Motor drive control device and motor drive control method

Abstract

The present application provides a motor drive control device and a motor drive control method, which can reliably avoid false detection of zero-crossing for energization switching caused by spikes or ringing appearing in voltage waveforms of an induced voltage and a reference voltage, regardless of motor load. The motor drive control device has a control circuit (1) that generates a drive control signal (Sd) for driving a motor (3) having at least one coil, a drive circuit (2), and a phase voltage detection circuit, wherein when the generation and elimination of an induced kick generated in the coil that becomes a non-energized phase is detected after switching the energized phase to the coil, the control circuit masks zero-crossing detection for a first prescribed time after detecting the elimination of the induced kick.

Description

Technical Field

[0001] This invention relates to a motor drive control device and a motor drive control method. Background Technology

[0002] Given: When driving a three-phase BLDC motor (brushless DC motor) with a sensorless 120-degree rectangular wave, the windings are energized by the energized phases of the drive phase and the GND (ground) phase through PWM (Pulse Width Modulation). The energization switching is performed by the zero-crossing detection timing of the differential voltage between the induced voltage appearing in the non-energized phase and the reference voltage, which is half of the neutral point voltage or the power supply voltage.

[0003] Existing technical documents Patent documents Patent Document 1: Japanese Patent Application Publication No. 10-28395 Summary of the Invention

[0004] The problem that the invention aims to solve When driving a three-phase BLDC motor with a sensorless 120-degree rectangular wave, the induced voltage and the reference voltage are branched from the winding or power input and input to the measurement circuit composed of a comparator or A / D converter through a resistor voltage divider circuit and a delay circuit that limit the voltage range, respectively, for zero-crossing detection.

[0005] It is known that in this circuit configuration, when the motor is driven by sequentially switching the power-on mode and using zero-crossing detection for power-on switching, spikes and ringing are generated in the voltage waveforms of the induced voltage and the reference voltage as the rectangular wave switches. Sometimes, these spikes and ringing are mistakenly detected as zero-crossings used for power-on switching. When these spikes and ringing generated in the induced voltage and the reference voltage are mistakenly detected as zero-crossings used for power-on switching, the power-on switching occurs at a timing earlier than it should have been. This results in the adverse effects of unstable motor speed and higher motor speed, leading to a deviation of power consumption per speed from the optimal state.

[0006] In the existing method, in addition to the delay circuit for determining the path, a configuration is also set in the zero-crossing detection of the determination circuit to set the shielding time from the start of the FET switching to not detect the zero-crossing time, so as to avoid falsely detecting spikes and ringing as zero-crossings used for power-on switching.

[0007] By setting the shielding time from the start of the FET switching, even if spikes or ringing caused by the FET switching occur depending on the motor's drive conditions, they will not be falsely detected as zero crossings for power-on switching.

[0008] Despite such avoidance measures, when using high-voltage / multi-pole motors for drones to drive the motor through the aforementioned power-on switching under high rotation / high output / high load conditions, the duration of the induced flyback generated by the power-on switching becomes longer. As a result, spikes and ringing caused by the elimination of induced flyback are sometimes generated in the voltage waveforms of the induced voltage and the reference voltage, which are then mistakenly detected as zero crossings for power-on switching.

[0009] For example, Patent Document 1 describes a method for position detection performed via a position detection shielding time setting unit. This unit begins position detection after a position detection shielding time (zero-crossing non-detection time) has elapsed. This position detection shielding time is a predetermined period immediately following the switching of the energized stator windings without detecting changes in the induced voltage generated in the stator windings. In this method, it is further described that, in order to perform high-precision position detection from low-speed rotation to high-speed rotation, the position detection shielding time is changed individually based on any one of the motor's operating current, applied voltage, or rotational speed, or a combination thereof, and position detection is then performed.

[0010] However, in the method of Patent Document 1, the duration of induced backlash is assumed and set only based on speculation based on motor load. Therefore, deviations may occur in zero crossings caused by spikes appearing in the voltage waveforms of the actual generated induced voltage and the reference voltage. In this case, the problem of false zero crossing detection cannot be eliminated. Furthermore, in the case of power-on switching under high rotation / high output / high load, it is impossible to cope with false zero crossing detections caused by spikes and ringing during induced backlash elimination.

[0011] Therefore, a motor drive control device is desired that can reliably avoid false detection of zero crossings during power-on switching caused by spikes and ringing in the voltage waveforms of the induced voltage and reference voltage, even when driven under high rotation / high output / high load conditions.

[0012] The present invention aims to eliminate the above-mentioned technical problems and provides a motor drive control device that can reliably avoid false detection of zero crossings during power-on switching caused by spikes or ringing in the voltage waveform of the induced voltage or reference voltage, regardless of the motor load.

[0013] Solution for solving the problem A representative embodiment of the motor drive control device of the present invention is characterized by comprising: a control circuit for generating a drive control signal for driving a motor having a coil having at least one phase; a drive circuit having an inverter circuit including switches connected in series with each other and corresponding to the coils of each phase of the motor, the drive circuit responding to the drive control signal to turn the switches on / off to energize the coils of the corresponding phases, and switching the energized phases at predetermined time intervals, thereby rotating the rotor of the motor; and a phase voltage detection circuit for detecting the phase voltage generated between the inverter circuit and the coils of each phase of the motor, the control circuit having: a differential voltage detection circuit, based on the detected phase voltages of each phase, outputting a differential voltage detection signal, which is a signal generated when the motor is not in operation. The differential voltage between the induced voltage generated in the coil of the electrical phase and the reference voltage; and the PWM signal generation unit, which generates the drive control signal based on the zero-crossing detection using the differential voltage detection signal, the drive control signal being a rectangular wave signal that turns the inverter circuit on / off in such a way as switching the energized phase of the coil and switching the energized state of the coil that is in the energized phase, when the generation and elimination of induced backlash generated in the coil that is in the non-energized phase are detected after the energized phase of the coil is switched, the control circuit shields the zero-crossing detection for a first predetermined time after detecting the elimination of the induced backlash, and shields the zero-crossing detection for a second predetermined time when the rising and falling edges of the rectangular wave signal arrive at the timed arrival.

[0014] Invention Effects According to one aspect of the present invention, the motor drive control device can reliably avoid false detections of zero crossings during power-on switching caused by spikes and ringing in the voltage waveforms of the induced voltage and the reference voltage, regardless of the motor load. Attached Figure Description

[0015] Figure 1 This is a diagram showing the configuration of the motor unit 100 of the motor drive control device 10 with the embodiment.

[0016] Figure 2 This is a diagram showing the functional block configuration of the control circuit 1 in the motor drive control device 10 of the embodiment.

[0017] Figure 3 This is a diagram showing an example of the configuration of the differential voltage detection circuit 15.

[0018] Figure 4 This is a timing diagram illustrating the detection of zero crossings during the rotation (electric angle 360 ​​degrees) of the motor 1 in the motor drive control device 10 of the embodiment.

[0019] Figure 5This is a diagram illustrating the timing of the PWM drive shielding (synthesis), PWM power-on cut-off shielding, and backlash elimination shielding in the implementation method.

[0020] Figure 6 This is a diagram illustrating the timing of the PWM drive shielding (synthesis), PWM power-on cut-off shielding, and backlash elimination shielding in the implementation method.

[0021] Figure 7 This is a diagram illustrating the timing of the PWM drive shielding (synthesis), PWM power-on cut-off shielding, and backlash elimination shielding in the implementation method.

[0022] Figure 8 This is a diagram illustrating the timing of the PWM drive shielding (synthesis), PWM power-on cut-off shielding, and backlash elimination shielding in the implementation method.

[0023] Figure 9 This is a flowchart illustrating an example of the processing flow during shielding in PWM shielding (combined) based on the second shielding time (PWM drive shielding) and the shielding time during the power-on and power-off period of the energized phase (PWM power-on and power-off shielding).

[0024] Figure 10 This diagram illustrates the timing of PWM shielding (combined) within one cycle of a PWM drive, including PWM drive shielding and PWM power-on / off shielding.

[0025] Figure 11 This is a flowchart illustrating an example of the processing flow during the shielding process of performing the first shielding time (backflush shielding) in the LO side power-on switching.

[0026] Figure 12 This is a flowchart illustrating an example of the processing flow during the shielding process of performing the first shielding time (backflush shielding) in the HI-side power-on switching. Detailed Implementation

[0027] 1. Overview of the implementation method First, a summary of representative embodiments of the invention disclosed in this application will be given. It should be noted that, as an example, in the following description, reference numerals on the accompanying drawings corresponding to the constituent elements of the invention are indicated by parentheses.

[0028] [1] A representative embodiment of the motor drive control device (10) of the present invention is characterized by comprising: a control circuit (1) for generating a drive control signal (Sd) for driving a motor (3) having a coil having at least one phase; a drive circuit (2) having an inverter circuit (2a) comprising switches connected in series with each phase coil of the motor, the drive circuit (2) energizing the corresponding phase coil by turning the switches on / off in response to the drive control signal, and switching the energized phase at a predetermined time, thereby rotating the rotor of the motor; and a phase voltage detection circuit for detecting the phase voltage generated between the inverter circuit and the coil of each phase of the motor, the control circuit comprising: a differential voltage detection circuit (15) for outputting a differential voltage based on the detected phase voltage of each phase. The differential voltage between the induced voltage generated in the non-energized phase coil of the voltage detection signal (Vd) and the reference voltage; and the PWM signal generation unit (14), which generates the drive control signal based on the zero-crossing detection of the differential voltage detection signal, the drive control signal being a rectangular wave signal that turns the inverter circuit on / off by switching the energized phase of the coil and switching the energized state of the coil that is in the energized phase, when the generation and elimination of the induced backlash generated in the coil that is in the non-energized phase are detected after the energized phase of the coil is switched, the control circuit shields the zero-crossing detection for a first predetermined time after detecting the elimination of the induced backlash, and shields the zero-crossing detection for a second predetermined time when the rising and falling edges of the rectangular wave signal arrive at the timing.

[0029] [2] In the motor drive control device described in [1] above, the inverter circuit switches may include high-side switches (Q1, Q3, Q5) and low-side switches (Q2, Q4, Q6). The PWM signal generation unit drives the motor by generating drive control signals that turn on / off the high-side switches and the low-side switches of the inverter circuit that energize the coil. The control circuit shields the zero-crossing detection when the timing of the on / off of the PWM drive phase that is the energized phase in the high-side switches and the low-side switches of the inverter circuit arrives, covering the second predetermined time.

[0030] [3] In the motor drive control device described in [1] above, the control circuit may also perform a backlash elimination shielding process that covers the first predetermined time after the execution of the PWM drive shielding process that covers the second predetermined time to shield the zero-crossing detection has ended.

[0031] [4] In the motor drive control device described in [2] above, the inverter circuit switch may include a high-side switch and a low-side switch, and the PWM signal generation unit drives the motor by generating the drive control signal that turns on / off the switch of the inverter circuit that energizes the coil. The control circuit covers the shielding of the zero-crossing detection during the power-on and power-off period, which is the period during which the switch of the PWM drive phase of the energized phase is turned off.

[0032] [5] In the motor drive control device described in [1] above, the control circuit may further detect the generation and elimination of induced backlash generated in the coil that becomes the non-energized phase after switching the energized phase of the coil. When the power supply side of the energized phase is switched by switching the energization of the HI side, the change detection direction of the differential voltage detection signal when induced backlash is generated is changed from positive to negative, and the change detection direction of the differential voltage detection signal when induced backlash is eliminated is changed from negative to positive. When the GND side of the energized phase is switched by switching the energization of the LO side, the change detection direction of the differential voltage detection signal when induced backlash is generated is changed from negative to positive, and the change detection direction of the differential voltage detection signal when induced backlash is eliminated is changed from positive to negative. Thus, the detection method based on the zero crossing of the differential voltage detection signal is switched according to the energization switching method.

[0033] [6] In the motor drive control device described in [1] above, the control circuit may detect the generation of the induced backlash when it detects the first zero crossing within one cycle of PWM drive from the time the energized phase of the coil is switched.

