Motor driving device and semiconductor device

Abstract

The invention provides a motor driving device and a semiconductor device, which can realize silence and stable starting at the same time. A motor drive device (10) for driving a DC motor (1) in which the mechanical angle of a rotor can be detected every 60 degrees by three position detection elements, the motor drive device (10) comprising: an inverter (12) having a three-phase bridge structure for converting a DC power supply input (VBB) into AC drive power and supplying the AC drive power to the DC motor (1); and a start-up control unit (151) that drives and controls the inverter (12) by a 180-degree energization rectangular wave drive that is generated by expanding the energization section of the 120-degree energization rectangular wave by 60 degrees in the advancing direction or expanding the energization section of the 120-degree energization rectangular wave by 60 degrees in the lagging direction, as a start-up operation at the time of start-up, and that drives and controls the inverter (12) by a 180-degree energization rectangular wave drive that is generated by expanding the energization section of the 120-degree energization rectangular wave by 60 degrees in the advancing direction or the lagging direction.

Description

Technical Field

[0001] The present invention relates to a motor driving device for controlling a brushless DC motor (hereinafter referred to as a BLDC motor). Background Art

[0002] The starting method of the BLDC motor generally includes 120-degree energization rectangular wave starting, sine wave starting, etc. For each starting method, research has been conducted using a rotor position detection method, switching to normal operation, etc. (for example, refer to Patent Document 1).

[0003] Patent Document 1: Japanese Patent Application Publication No. 2008-306879

[0004] The 120-degree rectangular wave drive can start quickly, but the noise caused by the sudden current change is a problem.

[0005] Sine wave starting can suppress the noise generated by 120-degree rectangular wave driving and achieve quietness. However, sine wave starting is an open-loop control, so the duty cycle, speed and other parameters at the time of starting need to be set in advance. In the case of hardware logic, since the number of parameter settings is limited, it is impossible to start stably if it is not tuned according to the load. When the load is light, the load responds sharply to the duty cycle and target speed, causing a sound, and when the load is heavy, it loses step and fails to start. Summary of the invention

[0006] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a motor drive device capable of achieving both quietness and stable starting.

[0007] The motor driving device of the present invention drives a BLDC motor, which can detect the mechanical angle of the rotor every 60 degrees through three position detection elements, and is characterized in that the motor driving device has: an inverter with a three-phase bridge structure, which converts a DC power supply input into an AC driving power and supplies it to the BLDC motor; and a starting control unit, which drives and controls the inverter with a 180-degree energized rectangular wave drive as a starting action at startup, wherein the 180-degree energized rectangular wave drive is generated by expanding the energization interval of the 120-degree energized rectangular wave in an advancing direction by 60 degrees or by expanding the energization interval of the 120-degree energized rectangular wave in a lagging direction by 60 degrees.

[0008] The motor drive device of the present invention can suppress a rapid current change during startup to achieve silence, and can quickly achieve stable startup without setting parameters such as duty cycle and rotation speed in advance. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1It is a diagram showing a configuration example of the motor drive device of the present invention.

[0010] Figure 2 It is shown Figure 1 A diagram showing an example of the configuration of an inverter.

[0011] Figure 3 It is shown Figure 1 The diagram shows the energization period when the inverter is started.

[0012] Figure 4 3 is a diagram showing the waveform of the U-phase current at the time of startup.

[0013] Description of Reference Numerals

[0014] 1: DC motor (brushless DC motor: BLDC motor); 3: rotor; 4 U , 4 V , 4 W : Position detection element; 10: Motor drive device; 11: Power supply circuit; 12: Inverter; 13: Speed ​​command determination unit; 14: Position estimation unit; 15: Rotation control unit; 16: Driver; 151: Start control unit; 152: Steady-state control unit; Q UH , Q VH , Q WH : Upper arm switching element; Q UL , Q VL , Q WL : Lower arm switch element. DETAILED DESCRIPTION

[0015] Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

[0016] Reference Figure 1 The motor driving device 10 of this embodiment drives the BLDC motor 1 (hereinafter referred to as the DC motor 1) according to the supplied power supply and control signal. A part or all of the motor driving device 10 can be configured as a semiconductor device integrated on a substrate, and in an electrical device having the DC motor 1, for example, it can be configured as a semiconductor IC for motor driving.

