WO2019186757A1

WO2019186757A1 - Drive device, drive method, drive program, and electric vehicle

Info

Publication number: WO2019186757A1
Application number: PCT/JP2018/012745
Authority: WO
Inventors: 一由希目黒; 雄大井ノ口
Original assignee: 新電元工業株式会社
Priority date: 2018-03-28
Filing date: 2018-03-28
Publication date: 2019-10-03
Also published as: TWI702338B; CN111869090A; JP6972305B2; TW201942466A; JPWO2019186757A1; CN111869090B

Abstract

An electric vehicle control device 1 is provided with: a signal receiving unit 11 for receiving a signal coming at intervals in accordance with the rotational speed of a motor 3; a rotational speed calculation unit 12 for calculating an instantaneous rotational speed of the motor 3 on the basis of the signal interval ΔT between a sensor signal S1 and a sensor signal S2; and a motor control unit 13 for generating a PWM signal on the basis of the calculated instantaneous rotational speed. When the variation of the instantaneous rotational speed is greater than or equal to a specific value, the motor control unit 13 corrects the duty ratio of the PWM signal on the basis of the instantaneous rotational speed so that the output voltage of a power conversion unit 30 becomes a value in accordance with the instantaneous rotational speed.

Description

Drive device, drive method, drive program, and electric vehicle

The present invention relates to a drive device, a drive method, a drive program, and an electric vehicle.

An electric vehicle such as a two-wheel EV includes a motor for driving wheels and a driving device having a control unit for controlling the motor. In an electric vehicle, a required torque can be obtained from a low rotation range to a high rotation range even when the gear is fixed. For this reason, the electric vehicle which does not provide a clutch is examined. In the case of such a clutchless electric vehicle, the motor directly receives an external force from a wheel that has been cut off by the clutch in the conventional electric vehicle.

Patent Document 1 describes an engine speed control device that controls the engine speed and performs PWM control of a motor that drives the opening and closing of a throttle valve. Further, it is described that a PWM duty correction value for correcting the duty ratio of the PWM signal is calculated according to the target engine speed change amount.

JP 2005-207416 A

Rotational position sensor for detecting the rotational position of the rotor is provided in the stator of the motor of the electric vehicle. The control unit of the driving device receives a rising edge signal or a falling edge signal (hereinafter, also collectively referred to as “sensor signal”) for each predetermined electrical angle from the rotational position sensor. Based on the sensor signal, the control unit grasps the rotation speed of the motor and controls the motor.

As described above, in the clutchless electric vehicle, an external force corresponding to the road surface condition is directly applied to the motor. For this reason, the rotational speed of the motor may fluctuate instantaneously depending on the road surface condition. Since the output of the inverter cannot follow such instantaneous fluctuations in the rotational speed, the motor output torque may deviate from the target value. This will be specifically described below with reference to FIG.

As shown in FIG. 14, when the instantaneous rotation speed of the motor decreases, the voltage induced by the rotation of the motor (motor induced voltage) decreases instantaneously by the voltage Va. On the other hand, while the motor induced voltage is decreasing, the output of the inverter that supplies AC power to the motor remains constant. For this reason, the voltage difference between the output voltage of the inverter and the motor induced voltage increases from V0 to Vb (= V0 + Va). Here, the voltage difference V0 is a value set so as to obtain the target torque. As a result of the increase in the voltage difference, a current larger than the current necessary for obtaining the target torque is supplied to the motor, and the motor outputs a torque larger than the target torque.

On the other hand, when the rotational speed increases instantaneously, the motor induced voltage increases instantaneously, while the output of the inverter remains constant, so that the difference between the inverter output voltage and the motor induced voltage is shown in FIG. Decreases from Vb to Vc. As a result, only a current smaller than the current necessary for obtaining the target torque is supplied to the motor, and the output torque of the motor becomes too small.

As described above, since the motor output torque fluctuates with respect to the target torque due to an instantaneous fluctuation of the motor rotation speed, there is a problem that it is difficult to perform appropriate motor control.

Therefore, the present invention provides a drive device, an electric vehicle control method, an electric vehicle control program, and an electric vehicle capable of performing appropriate motor control even when the rotational speed of the motor instantaneously varies due to an external force. With the goal.