[0034] [7] A representative embodiment of the motor drive control method of the present invention is characterized in that it is executed in a motor drive control device (10), the motor drive control device (10) comprising: a control circuit (1) for generating a drive control signal (Sd) for driving a motor (3) having a coil having at least one phase; a drive circuit (2) having a switch inverter circuit (2a) comprising interconnected in series with each phase coil of the motor, the drive circuit (2a) energizing the corresponding phase coil by turning the switch on / off in response to the drive control signal, and switching the energized phase at a predetermined time, thereby rotating the rotor of the motor; and a phase voltage detection circuit for detecting the phase voltage generated between the inverter circuit and the coil of each phase of the motor, the motor drive control method comprising: a first step, based on the detected phase voltage of each phase... The first step involves the output of a differential voltage detection signal (Vd) between the induced voltage generated in the coil of the non-energized phase and a reference voltage. The second step involves zero-crossing detection based on the differential voltage detection signal. The third step involves generating a drive control signal based on the zero-crossing detection. This drive control signal is a rectangular wave signal that switches the inverter circuit on / off by switching the energized phase of the coil and the energized state of the coil in the energized phase. The fourth step involves detecting and eliminating the induced backlash generated in the coil of the non-energized phase after switching the energized phase of the coil. The fifth step involves shielding the zero-crossing detection for a first predetermined time after detecting the elimination of the induced backlash, and shielding the zero-crossing detection for a second predetermined time when the rising and falling edges of the rectangular wave signal arrive.

[0035] 2. Specific examples of implementation methods Hereinafter, specific examples of embodiments of the present invention will be described with reference to the accompanying drawings. It should be noted that in the following description, common components in various embodiments will be labeled with the same reference numerals, and repeated descriptions will be omitted.

[0036] Implementation Method Figure 1 This is a diagram showing the configuration of the motor unit 100 of the motor drive control device 10 with the embodiment.

[0037] like Figure 1 As shown, the motor unit 100 includes: a motor 3; and a motor drive control device 10 for controlling the rotation of the motor 3. The motor unit 100 can be applied, for example, to various devices that use motors as a drive source, such as fans, drones (unmanned aerial vehicles).

[0038] Motor 3 is, for example, a permanent magnet synchronous motor (PMSM). In this embodiment, motor 3 is, for example, a surface magnet synchronous motor (SPMSM) with three-phase coils (windings) Lu, Lv, and Lw. The coils Lu, Lv, and Lw are connected to each other in a Y (star) configuration, for example. Alternatively, the coils can be connected in a Δ (delta) configuration.

[0039] The motor drive control device 10, for example, provides a 120-degree energized rectangular wave drive signal to the motor 3, causing the drive current to flow periodically in the three-phase coils Lu, Lv, and Lw of the motor 3, thereby causing the rotor of the motor 3 to rotate.

[0040] The motor drive control device 10 has a control circuit 1 and a drive circuit 2.

[0041] It should be noted that, Figure 1 The components of the motor drive control device 10 shown are part of a whole. In addition to having… Figure 1 In addition to the constituent elements shown, there may be other constituent elements.

[0042] The drive circuit 2 drives the motor 3 based on the drive control signal Sd output from the control circuit 1 (described later). The drive circuit 2 includes, for example, an inverter circuit 2a and a pre-drive circuit 2b. The inverter circuit 2a of the drive circuit 2 is configured between the DC power supply Vin and the ground potential.

[0043] The inverter circuit 2a is a circuit that drives the coils Lu, Lv, and Lw of the motor 3, which is the load, based on the drive control signal Sd output from the control circuit 1 and input via the pre-drive circuit 2b. Specifically, in the embodiment, the inverter circuit 2a has three switching branches, each including two drive transistors connected in series. The two drive transistors alternately turn on / off (switching action) based on the input drive control signal Sd, thereby driving the motor 3, which is the load.

[0044] More specifically, inverter circuit 2a has switching branches corresponding to the U phase, V phase, and W phase of motor 3, respectively. For example... Figure 1 As shown, each corresponding switching branch has two driving transistors (hereinafter also referred to as "switching elements") Q1 and Q2, Q3 and Q4, Q5 and Q6 connected in series between the DC power supply Vin and the ground potential.

[0045] Here, the driving transistors Q1, Q3, and Q5 (equivalent to high-side switches) of the upper bridge arm of the motor 3 coil are, for example, N-channel MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors), and the driving transistors Q2, Q4, and Q6 (equivalent to low-side switches) of the lower bridge arm of the motor 3 coil are, for example, N-channel MOSFETs. It should be noted that the driving transistors Q1 to Q6 can also be other types of FETs, such as IGBTs (Insulated Gate Bipolar Transistors) or other types of transistors.

[0046] For example, the switching branch corresponding to U has switching elements Q1 and Q2 connected in series. The common connection point of switching elements Q1 and Q2 is connected to one end of coil Lu, which serves as the load. The switching branch corresponding to V has switching elements Q3 and Q4 connected in series. The common connection point of switching elements Q3 and Q4 is connected to one end of coil Lv, which serves as the load. The switching branch corresponding to W has switching elements Q5 and Q6 connected in series. The common connection point of switching elements Q5 and Q6 is connected to one end of coil Lw, which serves as the load. Furthermore, switching elements Q1 and Q2, Q3 and Q4, and Q5 and Q6 each have parasitic diode characteristics from the GND side to the power supply side. Figure 1 (Not shown in the image).

[0047] The pre-drive circuit 2b generates a drive signal for driving the inverter circuit 2a based on the drive control signal Sd output from the control circuit 1.

[0048] The drive control signal Sd is a signal used to control the drive of motor 3, and is a rectangular wave signal such as a PWM (Pulse Width Modulation) signal. Specifically, the drive control signal Sd is used to switch the energizing modes of the coils Lu, Lv, and Lw of motor 3, which are determined by the on / off states of the switching elements constituting inverter circuit 2a. More specifically, the drive control signal Sd includes six PWM signals corresponding to the switching elements Q1 to Q6 of inverter circuit 2a.

[0049] The pre-drive circuit 2b generates six drive signals Vuh, Vul, Vvh, Vvl, Vwh, and Vwl based on the six PWM signals (rectangular wave signals) supplied from the control circuit 1 as drive control signals Sd. These signals can supply sufficient power to the control electrodes (gate electrodes) of the switching elements Q1 to Q6 of the drive inverter circuit 2a.

[0050] These drive signals Vuh, Vul, Vvh, Vvl, Vwh, and Vwl are input to the control electrodes (gate electrodes) of the switching elements Q1 to Q6 in the inverter circuit 2a to cause the switching elements Q1 to Q6 to perform on / off operations (switching operations). For example, the switching elements Q1, Q3, and Q5 of the upper bridge arm and the switching elements Q2, Q4, and Q6 of the lower bridge arm of the corresponding switching branch are alternately turned on / off. As a result, power is supplied from the DC power supply Vin to each phase of the motor 3, causing the motor 3 to rotate.

[0051] A wiring system (hereinafter also referred to as a "phase voltage detection circuit") for measuring the phase voltage signals Vu, Vv, and Vw generated in each phase is connected between the inverter circuit 2a and the coils Lu, Lv, and Lw of each phase of the motor 3, and input to the control circuit 1. In the control circuit 1, during zero-crossing detection (described later), a differential voltage (the differential voltage between the phase voltage of the selected non-energized phase, i.e., the induced voltage, and a reference voltage equal to half the neutral point voltage or power supply voltage) is used, based on the phase voltage signals Vu, Vv, and Vw generated in each phase; the value corresponding to the phase voltage of the selected phase). That is, zero-crossing can be detected by detecting that the differential voltage signal Vd between the induced voltage and the reference voltage becomes 0.

[0052] In driving the motor, control circuit 1 generates a drive control signal Sd for driving motor 3 based on a speed command signal Sc, for example, an externally input signal indicating the target state of motor 3's operation, thereby controlling the drive of motor 3. Specifically, control circuit 1 generates the drive control signal Sd and provides it to drive circuit 2 to make motor 3 operate in the state specified by the speed command signal Sc. At this time, control circuit 1 uses the differential voltage measured based on phase voltage signals Vu, Vv, and Vw to detect the zero-crossing for energization switching and generates the drive control signal Sd, which is similar to switching the energized phase of motor 3 at an appropriate timing.

[0053] In an embodiment, the control circuit 1 may be a program processing device (e.g., a microcontroller) configured as follows: a processor such as a CPU (Central Processing Unit), various storage devices such as RAM (Random Access Memory) and ROM (Read-Only Memory), and peripheral circuits such as counters (timers), A / D (Analog to Digital) conversion circuits, D / A (Digital to Analog) conversion circuits, clock generation circuits, and input / output (I / F) circuits, interconnected via buses and dedicated lines. Furthermore, the control circuit 1 may also include a differential voltage detection circuit 15 configured as an analog circuit, as described later.

[0054] It should be noted that the motor drive control device 10 can be configured such that at least a part of the control circuit 1 and at least a part of the drive circuit 2 are packaged into an integrated circuit device (IC), or the control circuit 1 and the drive circuit 2 can be packaged into their own independent integrated circuit devices.

[0055] Figure 2 This is a diagram showing the functional block configuration of the control circuit 1 in the motor drive control device 10 of the embodiment.

[0056] like Figure 2 As shown, the control circuit 1, for example in the drive of a motor based on a 120-degree energized rectangular wave drive method, includes a drive command acquisition unit 11, a state control unit 12, a rectangular wave control unit 13, a PWM signal generation unit 14, and a differential voltage detection circuit 15 as a functional block for generating the drive control signal Sd. Furthermore, the state control unit 12 includes a zero-crossing detection signal generation unit 121, an induction recoil detection unit 122, and an induction recoil shielding processing unit 123, and as described later, outputs the zero-crossing detection signal Zo to the rectangular wave control unit 13 only at necessary timings.

[0057] These functional blocks, for example in the program processing device that serves as control circuit 1, are implemented by the processor performing various arithmetic operations according to the program stored in the memory, and controlling peripheral circuits such as counters and A / D conversion circuits.

[0058] The drive command acquisition unit 11 receives a speed command signal Sc from the outside and obtains a value specifying the action state of the motor 3 as specified by the speed command signal Sc by parsing the received speed command signal Sc.

[0059] The speed command signal Sc includes a value indicating the target state of the motor 3's operation. The speed command signal Sc is, for example, a signal output from a host device located outside the motor drive control device 10 for controlling the motor unit 100.

[0060] In this implementation, the speed command signal Sc specifies, for example, the rotational speed of the rotor of motor 3. The speed command signal Sc includes a value ωref that represents the target rotational speed (target rotational speed) of the rotor of motor 3.

[0061] The speed command signal Sc is, for example, a PWM signal with a duty cycle corresponding to a specified target rotational speed ωref. The drive command acquisition unit 11, for example, measures the duty cycle of the PWM signal of the speed command signal Sc and outputs the rotational speed corresponding to the measured duty cycle as the target rotational speed ωref.

[0062] During motor drive, the state control unit 12 directly outputs the target rotational speed ωref to the rectangular wave control unit 13, and outputs a zero-crossing detection signal Zo, generated based on the differential voltage detection signal Vd output from the differential voltage detection circuit 15 (described later), to the rectangular wave control unit 13 as needed. The differential voltage detection signal Vd is obtained by comparing the variation of the induced voltage generated in the coil of the non-energized phase based on the phase voltage of each phase of the coil with a reference voltage.

[0063] The state control unit 12 outputs the zero-crossing detection signal Zo, which can be detected based on the differential voltage detection signal Vd, to the rectangular wave control unit 13 only at necessary timings, and does not output the zero-crossing detection signal Zo at timings where spikes or ringing occur. With this configuration, the zero-crossing detection signal Zo, which is incorrectly detected as a zero-crossing event, is prevented from being output to the rectangular wave control unit 13. The functional unit that performs this process will be described later.

[0064] The rectangular wave control unit 13 outputs a drive command signal So to the PWM signal generation unit 14 during motor driving, and outputs a phase selection signal Sm to the differential voltage detection circuit 15. The phase selection signal Sm is used to select the phase in the motor coil that will be detected in the differential voltage detection circuit 15. The rectangular wave control unit 13 can select the non-energized phase as the detection target in the differential voltage detection circuit 15.