[0017] The DC motor 1 includes three-phase coils 2U, 2V, and 2W of the U phase, the V phase, and the W phase, and a permanent magnet rotor 3. The DC motor 1 includes three position detection elements 4 for detecting the position of the rotor 3. U , 4 V , 4 W . 3 position detection elements 4 U , 4 V , 4 W The positions are provided every 120 degrees so that the mechanical angle of the rotor 3 can be detected every 60 degrees.

[0018] Reference Figure 1 The motor drive device 10 includes a power supply circuit 11 , an inverter 12 , a speed command determination unit 13 , a position estimation unit 14 , a rotation control unit 15 , and a driver 16 .

[0019] The power supply circuit 11 is a voltage regulator that generates an internal power supply voltage based on a control circuit power supply input VCC.

[0020] like Figure 2 As shown, the inverter 12 has upper arm switching elements Q of the U, V, and W phases of the three-phase bridge structure. UH , Q VH , Q WH and the lower arm switching element Q of the U, V, and W phases UL , Q VL , Q WL . Upper arm switching element Q UH , Q VH , Q WH , lower arm switching element Q UL , Q VL , Q WL The inverter 12 converts the DC power supply input VBB into AC driving power (U-phase outputs U, V-phase outputs V, and W-phase outputs W), and supplies the converted driving power to the DC motor 1 .

[0021] The speed command determination unit 13 generates a speed command value sp based on a speed command input VSP input from the outside. The rotation speed of the DC motor 1 is controlled by the speed command input VSP. The speed command determination unit 13 generates a speed command value sp indicating the rotation speed of the DC motor 1 based on the speed command input VSP within the range of the lower threshold voltage to the upper threshold voltage, and outputs the generated speed command value sp to the rotation control unit 15.

[0022] The position estimation unit 14 detects the position of the DC motor 1 based on the position of the DC motor 1 U , 4 V , 4 W Input position detection element signal input H U , Position detection element signal input H V , Position detection element signal input H W , estimates the position (mechanical angle) of the rotor 3 of the DC motor 1, and outputs a position estimation signal to the rotation control unit 15. U , 4 V , 4 W Since the positions are provided every 120 degrees, the position estimation unit 14 detects the mechanical angle of the rotor 3 every 60 degrees.

[0023] In addition, the position estimation unit 14 receives the position detection element signal HU , Position detection element signal input H V , Position detection element signal input H W , generates and outputs a rotation speed detection output FG for monitoring the rotation speed of the DC motor 1.

[0024] The rotation control unit 15 outputs a drive control signal to the driver 16 for rotating the DC motor 1 at a rotation speed of the speed command value sp based on the speed command value sp input from the speed command determination unit 13 and the position estimation signal input from the position estimation unit 14. The driver 16 generates a drive signal for driving and controlling the inverter 12 and outputs the generated drive signal to the inverter 12.

[0025] The rotation control unit 15 functions as a start control unit 151. Figure 3 The inverter 12 is driven and controlled by the 180-degree rectangular wave drive shown in (a) or (b) as a startup action at startup. The startup is a period from when the speed command value sp is input in a state where the position estimation unit 14 cannot estimate the position (mechanical angle) of the rotor 3 until the DC motor 1 reaches a preset rotation speed. Figure 3 The upper arm switching element Q of the inverter 12 is shown. UH , Q VH , Q WH , lower arm switching element Q UL , Q VL , Q WL Their respective power supply ranges.

[0026] Figure 3 The 180-degree rectangular wave drive shown in (a) is to make Figure 3 The current interval of the conventional 120-degree rectangular wave drive shown in (c) is extended by 60 degrees in the leading direction. With the 180-degree rectangular wave drive, the non-energized interval disappears, the current waveform is closer to a sine wave, and the startup starts smoothly, which can suppress the ringing.

[0027] Figure 3 The 180-degree rectangular wave drive shown in (b) is to make Figure 3 The conventional 120-degree rectangular wave drive shown in (c) has an energized interval extended by 60 degrees in the lagging direction. With this 180-degree rectangular wave drive, the non-energized interval also disappears, the current waveform is closer to a sine wave, and the startup starts smoothly, which can suppress the ringing.

