JP7718328B2 - Motor control device - Google Patents

Description

This disclosure relates to a motor control device.

One example of a conventional motor control device is the brushless motor drive control device disclosed in Patent Document 1. In this brushless motor drive control device, a synchronization signal generating means outputs a synchronization signal that generates a rotating magnetic field in the armature winding of the brushless motor in a predetermined pattern for a certain period of time after the motor starts. Then, in synchronization with this, the brushless motor drive control device outputs a startup duty in a predetermined pattern from a startup duty command means. The brushless motor drive control device also compares the DC voltage supplied to the inverter circuit with a predetermined reference voltage to determine the magnitude of the DC voltage, and adjusts the startup duty based on the magnitude of the DC voltage.

Japanese Patent Application Publication No. 11-243698

However, Patent Document 1 does not take into account changes in motor characteristics due to the operating environment or the effects of increased load due to aging. As a result, Patent Document 1 may not provide enough torque when motor control begins, which could result in a delay in the start of motor rotation when control begins.

One disclosed objective is to provide a motor control device that can improve responsiveness when starting motor control.

The motor control device disclosed herein comprises:
A motor control device that controls a motor (40),
a processing device (13, 14) that generates a motor output voltage based on the duty ratio and controls the motor using the generated motor output voltage;
a memory device (16) in which an offset value to be added to the duty ratio is stored;
The processing device
a calculation step (S61) of calculating a duty ratio using a target rotation speed of the motor and an actual rotation speed that is an actual rotation speed of the motor at a predetermined period;
and a generation step (S63) of reading an offset value from the memory device and adding it to the calculated duty ratio to generate a startup duty ratio for generating the torque required to start the motor .

The motor control device disclosed herein generates a startup duty ratio by adding an offset value read from a memory device to the calculated duty ratio. This allows the motor control device to prevent a shortage of torque required when starting motor control, improving responsiveness when starting motor control.

The various aspects disclosed in this specification employ different technical means to achieve their respective objectives. The reference symbols in parentheses in the claims and this section are intended to illustratively indicate the correspondence with the embodiments described below and are not intended to limit the technical scope. The objectives, features, and advantages disclosed in this specification will become clearer with reference to the detailed description that follows and the accompanying drawings.

FIG. 1 is a block diagram showing a schematic configuration of a motor control device. 1 is a diagram showing a memory arrangement. 4 is a flowchart showing a main process of the motor control device. 4 is a flowchart showing a PI calculation process of the motor control device. 10 is a graph showing changes in motor rotation speed and PI duty ratio when there is a delay in starting the motor. 4 is a time chart showing a sensor signal of each phase; 10 is a graph showing a change in the deviation integral value when there is a delay in starting the motor. 10 is a graph showing a change in the deviation integral value when there is no delay in starting the motor. FIG. 9 is an enlarged view of a portion IX in FIG. 8 .

Below, several embodiments for implementing the present disclosure will be described with reference to the drawings. In each embodiment, parts corresponding to matters described in the preceding embodiment may be assigned the same reference numerals, and duplicate explanations may be omitted. In each embodiment, when only a portion of the configuration is described, the other portions of the configuration can be applied by referring to the other previously described embodiments.

(First embodiment)
A motor control device according to a first embodiment will be described with reference to Figures 1 to 6. The motor control device controls a motor 40. For example, the motor 40 may be a brushless blower motor for driving a blower fan in a vehicle air conditioning unit. However, the present disclosure is not limited to this, and may also be applied to a motor control device for controlling a motor 40 used in another device (unit).

<Overall structure>
The motor control device may include at least a microcomputer 10. As shown in FIG. 1 , the microcomputer 10 is connected to a motor 40 via a pre-driver 20 and a three-phase inverter 30. A Hall IC 50 is connected to the microcomputer 10. The motor control device may include at least one of the pre-driver 20, the three-phase inverter 30, and the Hall IC 50 in addition to the microcomputer 10. In the drawings, the pre-driver 20 is referred to as PRD, the three-phase inverter 30 as INV, the motor 40 as M, and the Hall IC 50 as HIC.