[0065] In order to obtain the switching timing of the six energizing modes under the drive control mode based on a 120-degree rectangular wave during the motor drive, the rectangular wave control unit 13 sets the following settings: outputs a measurement phase selection signal Sm corresponding to non-energized phase to the differential voltage detection circuit 15, and generates a differential voltage detection signal Vd by comparing the induced voltage of the selected non-energized phase with the neutral point voltage (an example of a reference voltage).

[0066] In driving the motor, the rectangular wave control unit 13 utilizes a drive control method based on a 120-degree rectangular wave. It generates a drive command signal So based on the target speed ωref input from the state control unit 12 and the zero-crossing detection signal Zo, and outputs this signal to the PWM signal generation unit 14, thereby performing motor drive control. The zero-crossing detection signal Zo is a signal generated by the state control unit 12 indicating the timing of the zero-crossing detection for power-on switching.

[0067] Therefore, the rectangular wave control unit 13, for example, energizes the windings from phase U to phase V through one-phase excitation. In the differential voltage detection circuit 15, it measures the differential voltage between the induced voltage (phase voltage) generated in the non-energized phase W and the neutral point voltage (reference voltage), generating a differential voltage detection signal Vd. The rectangular wave control unit 13 outputs a drive command signal So to the PWM signal generation unit 14, thereby performing motor drive control. This drive command signal So is adjusted to use a zero-crossing detection signal Zo, representing the zero-crossing timing, generated by the state control unit 12 based on the generated differential voltage detection signal Vd, for energization switching. At this time, the neutral point voltage, which serves as the reference voltage, can be replaced by a DC power supply Vin / 2 instead of the voltage obtained by synthesizing the phase voltages of all phases. Furthermore, the rectangular wave control unit 13 may have a PWM period timer Tpwm for adjusting the switching timing of the drive signal for the PWM drive phase and an energization switching timer Tsector for adjusting the energization switching timing.

[0068] The power-on switching timer Tsector is a timer that is reset each time power is switched on. Power-on switching occurs within a 60-degree electrical angle, and the time from power-on switching to zero-crossing detection is 30 degrees electrical angle. Therefore, it is used to measure the time from power-on switching to zero-crossing detection and the power-on phase switching time from zero-crossing detection to the next power-on switching. When the motor is rotating at high speed, waiting for the 30-degree electrical angle before power-on switching may be later than the rotor's optimal power-on switching timing. Therefore, the power-on switching can also be performed by subtracting the advance angle time corresponding to the speed from the 30-degree electrical angle switching time. Furthermore, the power-on switching timer Tsector can also be used to measure the time between the previous zero-crossing and the current zero-crossing. That is, the power-on switching timer Tsector can also be used to measure the time between zero-crossing detections. It should be noted that... Figure 2 Although not specifically shown, the rectangular wave control unit 13 may also have a functional unit for performing this process. The rectangular wave control unit 13 also outputs a drive command signal So to the status control unit 12 in order to perform the shielding process described later.

[0069] In the motor drive, the PWM signal generation unit 14 generates a drive control signal Sd based on the drive command signal So received from the rectangular wave control unit 13 and outputs it to the drive circuit 2 to perform PWM control on the drive circuit 2.

[0070] The differential voltage detection circuit 15 is configured to output the phase voltage of the selected phase as a differential voltage detection signal Vd to the zero-crossing detection signal generation unit 121.

[0071] Figure 3 This diagram illustrates an example of the configuration of the differential voltage detection circuit 15. Here, an example of the configuration of the differential voltage detection circuit 15 will be explained.

[0072] The differential voltage detection circuit 15 receives the phase voltage signals Vu, Vv, and Vw of each phase and the phase selection signal Sm for measurement, and outputs a differential voltage detection signal Vd. The differential voltage detection circuit 15 consists of multiple resistive elements 151 for DC current limiting and voltage adjustment, a multiplexer (MUX) 152 for phase selection, and a differential amplifier circuit 153. The differential voltage detection circuit 15 branches the input of the phase voltage signals Vu, Vv, and Vw of each phase into two branches, synthesizes one branch into a synthesized signal (neutral point voltage) Vn, and inputs it to the differential amplifier circuit 153. The other branch is input to the phase selection multiplexer 152. The differential amplifier circuit 153 also receives the output from the phase selection multiplexer 152. At this time, the resistive elements 151 are set so that the voltage division ratio of each phase voltage is the same as the voltage division ratio of the neutral point voltage. Furthermore, if a delay circuit is included, the time constant of each phase voltage is set to the same value as the time constant of the neutral point voltage.

[0073] In the differential voltage detection circuit 15, the phase selection multiplexer 152 selects any one of the three phase voltage signals Vu, Vv, and Vw as the selected phase voltage signal Vm based on the phase selection signal Sm input from the rectangular wave control unit 13, and outputs it to the differential amplifier circuit 153. The differential amplifier circuit 153 receives a composite signal Vn, which is the voltage corresponding to the selected phase voltage and the neutral point voltage of the motor coil. That is, the differential amplifier circuit 153 receives a signal equivalent to the differential voltage detection signal Vd'. The differential voltage detection signal Vd' generated based on the selected phase voltage signal Vm and the neutral point voltage Vn has both positive and negative polarities during motor driving. Therefore, the differential amplifier circuit 153 scales (amplifies / reduces) the signal and shifts the DC power supply Vdc / 2, resulting in a differential voltage detection signal Vd output that saturates within a voltage range of 0V to Vdc, approximately similar to the differential voltage detection signal Vd' and centered at Vdc / 2. In other words, the differential voltage detection signal Vd becomes a signal corresponding to the phase voltage of the selected phase.

[0074] Figure 4 This is a timing diagram illustrating the zero-crossing detection in the motor drive control device 10 of the embodiment.

[0075] exist Figure 4 In the diagram, starting from the top, the waveforms of the drive signals Vuh, Vul, Vvh, Vvl, Vwh, and Vwl generated in the pre-drive circuit 2b, corresponding to the drive control signal Sd generated by the PWM signal generation unit 14 of the control circuit 1, are shown in both the electrical angle and energizing modes. The following sections show the waveforms of the phase voltage signals generated in each phase of the coils Lu, Lv, and Lw of the motor 3, and the waveform of half the power supply voltage, which serves as the reference voltage. The waveforms of the phase voltage signals shown in this diagram are not from the... Figure 1 and Figure 2 The waveforms shown in the motor drive control device 10 of this embodiment are not the actual measured waveforms, but the theoretically generated phase voltages. That is, the timing diagram shows the relationship between the phase voltage signals Vu, Vv, and Vw theoretically generated in each phase Lu, Lv, and Lw of the motor 3 coil when the drive signals Vuh, Vul, Vvh, Vvl, Vwh, and Vwl of each phase are switched based on the drive control signal Sd.

[0076] exist Figure 4 In this circuit, each power-on mode at 60 degrees per electrical angle is counted by a power-on switching timer Tsector. Furthermore, regarding the drive signal generated in the pre-drive circuit 2b, it is controlled by a center-aligned PWM drive using a PWM cycle timer Tpwm, which counts per PWM cycle in the rectangular wave control unit 13, driven by a PWM cycle Tperiod and a duty cycle Tduty. At this time, the duty cycle of the drive signal is Tduty / Tperiod. It should be noted that in... Figure 4 In this system, half of the power supply voltage is used as the reference voltage. When the neutral point voltage obtained by synthesizing the voltages of each phase is used as the reference voltage, the neutral point voltage changes due to the switching on / off of the energized phases achieved by the switching on / off of the PWM driven phases. Therefore, the reference voltage also changes. However, the reference voltage at the zero crossing under the energized state is the same value as half of the neutral point voltage and the power supply voltage.

[0077] Control circuit 1 generates a drive control signal Sd simultaneously with switching the energized phase by detecting the zero-crossing of the differential voltage signal Vd, which is the differential voltage used as a reference voltage, between the zero-crossing of the induced voltage and the zero-crossing of the differential voltage signal Vd. Specifically, control circuit 1 generates a drive control signal Sd adjusted to energize coil Lu to coil Lv between electrical angles of 0 degrees and 60 degrees, switches the energized phase (LO side energization switching) at electrical angle 60 degrees, and generates a drive control signal Sd adjusted to energize coil Lu to coil Lw between electrical angles of 60 degrees and 120 degrees.

[0078] At that time, such as Figure 4 As shown, the drive signals Vuh and Vul are switched complementaryly. On the other hand, the following switching occurs: drive signal Vvl is set to a high level between electrical angles of 0 and 60 degrees, and then drive signal Vwl is set to a high level between electrical angles of 60 and 120 degrees. In this case, phase W is the non-energized phase between electrical angles of 0 and 60 degrees, and phase V is the non-energized phase between electrical angles of 60 and 120 degrees.

[0079] Next, control circuit 1 switches the energized phase at an electrical angle of 120 degrees (HI-side energization switching) and generates a drive control signal Sd adjusted to energize coil Lv to coil Lw between electrical angles of 120 and 180 degrees. It also switches the energized phase at an electrical angle of 180 degrees (LO-side energization switching) and generates a drive control signal Sd adjusted to energize coil Lv to coil Lu between electrical angles of 180 and 240 degrees. HI-side energization switching refers to switching the energization on the power supply side of the energized phase, and LO-side energization switching refers to switching the energization on the GND side of the energized phase.

[0080] At that time, such as Figure 4 As shown, the drive signals Vvh and Vvl are switched complementaryly. On the other hand, the following switching occurs: drive signal Vwl is made high between electrical angles of 120 and 180 degrees, and then drive signal Vul is made high between electrical angles of 180 and 240 degrees. In this case, phase U is the non-energized phase between electrical angles of 120 and 180 degrees, and phase W is the non-energized phase between electrical angles of 180 and 240 degrees.

[0081] Furthermore, the control circuit 1 switches the energizing phase (HI-side energizing switch) at an electrical angle of 240 degrees and generates a drive control signal Sd adjusted to energize coil Lw to coil Lu between electrical angles of 240 degrees and 300 degrees. It also switches the energizing phase (LO-side energizing switch) at an electrical angle of 300 degrees and generates a drive control signal Sd adjusted to energize coil Lw to coil Lv between electrical angles of 300 degrees and 360 degrees.

[0082] At that time, such as Figure 4 As shown, the drive signals Vwh and Vwl are switched complementaryly. On the other hand, the following switching occurs: the drive signal Vul is made high between electrical angles of 240 and 300 degrees, and then the drive signal Vvl is made high between electrical angles of 300 and 360 degrees. In this case, the V phase is non-energized between electrical angles of 240 and 300 degrees, and the U phase is non-energized between electrical angles of 300 and 360 degrees.

[0083] Next, control circuit 1 switches the energized phase (HI side energization switch) at an electrical angle of 360 degrees and returns to the original electrical angle.

[0084] In this way, control circuit 1 generates a drive control signal Sd while switching the energized phase, thereby driving the motor so that the motor rotor rotates within a 360-degree electrical angle range.

[0085] like Figure 4 As shown, when motor 3 rotates in response to the drive control signal Sd generated by the PWM signal generation unit 14 of control circuit 1, the phase voltage signal of the energized phase becomes either the power supply voltage or zero, but the phase voltage signal of the non-energized phase gradually changes as the motor rotates. This is because an induced voltage is generated in the non-energized phase, which varies according to the rotational position of the motor rotor; the induced voltage of the non-energized phase represents the rotational position of the motor 3 rotor. Figure 4 It is known that when the rotor of motor 3 rotates ideally, the induced voltage of the non-energized phase coincides with the reference voltage at a predetermined timing. Therefore, it is known that the timing detection of the differential voltage between the induced voltage of the non-energized phase and the reference voltage becoming zero is called zero crossing. The energized phase of the motor is switched using the zero crossing detection timing, thereby causing the rotor of motor 3 to rotate ideally. On the other hand, when the generation and elimination of induced backlash, spikes, and ringing errors are mistakenly detected as zero crossings for energization switching, the drive control signal Sd is output in a way that performs energization switching earlier than it should. There is a possibility that the motor speed becomes unstable, and that the motor speed increases while the power consumption per speed deviates from the optimal state.

