Motor drive device, motor drive system, and semiconductor drive circuit

Abstract

To suppress heat generation of a control circuit.SOLUTION: A semiconductor drive circuit including a plurality of switching elements for driving a motor, and a first power supply terminal and a second power supply terminal connected to a power supply line, and configured to drive the plurality of switching elements, the semiconductor drive circuit being connected between the power supply line and the first power supply terminal, A voltage drop element that drops a voltage of the first power supply terminal to be lower than a voltage of the power supply line, wherein the semiconductor drive circuit includes a control circuit that operates at a first power supply voltage equal to or lower than the voltage of the first power supply terminal and generates a control signal, and a gate driver that operates at a second power supply voltage equal to or lower than the voltage of the second power supply terminal and drives gates of the plurality of switching elements according to the control signal.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a motor drive device, a motor drive system, and a semiconductor drive circuit. [Background technology]

[0002] Conventionally, a motor drive device has been known that includes an inverter unit that receives a voltage from a control power supply and supplies power from a main power supply to a drive winding of a motor, and a control unit that uses the control power supply as a power source and generates a power supply signal to the inverter unit (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-99231 Summary of the Invention [Problem to be solved by the invention]

[0004] The control circuit for driving the motor consumes a relatively large amount of power, which causes the control circuit to generate heat, which in turn increases the temperature of the integrated circuit (IC) that contains the control circuit.

[0005] An object of the present disclosure is to suppress heat generation in a control circuit. [Means for solving the problem]

[0006] A motor drive device according to one aspect of the present disclosure includes: a plurality of switching elements for driving the motor; a semiconductor drive circuit having a first power supply terminal and a second power supply terminal connected to a power supply line, the semiconductor drive circuit driving the plurality of switching elements; a voltage drop element connected between the power supply line and the first power supply terminal, for causing a voltage of the first power supply terminal to drop below a voltage of the power supply line; Equipped with The semiconductor drive circuit includes: a control circuit that operates at a first power supply voltage that is equal to or lower than the voltage of the first power supply terminal and generates a control signal; a gate driver that operates at a second power supply voltage that is equal to or lower than the voltage of the second power supply terminal and drives gates of the plurality of switching elements in response to the control signal. [Effects of the Invention]

[0007] According to the present disclosure, heat generation in the control circuit can be suppressed. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is an overall configuration diagram of a motor drive device according to an embodiment of the present disclosure. [Figure 2] 1 is a schematic configuration diagram of a motor drive device according to an embodiment of the present disclosure. [Figure 3] FIG. 10 is a schematic configuration diagram of a motor drive device according to a modified example of an embodiment of the present disclosure. [Figure 4] 1 is an overall configuration diagram of a motor drive system according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, the embodiments will be described with reference to the drawings. In each drawing, the same components are denoted by the same reference numerals, and duplicate explanations may be omitted. Note that "connection" is not limited to direct connection, but may also include conductive connection via a resistor or a diode (including a body diode of a transistor), etc.

[0010] [Embodiment] 1 is a diagram illustrating the overall configuration of a motor drive device 10 according to an embodiment of the present disclosure. The motor drive device 10 drives a motor 11. The motor drive device 10 includes a driver 12, a drive IC 20, and a resistor R1. The motor drive device 10 may also include capacitors C1, C2, C3, and C4.

[0011] The operating state of the motor 11, such as its rotation speed, is controlled by a driver 12. The driver 12 includes a plurality of switching elements M1 to M6 that control the voltage for driving the motor 11. The plurality of switching elements M1 to M6 are switches for driving the motor 11.

[0012] The switching elements M1 to M6 included in the driver 12 may be MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors), but are not limited to these and may be other semiconductor switches such as bipolar transistors. The driver 12 is a three-phase inverter that converts a DC voltage supplied from, for example, a power supply 32 into a three-phase AC voltage of, for example, U-phase, V-phase, and W-phase, and outputs the AC voltage to the motor 11.

[0013] The driving IC 20 is an example of a semiconductor driving circuit that drives a plurality of switching elements for driving a motor. The driving IC 20 includes a first power supply terminal 41 and a second power supply terminal 42. The first power supply terminal 41 and the second power supply terminal 42 are electrically connected to a power supply line 50. The first power supply terminal 41 and the second power supply terminal 42 are terminals for receiving power supplied from a power supply 32 via the power supply line 50. The first power supply terminal 41 is connected to the power supply line 50 via a resistor R1. The driving IC 20 controls the driving of the motor 11 by driving a plurality of switching elements M1 to M6. The operation of the driving IC 20 is controlled by a processor 31.