The motor 40 is a three-phase motor that includes, for example, a stator, a rotor, and a shaft attached to the rotor. The stator has three phases: U, V, and W. Each of the stator's U, V, and W phases generates a rotating magnetic field by switching the polarity of the magnetic field generated by an electromagnet under the control of the microcomputer 10. The rotor is provided with a rotor magnet. The rotor magnet rotates the rotor using the rotating magnetic field generated by the stator. A shaft and fan are fixed to the rotor. The shaft and fan rotate in conjunction with the rotation of the rotor. The vehicle air conditioning unit is able to blow air when the fan rotates with the shaft. Note that, below, rotation of the motor 40 is synonymous with rotation of the rotor. Furthermore, acceleration of the motor 40 refers to acceleration of the rotor.

The pre-driver 20 amplifies the PWM signal input from the microcomputer 10 and generates a drive signal for switching each switching element of the three-phase inverter 30. The pre-driver 20 applies the drive signal to each switching element.

The three-phase inverter 30 includes, for example, a bridge circuit using six switching elements. The three-phase inverter 30 switches the power supplied to each phase coil of the stator of the motor 40 in response to a drive signal from the pre-driver 20.

The Hall IC 50 outputs a sensor signal that changes in response to the rotation of the motor 40. The Hall IC 50 is equipped with three sensor elements: a sensor element for the U phase, a sensor element for the V phase, and a sensor element for the W phase, in order to output a sensor signal corresponding to the stator coil of each phase. Therefore, as shown in FIG. 6, the Hall IC 50 outputs pulse wave sensor signals for each of the U phase, V phase, and W phase. The Hall IC 50 corresponds to a rotation sensor. In this embodiment, the Hall IC 50 is used as the rotation sensor, but this is not limited to this.

<Configuration of microcomputer 10>
The configuration of the microcomputer 10 will be described with reference to Figures 1 and 2. The microcomputer 10 includes a processor, a memory device 16, an input/output interface, etc. The microcomputer 10 may also include peripheral circuits such as a timer and an AD converter. The memory device 16 includes a RAM 161 and a non-volatile memory 162.

In the microcomputer 10, the processor executes a program stored in the memory device 16. By executing the program, the processor performs arithmetic processing using data stored in the memory device 16 and data input from the input/output interface. In the microcomputer 10, the processor executes arithmetic processing at a predetermined control period. The control period is, for example, 2 ms. However, the control period is not limited to this. The control period corresponds to the predetermined period.

The microcomputer 10 can realize various functions by performing arithmetic processing. For example, the microcomputer 10 controls the motor 40 via the pre-driver 20 by outputting a PWM signal, which is the result of the arithmetic processing, from the input/output interface. The microcomputer 10 can also be said to be equipped with various functions. Figure 1 shows functional blocks indicating the various functions of the microcomputer 10. In addition to the functional blocks, Figure 1 also shows a memory device 16.

The command speed calculation unit 11 calculates a command rotation speed based on a command signal from a host ECU or the like. The command signal is a control signal including a speed command value related to the rotation speed of the motor 40 (rotor). The command signal is output, for example, based on operation of an operating unit inside the vehicle. The target speed calculation unit 12 calculates a target rotation speed, which is a target value, from the command rotation speed and outputs the target rotation speed to the calculation processing unit 13 via a subtractor. The command rotation speed and target rotation speed are speeds related to the rotation speed of the rotor in the motor 40.

The calculation processing unit 13 includes a PI control unit 131 and a voltage compensation unit 132. The PI control unit 131 receives the deviation between the target rotation speed calculated by the subtractor and the actual rotation speed. The PI control unit 131 performs feedback control (PI control) based on this deviation.

The PI control unit 131 calculates the proportional component (proportional term) by multiplying the deviation by the proportional gain of P (proportional) control, and calculates the integral component (integral term) by multiplying the integral value of the deviation by the integral gain of I (integral) control. The PI control unit 131 then calculates the duty ratio by adding these proportional and integral components using an adder, and outputs this duty ratio to the voltage compensation unit 132. The actual rotation speed is the actual rotation speed of the rotor calculated by the motor speed calculation unit 15. The duty ratio obtained by the calculation by the PI control unit 131 can also be referred to as the calculated duty ratio or the PI calculation result. The calculation processing unit 13 may calculate the rotational position of the motor 40 based on the sensor signal from the Hall IC 50.