[0086] In the motor drive control device 10 of this embodiment, by means of shielding, the zero-crossing detection signal Zo is output to the rectangular wave control unit 13 only at necessary timings, thereby avoiding adverse effects on the motor drive.

[0087] Figures 5 to 8 This is a timing diagram illustrating the timing of the backlash elimination shielding in the implementation method. Figure 5 , Figure 6 This is an example where the time from the generation of induced backlash to its elimination is relatively short due to low load. Figure 7 , Figure 8 This is an example where the time from the generation of induced backlash to its elimination is relatively long due to high load. Induced backlash is a spike or drop in induced voltage generated in the non-energized phase as the energized phase switches.

[0088] exist Figures 5 to 8The diagram, starting from the top, shows the waveforms of the drive signals on the HI side of the PWM drive phase, the LO side of the PWM drive phase, the LO side of the GND phase, and the phase voltage signal of the induced voltage phase in the power-on switching timer Tsector and the PWM period timer Tpwm. It also shows the PWM drive masks (synthesized) Tpwm_mask_f and Tpwm_mask_r, the PWM power-on cut-off masks Tde_mask_f and Tde_mask_r, the recoil cancellation mask Tkb_end_mask, the zero-crossing detection signal Zo, and the zero-crossing detection mode. The HI side and LO side of the PWM drive phase (power-on phase) are the same phase, and in this example, they are switched complementaryly. The PWM drive mask (synthesized) and the PWM power-on cut-off mask are shown as the first and second halves of the center-aligned PWM.

[0089] exist Figures 5 to 8 In this process, the drive signals of the HI side and LO side of the PWM drive phase on the power supply side, which is the energized phase, are switched complementaryly, and the drive signal of the LO side of the GND phase on the GND side, which is the energized phase, becomes high level. Figure 5 , Figure 7 This is an example of a situation where the energizing phase is switched by switching the GND phase on the GND side (LO side energizing switch). Figure 6 , Figure 8 This is an example of a case where the energizing phase is switched by changing the PWM drive phase on the power supply side (HI side energizing switch). It should be noted that, compared to... Figure 4 Similarly, in Figures 5 to 8 In this case, half of the power supply voltage is used as the reference voltage.

[0090] like Figure 5 , Figure 7 As shown, when the energized phase is switched by switching the GND phase on the GND side (LO side energization switching), an induced backlash is generated in the power supply direction. After the induced backlash is eliminated, an induced voltage appears, and the induced voltage gradually increases, as shown... Figure 6 , Figure 8 As shown, when the energized phase is switched by switching the PWM drive phase on the power supply side (HI side energization switching), an induced backlash is generated in the GND direction. After the induced backlash is eliminated, an induced voltage appears, and the induced voltage gradually decreases.

[0091] In any diagram, when the energized phase is switched, an induced backlash is immediately generated in the non-energized phase. It is also known that regardless of the length of time from the generation to the elimination of the induced backlash, spikes and ringing occur in the non-energized phase for a period after the induced backlash is eliminated. Furthermore, it is known that spikes and ringing occur each time the drive signal of the PWM drive phase of the energized phase is switched.

[0092] Regarding the existing zero-crossing detection shielding time, the generation of the zero-crossing detection signal Zo is shielded each time the drive signal of the PWM drive phase of the energized phase is switched. The time for shielding the drive signal of the PWM drive phase of the energized phase is called the second shielding time (PWM drive shielding). With this configuration, spikes and ringing generated by the switching on / off of the switch implemented by the switching of the PWM drive phase of the energized phase are prevented from being erroneously detected as zero-crossings used for energization switching.

[0093] In the control circuit 1 of the motor drive control device 10 of this embodiment, in addition to the second shielding time, the generation of the zero-crossing detection signal Zo is further shielded in the state control unit 12 for a period of time after the elimination of induced backlash. The time during which shielding is implemented as induced backlash is eliminated is called the first shielding time (backlash elimination shielding). With this configuration, spikes and ringing caused by the elimination of induced backlash that is out of sync with the drive signal of the PWM drive phase are prevented from being mistakenly detected as zero-crossings for power-on switching. The first shielding time (backlash elimination shielding) is... Figures 5 to 8 The middle section represents the interval indicated by the diagonal lines.

[0094] Thus, in the control circuit 1 of the motor drive control device 10 of this embodiment, by performing shielding processing covering both the first shielding time and the second shielding time, the zero-crossing detection signal Zo is output to the rectangular wave control unit 13 only at the necessary timing.

[0095] In the control circuit 1 of the motor drive control device 10 of this embodiment, the generation and elimination of induced backlash are detected based on the differential voltage detection signal Vd generated according to the induced voltage of the non-energized phase, thus enabling high-precision detection of induced backlash.

[0096] Here, the configuration of the functional unit in the state control unit 12 that outputs the zero-crossing detection signal Zo to the rectangular wave control unit 13 only at necessary timings will be described. This functional unit is implemented by the zero-crossing detection signal generation unit 121, the inductive recoil detection unit 122, and the inductive recoil shielding processing unit 123.

[0097] The zero-crossing detection signal generation unit 121 generates a zero-crossing detection signal Zo indicating that a zero crossing has been detected based on the differential voltage detection signal Vd. The zero-crossing detection signal generation unit 121 receives the differential voltage detection signal Vd, detects the moment when the differential voltage detection signal Vd reaches a predetermined value in a predetermined direction of change as a zero crossing, and generates the zero-crossing detection signal Zo. The predetermined value is, for example, set to "zero (0)".

[0098] The zero-crossing detection signal generation unit 121 can use the differential voltage detection signal Vd, which is a digital signal, to detect changes in the differential voltage detection signal Vd. The moment when the value of the differential voltage detection signal Vd becomes "zero" is detected as a zero-crossing. However, it can also be configured to use a comparator to compare the differential voltage detection signal Vd, which is an analog signal, with the voltage value corresponding to the zero-crossing to determine the zero-crossing. Furthermore, it can be configured to use an A / D converter to compare the differential voltage detection signal Vd, which is an analog signal, with the voltage value corresponding to the zero-crossing to determine the zero-crossing. Alternatively, it can be configured to compare the voltage value obtained by quantifying the selected phase voltage signal Vm, which is the induced voltage, and the neutral point voltage Vn to determine the zero-crossing.

[0099] The zero-crossing detection signal generation unit 121 shields the generation of the zero-crossing detection signal Zo for a second predetermined time when the rising and falling edges of the rectangular wave signal based on the drive command signal So input from the rectangular wave control unit 13 to the state control unit 12 arrive at the appointed time. The second predetermined time is set to be sufficient time for the spikes and ringing caused by the switching of the PWM signal to stop.

[0100] The zero-crossing detection signal generation unit 121 includes a PWM drive shielding timer for timing the second shielding time in order to determine whether shielding processing in the second shielding time (PWM drive shielding) is performed. The zero-crossing detection signal generation unit 121 performs shielding processing during the period when the time counted by the PWM drive shielding timer is within the time equivalent to the second shielding time, and does not generate a zero-crossing detection signal Zo. On the other hand, the zero-crossing detection signal generation unit 121 generates a zero-crossing detection signal Zo during the period when the time counted by the PWM drive shielding timer is not within the time equivalent to the second shielding time, without performing shielding processing. It should be noted that, in addition to the second shielding time (PWM drive shielding), the zero-crossing detection signal generation unit 121 can also perform shielding processing during the shielding time (PWM power-on cut-off shielding) during the power-on and power-off period of the energized phase where the HI side of the PWM drive phase is low, using the PWM shielding timer described later.

[0101] The zero-crossing detection signal generation unit 121 performs a second shielding process to shield the generation of the zero-crossing detection signal Zo for a second predetermined time when the on / off timing of the PWM drive phase in the energized phase of the high-side switch and low-side switch of the inverter circuit 2a arrives.

[0102] When the zero-crossing detection signal generation unit 121 generates a zero-crossing during the shielding period based on PWM drive shielding or PWM power-on / off shielding, and the shielding is released after the shielding period, it is assumed that a zero-crossing has occurred and the generation of the zero-crossing detection signal Zo is delayed if the state after the zero-crossing is maintained (the state after the polarity of the differential voltage signal Vd, which represents the differential voltage between the induced voltage and the reference voltage, temporarily becomes zero). On the other hand, when the zero-crossing generated during the shielding period is eliminated and the shielding is released after the shielding period, it is assumed that no zero-crossing has occurred and the zero-crossing detection signal Zo is not generated if the zero-crossing state is released (the state before the polarity of the differential voltage signal Vd, which represents the differential voltage between the induced voltage and the reference voltage, temporarily becomes zero).

[0103] The inductive recoil detection unit 122 monitors the zero-crossing detection signal Zo input from the zero-crossing detection signal generation unit 121, determines the generation and elimination of inductive recoil in the coil that becomes a non-energized phase after switching the energized phase of the coil, and the zero-crossing used for energization switching, and notifies the inductive recoil shielding processing unit 123 of the timing of the detected generation and elimination of inductive recoil and the zero-crossing used for energization switching.

[0104] The inductive recoil detection unit 122 determines the generation and elimination of inductive recoil and the zero-crossing used for power-on switching by monitoring the zero-crossing detection signal Zo generated in the zero-crossing detection signal generation unit 121. The inductive recoil detection unit 122 monitors the zero-crossing detection signal Zo generated in the zero-crossing detection signal generation unit 121 and determines the generation and elimination of inductive recoil and the zero-crossing used for power-on switching based on the generation sequence of the zero-crossing detection signals Zo from the power-on switching.

[0105] In energized mode, the zero-crossing detection signal generation unit 121 switches the detection direction (comparator detection direction) of the differential voltage detection signal Vd from negative to positive or from positive to negative depending on whether the detection inductive backlash is generated or eliminated. For example, as Figure 5 , Figure 7 As shown, when the energizing phase is switched by switching the GND phase on the GND side (LO side energizing switch), the direction of the change in the differential voltage detection signal Vd when induced backlash occurs is from negative to positive, and the direction of the change in the differential voltage detection signal Vd when induced backlash is eliminated is from positive to negative. On the other hand, as Figure 6 , Figure 8As shown, when the energizing phase is switched by switching the PWM drive phase on the power supply side (HI-side energizing switch), the direction of the change detection of the differential voltage detection signal Vd when induced backlash is generated is from positive to negative, and the direction of the change detection of the differential voltage detection signal Vd when induced backlash is eliminated is from negative to positive. The zero-crossing detection signal generation unit 121 generates a zero-crossing detection signal Zo based on backlash generation and backlash elimination in sequence by switching this change detection direction.

[0106] After detecting the generation and elimination of induced recoil, the recoil detection unit 122 detects the zero-crossing for power-on switching by switching the detection direction (comparator detection direction) of the differential voltage detection signal Vd from negative to positive or from positive to negative. For example, as Figure 5 , Figure 7 As shown, when the energizing phase is switched by switching the GND phase on the GND side (LO side energizing switch), the detection direction of the differential voltage detection signal Vd is switched from negative to positive to perform zero-crossing detection for energizing switch. On the other hand, as Figure 6 , Figure 8 As shown, when the energized phase is switched by switching the PWM drive phase on the power supply side (HI-side energization switching), the change detection direction of the differential voltage detection signal Vd is switched from positive to negative to perform zero-crossing detection for energization switching. The zero-crossing detection signal generation unit 121 generates a zero-crossing detection signal Zo based on the backlash generation and backlash elimination for zero-crossing detection during energization switching by switching the change detection direction.

[0107] like Figures 5 to 8 As shown by the dotted line in the timing diagram representing the zero-crossing detection signal Zo, the inductive recoil detection unit 122 does not output the zero-crossing detection signal Zo, which is determined to be either recoil generation or recoil cancellation, to the rectangular wave control unit 13, but instead performs cancellation processing. It should be noted that the output of the zero-crossing detection signal Zo based on the zero-crossing detection used for power-on switching is not affected by the cancellation processing.

