JP7537857B2 - MOTOR DRIVE CONTROL DEVICE AND MOTOR DRIVE CONTROL METHOD - Google Patents

Description

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

Conventionally, there are known motors mounted on fans that suppress heat generation in a target system, and motor drive control devices that control the drive of such motors. Some motor drive control devices increase motor power when motor rotation is detected after the motor is started, while determining that the motor is in a constrained state when the motor's rotation state remains fixed for a certain period of time or more, thereby suppressing heat generation by stopping the motor.

JP 2008-125154 A

However, with conventional technology, for example, when the blades are heavy or the motor has a large starting torque, the increase in rotation speed at start-up is slow, making it difficult to shorten the start-up period from start-up to normal operation. In this regard, if the rotation speed were to be increased suddenly immediately after the motor was started, regardless of whether rotation was detected, the motor would continue to be instructed to increase its speed even when in a locked state, which would result in the motor generating a lot of heat.

The present invention has been made in consideration of the above, and aims to provide a motor drive control device and a motor drive control method that can rapidly start up while suppressing heat generation in the motor.

In order to solve the above-mentioned problems and achieve the object, a motor drive control device according to one aspect of the present invention includes a motor drive unit, a motor control unit, a rotational position detection unit, and a constraint determination unit. The motor drive unit drives a motor. The motor control unit outputs a drive control signal with a predetermined duty ratio to the motor drive unit. The rotational position detection unit detects the rotational position of the motor. The constraint determination unit determines whether the motor is in a constraint state based on the rotational position. The constraint determination unit continuously determines the constraint state in a first period after the motor is started and in a second period after the rotational speed has increased. In addition, the motor control unit increases the duty ratio of the drive control signal in the first period to increase the rotational speed in accordance with the detection timing of the rotational position, and when it is determined that the motor is not in a constraint state in the first period, continuously increases the duty ratio of the drive control signal regardless of the detection timing of the rotational position in the second period in which the rotational speed has increased . In addition, the motor control unit stops outputting the drive control signal if it is determined that the motor is in a locked state during the first period, and stops outputting the drive control signal if it is determined that the motor is in a locked state during the second period .

According to one aspect of the present invention, it is possible to rapidly start up the motor while suppressing heat generation.

FIG. 1 is a block diagram showing a circuit configuration of a motor drive control device according to an embodiment. FIG. 2 is a block diagram showing the configuration of the monitoring unit. FIG. 3 is a timing chart showing an example of an operation when the motor is started normally. FIG. 4 is a timing chart showing an example of operation when the motor is locked during the startup preparation period. FIG. 5 is a timing chart showing an example of operation when the motor is in a locked state during the start-up process. FIG. 6 is a flowchart showing the procedure of the process executed by the motor drive control device. FIG. 7 is a flowchart showing the procedure of the process executed by the motor drive control device.

The motor drive control device and the motor drive control method according to the embodiments will be described below with reference to the drawings. Note that the present invention is not limited to the embodiments described below.

(Embodiment)
1 is a block diagram showing a circuit configuration of a motor drive control device 1 according to an embodiment. The motor drive control device 1 according to the embodiment executes a motor drive control method. Specifically, in the motor drive control method according to the embodiment, the motor drive control device 1 outputs a drive control signal that increases the rotation speed in accordance with the detection timing of the rotation position of the motor 20 during a start-up preparation period (corresponding to a first period) after the start-up of the motor 20. Furthermore, when it is determined that the motor 20 is not in a constrained state during the start-up preparation period, the motor drive control device 1 outputs a drive control signal that continuously increases the rotation speed regardless of the detection timing of the rotation position during a start-up processing period (corresponding to a second period) after the start-up preparation period. Although details will be described later, the motor drive control method executed by the motor drive control device 1 includes a motor driving process for driving the motor 20, a motor control process for outputting a drive control signal to the motor drive unit 2 that executes the motor driving process, a rotational position detection process for detecting the rotational position of the motor 20, and a constraint determination process for determining whether or not the motor 20 is in a constraint state based on the rotational position, in which the motor control process increases the rotational speed in accordance with the detection timing of the rotational position during a startup preparation period (corresponding to a first period) after starting the motor 20, and if it is determined that the motor 20 is not in a constraint state during the startup preparation period, outputs a drive control signal that continuously increases the rotational speed during a startup processing period (corresponding to a second period) after the startup preparation period.