The drive device according to the present invention is
A signal receiving unit that receives a plurality of signals output from the rotational position sensor during one rotation of the motor that drives the load and that arrives at an interval corresponding to the rotational speed of the motor;
Based on the signal interval between the reception time of the first signal most recently received by the signal receiving unit and the reception time of the second signal received before the first signal, the instantaneous moment of the motor A rotation speed calculation unit for calculating the rotation speed;
A motor control unit that generates a PWM signal based on the instantaneous rotational speed and transmits the PWM signal to an inverter that supplies AC power to the motor to control the motor;
When the amount of change in the instantaneous rotation speed is equal to or greater than a predetermined value, the motor control unit determines the duty ratio of the PWM signal based on the instantaneous rotation speed, and the output voltage of the inverter corresponds to the instantaneous rotation speed. The correction is made so that

In the driving device,
The motor control unit may correct the duty ratio by linear interpolation using a characteristic straight line indicating a relationship between the instantaneous rotation speed and the corrected duty ratio.

In the driving device,
The linear interpolation may be performed every time the instantaneous rotational speed is calculated.

In the driving device,
The characteristic line is
A first point defined by a lower limit value of a rotation speed range centered on an average rotation speed calculated from a time during which the motor makes one rotation, and a duty ratio corresponding to the lower limit value;
A straight line connecting the upper limit value of the rotation speed range and the second point defined by the duty ratio corresponding to the upper limit value may be used.

In the driving device,
The rotation speed range may be determined in consideration of the fluctuation range of the instantaneous rotation speed of the motor.

In the driving device,
The characteristic line may be updated each time the average rotation speed is calculated.

In the driving device,
The rotation speed calculation unit is configured to multiply the count number counted for each monitoring time interval from when the second signal is received until the first signal is received by multiplying the signal by the monitoring time interval. The interval may be calculated.

In the driving device,
When the second signal is a signal received immediately before the first signal, the rotation speed calculation unit may calculate the instantaneous rotation speed according to the following equation.
n = 60000 / (ΔT × Np)
Here, n is the instantaneous rotational speed [rpm], ΔT is the signal interval [mSec], and Np is the number of the signals received by the signal receiving unit while the motor makes one electrical rotation. Is a value indicating

In the driving device,
The motor control unit searches a duty ratio map indicating a relationship among the target torque of the motor, the rotational speed of the motor, and the duty ratio of the PWM signal, using the target torque of the motor and the instantaneous rotational speed. By doing so, the duty ratio may be acquired.

In the driving device,
The load is a wheel of an electric vehicle,
The motor control unit may gradually increase the duty ratio of the PWM signal when the electric vehicle is started when the motor directly drives the wheels.

In the driving device,
The signal received by the signal receiving unit may be a rising edge signal or a falling edge signal of a pulse signal output from a rotational position sensor provided in the motor.

The electric vehicle according to the present invention is
It is the said drive device, Comprising: The said load is a drive device which is a wheel of an electric vehicle, It is characterized by the above-mentioned.

In the electric vehicle,
The wheel and the motor may be mechanically connected without a clutch.

The driving method according to the present invention includes:
A signal receiving unit that receives a plurality of signals output from the rotational position sensor while the motor driving the load makes one rotation and that arrives at an interval corresponding to the rotational speed of the motor;
The rotation speed calculation unit is based on a signal interval between the reception time of the first signal most recently received by the signal reception unit and the reception time of the second signal received before the first signal. Calculating the instantaneous rotational speed of the motor;
A motor control unit that generates a PWM signal based on the instantaneous rotational speed, and transmits the PWM signal to an inverter that supplies AC power to the motor to control the motor, and
When the amount of change in the instantaneous rotation speed is equal to or greater than a predetermined value, the motor control unit determines the duty ratio of the PWM signal based on the instantaneous rotation speed, and the output voltage of the inverter corresponds to the instantaneous rotation speed. The correction is made so that

The drive program according to the present invention is:
A signal receiving unit that receives a plurality of signals output from the rotational position sensor while the motor driving the load makes one rotation and that arrives at an interval corresponding to the rotational speed of the motor;
The rotation speed calculation unit is based on a signal interval between the reception time of the first signal most recently received by the signal reception unit and the reception time of the second signal received before the first signal. Calculating the instantaneous rotational speed of the motor;
A motor control unit that generates a PWM signal based on the instantaneous rotation speed, and transmits the PWM signal to an inverter that supplies AC power to the motor to control the motor; Because
When the amount of change in the instantaneous rotation speed is equal to or greater than a predetermined value, the motor control unit determines the duty ratio of the PWM signal based on the instantaneous rotation speed, and the output voltage of the inverter corresponds to the instantaneous rotation speed. The correction is made so that