[0108] The state control unit 12 sets multiple zero-crossing detection modes during recoil generation, recoil elimination, and zero-crossing detection for power-on switching. These multiple zero-crossing detection modes include, for example, recoil / zero-crossing detection mode, recoil start mode, recoil end mode, and zero-crossing detection post-mode. The recoil / zero-crossing detection mode is set when recoil generation or zero-crossing for power-on switching is detected during power-on switching. The recoil start mode is set when recoil elimination is detected during recoil generation. The recoil end mode is set when zero-crossing for power-on switching is detected during recoil elimination. The zero-crossing detection post-mode is set by zero-crossing detection and remains in effect until the next power-on switching. It should be noted that when recoil is generated, the recoil / zero-crossing detection mode, recoil start mode, recoil end mode, and zero-crossing detection post-mode are set sequentially. When no recoil is generated or the recoil duration is extremely short, the zero-crossing detection post-mode is set after the recoil / zero-crossing detection mode.

[0109] Furthermore, the state control unit 12 uses a timer (power-on switching timer) that measures the time from the power-on switching of the rectangular wave control unit 13 to measure the various detection times from the power-on switching, including the generation of recoil, the elimination of recoil, and the zero crossing for power-on switching, which are detected by the zero-crossing detection signal generation unit 121 and determined by the inductive recoil detection unit 122.

[0110] During energization switching, there are situations where low load may prevent induced backlash, or where the time from the occurrence of induced backlash to its elimination is extremely short, making it impossible to detect zero-crossing caused by induced backlash. In such cases, when zero-crossing caused by induced backlash cannot be detected, based on the motor's characteristics, zero-crossings of both the induced voltage and the reference voltage used for energization switching occur within a certain time range, centered at an electrical angle of 30 degrees from the immediate energization switching. Since both the zero-crossing caused by induced backlash and the zero-crossing used for energization switching change in the same direction of sign change in the differential voltage between the induced voltage and the reference voltage, identifying them is crucial.

[0111] On the other hand, if the time from the generation of induced backlash to its elimination is sufficiently long, a zero-crossing caused by the generation of induced backlash occurs immediately after the power-on switch. At this time, for zero-crossings generated during the shielding period based on PWM drive shielding or PWM power-on cut-off shielding, they are detected by maintaining the zero-crossing state (later than the actual generation of the zero-crossing) when the shielding is released after the shielding period has elapsed. Therefore, for zero-crossings caused by induced backlash, the timing of the start of the PWM cycle is not synchronized with the power-on switch, but there is a period during which the PWM drive is not shielded or the PWM power-on cut-off shielding is not used until one cycle from the power-on switch to the PWM drive. Therefore, it can be detected within the elapsed time of one cycle from the power-on switch to the PWM drive.

[0112] In either of these cases, the zero crossing caused by induced backlash and the zero crossing used for energizing switching can be determined by using the elapsed time from the immediate energizing switching to the generation of the first zero crossing, rather than by using the direction of the change in the sign of the differential voltage between the induced voltage and the reference voltage.

[0113] When the state control unit 12 is set to the recoil / zero-crossing detection mode, when a zero-crossing detection signal Zo generated by the zero-crossing detection signal generation unit 121 is detected, the recoil detection unit 122 performs recoil / zero-crossing determination processing. That is, the recoil detection unit 122 performs determination processing based on the detection timing of the zero-crossing detection signal Zo in the recoil / zero-crossing detection mode to determine whether the detected zero-crossing is caused by recoil or based on the zero-crossing used for power-on switching.

[0114] Specifically, if the elapsed time since the power-on switching of the zero-crossing detection signal Zo is within a specified value, the inductive recoil detection unit 122 performs a recoil / zero-crossing determination process to determine that it is a recoil generated by recoil; if the elapsed time since the power-on switching of the zero-crossing detection signal Zo is not within the specified value, it performs a recoil / zero-crossing determination process to determine that it is a zero-crossing for power-on switching.

[0115] When the recoil detection unit 122 determines that recoil has occurred, it performs recoil detection processing. That is, the recoil detection unit 122 switches the state control unit 12 to recoil start mode and notifies the recoil shielding processing unit 123 of the occurrence of recoil.

[0116] When the state control unit 12 is set to the recoil start mode, when the zero-crossing detection signal Zo generated by the zero-crossing detection signal generation unit 121 is detected, the recoil detection unit 122 determines that recoil has been eliminated and performs recoil elimination detection processing. That is, the recoil detection unit 122 switches the state control unit 12 to the recoil end mode and notifies the recoil shielding processing unit 123 of the elimination of recoil.

[0117] When the state control unit 12 is set to the recoil / zero-crossing detection mode, the recoil / zero-crossing determination process determines that it is a zero-crossing situation for power-on switching. When the state control unit 12 is set to the recoil end mode and a zero-crossing detection signal Zo is detected, the recoil detection unit 122 performs zero-crossing detection processing. That is, the recoil detection unit 122 switches the state control unit 12 to the zero-crossing detection post-mode and notifies the recoil shielding processing unit 123 of the zero-crossing detection for power-on switching.

[0118] As described above, when the state control unit 12 is set to the recoil / zero-crossing detection mode or recoil start mode, when the generation and elimination of induced recoil are detected by detecting the zero-crossing detection signal Zo, the induced recoil detection unit 122 notifies the induced recoil shielding processing unit 123 of the generation and elimination of the detected induced recoil and the timing of the zero-crossing for power-on switching.

[0119] After the state control unit 12 switches to the recoil termination mode, and the new zero-crossing detection signal Zo is processed as a zero-crossing for power-on switching, the inductive recoil shielding processing unit 123 performs a process to shield the output of the zero-crossing detection signal Zo for a predetermined time. The process of shielding the output of the zero-crossing detection signal Zo is only required to prevent the zero-crossing detection signal Zo generated by the zero-crossing detection signal generation unit 121 from being output to the rectangular wave control unit 13 due to the generation of spikes and ringing caused by the elimination of inductive recoil.

[0120] After the elimination of induced recoil is detected by the induced recoil detection unit 122, the induced recoil shielding processing unit 123 shields the output of the zero-crossing detection signal Zo for a first predetermined time. The first predetermined time is set to be a sufficient time for the ringing generated after the elimination of induced recoil to stop. The first predetermined time and the second predetermined time are of the same length, but they can also be independently defined times.

[0121] The inductive recoil shielding processing unit 123 includes a recoil elimination shielding timer to determine whether to perform shielding processing within a first shielding time (recoil elimination shielding). The recoil elimination shielding timer counts the first shielding time upon receiving a notification of recoil elimination detected by the inductive recoil detection unit 122. During the period when the time counted by the recoil elimination shielding timer is equivalent to the first shielding time, the inductive recoil shielding processing unit 123 performs shielding processing and does not output the zero-crossing detection signal Zo generated by the zero-crossing detection signal generation unit 121 to the rectangular wave control unit 13. On the other hand, during periods other than the period when the time counted by the recoil elimination shielding timer is equivalent to the first shielding time, the inductive recoil shielding processing unit 123 outputs the zero-crossing detection signal Zo generated by the zero-crossing detection signal generation unit 121 to the rectangular wave control unit 13 without performing shielding processing.

[0122] exist Figure 5 In this circuit, the generation of induced backlash during LO-side power-on switching is indicated by the first × mark based on the zero-crossing of the induced voltage and the reference voltage. This zero-crossing is shielded from the generation of the zero-crossing detection signal Zo by PWM shielding (combined: obtained by combining PWM drive shielding (synthesis) and PWM power-on cut-off shielding). In this case, by making the induced voltage greater than the reference voltage, the zero-crossing detection signal Zo is generated at a delayed time after the shielding is released, and is used to detect the backlash generation in the induced backlash detection unit 122.

[0123] The elimination of induced recoil is indicated by a second × mark based on the zero crossing of the induced voltage and the reference voltage. A zero-crossing detection signal Zo is generated at this timing and used for the detection of recoil elimination in the induced recoil detection unit 122.

[0124] Regarding zero crossing for power-on switching, the PWM shield (comprehensive) generates a zero-crossing detection signal Zo during the off period, which is represented by a hollow + mark indicating zero crossing based on the induced voltage and the reference voltage, and is used for zero crossing detection for power-on switching in the induced backlash detection unit 122.

[0125] exist Figure 6 In the HI-side power-on switching, the generation of induced backlash is indicated by the first × mark based on the zero crossing of the induced voltage and the reference voltage. At this timing, a zero-crossing detection signal Zo is generated and used to detect the backlash generation in the induced backlash detection unit 122.

[0126] The elimination of induced recoil is indicated by a second × mark based on the zero-crossing of the induced voltage and the reference voltage. This zero-crossing is shielded by PWM shielding (integration) to prevent the generation of the zero-crossing detection signal Zo. By making the induced voltage greater than the reference voltage, the zero-crossing detection signal Zo is generated at a delayed time after the shielding is released, and is used for recoil elimination detection in the induced recoil detection unit 122. Therefore, the start of recoil elimination shielding is delayed.

[0127] Regarding the zero crossing used for power-on switching, the generation of the zero-crossing detection signal Zo is shielded by PWM shielding (combination). During the PWM shielding (combination) period, the zero-crossing detection signal Zo is generated at a timing of the delay indicated by the hollow + mark by the state of the induced voltage being less than the reference voltage. The generated zero-crossing detection signal Zo is used for zero-crossing detection in the induction recoil detection unit 122 for power-on switching.

[0128] exist Figure 7In the LO side power-on switching, the generation of induced backlash is indicated by the first × mark based on the zero crossing of the induced voltage and the reference voltage. This zero crossing is shielded by PWM shielding (integration) to prevent the generation of the zero-crossing detection signal Zo. By making the induced voltage greater than the reference voltage, the zero-crossing detection signal Zo is generated at a delayed time after the shielding is released, and is used to detect the backlash generation in the induced backlash detection unit 122.

[0129] The elimination of induced recoil is indicated by a second × mark based on the zero crossing of the induced voltage and the reference voltage. A zero-crossing detection signal Zo is generated at this timing and used for the detection of recoil elimination in the induced recoil detection unit 122.

[0130] The zero-crossing indicated by the hollow × mark is a state where the induced voltage is greater than the reference voltage, but the output of the zero-crossing detection signal Zo is shielded by the backflip to eliminate the shield.

[0131] Regarding zero crossing for power-on switching, the PWM shield (comprehensive) generates a zero-crossing detection signal Zo during the off period, which is represented by a hollow + mark indicating zero crossing based on the induced voltage and the reference voltage, and is used for zero crossing detection for power-on switching in the induced backlash detection unit 122.

[0132] exist Figure 8 In the HI-side power-on switching, the generation of induced backlash is indicated by the first × mark based on the zero crossing of the induced voltage and the reference voltage. At this timing, a zero-crossing detection signal Zo is generated and used to detect the backlash generation in the induced backlash detection unit 122.

[0133] The elimination of induced recoil is indicated by a second × mark based on the zero-crossing of the induced voltage and the reference voltage. This zero-crossing is shielded by PWM shielding (integration) to prevent the generation of the zero-crossing detection signal Zo. By making the induced voltage greater than the reference voltage, the zero-crossing detection signal Zo is generated at a delayed time after the shielding is released, and is used for recoil elimination detection in the induced recoil detection unit 122. Therefore, the start of recoil elimination shielding is delayed.

[0134] The zero-crossing indicated by the hollow × mark is a state where the induced voltage is less than the reference voltage, but the output of the zero-crossing detection signal Zo is shielded by the backflip to eliminate the shielding.

[0135] Regarding zero crossing for power-on switching, during the PWM shield (comprehensive) cut-off period, by becoming a state where the induced voltage is less than the reference voltage, the zero crossing detection signal Zo is generated at a timing of a delay represented by a hollow + mark, and the generated zero crossing detection signal Zo is used for zero crossing detection for power-on switching in the induced recoil detection unit 122.

[0136] Next, the operation of the shielding process accompanied by rectangular wave switching performed by the control circuit 1 of the motor drive control device 10 of the embodiment will be described.