In other words, in the motor drive control method according to the embodiment, during the startup preparation period, the rotation speed is gradually increased in accordance with the rotation of the motor 20 while determining whether or not the motor 20 is in a locked state, so that an excessive increase in current (increase in rotation speed) is suppressed and heat generation by the motor 20 is suppressed. Also, during the startup processing period, if the motor 20 is not in a locked state, the rotation speed is continuously increased regardless of the rotation of the motor 20, so startup can be accelerated. In other words, according to the motor drive control method according to the embodiment, startup can be performed quickly while suppressing heat generation by the motor 20.

The motor drive control device 1 that executes the motor drive control method described above is described in detail below.

As shown in FIG. 1, the motor drive control device 1 includes a motor drive unit 2 that drives a motor 20, a drive control unit 3, and a rotational position detection unit 4. The motor drive control device 1 may be an integrated circuit device (IC) in which the motor drive unit 2, drive control unit 3, and rotational position detection unit 4 are all packaged, or the motor drive unit 2, drive control unit 3, and part of the rotational position detection unit 4 may be packaged as a single integrated circuit device, or all or part of the motor drive control device 1 may be packaged together with other devices to form a single integrated circuit device.

The motor 20 is, for example, a three-phase brushless motor, and is a fan motor that rotates a rotating body (not shown), such as a fan. The rotational position detection unit 4 detects the rotational position of the rotor of the motor 20 and outputs a rotor rotational position signal (rotational position detection process). The motor drive unit 2 rotates the motor 20 by passing a sinusoidal drive current through the coils Lu, Lv, and Lw of the armature of the motor 20 based on the rotor rotational position signal output from the rotational position detection unit 4. Note that the number of phases of the motor 20 is not limited to three, and it is not limited to a brushless motor, and may be a brushed motor.

The motor drive unit 2 drives the motor 20 by outputting a drive signal generated based on a drive control signal output from the drive control unit 3 (described later) to the motor 20 (motor drive process). Specifically, the motor drive unit 2 includes an inverter circuit 21 and a pre-drive circuit 22.

The inverter circuit 21 outputs a drive signal to the motor 20 based on an output signal output from the pre-drive circuit 22 described later, and energizes the coils Lu, Lv, and Lw of the armature of the motor 20. The inverter circuit 21 is configured, for example, by arranging pairs of two series circuits of switch elements (a pair of switch elements Q1 and Q2, a pair of switch elements Q3 and Q4, and a pair of switch elements Q5 and Q6) provided at both ends of the DC power supply Vcc for the coils Lu, Lv, and Lw of each phase (U phase, V phase, and W phase). In each pair of two switch elements, the connection point between the switch elements becomes an output terminal, and the terminals connected to the coils Lu, Lv, and Lw of each phase of the motor 20 are connected to the output terminal. Specifically, the connection point between the switch elements Q1 and Q2 is the output terminal connected to the terminal of the coil Lu of the U phase. Also, the connection point between the switch elements Q3 and Q4 is the output terminal connected to the terminal of the coil Lv of the V phase. The connection point between the switch elements Q5 and Q6 is the output terminal connected to the terminal of the W-phase coil Lw. In addition, the end of one of the pair of switch elements Q2, Q4, and Q6, opposite the connection end of the other switch element Q1, Q3, and Q5, is grounded via resistor R1.