The voltage compensation unit 132 outputs a duty ratio, such as a startup duty ratio, used to generate the motor output voltage. During the period before it is determined that the motor 40 has started rotating or during acceleration, the voltage compensation unit 132 generates the startup duty ratio by adding the offset value read from the non-volatile memory 162 to the PI calculation result. The voltage compensation unit 132 then outputs the startup duty ratio. The startup duty ratio is a duty ratio generated to improve the responsiveness of the motor 40 at startup for a predetermined period from the start of control of the motor 40. The startup duty ratio can also be considered a duty ratio for generating the torque required to start the motor 40. Note that during non-acceleration, the voltage compensation unit 132 outputs the PI calculation result as the duty ratio used to generate the motor output voltage. Hereinafter, the offset value will also be referred to as the PI offset value (PIO).

In this embodiment, as an example, the calculation processing unit 13 is used, which determines that the motor has started to rotate when the sensor signal of the sensor element for each phase changes twice. This is to ensure that the motor has started to rotate. However, the present disclosure is not limited to this. For example, the calculation processing unit 13 may determine that the motor has started to rotate when the sensor signal of the sensor element for each phase changes once.

For a certain period of time after control of the motor 40 begins, a discrepancy may occur between the target rotation speed and the actual rotation speed. Figure 5 shows an example in which the timing at which the motor 40 actually starts rotating is delayed relative to the start of control of the motor 40 in response to a command signal. The upper part of Figure 5 shows the time change in the target rotation speed with a two-dot chain line, and the time change in the actual rotation speed with a solid line. The lower part of Figure 5 shows the time conversion of the PI duty ratio.

For this reason, the calculation processing unit 13 determines that the motor has started to rotate with a delay from when control of the motor 40 begins. Timing t2 is the timing at which the sensor signal first changes after control of the motor 40 begins. In this example, a startup delay of X [ms] occurs from when control of the motor 40 begins until timing t2. Note that timing t1 is the timing at which the PI offset value is read. Timing t3 is the timing at which the sensor signal of the sensor element for each phase changes twice and it is determined that the motor has started to rotate. This is the timing at which the sensor signal first changes after control of the motor 40 begins.

In this way, the calculation processing unit 13 controls the rotation speed of the motor 40 by adjusting the PI duty ratio of the PWM signal, thereby performing drive control of the motor 40 using so-called PWM control. Furthermore, the calculation processing unit 13 corrects the PI duty ratio of the PWM signal with a PI offset value, improving the responsiveness of the motor 40 when it is started.

The non-volatile memory 162 stores a PI offset value for improving the responsiveness of the motor 40 when it is started. The PI offset value is set so that the duty ratio at start-up becomes the PI duty ratio when the motor 40 actually starts to rotate. The PI offset value is a value that corresponds to the actual rotation of the motor 40. However, the PI offset value may also be a preset value.

As shown in FIG. 2, the memory device 16 stores, in a memory array, multiple PI duty ratios (PIDs) that are candidate values for the PI offset value. Each PI duty ratio is the result of a PI calculation performed by the PI control unit 131 according to the rotation of the motor 40. The multiple PI duty ratios are stored, for example, in RAM 161 of the memory device 16.

The calculation processing unit 13 stores, in the memory array of the memory device 16, multiple PI duty ratios calculated by the PI control unit 131 from the time control of the motor 40 begins until it is determined that the motor 40 has started rotating. More specifically, the calculation processing unit 13 stores the PI duty ratio calculated at each timing when the sensor signal of each phase changes. The calculation processing unit 13 also associates and stores the timing of the change in the sensor signal with the PI duty ratio calculated at the timing when the sensor signal changed. The start of control of the motor 40 is the timing (point in time) when control of the motor 40 actually begins. The start of control of the motor 40 can also be said to be the start of activation of the motor 40.

The timings at which the sensor signals for each phase change are, for example, timings U1, V1, W1, U2, V2, and W2 (timings 1 to 6) in Figure 6. Timings U1, V1, and W1 are the timings at which the sensor signals change for the first time in the sensor elements for the U phase, V phase, and W phase, respectively. Timings U2, V2, and W2 are the timings at which the sensor signals change for the second time in the sensor elements for the U phase, V phase, and W phase, respectively.