[0137] First, the processing flow for shielding in PWM shielding (comprehensive) including the second shielding time (PWM drive shielding) and the shielding time during the power-on and power-off period of the energized phase (PWM power-on and power-off shielding) is explained.

[0138] In this example, instead of using a PWM period timer Tpwm to time the shielding period for the second shielding time (PWM drive shielding) and the shielding period during the power-on / off period of the energized phase (PWM power-on / off shielding), a PWM shielding timer Toffset and Twindow are used to time the shielding period for the PWM shielding (combined) period, which includes the second shielding time (PWM drive shielding) and the shielding period during the power-on / off period of the energized phase (PWM power-on / off shielding). The zero-crossing detection signal generation unit 121 has a PWM shielding timer.

[0139] Figure 9 This is a flowchart illustrating an example of the processing flow during the shielding process in PWM shielding (comprehensive), which includes the second shielding time (PWM drive shielding) and the shielding time during the power-on and power-off period of the energized phase (PWM power-on and power-off shielding). Figure 10 This is a diagram used to illustrate the timing of PWM shielding (comprehensive), which includes PWM drive shielding and PWM power-on / off shielding.

[0140] exist Figure 10The diagram, starting from the top, shows a triangular wave representing one PWM cycle of the center-aligned PWM drive, the value of the PWM cycle timer Tpwm, the waveform of the drive signal on the HI side of the PWM drive phase (energized phase), the waveform of the drive signal on the LO side of the PWM drive phase (energized phase), the PWM drive shield (HI side of the PWM drive phase) as a shield accompanying the rectangular wave switching, the PWM drive shield (LO side of the PWM drive phase), the PWM drive shield (synthesized) obtained by combining the PWM drive shielding periods of the HI side and LO side of the PWM drive phase, the PWM energization cutoff shield, and the PWM shield (synthesized) obtained by combining the shielding periods accompanying the rectangular wave switching (PWM drive shield (synthesized) + PWM energization cutoff shield), the values ​​of the PWM shielding timers Toffset and Twindow. The PWM drive phase (energized phase) on the HI side and the PWM drive phase (energized phase) on the LO side are the same phase, and in this example, they switch complementaryly. At this time, in the PWM period Tperiod, the period from t1 to t2 and the period from t3 to t4 in the PWM period timer are the dead time, the period from 0 to t1 and the period from t4 to Tperiod are the PWM drive phase LO side on-time, and the period from t2 to t3 is the PWM drive phase HI side on-time. Therefore, the drive is performed with a duty cycle Tduty, and the duty cycle of the drive signal is Tduty / Tperiod.

[0141] It should be noted that in this example, the lower triangular wave defines the switching timing of the HI side of the PWM drive phase (energized phase), and the upper triangular wave defines the switching timing of the LO side of the PWM drive phase (energized phase). In this example, two triangular waves are used to set the dead time during switching to stagger the switching timings, but a single triangular wave can also be used to simultaneously and complementaryly perform the switching timings of the PWM energized phases on both sides.

[0142] To avoid false detection of spikes and ringing in the voltage waveforms of the induced voltage and reference voltage generated during the switching of the rectangular wave, PWM drive shielding sets Tpwm_on_mask for when the switch is turned on and Tpwm_off_mask for when the switch is turned off.

[0143] The PWM drive masking (synthesis) Tpwm_mask_f and Tpwm_mask_r obtained by synthesizing the HI side and LO side of the PWM drive mask are aligned in the center. The first half of a PWM cycle of the PWM drive is the time from the cut-off of the LO side of the PWM drive phase to the turn-on of the HI side of the PWM drive phase, which is the time elapsed by Tpwm_on_mask. The second half of the PWM cycle is the time from the cut-off of the HI side of the PWM drive phase to the turn-on of the LO side of the PWM drive phase, which is the time elapsed by Tpwm_on_mask.

[0144] The PWM power-on / off shield is used to prevent the influence of external electromagnetic noise on the induced voltage and reference voltage during the non-energized period of the HI side of the PWM drive phase, and in situations where half of the power supply voltage is used in the reference voltage but the differential voltage between the reference voltage and the induced voltage cannot be utilized because the reference voltage does not change. In the case of center-aligned PWM drive, the PWM power-on / off shield has a Tde_mask_f for the first half of the PWM cycle and a Tde_mask_r for the second half. The power-on / off period of the energized phase based on this PWM power-on / off shield varies according to the PWM drive duty cycle.

[0145] like Figure 10 As shown in the slanted section, the shielding that combines the PWM drive shielding and the PWM power-on / off shielding, which is accompanied by rectangular wave switching, is the PWM shielding (combined). The first half of a PWM cycle of the PWM drive is the time from the start of the PWM cycle and the turn-on of the HI side of the PWM drive phase until the time Tpwm_on_mask has elapsed. The second half is the time from the turn-off of the HI side of the PWM drive phase to the end of the PWM cycle, i.e., the PWM cycle Tperiod.

[0146] In PWM masking (synthesis), the PWM masking timer Toffset, which starts timing synchronously with the PWM period timer Tpwm, masks the first half of the PWM period from 0 to t101, and the PWM masking timer Twindow, which starts timing from t101, masks the second half of the PWM period from t102 to the PWM period Tperiod.

[0147] In this embodiment, the state control unit 12 of the zero-crossing detection signal generation unit 121 receives the drive command signal So generated by the rectangular wave control unit 13, and the zero-crossing detection signal generation unit 121 performs processing at a predetermined timing. However, it is not limited to this; alternatively, the state control unit 12 or the zero-crossing detection signal generation unit 121 and the rectangular wave control unit 13 may control their respective timers based on the same triangular wave timing, thereby executing independently.

[0148] like Figure 9 As shown, in the shielding process (step S100) of PWM shielding (synthesis), firstly, at the timing of the beginning of the triangular wave period, the rectangular wave control unit 13 starts timing based on the PWM period timer Tpwm, and the zero-crossing detection signal generation unit 121 starts timing based on the PWM shielding timer Toffset (step S110). After the rectangular wave control unit 13 starts timing based on the PWM period timer Tpwm, it determines whether the PWM period timer Tpwm has reached t1, which is the LO side off time (step S120). At this time, from the beginning time of the PWM period, the zero-crossing detection signal generation unit 121 performs shielding processing without generating the zero-crossing detection signal Zo.

[0149] When it is determined that the PWM period timer Tpwm reaches t1, which is the LO side cutoff time (step S120: Yes), the rectangular wave control unit 13 generates a drive command signal So for cutting off the LO side FET of the PWM drive phase (step S130).

[0150] After generating the drive command signal So for cutting off the LO-side FET of the PWM drive phase, the rectangular wave control unit 13 further determines whether the PWM period timer Tpwm has reached t2, which is the HI-side turn-on time (step S140). When it is determined that the PWM period timer Tpwm has reached t2, which is the HI-side turn-on time (step S140: yes), the drive command signal So for turning on the HI-side FET of the PWM drive phase is generated (step S150).

[0151] After receiving the drive command signal So for turning on the HI-side FET of the generated PWM drive phase, the zero-crossing detection signal generation unit 121 further determines whether the PWM masking timer Toffset has reached the offset time t101 (step S160).

[0152] When it is determined that the PWM masking timer Toffset has reached the offset time t101 (step S160: Yes), the zero-crossing detection signal generation unit 121 performs a process to enable the output of the zero-crossing detection signal Zo, and starts timing based on the PWM masking timer Twindow from zero (step S170). Then, it determines whether the PWM masking timer Twindow has reached the window time t102 (step S180). During this period, the masking is deactivated in a manner that allows the zero-crossing detection signal Zo to be output to the induction backlash detection unit 122.

[0153] When it is determined that the PWM masking timer Twindow has reached the window time t102 (step S180: Yes), the zero-crossing detection signal generation unit 121 performs the process of invalidating the output of the zero-crossing detection signal Zo again (step S190). At this time, the masking process starts again without outputting the zero-crossing detection signal Zo to the induction backflash detection unit 122.

[0154] The rectangular wave control unit 13 determines whether the HI side cutoff time, which is the PWM period timer Tpwm, has been reached (step S200). When it is determined that the HI side cutoff time, which is the PWM period timer Tpwm, has been reached (step S200: yes), a drive command signal So for cutting off the HI side FET of the PWM drive phase is generated (step S210).

[0155] The rectangular wave control unit 13 further determines whether the PWM period timer Tpwm has reached t4, which is the LO side turn-on time (step S220). When it is determined that the PWM period timer Tpwm has reached t4, which is the LO side turn-on time (step S220: yes), a drive command signal So for turning on the LO side FET of the PWM drive phase is generated (step S230).

[0156] The rectangular wave control unit 13 determines whether the PWM period timer Tpwm has reached the PWM period Tperiod (step S240). If the PWM period timer Tpwm has reached the PWM period Tperiod, it returns to step S110. In this example, the offset time t101 and window time t102 of the PWM mask timer are configured to operate independently of the PWM period timer. However, the offset time t101 of the PWM mask timer can be synchronized with t2+Tpwm_on_mask of the PWM period timer, and the window time t102 of the PWM mask timer can also be synchronized with t3 of the PWM period timer.

[0157] Next, based on Figure 11 , Figure 12 The process flow for the first shielding time (backflush shielding) is explained.

[0158] Figure 11 , Figure 12 This is a flowchart illustrating an example of the processing flow during the first shielding time (backflush shielding). Figure 11 This is an example of a power-on switching scenario on the LO side. Figure 12 This is an example of a power-on switching scenario on the HI side. Figure 11 Examples and Figure 5 , Figure 7 The corresponding timing diagram, Figure 12 Examples and Figure 6 , Figure 8 The corresponding timing diagram.

[0159] like Figure 11 As shown, in the shielding process during LO side power-on switching (step S300), firstly, LO side power-on switching processing is performed in control circuit 1 (step S310). Specifically, the rectangular wave control unit 13 changes the setting of the power-on phase of inverter circuit 2a (power-on switching). Afterwards, the rectangular wave control unit 13 resets the power-on switching timer Tsector in the counter (step S311). Moreover, the induction recoil detection unit 122 sets the state control unit 12 to recoil / zero-crossing detection mode (step S312), and switches the change detection direction of the differential voltage detection signal Vd in the zero-crossing detection signal generation unit 121 from negative to positive.

[0160] The inductive recoil detection unit 122 determines whether a zero crossing has been detected by monitoring the zero-crossing detection signal Zo generated in the zero-crossing detection signal generation unit 121 (step S320). Zero crossing detection can be determined by the signal of the differential voltage detection signal Vd in the zero-crossing detection signal generation unit 121 changing from positive to negative or from negative to positive. However, in step S310, the direction of the change detection of the differential voltage detection signal Vd in the zero-crossing detection signal generation unit 121 is switched from negative to positive. Therefore, when the signal of the differential voltage detection signal Vd changes from negative to positive, a zero-crossing detection signal Zo can be generated, and a zero-crossing detection is determined (step S320: Yes).

[0161] When the recoil detection unit 122 determines that a zero crossing has been detected (step S320: Yes), it determines whether the current setting of the state control unit 12 is a recoil / zero crossing detection mode (step S330). If the first zero crossing since the power-on switch is detected, the state control unit 12 is set to the recoil / zero crossing detection mode in step S312, so it can be determined that the current setting is the recoil / zero crossing detection mode (step S330: Yes).

[0162] When the state control unit 12 is determined to be in the backflip / zero-crossing detection mode (step S330: Yes), the induction backflip detection unit 122 determines whether the elapsed time of the power-on switching timer Tsector, which was reset in the LO-side power-on switching process of step S310, is within a predetermined value (step S340). The predetermined value of the elapsed time is set to a sufficiently short time that may generate induction backflip, for example, it is set to the time of one cycle of PWM drive. That is, if the induction backflip detection unit 122 detects a zero-crossing within one cycle of PWM drive from the time the energized phase of the coil is switched, it is assumed that induction backflip has occurred, and the induction backflip detection unit 122 performs backflip generation detection processing (step S350). On the other hand, if the induction backflip detection unit 122 detects a zero-crossing after the predetermined value, it is assumed that a zero-crossing for power-on switching is detected, and no backflip generation detection processing or backflip elimination detection processing is performed, but the zero-crossing detection processing described later in step S360 is performed.

