regenerative voltage k1 is superimposed on the power supply voltage Vdd, and the power supply voltage Vdd may exceed the threshold value Vth in a short time. In the power supply voltage Vdd within the working voltage range, it is not preferable to stop energization exceeding the threshold value Vth even for a short time. For this reason, it is conceivable to set the Zener voltage Vz high, but this case is not preferable because the effect of limiting the regenerative voltage k1 is reduced. For this reason, it is desirable to continue the energization without stopping for a short-time increase in the power supply voltage Vdd.

  Therefore, the voltage identification circuit 8 includes filter means for attenuating the high frequency component of the monitoring voltage Vc. The voltage identification circuit 8 is provided with a low-pass filter including resistors R11 and R12 and a capacitor C11 as such filter means, and is configured to attenuate the high-frequency component of the monitoring voltage Vc generated by dividing by the resistors R11 and R12. doing. Capacitor C11 is connected in parallel with resistor R12. Since the pulsed voltage fluctuation is input to the input terminal 4c of the control circuit unit 4 after being smoothed by the low-pass filter, the possibility that the energization is stopped at the power supply voltage Vdd in the operating voltage range can be reduced. The low-pass filter can obtain a desired smoothing characteristic by adjusting its cutoff frequency.

  FIG. 4 is an explanatory diagram for explaining fluctuations in the smoothed monitoring voltage Vc. In FIG. 4, for easy understanding, the monitoring voltage Vc on the vertical axis is displayed corresponding to the voltage before voltage division. In particular, the ellipse N corresponds to the ellipse S in FIG. As indicated by an ellipse N, the regenerative voltage k1 superimposed on the monitoring voltage Vc is a smoothed voltage k2, and the superimposed portion is also smaller than the threshold value Vth.

  Next, the interruption circuit 9 will be described. The interruption circuit 9 includes a resistor R4, a transistor Q13, a resistor R3, transistors Q12 and Q14, and a capacitor C1. The transistor Q14 (an example of the first switching element) performs on / off operation of energization to the Zener diode ZD31 and the inverter circuit 2. The transistor Q12 (an example of the second switching element) controls the on / off operation of the transistor Q14 by being controlled by the transistor Q13 according to the stop signal FD. The transistor Q13 is a third switching element that controls the on / off operation of the transistor Q12 according to the stop signal FD.

  A constant voltage Vg is supplied from the constant voltage circuit 44 to the voltage identification circuit 8 and the cutoff circuit 9. The constant voltage circuit 44 includes, for example, a three-terminal regulator, the power supply voltage Vdd is input to the input unit IN, and the constant voltage Vg is output to the output unit OUT. The constant voltage Vg may be 5 v, for example. Capacitors C2 and C3 are connected to the input section IN and the output section OUT of the constant voltage circuit 44, respectively, to suppress the influence of high frequency components.

  The transistor Q13 is an NPN transistor, and the collector is connected to the power supply line Vq (the previous stage of the cutoff circuit 9) through the resistor R3. A constant voltage Vg is input to the base of the transistor Q13, and a stop signal FD is input to the emitter of the transistor Q13 through the resistor R4. Therefore, when the stop signal FD is at the H level, the transistor Q13 does not conduct, so the collector potential is at the level of the power supply line Vq. On the other hand, when the stop signal FD becomes L level, the transistor Q13 becomes conductive, so that the collector potential is lowered to near the constant voltage Vg. That is, the transistor Q13 is ON / OFF controlled by the stop signal FD, and the collector potential changes between the level of the power supply line Vq and the level of the constant voltage Vg.

  The transistor Q12 is a PchMOSFET, the source is connected to the power supply line Vq, the drain is connected to the gate of the transistor Q14, and the gate is connected to the collector of the transistor Q13. The transistor Q12 is turned off when the collector potential of the transistor Q13 is at the level of the power supply line Vq, and turned on when the collector potential of the transistor Q13 is at the level of the constant voltage Vg. That is, the transistor Q12 is on / off controlled in synchronization with the on / off state of the transistor Q13.

  The transistor Q14 is a PchMOSFET, the source is connected to the power supply line Vq, the drain is connected to the power supply line Vp, and the gate is connected to the drain of the transistor Q12. The voltage Ve divided by the resistors R1 and R2 from the power supply line Vq is input to the gate of the transistor Q14. Therefore, when the transistor Q12 is off, the transistor Q14 is turned on, and the power supply line Vq and the power supply line Vp are conducted. On the other hand, when the transistor Q12 is turned on, the transistor Q14 is turned off when the gate and the source have substantially the same potential. That is, the transistor Q14 is on / off controlled by inverting the off / on state of the transistor Q12.