The pre-drive circuit 22 generates an output signal for driving the inverter circuit 21 based on the drive control signal output from the drive control unit 3, and outputs it to the inverter circuit 21. The generated output signals are, for example, Vuu, Vul, Vvu, Vvl, Vwu, and Vwl, which correspond to the switch elements Q1 to Q6 of the inverter circuit 21, respectively. Specifically, the output signal Vuu is output to the switch element Q1, and the output signal Vul is output to the switch element Q2. The output signal Vvu is output to the switch element Q3, and the output signal Vvl is output to the switch element Q4. The output signal Vwu is output to the switch element Q5, and the output signal Vwl is output to the switch element Q6. Based on these output signals, the switch elements Q1 to Q6 corresponding to each output signal perform an on/off operation, and a drive signal is output to the motor 20 to supply power to the coils of each phase of the motor 20. When the rotation of the motor 20 is stopped, all of the switch elements Q1 to Q6 are turned off.

The pre-drive circuit 22 also outputs a motor rotation speed signal to the drive control unit 3. The motor rotation speed signal is input from the rotation position detection unit 4 to the drive control unit 3 via the pre-drive circuit 22. The motor rotation speed signal is, for example, an FG signal corresponding to the rotation position of the rotor of the motor 20. That is, the motor rotation speed signal is rotation speed information indicating the detection result of the rotation speed of the motor 20. The FG signal may be a signal (pattern FG) generated using a coil pattern provided on a board on the rotor side, or a signal (hall FG) generated using the output of a hall element arranged on the motor 20. In addition, a rotation position detection circuit that detects the back electromotive voltage induced in each phase (U, V, W phase) of the motor 20 may be configured as the rotation position detection unit 4, and the rotation position and rotation speed of the rotor of the motor 20 may be detected based on the detected back electromotive voltage, or a sensor signal such as an encoder that detects the rotation speed and rotation position of the motor 20 may be used.

The drive control unit 3 includes a motor control unit 31, a monitoring unit 32, a restraint determination unit 33, and a startup determination unit 34. The drive control unit 3 is configured, for example, with a microcomputer, a digital circuit, or the like. The drive control unit 3 also has a storage unit (not shown) in which various setting values for controlling various processes in the motor control unit 31, the monitoring unit 32, the restraint determination unit 33, and the startup determination unit 34 are stored in advance. Such a storage unit is configured, for example, with a non-volatile memory such as an EEPROM (Electrically Erasable Programmable Read-Only Memory). The drive control unit 3 is also supplied with a power supply voltage, which is the drive power, obtained by stepping down the DC power supply Vcc with a resistor R2, for example.

The motor control unit 31 generates a drive control signal, which is a PWM (pulse width modulation) signal, based on a speed command signal (a clock signal with a frequency corresponding to the target rotation speed) set by the user via an external terminal or the like and a motor rotation speed signal, and outputs the generated drive control signal to the pre-drive circuit 22 (motor control process). That is, the motor control unit 31 outputs a drive control signal for driving the motor 20 to the pre-drive circuit 22 while performing feedback by comparing the target rotation speed with the actual rotation speed (rotation speed) of the motor 20, thereby controlling the rotation of the motor 20. The speed command signal may be a PWM signal or a DC (direct current) signal.

When the motor control unit 31 receives a speed command signal, the motor control unit 31 transitions the control state from a stopped state to a startup preparation period state. Specifically, when the motor control unit 31 transitions to the startup preparation period, it outputs a drive control signal that increases the rotation speed according to the detection timing of the rotation position of the motor 20.

When the motor control unit 31 receives a judgment result indicating a transition to the startup processing period from the startup judgment unit 34 described below, the motor control unit 31 transitions the control state from the startup preparation period state to the startup processing period state. Specifically, when the motor control unit 31 transitions to the startup processing period, it outputs a drive control signal that continuously increases the rotation speed of the motor 20 regardless of the detection timing of the rotation position.