[0163] When it is determined that the elapsed time since the first zero crossing from the power-on switch is within a specified value (step S340: Yes), the inductive recoil detection unit 122 is set to have generated an inductive recoil, and recoil generation detection processing is performed (step S350). The state control unit 12 is set to recoil start mode (step S351), and the process returns to step S320. The recoil generation detection processing is the processing that accompanies the detection of inductive recoil generation. In the recoil generation detection processing, the inductive recoil detection unit 122 notifies the inductive recoil shielding processing unit 123 of the generation of inductive recoil, and cancels the output of the rectangular wave control unit 13 on the zero-crossing detection signal Zo generated by the generation of inductive recoil. In the zero-crossing detection signal generation unit 121, the change detection direction of the differential voltage detection signal Vd is switched from positive to negative.

[0164] If the recoil detection unit 122 determines that a second zero crossing has been detected since the power-on switch (step S320: Yes), it again determines whether the state control unit 12 is in recoil / zero crossing detection mode (step S330). However, since the state control unit 12 was already set to recoil start mode in the previous step S351, the result is no. In this case, it further determines whether the state control unit 12 is in recoil start mode (step S400). However, since the state control unit 12 was already set to recoil start mode in the previous step S351, the result is yes.

[0165] When the state control unit 12 is determined to be in recoil start mode during the second zero-crossing detection after power-on switching (step S400: Yes), the recoil detection unit 122 is set to recoil elimination, and recoil elimination detection processing is performed (step S410). Recoil elimination detection processing is a process that accompanies the detection of recoil elimination. In recoil elimination detection processing, the recoil detection unit 122 notifies the recoil shielding processing unit 123 of recoil elimination, and cancels the output of the rectangular wave control unit 13 by cancelling the generated zero-crossing detection signal Zo.

[0166] When a notification of induced recoil cancellation is received, the induced recoil shielding processing unit 123 starts the recoil cancellation shielding timer Tkb_end_mask (step S411). On the other hand, the induced recoil detection unit 122 further changes the state control unit 12 from recoil start mode to recoil end mode (step S412), and switches the direction of change detection of the differential voltage detection signal Vd from negative to positive in the zero-crossing detection signal generation unit 121.

[0167] When the state control unit 12 is set to the recoil end mode, the recoil shielding processing unit 123 invalidates the output of the zero-crossing detection signal Zo (step S413) and determines whether the recoil elimination shielding timer has reached the first shielding time (step S420). If the recoil shielding processing unit 123 determines that the recoil elimination shielding timer has reached the first shielding time (step S420: Yes), it invalidates the output of the zero-crossing detection signal Zo (step S421), de-shields the process, and returns to the process in step S320.

[0168] If the recoil detection unit 122 determines that a third zero crossing has been detected since the power-on switch (step S320: Yes), the recoil detection unit 122 again determines whether the state control unit 12 is in recoil / zero crossing detection mode (step S330). However, since the state control unit 12 was already set to recoil end mode in the previous step S412, it is no. In this case, it further determines whether the state control unit 12 is in recoil start mode (step S400). However, since the state control unit 12 was already set to recoil end mode in the previous step S412, it is no.

[0169] The inductive recoil detection unit 122 sets the zero-crossing detection when the state control unit 12 is set to the recoil end mode, i.e., the third zero-crossing detection from the power-on switching, to detect the zero-crossing used for power-on switching, and performs zero-crossing detection processing (step S360). If no inductive recoil occurs, zero-crossing detection processing is also performed at the first zero-crossing from the power-on switching (step S360). After the zero-crossing detection processing in step S360, the inductive recoil detection unit 122 sets the state control unit 12 to the zero-crossing detection post-mode (step S361), sets the zero-crossing detection signal Zo to the zero-crossing used for power-on switching, and notifies the inductive recoil shielding processing unit 123 of the detection of the zero-crossing used for power-on switching.

[0170] The inductive recoil shielding processing unit 123 sets the zero-crossing detection signal Zo in step S360 as a zero-crossing detection for power-on switching. When a notification for zero-crossing detection for power-on switching is received, the first shielding time has elapsed (step S420: Yes), and the shielding processing is released. Therefore, the zero-crossing detection signal Zo generated by the zero-crossing detection signal generation unit 121 is output to the rectangular wave control unit 13. The rectangular wave control unit 13 sets the power-on phase switching time in the power-on switching timer Tsector (step S362), and determines whether the power-on switching timer Tsector has reached the power-on phase switching time (step S370).

[0171] When it is determined that the power-on switching timer Tsector of the rectangular wave control unit 13 has reached the power-on phase switching time (step S370: Yes), the control circuit 1 switches to... Figure 12 The HI side power-on switching is shown in step S380.

[0172] like Figure 12 As shown, in the shielding process during HI-side power-on switching (step S500), firstly, HI-side power-on switching processing is performed in control circuit 1 (step S510). Specifically, the rectangular wave control unit 13 changes the setting of the power-on phase of inverter circuit 2a (power-on switching). Afterwards, the rectangular wave control unit 13 resets the power-on switching timer Tsector in the counter (step S511). Moreover, the induction recoil detection unit 122 sets the state control unit 12 to recoil / zero-crossing detection mode (step S512), and switches the direction of change detection of the differential voltage detection signal Vd in the zero-crossing detection signal generation unit 121 from positive to negative.

[0173] The inductive recoil detection unit 122 determines whether a zero-crossing has been detected by monitoring the zero-crossing detection signal Zo generated in the zero-crossing detection signal generation unit 121 (step S520). Zero-crossing detection can be determined by the change in the differential voltage detection signal Vd in the zero-crossing detection signal generation unit 121 from positive to negative or from negative to positive. However, in step S510, the direction of the change in the differential voltage detection signal Vd in the zero-crossing detection signal generation unit 121 is switched from positive to negative. Therefore, when the differential voltage detection signal Vd changes from positive to negative, a zero-crossing detection signal Zo can be generated, and a zero-crossing detection is determined (step S520: Yes).

[0174] When the recoil detection unit 122 determines that a zero crossing has been detected (step S520: Yes), it determines whether the current setting of the state control unit 12 is a recoil / zero crossing detection mode (step S530). If the first zero crossing since the power-on switch is detected, the state control unit 12 is set to the recoil / zero crossing detection mode in step S512, so it can be determined that the current setting is the recoil / zero crossing detection mode (step S530: Yes).

[0175] When the state control unit 12 is determined to be in recoil / zero-crossing detection mode (step S530: Yes), the recoil detection unit 122 determines whether the elapsed time of the power-on switching timer Tsector, which was reset in the HI-side power-on switching process of step S510, is within a predetermined value (step S540). The predetermined value of the elapsed time is set to a sufficiently short time that may generate recoil, for example, it is set to the time of one cycle of PWM drive. That is, if the recoil detection unit 122 detects a zero-crossing within one cycle of PWM drive from the time the energized phase of the coil is switched, it is assumed that recoil has occurred, and the recoil detection unit 122 performs recoil generation detection processing (step S550). On the other hand, if the recoil detection unit 122 detects a zero-crossing after the predetermined value, it is assumed that a zero-crossing for power-on switching is detected, and recoil generation detection processing and recoil elimination detection processing are not performed, but the zero-crossing detection processing described later in step S560 is performed.

[0176] When it is determined that the elapsed time since the first zero crossing from the power-on switch is within a predetermined value (step S540: Yes), the induction recoil detection unit 122 is set to have generated induction recoil, and recoil generation detection processing is performed (step S550). The state control unit 12 is set to recoil start mode (step S551), and the process returns to step S520. The recoil generation detection processing is the processing that accompanies the detection of induction recoil generation. In the recoil generation detection processing, the induction recoil detection unit 122 notifies the induction recoil shielding processing unit 123 of the generation of induction recoil, and cancels the output of the rectangular wave control unit 13 on the zero-crossing detection signal Zo generated by the generation of induction recoil. In the zero-crossing detection signal generation unit 121, the change detection direction of the differential voltage detection signal Vd is switched from negative to positive.

[0177] If the recoil detection unit 122 determines that a second zero crossing has been detected since the power-on switch (step S520: Yes), it again determines whether the state control unit 12 is in recoil / zero crossing detection mode (step S530). However, since the state control unit 12 was already set to recoil start mode in the previous step S551, the result is no. In this case, it further determines whether the state control unit 12 is in recoil start mode (step S600). However, since the state control unit 12 was already set to recoil start mode in the previous step S551, the result is yes.

[0178] When the state control unit 12 is determined to be in recoil start mode during the second zero-crossing detection after power-on switching (step S600: Yes), the inductive recoil detection unit 122 is set to inductive recoil cancellation, and recoil cancellation detection processing is performed (step S610). Recoil cancellation detection processing is a process that accompanies the detection of inductive recoil cancellation. In recoil cancellation detection processing, the inductive recoil detection unit 122 notifies the inductive recoil shielding processing unit 123 of the cancellation of inductive recoil, and cancels the output of the rectangular wave control unit 13 by cancelling the generated zero-crossing detection signal Zo.

[0179] When a notification of induced recoil cancellation is received, the induced recoil shielding processing unit 123 starts the recoil cancellation shielding timer Tkb_end_mask (step S611). On the other hand, the induced recoil detection unit 122 further changes the state control unit 12 from recoil start mode to recoil end mode (step S612), and switches the direction of change detection of differential voltage detection signal Vd from positive to negative in the zero-crossing detection signal generation unit 121.

[0180] When the state control unit 12 is set to the recoil end mode, the recoil shielding processing unit 123 invalidates the output of the zero-crossing detection signal Zo (step S613) and determines whether the recoil elimination shielding timer has reached the first shielding time (step S620). If the recoil shielding processing unit 123 determines that the recoil elimination shielding timer has reached the first shielding time (step S620: Yes), it invalidates the output of the zero-crossing detection signal Zo (step S621), de-shields the process, and returns to the process in step S520.

[0181] If the recoil detection unit 122 determines that a third zero-crossing has been detected since the power-on switch (step S520: Yes), the recoil detection unit 122 again determines whether the state control unit 12 is in recoil / zero-crossing detection mode (step S530). However, since the state control unit 12 was already set to recoil end mode in the previous step S612, it is no. In this case, it further determines whether the state control unit 12 is in recoil start mode (step S600). However, since the state control unit 12 was already set to recoil end mode in the previous step S612, it is no.

[0182] The inductive recoil detection unit 122 sets the zero-crossing detection when the state control unit 12 is set to the recoil end mode, i.e., the third zero-crossing detection from the power-on switching, to detect the zero-crossing used for power-on switching, and performs zero-crossing detection processing (step S560). If no inductive recoil occurs, zero-crossing detection processing is also performed at the first zero-crossing from the power-on switching (step S560). After the zero-crossing detection processing in step S560, the inductive recoil detection unit 122 sets the state control unit 12 to the zero-crossing detection post-mode (step S561), sets the zero-crossing detection signal Zo to the zero-crossing used for power-on switching, and notifies the inductive recoil shielding processing unit 123 of the detection of the zero-crossing used for power-on switching.

[0183] The inductive recoil shielding processing unit 123 sets the zero-crossing detection signal Zo in step S560 as a zero-crossing detection for power-on switching. When a notification for zero-crossing detection for power-on switching is received, the first shielding time has elapsed (step S620: Yes), and the shielding processing is released. Therefore, the zero-crossing detection signal Zo generated by the zero-crossing detection signal generation unit 121 is output to the rectangular wave control unit 13. The rectangular wave control unit 13 sets the power-on phase switching time in the power-on switching timer Tsector (step S562), and determines whether the power-on switching timer Tsector has reached the power-on phase switching time (step S570).

[0184] When it is determined that the power-on switching timer Tsector of the rectangular wave control unit 13 has reached the power-on phase switching time (step S570: Yes), the control circuit 1 switches to... Figure 11The LO side power-on switching is shown in step S580.