  FIG. 5 is a flowchart for explaining the operation of the overvoltage protection circuit 6, and FIG. 6 is a timing chart for explaining the operation of the overvoltage protection circuit 6. In FIG. 5, when the power is turned on (S201), the voltage identification circuit 8 starts monitoring the monitoring voltage Vc (S202). When the monitoring voltage Vc is equal to or lower than the threshold value Vth, the stop signal FD is at the H level, and as shown in FIG. 6, the transistors Q13 and Q12 are turned off and the transistor Q14 is turned on. Energization of Vp is started from the power supply line Vq, and the motor 20 starts a predetermined rotation operation.

  As shown by an ellipse L in FIG. 4, when the monitoring voltage Vc becomes equal to or higher than the comparison value Vx (= threshold value Vth or higher), the stop signal FD changes to L level, and the transistors Q13 and Q12 are turned on as shown in FIG. Then, the transistor Q14 is turned off, and the power supply to the power supply line Vp is stopped (S203). The voltage identification circuit 8 continues to monitor the monitoring voltage Vc (S204). When the monitoring voltage Vc becomes lower than the comparison value Vx, the stop signal FD changes to H level, the transistors Q13 and Q12 are turned off, and the transistor Q14 is turned on. Then, energization to the power supply line Vp is resumed (S205).

  By operating the overvoltage protection circuit 6 in this way, as shown by an ellipse L in FIG. 4, when the power supply voltage Vdd exceeds the operating range, the energization to the power supply line Vp is stopped and the zener diode ZD31 is protected from excessive current. The threshold Vth is set lower than the overvoltage Vin3, the Zener voltage Vz is lower than the overvoltage Vin3 and higher than the threshold Vth, and can be set between the overvoltage Vin3 and the threshold Vth. Note that the Zener voltage Vz may be set to a voltage closer to the overvoltage Vin3 than the threshold value Vth in consideration of the superimposed regenerative voltage k1.

(Inrush current)
When the power supply line Vp rises, an inrush current (charging current) flows through the path from the power supply voltage Vdd to the capacitor C31. This may be a factor that reduces the reliability of the system. Therefore, in the motor drive control device 100, in order to reduce the inrush current, the cutoff circuit 9 includes a delay circuit configured so that energization to the Zener diode ZD31 and the inverter circuit 2 is started gently. The delay circuit includes a capacitor C1 connected between the gate and source of the transistor Q14 and resistors R1 and R2. Capacitor C1 and resistors R1 and R2 moderate the voltage change between the gate and source of transistor Q14 as a first-order lag element. As a result, the transistor Q14 gradually shifts to the on state, so that energization to the Zener diode ZD31 and the inverter circuit 2 is started gradually, and the inrush current of the transistor Q14 can be reduced.

(Reverse connection protection)
When the motor drive control device 100 is attached to the main body device, the power supply input terminals 12 and 14 of the motor drive control device 100 may be mistakenly connected to the positive and negative connectors of the power supply. In this case, a forward excessive current flows through the Zener diode ZD31 that limits the regenerative voltage k1, and circuit components such as the Zener diode ZD31 may be damaged. Therefore, in the motor drive control device 100, reverse connection protection configured to stop energization to the Zener diode ZD31 and the inverter circuit 2 when the connector from the power source is reversely connected and the power supply voltage Vdd has the reverse polarity. Circuit 5 is included. Reverse connection protection circuit 5 includes a transistor Q11 and resistors R1 and R2. The transistor Q11 is a switching element that is turned off in response to the stop signal FD. The resistor R1 is connected between the gate and the source of the transistor Q11, and the resistor R2 is connected between the gate of the transistor Q11 and the power input terminal 14. The transistor Q11 is a Pch MOSFET. When the connector from the power supply is correctly connected to the power input terminals 12 and 14, the gate of the transistor Q11 is connected to the lower potential side than the source through the resistor R2, so that the transistor Q11 is turned on to the source side. Start energizing. When the connector from the power source is connected to the power input terminals 12 and 14 in reverse, the gate of the transistor Q11 is connected to the higher potential side than the source, and the transistor Q11 is turned off to cut off the energization to the source side. To do. As a result, the Zener diode ZD31, the inverter circuit 2 and the like provided on the source side of the transistor Q11 can be protected.