In the example of Figure 2, the PI duty ratios stored are 10% at timing U1, 11% at timing V1, 12% at timing W1, 13% at timing U2, 14% at timing V2, and 15% at timing W2. In Figure 2, timing U1 is timing 1, timing V1 is timing 2, timing W1 is timing 3, timing U2 is timing 4, timing V2 is timing 5, and timing W2 is timing 6.

Then, the calculation processing unit 13 selects a PI offset value from the multiple PI duty ratios. In other words, the calculation processing unit 13 selects one from the multiple PI duty ratios and stores the selected PC duty ratio as the PI offset value in the non-volatile memory 162. At this time, the calculation processing unit 13 stores the PI duty ratio stored at the timing closest to the actual start of control of the motor 40 as the PI offset value. In the example of Figure 2, the PI duty ratio of 10%, which is associated with timing U1, is stored as the PI offset value. Therefore, it can be said that the PI duty ratio and PI offset value are stored in the memory device 16 (non-volatile memory 162) in a changeable (updatable) state. Note that before the motor 40 is actually rotated, a default value for the PI offset value is stored.

The motor output calculation unit 14 generates a PWM signal for controlling the three-phase inverter 30 based on the startup duty ratio generated by the voltage compensation unit 132. The motor output calculation unit 14 outputs the generated PWM signal to the pre-driver 20. The calculation processing unit 13 and the motor output calculation unit 14 correspond to a processing device.

The motor speed calculation unit 15 calculates the rotor rotation speed (actual rotation speed) based on the sensor signal from the Hall IC 50.

<Processing Operation>
The processing operation of the microcomputer 10 will be described using Figures 3 to 6. When the microcomputer 10 is powered on, it starts executing the flowchart (main processing) shown in Figure 3. The microcomputer 10 also starts executing the flowchart shown in Figure 3 for each control cycle from when the power is turned on until when the power is turned off. Note that powering on can also be considered as the start of supplying operating power to the microcomputer 10.

In step S10, the PI offset value is read. The calculation processing unit 13 reads the PI offset value stored in the non-volatile memory 162. The calculation processing unit 13 reads the PI offset value at timing t1 in Figure 5.

In step S20, it is determined whether the motor 40 is stopped. If the calculation processing unit 13 determines that the motor 40 is stopped, the process proceeds to step S30; if it does not determine that the motor 40 is stopped, the process proceeds to step S40. This is because the PI duty ratio after the motor 40 starts moving is stored in the non-volatile memory 162. The calculation processing unit 13 determines whether the motor 40 is stopped based on the sensor signal from the Hall IC 50. The calculation processing unit 13 determines that the motor 40 is stopped until the sensor signal from the sensor element for each phase changes twice, and does not determine that the motor is stopped if the sensor signal changes twice.

In step S30, the rotation start flag is set to off. The calculation processing unit 13 sets the rotation start flag to off. The rotation start flag is stored in part of the memory device 16.

In step S40, the target rotation speed is acquired. The command speed calculation unit 11 calculates the command rotation speed. The target speed calculation unit 12 calculates the target rotation speed, which is the target value, from the command rotation speed. In other words, the target speed calculation unit 12 acquires the target rotation speed through calculation.

In step S50, the target rotation speed is set. The calculation processing unit 13 sets the target rotation speed to be reached for each control cycle in order to increase the speed at a predetermined acceleration.

In step S60, PI calculation processing is performed. The calculation processing unit 13 performs PI calculation processing. The PI calculation processing will be explained later using Figure 4.

In step S70, the motor output is updated. The motor output calculation unit 14 generates a PWM signal for controlling the three-phase inverter 30 based on the duty ratio output from the voltage compensation unit 132, and outputs the PWM signal to the pre-driver 20. The duty ratio output from the voltage compensation unit 132 is updated in steps S61 and S63, which will be described later. Therefore, the motor output calculation unit 14 updates the motor output by outputting a PWM signal generated based on the duty ratio output from the voltage compensation unit 132.