[0028] The rotation control unit 15 functions as a steady-state control unit 152 that drives and controls the inverter 12 in a steady-state operation in a steady state after the DC motor 1 reaches a preset rotation speed. The steady-state operation of the steady-state control unit 152 is, for example, a sine wave drive.

[0029] In addition, the steady-state operation of the steady-state control unit 152 may also be Figure 3 In this case, the control logic of the startup control unit 151 and the steady-state control unit 152 can be shared, and the device can be simplified and the cost can be reduced.

[0030] Figure 4 (a) is the U-phase current waveform when a 120-degree rectangular wave drive is used in the startup operation at startup. Figure 4 As can be seen from (a), a sudden current change occurs. When a 120-degree energization rectangular wave drive is used in the startup operation, noise may become a problem due to the sudden current change.

[0031] Figure 4 (b) is the U-phase current waveform when a sine wave PWM waveform drive is used in the startup operation at startup. Figure 4 (b) can suppress rapid current changes. However, when a sine wave PWM waveform drive is used in the startup operation, it is necessary to ensure the initial excitation mechanism and forced commutation period, which sometimes causes problems such as startup delay.

[0032] Figure 4 (c) is a U-phase current waveform when the 180-degree energization rectangular wave drive of this embodiment is used in the startup operation at the time of startup. Figure 4 As can be seen from (c), when a 180-degree rectangular wave drive is used in the starting operation, a sudden current change can be suppressed and the starting can be rapid.

[0033] As described above, the present embodiment is a motor driving device 10 that drives a DC motor 1 (brushless DC motor: BLDC motor) that can detect position of the motor 1 by means of three position detection elements 4. U , 4 V , 4 W The mechanical angle of the rotor is detected every 60 degrees, wherein the motor drive device 10 comprises: a three-phase bridge structure inverter 12, which converts the DC power input VBB into AC driving power and supplies it to the DC motor 1; and a starting control unit 151, which drives and controls the inverter 12 with a 180-degree energized rectangular wave drive as a starting action during startup.

[0034] According to this configuration, a rapid current change at the time of starting can be suppressed to achieve quietness, and stable starting can be achieved quickly without setting parameters such as a duty ratio and a rotation speed in advance.

[0035] Furthermore, the present embodiment includes a steady-state control unit 152 that drives and controls the inverter 12 by sinusoidal PWM waveform drive or 120-degree energization rectangular wave drive after reaching a preset rotation speed.

[0036] When the inverter 12 is driven and controlled by 120-degree energization rectangular wave driving after reaching a preset rotation speed, the control logic of the startup control unit 151 and the steady-state control unit 152 can be shared, thereby simplifying the device and reducing costs.

[0037] In addition, the present invention is not limited to the above-mentioned embodiments, and it is known that the embodiments can be appropriately changed within the scope of the technical concept of the present invention. In addition, the number, position, shape, etc. of the above-mentioned structural components are not limited to the above-mentioned embodiments, and can be set to appropriate numbers, positions, shapes, etc. in terms of implementing the present invention. In addition, in each of the drawings, the same structural elements are marked with the same reference numerals.

Claims

1. A motor driving device that drives a brushless DC motor capable of detecting a mechanical angle of a rotor at intervals of 60 degrees by means of three position detection elements, characterized in that: The motor drive device has: An inverter of a three-phase bridge structure, which converts a DC power input into an AC driving power and supplies it to the brushless DC motor; and A starting control unit drives and controls the inverter with a 180-degree energized rectangular wave drive as a starting action at startup, wherein the 180-degree energized rectangular wave drive is generated by expanding the energized interval of the 120-degree energized rectangular wave in an advancing direction by 60 degrees or by expanding the energized interval of the 120-degree energized rectangular wave in a lagging direction by 60 degrees.

2. The motor drive device according to claim 1, characterized in that: The motor drive device further includes a steady-state control unit that drives and controls the inverter by 120-degree energization rectangular wave drive or sine wave PWM waveform drive after reaching a preset rotation speed.

3. A semiconductor device, characterized in that: The motor drive device according to claim 1 or 2 is integrated on a substrate.

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