  As described above, the motor drive control device 100 includes the voltage identification circuit 8 and the constant voltage circuit 44 that supplies the constant voltage Vg to the cutoff circuit 9. When the input part IN of the constant voltage circuit 44 is connected to the subsequent stage of the cutoff circuit 9, when the cutoff circuit 9 is turned off, the operation of the constant voltage circuit 44 is stopped and the voltage identification circuit 8 and the cutoff circuit 9 operate. May become unstable. Therefore, in the motor drive control device 100, the input section IN of the constant voltage circuit 44 is connected to the power supply line Vq that is the previous stage of the cutoff circuit 9. As a result, even when the cutoff circuit 9 is turned off, the operation of the constant voltage circuit 44 is maintained, and the voltage identification circuit 8 and the cutoff circuit 9 can operate stably.

  When a voltage higher than the withstand voltage is input between the gate and source of the transistor Q14, the transistor Q14 may be deteriorated or damaged. Although it is conceivable to use a transistor having a high withstand voltage, in this case, there are problems of cost increase and element enlargement. Therefore, in the motor drive control device 100, a Zener diode ZD1 is connected between the gate and the source in order to clamp the gate-source voltage of the transistor Q14. In particular, the Zener diode ZD1 has its cathode connected to the source of the transistor Q14 and its anode connected to the gate of the transistor Q14. The Zener voltage of the Zener diode ZD1 may be set to a voltage (for example, 15V) lower than the withstand voltage (for example, 20V) between the gate and the source of the transistor Q14. By providing the Zener diode ZD1, the gate-source voltage of the transistor Q14 is suppressed, and the transistor Q14 is protected. The Zener diode ZD1 also clamps the voltage between the gate and source of the transistor Q11.

  The control circuit unit 4 may include an MCU (Micro Control Unit) that is a circuit device capable of performing software processing and digital processing. The control circuit unit 4 may be configured to compare the monitoring voltage Vc and the threshold value Vth by software processing or digital processing and output the stop signal FD. Further, the control circuit unit 4 may generate the drive control signal Sd from the position signal Sp by software processing or digital processing and output it to the pre-drive circuit 3.

Next, the operation of the motor drive control device 100 configured as described above will be described.
When the power supply is turned on, the voltage identification circuit 8 starts monitoring the monitoring voltage Vc. When the monitoring voltage Vc is lower than the comparison value Vx, the stop signal FD is output at H level, the transistor Q14 is turned on, and the power supply Energization of the line Vp is started.
On the other hand, when the control circuit unit 4 outputs the drive control signal Sd corresponding to the position signal Sp of the position detection means 30, the pre-drive circuit 3 outputs a PWM signal to the inverter circuit 2. When the inverter circuit 2 outputs the drive signals 2a and 2b according to the PWM signal, the motor 20 is rotationally driven by a known brushless motor mechanism. When the monitoring voltage Vc becomes equal to or higher than the comparison value Vx, the stop signal FD changes to L level, the transistor Q14 is turned off, and the power supply to the power supply line Vp is stopped. When the monitoring voltage Vc becomes lower than the comparison value Vx, the stop signal FD changes to H level, the transistor Q14 is turned on, and energization to the power supply line Vp is resumed. By operating in this way, the Zener diode ZD31 is protected from an excessive voltage.

  Next, a motor drive control method executed by the motor drive control device 100 configured as described above will be described. This motor drive control method includes outputting a stop signal FD when the power supply voltage Vdd exceeds a predetermined threshold value Vth, and stopping energization to the Zener diode ZD31 in response to the stop signal FD.

Next, features of the motor drive control device 100 configured as described above will be described.
Since the motor drive control device 100 includes the Zener diode ZD31, the motor drive control device 100 can limit the regenerative voltage generated by the motor 20 and suppress the wraparound to the power supply voltage Vdd. In addition, a voltage identification circuit 8 that outputs a stop signal FD when the power supply voltage Vdd exceeds a predetermined threshold, and a cutoff circuit 9 that is configured to stop energization of the Zener diode ZD31 in response to the stop signal FD, Therefore, the Zener diode ZD31 can be protected when the power supply voltage Vdd rises excessively. With this configuration, it is possible to realize durability that does not break even if an excessive voltage (for example, a voltage twice the rated voltage) higher than the power supply voltage Vdd is continuously input for a predetermined time.