Here, the PI calculation process will be explained using Figure 4. The calculation processing unit 13 executes the process shown in the flowchart in Figure 4 for each control cycle.

In step S61, a PI calculation is performed using the target rotation speed and the actual rotation speed (calculation step). As described above, the PI control unit 131 calculates the PI calculation result using the target rotation speed and the actual rotation speed. As described above, the calculation processing unit 13 stores the PI calculation result (PI duty ratio) in the memory array of the memory device 16 each time the sensor signal for each phase changes from the time control of the motor 40 begins until it is determined that the motor 40 has started rotating.

In step S62, it is determined whether or not the motor is accelerating. The calculation processing unit 13 determines whether or not the motor is accelerating based on the target rotation speed set in step S50. The calculation processing unit 13 proceeds to step S63, where it determines that the motor 40 is accelerating. If the calculation processing unit 13 does not determine that the motor 40 is accelerating, it ends the flowchart in Figure 4.

In step S63, the PI calculation result is obtained by adding the PI offset value to the PI calculation result (generation step). That is, the voltage compensation unit 132 adds the PI offset value read in step S10 to the PI calculation result calculated in step S61 to obtain a new PI calculation result. In other words, the voltage compensation unit 132 corrects the duty ratio used to generate the motor output voltage by adding the PI offset value to the PI calculation result calculated in step S61. The new PI calculation result is the startup duty ratio.

For this reason, when the voltage compensation unit 132 does not determine that acceleration is occurring (when not accelerating), it outputs the PI calculation result of step S61 as the duty ratio used to generate the motor output voltage. On the other hand, when the voltage compensation unit 132 determines that acceleration is occurring, it outputs the new PI calculation result calculated in step S63 as the duty ratio used to generate the motor output voltage. Also, the motor 40 is accelerating during the period before it is determined that the motor 40 has started rotating. Therefore, the voltage compensation unit 132 determines that the period before it is determined that the motor 40 has started rotating is during acceleration. Therefore, during the period before it is determined that the motor 40 has started rotating, the voltage compensation unit 132 outputs the new PI calculation result calculated in step S63 as the duty ratio used to generate the motor output voltage.

In step S64, it is determined whether the motor has started to rotate (start determination step). The calculation processing unit 13 determines that the motor 40 has started to rotate based on the sensor signal. In this embodiment, the calculation processing unit 13 determines that the motor has started to rotate when the sensor signal of the sensor element for each phase changes twice.

In step S65, it is determined whether it is time to save the PI offset value. If the calculation processing unit 13 determines in step S64 that the motor has started to rotate and further determines that the rotation start flag is set to OFF, it considers it time to save the PI offset value and proceeds to step S66. On the other hand, if the calculation processing unit 13 determines in step S64 that the motor has started to rotate and further determines that the rotation start flag is not set to OFF, it considers it not time to save the PI offset value and ends the flowchart in Figure 4. A YES determination in step S66 can be considered a branch before the determination that the motor has started to rotate. On the other hand, a NO determination in step S66 can be considered a branch after the determination that the motor has started to rotate.

In step S66, the rotation start flag is set to ON. The calculation processing unit 13 sets the rotation start flag to ON. In other words, the calculation processing unit 13 switches the rotation start flag from OFF to ON.

In step S67, the PI duty ratio of the PI offset value candidate is acquired (acquisition step). In this embodiment, as an example, the PI duty ratio of the PI offset value candidate is read from RAM 161. The calculation processing unit 13 reads, from the multiple PI duty ratios stored in RAM 161, the PI duty ratio at which there was the first change in the sensor signal as the PI offset value candidate. For example, at timing t3 in Figure 5, the calculation processing unit 13 reads the PI offset value at timing t2. The read PI duty ratio corresponds to the PI duty ratio to be stored in non-volatile memory 162 as the PI offset value.

In step S68, it is determined whether PID - PIO > ± threshold value [%] (determination step). Here, PID is the PI duty ratio obtained in step S67. PIO is the PI offset value read in step S10. Therefore, the calculation processing unit 13 determines whether the difference between the PI offset value stored in non-volatile memory 162 and the PI duty ratio obtained in step S67 exceeds the threshold value. The threshold value is a preset value.