In the present invention, the signal receiving unit receives a plurality of signals output from the rotational position sensor during one rotation of the motor and arrives at an interval corresponding to the rotational speed of the motor, and the rotational speed calculating unit The instantaneous rotation speed of the motor is calculated based on the signal interval between the first signal and the second signal, and the motor control unit instantaneously rotates when the calculated change amount of the instantaneous rotation speed is equal to or greater than a specified value. The duty ratio of the PWM signal is corrected based on the speed. The duty ratio is corrected so that the output voltage of the power converter becomes a value corresponding to the instantaneous rotation speed. Thus, according to the present invention, even when the rotational speed of the motor varies instantaneously due to an external force applied to the motor in accordance with the road surface condition or the like, the fluctuation of the output torque of the motor is suppressed and appropriate motor control is performed. Can do.

1 is a diagram showing a schematic configuration of an electric vehicle 100 according to an embodiment of the present invention. FIG. 3 is a diagram illustrating a schematic configuration of a power conversion unit 30 and a motor 3. 3 is a diagram showing a magnet provided on a rotor 3r of a motor 3 and an angle sensor 4. FIG. It is a figure which shows the relationship between a rotor angle and the output of an angle sensor. It is a timing chart for demonstrating the PWM control which concerns on embodiment. 2 is a functional block diagram of a control unit 10 of the electric vehicle control device 1. FIG. It is a figure for demonstrating the relationship between a sensor signal, and a count number. It is a figure for demonstrating the calculation process of the duty ratio of a PWM signal, or an output angle. (A) shows the configuration of the torque map, (b) shows the configuration of the duty ratio map, and (c) shows the configuration of the output angle map. It is a figure for demonstrating the time change of the output voltage of the inverter which concerns on this embodiment. It is a figure for demonstrating the instantaneous correction | amendment of the duty ratio by linear interpolation. It is a flowchart for demonstrating an example of the electric vehicle control method which concerns on embodiment. It is a graph which shows the time change of the duty ratio in the case of direct drive. It is a figure for demonstrating the subject of a prior art.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, an electric vehicle control device that drives and controls an electric vehicle will be described as an embodiment of the drive device according to the present invention. The drive device according to the present invention may drive a load other than the wheels of the electric vehicle.

First, an electric vehicle 100 according to the embodiment will be described with reference to FIG.

The electric vehicle 100 is a vehicle that travels by driving a motor using electric power supplied from a battery. In the present embodiment, the electric vehicle 100 is an electric motorcycle such as an electric motorcycle. More specifically, as shown in FIG. 1, the electric motorcycle 100 in which the motor 3 and the wheels 8 are mechanically directly connected without using a clutch. It is. The electric vehicle according to the present invention may be a vehicle in which the motor 3 and the wheels 8 are connected via a clutch. Moreover, it is not limited to a two-wheeled vehicle, For example, a three-wheeled or four-wheeled electric vehicle may be sufficient.

As shown in FIG. 1, the electric vehicle 100 includes an electric vehicle control device 1, a battery 2, a motor 3, an angle sensor (rotational position sensor) 4, an accelerator position sensor 5, an assist switch 6, a meter ( Display portion) 7, wheels 8, and charger 9.

Hereinafter, each component of the electric vehicle 100 will be described in detail.

The electric vehicle control device 1 is a device that controls the electric vehicle 100, and includes a control unit 10, a storage unit 20, and a power conversion unit (driver) 30. The electric vehicle control apparatus 1 may be configured as an ECU (Electronic Control Unit) that controls the entire electric vehicle 100.

Next, each component of the electric vehicle control device 1 will be described in detail.

The control unit 10 inputs information from various devices connected to the electric vehicle control device 1. Specifically, the control unit 10 receives various signals output from the battery 2, the angle sensor (rotational position sensor) 4, the accelerator position sensor 5, the assist switch 6, and the charger 9. The control unit 10 outputs a signal to be displayed on the meter 7. In addition, the control unit 10 controls the motor 3 through the power conversion unit 30. Details of the control unit 10 will be described later.

The storage unit 20 stores information (such as various maps described later) used by the control unit 10 and a program for operating the control unit 10. The storage unit 20 is, for example, a nonvolatile semiconductor memory, but is not limited to this. Note that the storage unit 20 may be incorporated as a part of the control unit 10.