  In addition, when the power supply voltage Vdd increases excessively, the energization to the inverter circuit 2 and other circuits is also stopped. Therefore, it is possible to use parts having a low rated voltage for these circuits, and the motor drive control device 100. This is advantageous in terms of downsizing and cost reduction. In addition, since the time during which an excessive power supply voltage is applied is shortened, it is advantageous from the viewpoint of the reliability and life of these circuit components.

  In the motor drive control device 100, since the cutoff circuit 9 is configured so that the energization to the Zener diode ZD31 is started gently, the inrush current at the start of energization is compared with the case where the energization is started abruptly. Can be reduced.

  The motor drive control device 100 includes the reverse connection protection circuit 5 configured to stop the energization to the Zener diode ZD31 when the power supply voltage Vdd has a reverse polarity, so that the power supply is reversed. When connected, circuit components such as the Zener diode ZD31 can be protected.

  In motor drive control device 100, cutoff circuit 9 includes a transistor Q14 that performs on / off operation of energization to Zener diode ZD31, and a transistor Q12 that controls the on / off operation of transistor Q14 in response to stop signal FD. Therefore, when the power supply voltage Vdd exceeds a predetermined threshold value, the transistor Q14 can be controlled to be turned off, and the energization to the Zener diode ZD31 can be stopped.

  In the motor drive control device 100, since the voltage identification circuit 8 includes a diode D11 and a voltage dividing circuit connected to the diode D11, the monitor voltage Vc divided from the power supply voltage Vdd is reduced to a voltage with a low withstand voltage. It can be converted into a low pressure that can be processed by the identification circuit 8.

  In the motor drive control device 100, since the voltage identification circuit 8 includes filter means for attenuating the high frequency component of the monitoring voltage Vc generated from the power supply voltage Vdd, the operation of the voltage identification circuit 8 based on the high frequency component included in the power supply voltage Vdd. The influence on can be suppressed.

  In the motor drive control device 100, the voltage supply circuit 110 includes a constant voltage circuit 44 that supplies a constant voltage to the voltage identification circuit 8, and the input section IN of the constant voltage circuit 44 is connected to the preceding stage of the cutoff circuit 9. Even when the cutoff circuit 9 is turned off, the constant voltage Vg can be supplied from the constant voltage circuit 44 to the voltage identification circuit 8 and the cutoff circuit 9.

  In the above, it demonstrated based on embodiment of this invention. Those skilled in the art will understand that these embodiments are examples, and that various modifications and changes are possible within the scope of the claims of the present invention, and that such modifications and changes are also within the scope of the claims of the present invention. It is where it is done. Accordingly, the description and drawings herein are to be regarded as illustrative rather than restrictive. Each drawing explaining the embodiment shows an example of the configuration, and the present invention is not limited to this. Further, the steps shown in the flowcharts and the waveforms shown in the timing chart are examples, and the present invention is not limited to these. For example, another process may be inserted between the steps, the processes may be parallelized, the order of the processes may be changed, and a part of the processes may be deleted.

(Modification 1)
In the motor drive control device 100 according to the embodiment, the example in which the motor 20 is a single-phase brushless motor driven by the H-bridge type inverter circuit 2 has been described, but the present invention is not limited thereto. The motor to be controlled and driven may be a multiphase motor other than a single phase, for example, three or more phases.

(Modification 2)
In the motor drive control device 100 according to the embodiment, the position detection unit 30 has been described as an example including a hall sensor, but is not limited thereto. The position detection means may be means for detecting the position of the rotor in accordance with, for example, a counter electromotive force of a coil other than the Hall sensor. Further, the position detection means 30 may include a rotary encoder.

(Modification 3)
In the motor drive control device 100 according to the embodiment, the example in which the voltage identification circuit 8 is provided with the low-pass filter including the capacitor C11 has been described, but the present invention is not limited thereto. The filter means for attenuating the high frequency component of the monitoring voltage Vc may be a digital filter or a filter by software processing. For example, the control circuit unit 4 may include an MCU (Micro Control Unit), and the influence of the high-frequency component of the monitoring voltage Vc may be suppressed by timer means built in the MCU. In this case, the capacitor C11 can be omitted.

(Modification 4)
In the motor drive control device 100 according to the embodiment, the example in which the reverse connection protection circuit 5 is provided has been described. However, the present invention is not limited to this, and the reverse connection protection circuit 5 is not an essential configuration. When the reverse connection protection circuit 5 is not provided, the transistor Q11 can be omitted. The reverse connection protection circuit may be configured by a diode without a transistor. In this case, the regenerative voltage k1 is cut by the diode and is not superimposed on the power supply voltage Vdd, so that it is possible to omit the low-pass filter including the capacitor C11.