If the calculation processing unit 13 determines that PID-PIO > ±threshold, it considers that PIO needs to be updated and proceeds to step S69. On the other hand, if the calculation processing unit 13 does not determine that PID-PIO > ±threshold, it considers that PIO does not need to be updated and ends the flowchart in Figure 4. Note that step S68 can also be omitted. In other words, the calculation processing unit 13 may perform step S69 each time it executes step S67.

In step S69, the PI duty ratio is stored as a PI offset value (storage step). The calculation processing unit 13 stores the PI duty ratio acquired in step S67 as a PI offset value in the non-volatile memory 162, provided that the difference exceeds the threshold value. In other words, the calculation processing unit 13 updates the PI offset value stored in the non-volatile memory 162 to the PI duty ratio acquired in step S67. This allows the microcontroller 10 to prevent an increase in the number of times the non-volatile memory 162 is rewritten. In other words, the microcontroller 10 can reduce the frequency of writing to the non-volatile memory 162.

The means and/or functions provided by the microcomputer 10 can be provided by software recorded in the physical memory device 16 and a computer that executes it, by software alone, by hardware alone, or a combination of these. For example, if the microcomputer 10 is provided by electronic circuits that are hardware, it can be provided by digital circuits including multiple logic circuits, or by analog circuits.

<Effects>
As described above, the microcomputer 10 generates the startup duty ratio by adding the PI offset value read from the nonvolatile memory 162 to the calculated PI duty ratio. This allows the microcomputer 10 to prevent a shortage of the torque required when starting to control the motor 40, thereby improving responsiveness when starting to control the motor 40. The microcomputer 10 can also improve responsiveness even when the characteristics of the motor 40 change due to the operating environment or when an increase in load occurs due to aging.

In addition, the microcontroller 10 uses the PI duty ratio when the motor 40 is actually rotating as the PI offset value. This allows the microcontroller 10 to further reduce the effects of changes in the motor 40's characteristics due to its usage environment and increased load due to aging, improving responsiveness at the start of control.

Preferred embodiments of the present disclosure have been described above. However, the present disclosure is not limited to the above embodiments, and various modifications are possible without departing from the spirit of the present disclosure. Below, a second embodiment will be described as another form of the present disclosure. The above embodiment and the second embodiment can be implemented independently, or they can be implemented in appropriate combinations. The present disclosure is not limited to the combinations shown in the embodiments, and can be implemented in various combinations.

Second Embodiment
A motor control device according to a second embodiment will be described using Figures 7 to 9. In this embodiment, differences from the first embodiment will be mainly described. The motor control device according to this embodiment has the same configuration as the first embodiment. In this embodiment, the method of acquiring the duty ratio to be stored as a PI offset value by the microcomputer 10 (arithmetic processing unit 13) is different from that of the first embodiment.

In Figures 7 to 9, the change over time in the target rotation speed is shown by a two-dot chain line, the change over time in the program-recognized rotation speed by a dashed line, and the change over time in the actual rotation speed by a solid line. Timing t10 is the timing when the motor 40 actually starts. Timing t11 is the timing when the microcontroller 10 determines that the motor 40 has started to rotate. Starting the motor 40 means that the motor 40 has actually started to rotate.

In step S67, the calculation processing unit 13 multiplies the integral value of the deviation between the target rotation speed and the actual rotation speed when the motor 40 actually starts rotating by the integral term constant to obtain the PI duty ratio to be stored as the PI offset value (obtaining step). The integral term constant is the integral gain.

Note that when executing step S68, the calculation processing unit 13 may not store the PI duty ratio acquired here. Therefore, the PI duty ratio stored as the PI offset value can also be considered a PI duty ratio of a PI offset value candidate. Also, the calculation processing unit 13 does not need to execute step S68. In this case, the PI duty ratio acquired here can also be considered a PI offset value stored in the non-volatile memory 162. Hereinafter, the PI duty ratio stored as the PI offset value will also be simply referred to as the PI offset value.

First, the calculation processing unit 13 stores the actual deviation integral value (ADIV) in the memory device 16. As shown in the lower part of Figure 7, the actual deviation integral value is the deviation integral value when it is determined that the motor 40 has started to rotate.