In addition, the motor control unit 31 stops outputting the drive control signal when it receives a notification from the restraint determination unit 33 (described below) that the motor 20 is in a restrained state, regardless of whether the motor control unit 31 is in the startup preparation period or the startup processing period. In other words, the motor control unit 31 stops the motor 20.

The monitoring unit 32 receives a motor rotation speed signal from the pre-drive circuit 22 and monitors the rotation state of the motor 20. Specifically, when the monitoring unit 32 receives a speed command signal via an external terminal or the like while the power supply voltage is being supplied, it monitors the rotation state of the motor 20.

In FIG. 1, the speed command signal is input from the outside to the motor control unit 31 and the monitoring unit 32, but this is not limited to the above. The signal may be input to the drive control unit 3 and then input to the motor control unit 31 and the monitoring unit 32, or either the motor control unit 31 or the monitoring unit 32 may receive the speed command signal and output it to the other.

The configuration of the monitoring unit 32 will now be described in detail with reference to FIG. 2. FIG. 2 is a block diagram showing the configuration of the monitoring unit 32. As shown in FIG. 2, the monitoring unit 32 includes a start-up determination unit 321, a restraint detection timer 322, and a startup preparation timer 323.

When the power supply voltage and speed command signal are input, the start-up determination unit 321 determines that the motor 20 has started, and starts the lock detection timer 322 and the startup preparation timer 323.

The lock detection timer 322 is a timer for detecting the locked state of the motor 20. The lock detection timer 322 starts the timer in response to a start determination by the start determination unit 321. In addition, if a motor rotation speed signal is input after the timer has started in response to the start determination, the lock detection timer 322 resets the timer and restarts the timer.

If the motor rotation speed signal is not input for a predetermined lock detection period (corresponding to the third period) or longer, the lock detection timer 322 notifies the lock determination unit 33 of this fact. In other words, if the state in which the motor rotation speed signal is not input continues and the lock detection period expires, the lock detection timer 322 notifies the lock determination unit 33 of the expiration.

The startup preparation timer 323 is a timer for the startup preparation period. Specifically, the startup preparation timer 323 starts the timer upon startup determination, and when the timer reaches a preset time, ends the timer and notifies the startup determination unit 34 of the end. In other words, the start of the startup preparation timer 323 corresponds to the start timing of the startup preparation period, and the end of the startup preparation timer 323 corresponds to the end timing of the startup preparation period, in other words, the start timing of the startup processing period.

Returning to FIG. 1, the restraint determination unit 33 will be described. The restraint determination unit 33 determines whether the motor 20 is in a restrained state based on the rotational position of the motor 20 (restraint determination process). Specifically, the restraint determination unit 33 determines that the motor 20 is in a restrained state when it receives a notification from a restraint detection timer 322 that is controlled by a motor rotation speed signal output from the pre-drive circuit 22. In other words, the restraint determination unit 33 determines that the motor 20 is in a restrained state when the rotational position of the motor 20 is not detected for a period of time equal to or longer than the restraint detection period.

Then, if the restraint determination unit 33 determines that the motor 20 is in a restrained state, it notifies the motor control unit 31.

The constrained state of the motor 20 may include, in addition to a state in which the motor 20 is completely fixed and stops rotating (completely constrained state), a state in which the motor 20 rotates slowly (the rotation speed is equal to or lower than a predetermined value) or rotates unstably with an unstable rotation speed (incompletely constrained state). In other words, the monitoring unit 32 does not reset the constrained detection timer 322 if the rotation speed is equal to or lower than a predetermined value.

The startup determination unit 34 determines whether or not to transition from the startup preparation period to the startup processing period. Specifically, when the startup determination unit 34 receives a notification from the startup preparation timer 323 that the timer has ended, it determines that the transition to the startup processing period will occur.

When the startup determination unit 34 determines that the startup processing period should be entered, it notifies the motor control unit 31 of the determination result.