(Modification 5)
In the motor drive control device 100 according to the embodiment, the voltage identification circuit 8 has been described with respect to the example in which the voltage is identified by software processing or digital processing, but is not limited thereto. The voltage identification circuit may be subjected to analog processing by a voltage comparator (comparator).

(Modification 6)
In the motor drive control device 100 according to the embodiment, the example in which the three-terminal regulator is used for the constant voltage circuit 44 has been described, but the invention is not limited thereto. Constant voltage supply means other than a three-terminal regulator may be used for the constant voltage circuit.

(Modification 7)
Each component of the motor drive control device 100 may be integrated at least partially as necessary.

(Modification 8)
The voltage input to the voltage identification circuit 8 may be not the power supply voltage Vdd supplied from the power supply input terminal 12 but the voltage of the power supply line Vq before the cutoff circuit 9. In that case, a diode corresponding to the diode D11 is not essential.

  DESCRIPTION OF SYMBOLS 100 Motor drive control apparatus, 2 Inverter circuit, 3 Pre drive circuit, 4 Control circuit part, 5 Reverse connection protection circuit, 6 Overvoltage protection circuit, 8 Voltage identification circuit, 9 Shut-off circuit, 20 Motor, 30 Position detection means, 44 Constant voltage circuit, 110 voltage supply circuit, Q11 transistor, Q12 transistor (an example of the second switching element), Q13 transistor, Q14 transistor (an example of the first switching element), ZD31 Zener diode, D11 diode, R11, R12 resistance (minute) An example of a pressure circuit, a part of filter means), a C11 capacitor (a part of filter means), a Vdd power supply voltage, a k1 regenerative voltage, and an FD stop signal.

Claims (9)

A voltage supply circuit for supplying a power supply voltage to an inverter circuit connected to the motor;
The voltage supply circuit includes:
A Zener diode for limiting the regenerative voltage generated by the motor;
A voltage identification circuit that outputs a stop signal when the power supply voltage exceeds a predetermined threshold by superimposing the regenerative voltage on the power supply voltage ;
A cutoff circuit configured to stop energization of the Zener diode in response to the stop signal;
The motor drive control apparatus characterized by including.   2. The motor drive control device according to claim 1, wherein the cutoff circuit is configured so that energization to the Zener diode is gradually started.   3. The motor according to claim 1, wherein the voltage supply circuit includes a reverse connection protection circuit configured to stop energization of the Zener diode when the power supply voltage has a reverse polarity. 4. Drive control device.   The cutoff circuit includes a first switching element that performs on / off operation of energization to the Zener diode, and a second switching element that controls on / off operation of the first switching element according to the stop signal. The motor drive control device according to claim 1, wherein the motor drive control device is a motor drive control device. The voltage identification circuit, a voltage divider circuit seen including, the predetermined threshold value, the motor drive control according to any one of claims 1 to 4, characterized in that set on the basis of the voltage dividing ratio by the voltage dividing circuit apparatus. 6. The voltage identification circuit includes filter means for attenuating a high-frequency component of a monitoring voltage generated from the power supply voltage on which the regenerative voltage is superimposed in a pulse shape. Motor drive control device. The voltage supply circuit includes a constant voltage circuit for supplying a constant voltage to the voltage identification circuit,
The motor drive control device according to claim 1, wherein an input unit of the constant voltage circuit is connected to a preceding stage of the cutoff circuit.   Equipped with a voltage supply circuit that supplies power supply voltage to the inverter circuit connected to the motor
  The voltage supply circuit includes:
  A Zener diode for limiting the regenerative voltage generated by the motor;
  A voltage identification circuit that outputs a stop signal when the power supply voltage exceeds a predetermined threshold;
  A cutoff circuit configured to stop energization of the Zener diode in response to the stop signal;
  Including
  The cutoff circuit includes a first switching element that performs on / off operation of energization to the Zener diode, and a second switching element that controls on / off operation of the first switching element according to the stop signal. The motor drive control apparatus characterized by the above-mentioned. A motor drive control method executed by a motor drive control device including a voltage supply circuit that supplies a power supply voltage to an inverter circuit connected to a motor, and the voltage supply circuit includes a Zener diode that limits a regenerative voltage generated by the motor. There,
Outputting a stop signal when the power supply voltage exceeds a predetermined threshold by superimposing the regenerative voltage on the power supply voltage ;
Stopping energization of the Zener diode in response to the stop signal;
The motor drive control method characterized by including.

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