[0014] Resistor R1 is a resistive element connected between the power supply line 50 and the first power supply terminal 41. Resistor R1 is an example of a voltage dropping element that drops the voltage of the first power supply terminal 41 (input voltage VCC1) below the voltage of the power supply line 50. In this example, the voltage of the power supply line 50 is equal to the voltage of the second power supply terminal 42 (input voltage VCC2). When a current flows through resistor R1 from the power supply line 50 to the first power supply terminal 41, the input voltage VCC1 drops below the voltage of the power supply line 50 (input voltage VCC2).

[0015] The driving IC 20 includes a first linear regulator 21, a second linear regulator 22, a control circuit 23, a gate driver 24, an I / F (Interface) 25, a diode D1, a connection terminal 43, a connection terminal 44, and a ground terminal 45.

[0016] The first linear regulator 21 is a power supply circuit connected between the first power supply terminal 41 and the control circuit 23. The first linear regulator 21 generates a first power supply voltage VDD1 to be supplied to the control circuit 23 based on an input voltage VCC1. The second linear regulator 22 is a power supply circuit connected between the second power supply terminal 42 and the gate driver 24. The second linear regulator 22 generates a second power supply voltage VDD2 to be supplied to the gate driver 24 based on an input voltage VCC2. The first linear regulator 21 and the second linear regulator 22 may each be another type of power supply circuit, such as an LDO (Low Dropout) or a voltage limiting circuit. For example, the first linear regulator 21 may be replaced by a DC / DC converter that converts the input voltage VCC1 to the first power supply voltage VDD1, and the second linear regulator 22 may be replaced by a DC / DC converter that converts the input voltage VCC2 to the second power supply voltage VDD2.

[0017] The first linear regulator 21 maintains the first power supply voltage VDD1 at a predetermined first target value even when the input voltage VCC1 changes. The first linear regulator 21 is connected to a connection terminal 43 via a supply line 46 for the first power supply voltage VDD1, and may be connected from the connection terminal 43 to ground (GND) via a capacitor C3. The first power supply voltage VDD1 is smoothed by the capacitor C3. The ground terminal 45 is connected to ground (GND).

[0018] The second linear regulator 22 maintains the second power supply voltage VDD2 at a predetermined second target value even when the input voltage VCC2 changes. By setting the second target value higher than the first target value, the second power supply voltage VDD2 is generated to be higher than the first power supply voltage VDD1. The second linear regulator 22 may be connected to a connection terminal 44 via a supply line 47 for the second power supply voltage VDD2, and may be connected from the connection terminal 44 to ground (GND) via a capacitor C4. The second power supply voltage VDD2 is smoothed by the capacitor C4.

[0019] The control circuit 23 operates on a first power supply voltage VDD1 that is equal to or lower than the input voltage VCC1, and generates a control signal for driving the motor 11. The control circuit 23 transmits the generated control signal to the gate driver 24. The control circuit 23 is a program processing device having a configuration in which a processor such as a CPU (Central Processing Unit), various storage devices such as RAM (Random Access Memory), ROM (Read Only Memory), and flash memory, and peripheral circuits such as a counter (timer), an A / D conversion circuit, a D / A conversion circuit, a clock generation circuit, and an input / output interface circuit are connected to each other via buses or dedicated lines.

[0020] The gate driver 24 is a circuit that operates on a second power supply voltage VDD2 that is equal to or lower than the input voltage VCC2, and drives the gates of the multiple switching elements M1 to M6 in response to a control signal sent from the control circuit 23. In response to the control signal from the control circuit 23, the gate driver 24 sends a drive signal to the driver 12 to drive the motor 11.

[0021] The I / F 25 is a communication interface between the driving IC 20 and a processor 31 that realizes each process in the driving IC 20.

[0022] The processor 31 executes functions and methods realized by codes or instructions included in a program that controls the driving IC 20. The processor 31 includes, for example, a CPU or an MPU (Micro Processing Unit). Each process in the driving IC 20 may be realized by a logic circuit (hardware) or a dedicated circuit formed on an IC chip, an LSI (Large Scale Integration), or the like.