Next, an example of the operation of the motor drive control device 1 will be specifically described with reference to Figures 3 to 5. Figure 3 is a timing chart showing an example of the operation when the motor 20 is started normally. Figure 4 is a timing chart showing an example of the operation when the motor 20 is in a constrained state during the startup preparation period. Figure 5 is a timing chart showing an example of the operation when the motor 20 is in a constrained state during the startup processing period.

First, an example of operation when the motor 20 is started normally will be described with reference to FIG. 3. Each of FIG. 3 to FIG. 5 shows a timing chart including items such as the motor state (control state), the startup preparation timer 323, the lock detection timer 322, the speed command signal, the target duty (target rotation speed), the drive control signal duty, and the motor rotation speed signal.

As shown in FIG. 3, first, at time t1, when the motor control unit 31 receives a speed command signal, it performs a startup process and transitions the motor state from stopped to a startup preparation period. Then, the motor control unit 31 transitions to the startup preparation period and outputs a drive control signal with a predetermined duty ratio. In addition, when the monitoring unit 32 receives a speed command signal, it starts the startup preparation timer 323 and the lock detection timer 322.

Then, at time t1a, when the monitoring unit 32 receives the second motor rotation speed signal from the pre-drive circuit 22 in association with the rotation of the motor 20, it resets and restarts the lock detection timer 322. Note that in FIG. 3, the lock detection timer 322 is not reset when the first motor rotation speed signal is received, but it may be reset. Also, at time t1a, when the motor control unit 31 receives the motor rotation speed signal, it increases the duty ratio of the drive control signal by one step. That is, during the startup preparation period, the motor control unit 31 increases the rotation speed stepwise according to the detection timing of the rotation position of the motor 20. Then, during the period from time t1a to time t2, the motor control unit 31 repeatedly performs the process of increasing the duty ratio of the drive control signal by one step each time the motor rotation speed signal is received.

Then, at time t2, if the startup preparation timer 323 reaches (expires) a preset time, the monitoring unit 32 notifies the startup determination unit 34, and the startup determination unit 34 determines to transition to the startup processing period based on the notification. Then, if the motor control unit 31 receives a determination result from the startup determination unit 34, it transitions the motor state from the startup preparation period to the startup processing period.

The motor control unit 31 continuously increases the duty ratio of the drive control signal to the target duty during the startup processing period, regardless of the motor rotation speed signal. In other words, the motor control unit 31 outputs a drive control signal that continuously increases the rotation speed of the motor 20 during the startup processing period. Note that the target value for continuously increasing the duty ratio of the drive control signal is not limited to the target duty and may be, for example, the target rotation speed.

When the monitoring unit 32 transitions from the startup preparation period to the startup processing period, the monitoring unit 32 continues to operate the lock detection timer 322, and resets and restarts it every time the motor rotation speed signal is input. In other words, the lock determination unit 33 continuously determines the lock state during the startup preparation period and the startup processing period.

Then, at time t3, when the duty ratio of the drive control signal reaches the target duty, the motor control unit 31 ends the startup processing period and transitions to normal operation, thereby ending the startup processing.

Next, using Figure 4, we will explain an example of operation when the motor 20 is in a constrained state during the startup preparation period.

As shown in FIG. 4, first, at time t1, when the motor control unit 31 receives a speed command signal, it performs a startup process and transitions the motor state from stopped to a startup preparation period. Then, the motor control unit 31 transitions to the startup preparation period and outputs a drive control signal with a predetermined duty ratio. In addition, when the monitoring unit 32 receives a speed command signal, it starts the startup preparation timer 323 and the lock detection timer 322.

Here, since the motor 20 is in a locked state, even if a drive control signal is output, no motor rotation speed signal is input from the pre-drive circuit 22. Then, at time t1b before the expiration time t2 of the startup preparation period, if the lock determination unit 33 receives from the monitoring unit 32 a notification that the lock detection timer 322 has expired, it determines that the motor 20 is in a locked state. Then, at time t1b, the motor control unit 31 sets the duty ratio of the drive control signal to 0%, i.e., stops outputting the drive control signal, based on the determination result notified by the lock determination unit 33 when the lock determination unit 33 determines that the motor 20 is in a locked state.