[0185] In the control circuit 1 of the motor drive control device 10 of this embodiment, a differential voltage detection signal is detected based on the phase voltage of each phase. This signal is the differential voltage between the induced voltage generated in the coil of the non-energized phase and the reference voltage. Based on the detection of the zero crossing of the detected differential voltage detection signal, a drive command signal (So) is generated to generate a drive control signal Sd in the PWM signal generation unit (14). This drive control signal Sd is a rectangular wave signal that turns the switch of the inverter circuit 2a on / off by switching the energized phase of the coil and the energized state of the coil that is in the energized phase. In this control circuit 1, after the energized phase of the coil is switched, the generation and elimination of induced backlash generated in the coil that is in the non-energized phase are detected. After the elimination of induced backlash is detected, the zero crossing detection is shielded for a first predetermined time. The zero crossing detection is shielded for a second predetermined time when the rising and falling edges of the rectangular wave signal arrive at the timed intervals.

[0186] Therefore, the motor drive control device 10 can reliably avoid false detections of zero crossings during power-on switching caused by spikes and ringing, even when driving under high rotation / high output / high load conditions.

[0187] In the control circuit 1 of the motor drive control device 10 of this embodiment, the motor is driven by generating a drive control signal Sd that turns on / off the high-side switch and the low-side switch of the inverter circuit 2a that energizes the coil. The zero-crossing detection is shielded when the on / off timing of the switch of the PWM drive phase of the energized phase in the high-side switch and the low-side switch of the inverter circuit 2a arrives, covering the second predetermined time.

[0188] Therefore, even when the motor drive control device 10 is driven by the control of switching the inverter circuit 2a on / off, it can reliably avoid false detection of zero crossings for power-on switching caused by spikes and ringing.

[0189] In the control circuit 1 of the motor drive control device 10 of this embodiment, after the execution of the PWM drive shielding process that shields the zero-crossing detection for a second predetermined time is completed, the recoil elimination shielding process that shields the zero-crossing detection for a first predetermined time is executed.

[0190] Therefore, by covering both the first and second shielding times, the motor drive control device 10 can avoid false detection of zero crossings during power-on switching.

[0191] In the control circuit 1 of the motor drive control device 10 of this embodiment, in addition to shielding based on the first predetermined time and the second predetermined time, the zero-crossing detection is also shielded during the power-on cut-off period, which is the period during which the switch of the PWM drive phase of the energized phase is cut off.

[0192] Therefore, even when the motor drive control device 10 is not powered on, it can accurately detect the zero crossing for power-on switching, even when it is necessary to avoid the influence of external electromagnetic noise on the induced voltage and reference voltage, and when using 1 / 2 of the power supply voltage in the reference voltage.

[0193] In the control circuit 1 of the motor drive control device 10 in this embodiment, the induction recoil detection unit 122 switches the zero-crossing detection mode based on the differential voltage detection signal according to the power-on switching method.

[0194] Therefore, even in the absence of induced backlash and when the duration of induced backlash is extremely short, the zero crossing used for power-on switching can be accurately detected.

[0195] In the control circuit 1 of the motor drive control device 10 in this embodiment, the induction backflip detection unit 122 may be configured to detect the first zero crossing within a time period of one cycle after switching the energized phase of the coil to become PWM drive, and then process it as the generation of induction backflip.

[0196] Therefore, even without induced backlash, the detected zero crossing can be accurately identified as the zero crossing used for power-on switching.

[0197] Extension of Implementation Methods The invention made by the inventor has been specifically described above based on the embodiments. However, the invention is not limited thereto and various modifications can be made without departing from its spirit.

[0198] Furthermore, in this embodiment, an example is shown where the speed command signal Sc includes a target value (target rotational speed) of the rotational speed of the motor 3, but it is not limited to this. For example, the speed command signal Sc could also be a torque command signal specifying the torque of the motor 3.

[0199] Furthermore, in the embodiments, the control circuit 1 is not limited to the circuit configuration described above. The control circuit 1 can be configured in various ways to meet the objectives of the present invention.

[0200] Specifically, for example, multiple comparators or A / D converters can be used instead of the multiplexer in the differential voltage detection circuit 15. The differential voltage detection circuit 15 is as follows: Figure 3The circuit shown can be configured as either an analog circuit or a digital circuit. Furthermore, the differential voltage detection circuit 15 may not require a 1 / 2 shift of the power supply voltage.

[0201] Furthermore, in the embodiment, the driving signal of the HI-side energized phase that drives the motor is used to complementary turn on / off the high-side transistors (any one of the high-side switches Q1, Q3, and Q5) and the low-side transistors (any one of the low-side switches Q2, Q4, and Q6). However, it is also possible to use a configuration where the driving signal of the HI-side energized phase only turns on / off the high-side transistors (any one of the high-side switches Q1, Q3, and Q5).

[0202] Furthermore, in this implementation, the example of setting the PWM drive to center alignment is given, but edge alignment can also be used.

[0203] Furthermore, in the embodiment, an example is given of a PWM drive with the power supply side of the inverter circuit set as the PWM drive phase and a gate drive with the GND side set as the GND phase, which is powered on by turning on the HI side switch of the PWM drive phase and the LO side switch of the GND phase. However, it is also possible to replace the power supply side of the inverter circuit with a gate drive on the GND side and replace the GND phase with a PWM drive on the power supply side, which is powered on by turning on the HI side switch of the power supply phase and the LO side switch of the PWM drive phase.

[0204] Furthermore, in this implementation, the motor drive is not limited to a 120-degree energized rectangular wave drive. A 150-degree energized rectangular wave drive or a sine wave drive can also be used.

[0205] Furthermore, in this embodiment, the example is given where the PWM drive mask Tpwm_on_mask and Tpwm_off_mask are set as the second predetermined time, and the same value is used as the masking time when the switching element is turned on and off. However, different values ​​can also be used.

[0206] Furthermore, in the implementation, a PWM power-on cut-off shield Tde_mask is used, which sets the power-on cut-off period of the energized phase as the shielding time. However, the center point voltage can also be used as the reference voltage instead of 1 / 2 of the power supply voltage, thereby not utilizing the PWM power-on cut-off shield.

[0207] In this embodiment, the number of phases of the motor 3 driven by the motor drive control device 10 is not limited to three phases.

[0208] The flowchart above is a specific example and is not limited to it. For example, other processes can be inserted between steps, and the processes can be parallelized.

[0209] Explanation of reference numerals in the attached figures 1: Control circuit; 2: Drive circuit; 2a: Inverter circuit; 2b: Pre-drive circuit; 3: Motor; 10: Motor drive control device; 11: Drive command acquisition unit; 12: Status control unit; 121: Zero-crossing detection signal generation unit; 122: Induction recoil detection unit; 123: Induction recoil shielding processing unit; 13: Square wave control unit; 14: PWM signal generation unit; 15: Differential voltage detection circuit; 151: Multiple resistive elements for DC current limiting and voltage adjustment; 152: Multiplexer for phase selection measurement; 153: Differential amplifier circuit; 100: Motor unit; Q1~Q6: Switching elements; Sc: Speed ​​command signal; Sd: Drive control signal; ωref: Target speed; Zo: Zero-crossing detection signal; So: Drive command signal; Sm: Phase selection signal; Vd, Vd': Differential voltage detection signal; Vm: Selected phase voltage signal; Vn: Neutral point voltage (synthesized signal); Vdc, Vin: DC power supply; Vuh, Vul, Vvh, Vvl, Vwh, Vwl: Drive signals; Vu, Vv, Vw: Phase voltage signals; Lu, Lv, Lw: Coils.

Claims

1. A motor drive control device, the motor drive control device comprising: The control circuit generates a drive control signal for driving a motor with a coil having at least one phase. The drive circuit includes an inverter circuit comprising switches connected in series with each other and corresponding to the coils of each phase of the motor. The drive circuit responds to the drive control signal by turning the switches on / off to energize the coils of the corresponding phases and switches the energized phases at predetermined intervals, thereby causing the rotor of the motor to rotate. and A phase voltage detection circuit is used to detect the phase voltage generated between the coils of each phase of the inverter circuit and the motor. The control circuit has: The differential voltage detection circuit outputs a differential voltage, which is the induced voltage generated in the coil of the non-energized phase and the reference voltage, based on the detected phase voltage of each phase. and The PWM signal generation unit generates the drive control signal based on zero-crossing detection using the differential voltage detection signal. The drive control signal is a rectangular wave signal that switches the inverter circuit on / off by switching the energized phase of the coil and the energized state of the coil in the energized phase. When the generation and elimination of induced backlash in the coil that becomes the non-energized phase are detected after the energized phase of the coil is switched, The control circuit shields the zero-crossing detection for a first predetermined time after detecting the elimination of the induced backlash, and shields the zero-crossing detection for a second predetermined time when the rising and falling edges of the rectangular wave signal arrive at the appointed times.

2. The motor drive control device according to claim 1, wherein, The inverter circuit includes a high-side switch and a low-side switch. The PWM signal generation unit drives the motor by generating drive control signals that turn the high-side switch and the low-side switch of the inverter circuit that energizes the coil on / off. The control circuit shields the zero-crossing detection during the on / off timing of the PWM drive phase, which is the energized phase in the high-side and low-side switches of the inverter circuit, covering the second predetermined time.

3. The motor drive control device according to claim 1, wherein, After the execution of the PWM drive shielding process that shields the zero-crossing detection for the second predetermined time is completed, the control circuit executes the backlash elimination shielding process that shields the zero-crossing detection for the first predetermined time.

4. The motor drive control device according to claim 2, wherein, The inverter circuit includes a high-side switch and a low-side switch. The PWM signal generation unit drives the motor by generating a drive control signal that turns the inverter circuit energized by the coil on / off. The control circuit includes shielding the zero-crossing detection during the power-on / off period, which is the period during which the switch of the PWM drive phase of the energized phase is turned off.

5. The motor drive control device according to claim 1, wherein, After switching the energized phase of the coil, the control circuit further detects and eliminates the induced backlash generated in the coil that becomes the non-energized phase. In the control circuit, when the power supply side of the energized phase is switched by switching the HI side power supply, the direction of the change detection of the differential voltage detection signal when induced backlash is generated is changed from positive to negative, and the direction of the change detection of the differential voltage detection signal when induced backlash is eliminated is changed from negative to positive. When the GND side of the energized phase is switched by switching the LO side power supply, the direction of the change detection of the differential voltage detection signal when induced backlash is generated is changed from negative to positive, and the direction of the change detection of the differential voltage detection signal when induced backlash is eliminated is changed from positive to negative. Thus, the detection method based on the zero crossing of the differential voltage detection signal is switched according to the power supply switching method.

6. The motor drive control device according to claim 1, wherein, The control circuit detects the generation of induced backlash when it detects the first zero crossing within one cycle of PWM drive starting from the time the energized phase of the coil is switched.

7. A method for driving a motor, the method being executed in a motor drive control device, the motor drive control device comprising: a control circuit for generating a drive control signal for driving a motor having coils of at least one phase; a drive circuit having an inverter circuit including switches connected in series with each other and corresponding to the coils of each phase of the motor, the drive circuit responding to the drive control signal by turning the switches on / off to energize the coils of the corresponding phases, and switching the energized phases at predetermined time intervals, thereby rotating the rotor of the motor; and a phase voltage detection circuit for detecting the phase voltage generated between the inverter circuit and the coils of each phase of the motor. The motor drive control method has the following features: The first step is to output the differential voltage between the induced voltage generated in the coil of the non-energized phase and the reference voltage, based on the detected phase voltage of each phase. The second step is to perform zero-crossing detection based on the differential voltage detection signal; The third step is to generate the drive control signal based on the zero-crossing detection. The drive control signal is a rectangular wave signal that turns the inverter circuit on / off by switching the energizing phase of the coil and the energizing state of the coil that is in the energizing phase. The fourth step is to detect and eliminate the induced backlash generated in the coil that has become the non-energized phase after switching the energized phase of the coil. and The fifth step involves shielding the zero-crossing detection for a first predetermined time after detecting the elimination of the induced recoil, and shielding the zero-crossing detection for a second predetermined time when the rising and falling edges of the rectangular wave signal arrive.

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