[0023] The power supply 32 is connected to a power supply line 50. The power supply 32 supplies power to the motor drive device 10 and the motor 11 via the power supply line 50. A diode D2 that blocks reverse current from the motor drive device 10 to the power supply 32 may be inserted in series in the power supply line 50 between the motor drive device 10 and the power supply 32.

[0024] 2 is a schematic diagram of a motor drive device 10 according to an embodiment of the present disclosure. Components that are the same as those already described using FIG. 1 are assigned the same reference numerals, and duplicated explanations will be omitted. A current consumption ICC1 of the control circuit 23 flows to the control circuit 23 via a power supply line 50, resistor R1, first power supply terminal 41, and first linear regulator 21. In the motor drive device 10 according to this embodiment, the control circuit 23, which consumes relatively large amounts of power among the components in the drive IC 20, generates a large amount of heat, so the motor drive device 10 aims to suppress heat generation in the control circuit 23.

[0025] As shown in the figure, the control circuit 23 is connected to a first power supply terminal 41 via a first linear regulator 21. The first power supply terminal 41 is connected to a supply line 47 of a second power supply voltage VDD2 via a diode D1. The diode D1 is a backflow prevention means connected with its anode on the supply line 47 side and its cathode on the first power supply terminal 41 side.

[0026] A voltage drop occurs across resistor R1 due to the current consumption ICC1 of control circuit 23. The total power consumption from power supply line 50 via resistor R1 is the product of the current consumption ICC1 of control circuit 23 and the voltage of power supply line 50 (input voltage VCC2). Due to the voltage drop across resistor R1, the total power consumption via resistor R1 (ICC1 x VCC2) can be divided into power consumption within driver IC 20 (VCC1 x ICC1) and power consumption at resistor R1 (R1 x ICC1 x ICC1). This makes it possible to suppress heat generation in control circuit 23.

[0027] The current consumption ICC1 causes a voltage drop across resistor R1, reducing the power consumed by control circuit 23. Without resistor R1 as a voltage drop means, the power consumed by control circuit 23 would be the product of input voltage VCC2 and current ICC1. Adding resistor R1 reduces the power consumption of control circuit 23 by (R1×ICC1×ICC1). Therefore, heat generation in control circuit 23 can be suppressed.

[0028] As described above, the driving IC 20 according to an embodiment of the present disclosure has the resistor R1 externally connected to the first power supply terminal 41, which reduces the voltage at the first power supply terminal 41 (input voltage VCC1) below the voltage at the power supply line 50 (input voltage VCC2). As described above, the voltage drop across the resistor R1 reduces the power consumed by the control circuit 23 compared to when the resistor R1 is not present. This reduces heat generation in the control circuit 23, thereby suppressing a temperature rise in the driving IC 20 including the control circuit 23. As a result, for example, the progression of deterioration due to a temperature rise in the driving IC 20 is slowed. Because the resistor R1 is connected externally to the driving IC 20, the effect of heat generation by the resistor R1 on a temperature rise in the driving IC 20 can be reduced.

[0029] The driving IC 20 according to one embodiment includes a diode D1 having an anode connected to a supply line 47 of a second power supply voltage VDD2 and a cathode connected to a first power supply terminal 41. When the second power supply voltage VDD2 is higher than the input voltage VCC1, the diode D1 is turned on, and power is supplied from the second linear regulator 22 to the first linear regulator 21 and the control circuit 23 via the diode D1. Since power is not supplied to the first linear regulator 21 and the control circuit 23 via the resistor R1 and the first power supply terminal 41, heat generation in the resistor R1 is suppressed.

[0030] Furthermore, for example, in a motor drive system shown in FIG. 4, where the power supply 32 includes a battery 32b, a decrease in the remaining capacity of the battery 32b may result in a decrease in the power supply voltage supplied to the motor drive device 10. When the power supply voltage supplied from the power supply 32 decreases, the input voltage VCC1 at the first power supply terminal 41 and the input voltage VCC2 at the second power supply terminal 42 decrease. When the input voltage VCC2 decreases, the diode D1 turns on when the relationship (VCC2 - voltage drop across resistor R1) ≤ VDD2 is satisfied. This allows power to be supplied from the second linear regulator 22 to the input of the first linear regulator 21 via the diode D1, thereby limiting the lower limit of the input voltage VCC1 to the second power supply voltage VDD2. This allows the first linear regulator 21 to stably supply the first power supply voltage VDD1 to the control circuit 23 even if the voltage on the power supply line 50 decreases, enabling low-voltage operation of the drive IC 20.