This allows the motor 20 to be stopped before the startup processing period begins, thereby reducing heat generation from the motor 20.

Next, using FIG. 5, we will explain an example of operation when the motor 20 is in a locked state during the startup processing preparation period.

As shown in FIG. 5, first, at time t1, when the motor control unit 31 receives a speed command signal, it performs a startup process and transitions the motor state from stopped to a startup preparation period. Then, the motor control unit 31 transitions to the startup preparation period and outputs a drive control signal with a predetermined duty ratio. In addition, when the monitoring unit 32 receives a speed command signal, it starts the startup preparation timer 323 and the lock detection timer 322.

Then, at time t1a, when the monitoring unit 32 receives a second motor rotation speed signal from the pre-drive circuit 22 in response to the rotation of the motor 20, it resets and restarts the lock detection timer 322. Also, at time t1a, when the motor control unit 31 receives the motor rotation speed signal, it increases the duty ratio of the drive control signal by one step.

Then, at time t2, i.e., when the startup preparation timer 323 expires, the monitoring unit 32 notifies the startup determination unit 34 that the startup preparation timer 323 has expired, and the startup determination unit 34 determines that a transition to the startup processing period will occur. Then, when the motor control unit 31 receives a determination result from the startup determination unit 34, it transitions the motor state from the startup preparation period to the startup processing period.

During the startup process, the motor control unit 31 continuously increases the duty ratio of the drive control signal to the target duty ratio regardless of the motor rotation speed signal. In other words, during the startup process, the motor control unit 31 outputs a drive control signal that continuously increases the rotation speed of the motor 20.

Here, if the motor 20 is in a locked state after time t2, i.e., during the startup processing period, the monitoring unit 32 will not receive the motor rotation speed signal after time t2. Then, at time t2a, if the lock determination unit 33 receives from the monitoring unit 32 a notification that the lock detection timer 322 has expired, it will determine that the motor 20 is in a locked state. Then, at time t2a, if the lock determination unit 33 determines that the motor 20 is in a locked state, the motor control unit 31 will set the duty ratio of the drive control signal to 0%, i.e., stop outputting the drive control signal.

In this way, during the startup processing period, the locked state is judged continuously from the startup preparation period, and if a locked state occurs before the expiration time t3 of the startup processing period, the motor 20 is stopped. This allows the motor 20 to be stopped sooner even if a locked state occurs during the startup processing period, thereby suppressing heat generation by the motor 20.

The degree of increase in the duty ratio of the drive control signal during the startup preparation period (the degree of increase in the duty ratio for each stage) can be increased by, for example, the minimum change width (the minimum resolution based on the clock signal) each time the motor rotation speed signal is input once. Alternatively, it may be increased by the minimum change width each time the motor rotation speed signal is input multiple times.

In addition, the lock detection timer 322 may be reset not only each time the motor rotation speed signal is received once, but also each time the motor rotation speed signal is received multiple times. In addition, the number of times the motor rotation speed signal is received to reset the lock detection timer 322 may be different for each of the startup preparation period and the startup processing period.

In addition, the startup preparation period, i.e., the time of the startup preparation timer 323, may be a preset fixed time, or may be dynamically changed according to the target duty. Alternatively, the startup preparation period may be set appropriately according to the specifications of the motor 20. For example, the duty ratio of the drive control signal during the startup preparation period may be set according to the size of the load (weight of the blades), and the length of the startup preparation period may be set based on this duty ratio.

The startup processing period may also be a preset fixed time, or may be dynamically changed according to the target duty. Alternatively, the rising slope of the duty ratio of the drive control signal may be preset, and the length of the startup processing period may be set according to this rising slope.