Next, the calculation processing unit 13 estimates time A. Time A is the time shown in the upper part of Figure 7. Time A is the elapsed time from the actual start timing (t10) of the motor 40 until the motor rotation start speed (SV) is reached (t11). Time A is estimated from the motor rotation start speed (SV), which is the program-recognized rotation speed when it is determined that the motor 40 has started rotating, and the set motor acceleration (SA). The program-recognized rotation speed is the speed recognized by the microcontroller 10. The set motor acceleration is specified along with a command signal from a higher-level ECU or the like. The calculation processing unit 13 estimates time A by calculating the motor rotation start speed (SV) / the set motor acceleration (SA).

Here, the calculation processing unit 13 calculates the ideal integral deviation value (IDIV). As shown in Figure 8, the ideal integral deviation value is the ideal integral deviation value when there is no start-up delay of the motor 40. The ideal integral deviation value is the integral deviation value from when the motor 40 actually starts up until the microcontroller 10 determines that the motor 40 has started rotating. The calculation processing unit 13 calculates the ideal integral deviation value by calculating the speed deviation (VDEV) x time A/control period. As shown in Figure 9, the speed deviation occurs every control period as the motor 40 accelerates. The speed deviation can be expressed as the motor acceleration x control period.

The calculation processing unit 13 also calculates the startup deviation integral value (SDIV). The startup deviation integral value is the deviation integral value when the motor 40 actually starts. The calculation processing unit 13 calculates the startup deviation integral value by subtracting the ideal deviation integral value from the actual deviation integral value.

Then, the calculation processing unit 13 calculates the PI offset value. The calculation processing unit 13 calculates the PI offset value from the startup deviation integral value. More specifically, the calculation processing unit 13 calculates the PI offset value by calculating the P term constant x rotational speed deviation + the I term constant x startup deviation integral value. When the motor actually starts, the speed deviation is 0. Therefore, the calculation processing unit 13 calculates the PI offset value by calculating the I term constant x startup deviation integral value. The P term constant is a proportional gain.

In this way, the microcomputer 10 of the second embodiment can calculate (obtain) the PI offset value through calculation. The motor control device of the second embodiment can achieve the same effects as the motor control device of the first embodiment.

While the present disclosure has been described with reference to embodiments, it is understood that the present disclosure is not limited to those embodiments or structures. The present disclosure also encompasses various modifications and variations within the scope of equivalents. In addition, while various combinations and forms are shown in the present disclosure, other combinations and forms including only one element, more, or less are also within the scope and spirit of the present disclosure.

Disclosed Technical Ideas This specification discloses multiple technical ideas described in the following paragraphs, and also discloses multiple combined technical ideas indicated by alternatively citing the preceding technical ideas in the subsequent technical ideas.

Technical thought 1
A motor control device that controls a motor (40),
a processing device (13, 14) that generates a motor output voltage based on the duty ratio and controls the motor using the generated motor output voltage;
a memory device (16) in which an offset value to be added to the duty ratio is stored;
The processing device includes:
a calculation step (S61) of calculating the duty ratio using a target rotation speed of the motor and an actual rotation speed that is an actual rotation speed of the motor at a predetermined period;
and a generation step (S63) of reading the offset value from the memory device and adding it to the calculated duty ratio to generate a startup duty ratio, which is the duty ratio used to generate the motor output voltage when control of the motor starts.

Technical thought 2
It is electrically connected to a rotation sensor (50) that outputs a sensor signal that changes according to the rotation of the motor,
The motor control device according to Technical Idea 1, wherein the processing device includes a storage step (S69) of storing the duty ratio at the time when the sensor signal first changes since control of the motor is started in the memory device as the offset value.

Technical thought 3
The processing device includes:
a start determination step (S64) of determining whether the motor has started to rotate based on the sensor signal;
an acquisition step (S67) of acquiring the duty ratio to be stored in the memory device as the offset value,
each time the sensor signal changes during the period from when control of the motor is started until it is determined that the motor has started to rotate, the timing of the change in the sensor signal is associated with the duty ratio calculated at the timing of the change in the sensor signal and stored in the memory device;
the obtaining step obtains from the memory device the duty ratio at the time when the sensor signal first changes after starting control of the motor;
The motor control device according to Technical Concept 2, wherein in the storing step, the duty ratio acquired in the acquiring step is stored in the memory device as the offset value.