[0031] <Modification> 3 is a schematic configuration diagram of a motor drive device 10 according to a modified example of an embodiment of the present disclosure. Unlike the embodiment of FIG. 2, the motor drive device 10 according to the modified example uses a Zener diode ZD as voltage drop means instead of resistor R1.

[0032] The Zener diode ZD is an example of a voltage drop element connected between the power supply line 50 and the first power supply terminal 41, with the anode on the first power supply terminal 41 side and the cathode on the power supply line 50 side. When the voltage applied to the Zener diode ZD is equal to or greater than the Zener voltage, a current flows from the power supply line 50 to the first power supply terminal 41. At this time, the voltage applied to the control circuit 23 drops by the Zener voltage. Therefore, similar to the case where the resistor R1 is used, the power consumption in the control circuit 23 is reduced by the power consumption of the Zener diode ZD (Zener voltage × ICC1). This makes it possible to suppress heat generation in the control circuit 23.

[0033] By connecting an external power supply other than the power supply 32 to the power supply line 50, it is possible to suppress heat generation in the control circuit 23 and other components and to suppress malfunctions of the control circuit 23 at low voltages; however, the addition of another external power supply increases costs.

[0034] Therefore, in the motor drive device 10 according to this embodiment, heat generation in the control circuit 23 can be suppressed by using a resistor R1 or a Zener diode ZD as a voltage drop means, and the control circuit 23 can operate stably even if the voltage of the power supply 32 temporarily drops.

[0035] <Motor drive system> Here, a motor drive system using the motor drive device 10 according to this embodiment will be described. As an example of the motor drive system, an unmanned aerial vehicle 30 will be described. The aerial vehicle may be a drone or any other aerial vehicle that flies by driving a motor 11.

[0036] 4 is an overall configuration diagram of a motor drive system according to an embodiment of the present disclosure. The unmanned aerial vehicle 30 includes a motor drive device 10, a motor 11, a processor 31, a power supply 32, a propeller 33, a sensor unit 34, a wireless communication device 35, and an external controller 36. The wireless communication device 35 may include an antenna 35a. The external controller 36 may include an antenna 36a. The power supply 32 may include a power supply circuit 32a and a battery 32b. The unmanned aerial vehicle 30 may include multiple motor drive devices 10, motors 11, and propellers 33.

[0037] The motor driving device 10 drives the motor 11. When the motor 11 is driven, the propeller 33 rotates. The propeller 33 is an example of a movable member configured to engage with the motor 11.

[0038] The processor 31 executes functions and methods realized by code or instructions included in a program that controls the unmanned aerial vehicle 30. The processor 31 may include, for example, a CPU (Central Processing Unit), an MPU (Micro Processing Unit), etc., and may realize each process in the unmanned aerial vehicle 30 by a logic circuit (hardware) or dedicated circuit formed on an IC (Integrated Circuit) chip, an LSI (Large Scale Integration), etc.

[0039] The power supply 32 includes a power supply circuit 32a and a battery 32b. The power supply 32 supplies a power supply voltage to the motor drive device 10 and the motor 11. The power supply circuit 32a supplies power from the battery 32b to the motor drive device 10. The power supply circuit 32a converts the power from the battery 32b into power required by the motor drive device 10 and the motor 11 and supplies it to the motor drive device 10. The battery 32b supplies power to the power supply circuit 32a and the processor 31.

[0040] The sensor unit 34 includes sensors necessary for controlling the attitude of the unmanned aerial vehicle 30, such as sensors that measure the angular velocity, speed, and surrounding environment of the unmanned aerial vehicle 30, and sensors that measure the status of the motor drive unit 10 and motor 11, etc. Sensors that measure the status of the surrounding environment of the unmanned aerial vehicle 30 include a wind volume sensor, a barometric pressure sensor, a temperature sensor, a humidity sensor, an illuminance sensor, etc. The sensor unit 34 may also include sensors that measure the status of the power source 32, such as the remaining charge of the battery 32b.