In addition, it is preferable that the lock detection period (third period), which is the time of the lock detection timer 322, is set to be equal to or shorter than the startup preparation period. This allows the lock state to be detected as soon as possible if the motor 20 is in a locked state from the time of startup, thereby suppressing heat generation by the motor 20.

The length of the lock detection period (third period) may also be different between the startup preparation period, the startup processing period, and during normal operation. For example, the lock detection period may be the longest during the startup preparation period, and gradually shorten during the startup processing period and during normal operation. This allows the lock detection period to be shortened as the motor 20 rotates at a higher speed, thereby suppressing heat generation by the motor 20 when it is locked.

Next, the processing procedure of the processing executed by the motor drive control device 1 according to the embodiment will be described with reference to Figs. 6 and 7. Figs. 6 and 7 are flowcharts showing the processing procedure of the processing executed by the motor drive control device 1. Fig. 6 shows the processing procedure during the startup preparation period, and Fig. 7 shows the processing procedure during the startup processing period.

As shown in FIG. 6, the drive control unit 3 determines whether or not a speed command signal has been input (step S101), and if no input has been received (step S101: No), executes step S101 again. Note that the condition for starting the process in this figure is that the power supply voltage applied to the drive control unit 3 must be within the operating range.

When a speed command signal is input (step S101: Yes), the drive control unit 3 starts the startup preparation timer 323 (step S102), starts the restraint detection timer 322 (step S103), and increases the duty ratio of the drive control signal by one step (step S104). Note that the processing order of steps S102, S103, and S104 may be reversed.

The drive control unit 3 then determines whether or not the motor rotation speed signal output from the predrive circuit 22 has been detected (step S105). If it has been detected (step S105: Yes), it resets and restarts the lock detection timer 322 (step S106) and increases the duty ratio of the drive control signal by one step (step S107). Note that the processing order of steps S106 and S107 may be reversed.

The drive control unit 3 then determines whether the startup preparation timer 323 has expired (step S108), and if the startup preparation timer 323 has not expired (step S108: No), returns to step S105. If the startup preparation timer 323 has expired (step S108: Yes), the drive control unit 3 transitions to the startup processing period (step S109) and ends the processing of the startup preparation period.

On the other hand, in step S105, if the drive control unit 3 does not detect the motor rotation speed signal (step S105: No), it determines whether the lock detection timer 322 has expired (step S110).

If the lock detection timer 322 has not expired (step S110: No), the drive control unit 3 returns to step S105. If the lock detection timer 322 has expired (step S110: Yes), the drive control unit 3 stops outputting the drive control signal, i.e., stops the motor 20 (step S111), and ends the process.

Next, the processing procedure during the startup process will be described with reference to FIG. 7. As shown in FIG. 7, during the startup process, the drive control unit 3 continuously increases the duty ratio of the drive control signal regardless of the detection timing of the rotational position of the motor 20 (step S201).

The drive control unit 3 then determines whether the duty ratio of the drive control signal has reached the target duty (step S202), and if it has reached the target duty (step S202: Yes), transitions the motor state to normal operation (step S203) and ends the processing for the startup processing period.

On the other hand, if the duty ratio of the drive control signal has not reached the target duty (step S202: No), the drive control unit 3 determines whether or not the motor rotation speed signal has been detected (step S204), and if not (step S204: No), determines whether or not the lock detection timer 322 has expired (step S206).

If the lock detection timer 322 has expired (step S206: Yes), the drive control unit 3 stops outputting the drive control signal, i.e., stops the motor 20 (step S207), and ends the process. On the other hand, if the lock detection timer 322 has not expired (step S206: No), the drive control unit 3 returns to step S201.

On the other hand, if the drive control unit 3 detects the motor rotation speed signal (step S204: Yes), it resets and restarts the lock detection timer 322 (step S208) and returns to step S201.