Technical thought 4
The processing device includes:
In the calculation step, the duty ratio is calculated using a proportional term and an integral term in accordance with a deviation between the target rotation speed and the actual rotation speed,
an acquisition step (S67) of acquiring the duty ratio to be stored as the offset value by multiplying an integral value of a deviation between the target rotation speed and the actual rotation speed when the motor actually starts to rotate by a constant of the integral term;
The motor control device according to Technical Concept 2, wherein in the storing step, the duty ratio acquired in the acquiring step is stored in the memory device as the offset value.

Technical thought 5
The processing device includes:
a determination step (S68) of determining whether or not a difference between the offset value stored in the memory device and the duty ratio acquired in the acquisition step exceeds a threshold value;
A motor control device according to Technical Idea 3 or Technical Idea 4, wherein in the storage step, the duty ratio acquired in the acquisition step is stored in the memory device as the offset value, provided that the difference exceeds the threshold value.

Technical thought 6
A motor control device described in any one of technical ideas 1 to 5, wherein the offset value is set so that the startup duty ratio becomes the duty ratio when the motor actually starts rotating.

10...Microcomputer, 11...Command speed calculation unit, 12...Target speed calculation unit, 13...Calculation processing unit, 131...PI control unit, 132...Voltage compensation unit, 14...Motor output calculation unit, 15...Motor speed calculation unit, 16...Non-volatile memory, 20...Pre-driver, 30...Three-phase inverter, 40...Motor, 50...Hall IC

Claims (6)

A motor control device that controls a motor (40),
a processing device (13, 14) that generates a motor output voltage based on the duty ratio and controls the motor using the generated motor output voltage;
a memory device (16) in which an offset value to be added to the duty ratio is stored;
The processing device includes:
a calculation step (S61) of calculating the duty ratio using a target rotation speed of the motor and an actual rotation speed that is an actual rotation speed of the motor at a predetermined period;
and a generating step (S63) of reading the offset value from the memory device and adding it to the calculated duty ratio to generate a startup duty ratio for generating the torque required to start the motor . It is electrically connected to a rotation sensor (50) that outputs a sensor signal that changes according to the rotation of the motor,
2. The motor control device according to claim 1, further comprising a storage step (S69) in which the processing device stores the duty ratio at the time when the sensor signal first changes since control of the motor is started in the memory device as the offset value. The processing device includes:
a start determination step (S64) of determining whether the motor has started to rotate based on the sensor signal;
an acquisition step (S67) of acquiring the duty ratio to be stored in the memory device as the offset value,
each time the sensor signal changes during the period from when control of the motor is started until it is determined that the motor has started to rotate, the timing of the change in the sensor signal is associated with the duty ratio calculated at the timing of the change in the sensor signal and stored in the memory device;
the obtaining step obtains from the memory device the duty ratio at the time when the sensor signal first changes after starting control of the motor;
3. The motor control device according to claim 2, wherein the storing step stores the duty ratio acquired in the acquiring step as the offset value in the memory device. The processing device includes:
In the calculation step, the duty ratio is calculated using a proportional term and an integral term in accordance with a deviation between the target rotation speed and the actual rotation speed,
an acquisition step (S67) of acquiring the duty ratio to be stored as the offset value by multiplying an integral value of a deviation between the target rotation speed and the actual rotation speed when the motor actually starts to rotate by a constant of the integral term;
3. The motor control device according to claim 2, wherein the storing step stores the duty ratio acquired in the acquiring step as the offset value in the memory device. The processing device includes:
a determination step (S68) of determining whether or not a difference between the offset value stored in the memory device and the duty ratio acquired in the acquisition step exceeds a threshold value;
5. The motor control device according to claim 3, wherein the storing step stores the duty ratio acquired in the acquiring step as the offset value in the memory device on the condition that the difference exceeds the threshold value. A motor control device as described in claim 1, wherein the offset value is set so that the startup duty ratio becomes the duty ratio when the motor actually starts rotating.