[0041] The wireless communication device 35 is a communication circuit that performs transmission and reception processes to transmit and receive signals via a mobile communication network and antenna 35a that supports LTE, NR, etc. The antenna 35a is an antenna for communication via a mobile communication network that supports LTE (Long Term Evolution), NR (New Radio), etc. The antenna 35a is an antenna for communication with an external device, such as a parent aircraft or an aircraft parking facility, that is located in a short distance, for example, with a transmission distance of 10 m or less, using a frequency band of, for example, 2 MHz to 100 MHz.

[0042] The external controller 36 is a controller for controlling the movement of the unmanned aerial vehicle 30. The external controller 36 is configured by a board PC (personal computer) equipped with ROS (Robot Operating System), etc. An antenna 36a connected to the external controller 36 is used for communication with an antenna 35a connected to the wireless communication device 35.

[0043] Although an example has been shown in which the motor drive system according to this embodiment is used as an unmanned aerial vehicle 30, it is not limited to this and can also be used as a power tool, etc.

[0044] Although the embodiments have been described above, they are presented as examples and the present invention is not limited to the above embodiments. The above embodiments can be implemented in various other forms, and various combinations, omissions, substitutions, modifications, etc. can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as set forth in the claims. [Explanation of symbols]

[0045] 10 Motor drive device 11 Motor 12 Drivers 20 Driver IC 21 First linear regulator 22 Second linear regulator 23 Control circuit 24 gate drivers 30 Unmanned Aerial Vehicles 32 Power supply D1 Diode R1 Resistor ZD Zener diode

Claims

1. a plurality of switching elements for driving the motor; a semiconductor drive circuit having a first power supply terminal and a second power supply terminal connected to a power supply line, the semiconductor drive circuit driving the plurality of switching elements; a voltage drop element connected between the power supply line and the first power supply terminal, for dropping the voltage of the first power supply terminal below the voltage of the power supply line; Equipped with The semiconductor drive circuit includes: a control circuit that operates at a first power supply voltage that is equal to or lower than the voltage of the first power supply terminal and generates a control signal; a gate driver that operates on a second power supply voltage that is equal to or lower than the voltage of the second power supply terminal, and drives gates of the plurality of switching elements in response to the control signal.

2. 2. The motor drive device according to claim 1, wherein the semiconductor drive circuit includes a diode having an anode connected to a supply line of the second power supply voltage and a cathode connected to the first power supply terminal.

3. The semiconductor drive circuit includes: a first linear regulator connected between the first power supply terminal and the control circuit and configured to generate the first power supply voltage; 3. The motor drive device according to claim 2, further comprising: a second linear regulator connected between the second power supply terminal and the gate driver, the second linear regulator generating the second power supply voltage.

4. 2. The motor drive device according to claim 1, wherein the voltage drop element is a resistor.

5. 2. The motor drive device according to claim 1, wherein the voltage drop element is a Zener diode.

6. A motor drive system comprising: the motor drive device according to claim 1 ; a motor driven by the motor drive device; and a power supply connected to the power supply line.

7. 7. The motor drive system according to claim 6, wherein the power supply comprises a battery and a power supply circuit that supplies power from the battery to the motor drive device.

8. a first power supply terminal connectable to a power supply line; a second power supply terminal connectable to the power supply line via a voltage drop element; a control circuit that operates at a first power supply voltage that is equal to or lower than the voltage of the first power supply terminal and generates a control signal; a gate driver that operates on a second power supply voltage that is equal to or lower than the voltage of the second power supply terminal and that is capable of driving gates of a plurality of switching elements for driving a motor in response to the control signal; The voltage of the second power supply terminal is lowered by the voltage drop element to be lower than the voltage of the power supply line.

9. 9. The semiconductor drive circuit according to claim 8, further comprising a diode having an anode connected to a supply line of said second power supply voltage and a cathode connected to said first power supply terminal.

10. a first linear regulator connected between the first power supply terminal and the control circuit and configured to generate the first power supply voltage; 10. The semiconductor driver circuit according to claim 8, further comprising: a second linear regulator connected between the second power supply terminal and the gate driver, the second linear regulator generating the second power supply voltage.

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