As described above, the motor drive control device 1 according to the embodiment includes a motor drive unit 2 that drives the motor 20, a motor control unit 31 that outputs a drive control signal to the motor drive unit 2, a rotational position detection unit 4 that detects the rotational position of the motor 20, and a constraint determination unit 33 that determines whether the motor 20 is in a constrained state based on the rotational position of the motor 20. The motor control unit 31 increases the rotational speed in accordance with the detection timing of the rotational position during a startup preparation period (corresponding to a first period) after the start-up of the motor 20, and outputs a drive control signal that continuously increases the rotational speed regardless of the detection timing of the rotational position during a startup processing period (corresponding to a second period) after the startup preparation period if it is determined that the motor 20 is not in a constrained state during the startup preparation period. This allows the motor 20 to start up quickly while suppressing heat generation.

Furthermore, the present invention is not limited to the above-mentioned embodiment. The present invention also includes configurations in which the above-mentioned components are appropriately combined. Furthermore, further effects and modifications can be easily derived by those skilled in the art. Therefore, the broader aspects of the present invention are not limited to the above-mentioned embodiment, and various modifications are possible.

1 Motor drive control device, 2 Motor drive unit, 3 Drive control unit, 4 Rotation position detection unit, 20 Motor, 21 Inverter circuit, 22 Pre-drive circuit, 31 Motor control unit, 32 Monitoring unit, 33 Constraint determination unit, 34 Startup determination unit, 321 Startup determination unit, 322 Constraint detection timer, 323 Startup preparation timer

Claims (4)

a motor driving unit that drives the motor;
a motor control unit that outputs a drive control signal having a predetermined duty ratio to the motor drive unit;
a rotational position detection unit that detects a rotational position of the motor;
a restraint determination unit that determines whether or not the motor is in a restrained state based on the rotation position,
The restraint determination unit is
The locked state is continuously determined during a first period after the motor is started and during a second period after the rotation speed increases,
The motor control unit includes:
during the first period, a duty ratio of the drive control signal is increased in order to increase a rotation speed in response to a detection timing of the rotation position;
When it is determined that the motor is not in a locked state during the first period, during the second period in which the rotation speed increases, the duty ratio of the drive control signal is continuously increased regardless of the detection timing of the rotation position ,
When it is determined that the motor is in a locked state during the first period, output of the drive control signal is stopped;
When it is determined that the motor is in a locked state during the second period, output of the drive control signal is stopped .
Motor drive control device. The motor control unit includes:
2. The motor drive control device according to claim 1, wherein during the first period, a duty ratio of the drive control signal is increased to gradually increase the rotational speed in accordance with a detection timing of the rotational position, and during the second period after the rotational speed has increased, a duty ratio of the drive control signal is increased to continuously increase the rotational speed up to a target speed based on a speed command input from the outside. The restraint determination unit is
3 . The motor drive control device according to claim 1 , wherein, in the first period, if the rotational position is not detected within a predetermined third period, it is determined that the motor is in the locked state. a motor driving step of driving a motor;
a motor control step of outputting a drive control signal having a predetermined duty ratio to a motor drive unit that executes the motor drive step;
a rotational position detection step of detecting a rotational position of the motor;
a restraint determination step of determining whether or not the motor is in a restrained state based on the rotational position,
The restraint determination step includes:
The locked state is continuously determined during a first period after the motor is started and during a second period after the rotation speed increases,
The motor control step includes:
In the first period, a duty ratio of the drive control signal is increased in order to increase the rotation speed in response to a detection timing of the rotation position, and if it is determined that the motor is not in a locked state in the first period, in the second period in which the rotation speed has increased, the duty ratio of the drive control signal is continuously increased regardless of the detection timing of the rotation position ;
When it is determined that the motor is in a locked state during the first period, output of the drive control signal is stopped;
the motor drive control method comprising: stopping output of the drive control signal when it is determined that the motor is in a locked state during the second period .

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