The power converter 30 converts the DC power output from the battery 2 into AC power and supplies it to the motor 3. In the present embodiment, the power conversion unit 30 includes an inverter configured by a three-phase full bridge circuit as shown in FIG. Semiconductor switches Q1, Q3, and Q5 are high-side switches, and semiconductor switches Q2, Q4, and Q6 are low-side switches. The control terminals of the semiconductor switches Q1 to Q6 are electrically connected to the control unit 10. The semiconductor switches Q1 to Q6 are, for example, MOSFETs or IGBTs.

As shown in FIG. 2, a smoothing capacitor C is provided between the power supply terminal 30a and the power supply terminal 30b.

The input terminal 3 a is a U-phase input terminal of the motor 3, the input terminal 3 b is a V-phase input terminal of the motor 3, and the input terminal 3 c is a W-phase input terminal of the motor 3.

As shown in FIG. 2, the semiconductor switch Q <b> 1 is connected between a power supply terminal 30 a to which the positive electrode of the battery 2 is connected and an input terminal 3 a of the motor 3. Similarly, the semiconductor switch Q3 is connected between the power supply terminal 30a and the input terminal 3b of the motor 3. The semiconductor switch Q5 is connected between the power supply terminal 30a and the input terminal 3c of the motor 3.

The semiconductor switch Q2 is connected between the input terminal 3a of the motor 3 and the power supply terminal 30b to which the negative electrode of the battery 2 is connected. Similarly, the semiconductor switch Q4 is connected between the input terminal 3b of the motor 3 and the power supply terminal 30b. The semiconductor switch Q6 is connected between the input terminal 3c of the motor 3 and the power supply terminal 30b.

The battery 2 supplies power to the motor 3 that rotates the wheels 8 of the electric vehicle 100. The battery 2 supplies DC power to the power conversion unit 30. The battery 2 is, for example, a lithium ion battery, but may be another type of battery. Note that the number of the batteries 2 is not limited to one and may be plural. That is, the electric vehicle 100 may be provided with a plurality of batteries 2 connected in parallel or in series with each other. Further, the battery 2 may include a lead battery for supplying an operating voltage to the control unit 10.

Battery 2 includes a battery management unit (BMU). The battery management unit transmits battery information regarding the voltage of the battery 2 and the state of the battery 2 (charge rate, etc.) to the control unit 10.

The motor 3 is a motor that drives a load such as the wheel 8 by AC power supplied from the power conversion unit 30. In the present embodiment, the motor 3 is mechanically connected to the wheel 8 and rotates the wheel 8 in a desired direction. The motor 3 is a three-phase AC motor having a U phase, a V phase, and a W phase. As described above, the motor 3 is mechanically directly connected to the wheel 8 without using a clutch. In this embodiment, a three-phase brushless motor is used as the three-phase AC motor, but the type of the motor 3 is not limited to this.

The angle sensor 4 is a sensor that detects the rotational position of the rotor 3r of the motor 3. As shown in FIG. 3, N-pole and S-pole magnets (sensor magnets) are alternately attached to the circumferential surface of the rotor 3r. The angle sensor 4 is constituted by a Hall element, for example, and detects a change in the magnetic field accompanying the rotation of the motor 3. In addition, the number of the magnets shown in FIG. 3 is an example, and is not limited to this. Further, the magnet may be provided inside a flywheel (not shown).

As shown in FIG. 3, the angle sensor 4 includes a U-phase angle sensor 4 u associated with the U-phase of the motor 3, a V-phase angle sensor 4 v associated with the V-phase of the motor 3, and the W of the motor 3. And a W-phase angle sensor 4w associated with the phase. The

angle sensors

4u, 4v, 4w for each phase are provided in the motor 3. In the present embodiment, the U-phase angle sensor 4u and the V-phase angle sensor 4v are arranged so as to form an angle of 30 ° with respect to the rotor 3r. Similarly, the V-phase angle sensor 4v and the W-phase angle sensor 4w are arranged to form an angle of 30 ° with respect to the rotor 3r of the motor 3.

As shown in FIG. 4, the U-phase angle sensor 4u, the V-phase angle sensor 4v, and the W-phase angle sensor 4w output a pulse signal having a phase corresponding to the rotational position of the rotor 3r. The width of this pulse signal (or the time interval of the sensor signal) becomes narrower as the rotational speed of the motor 3 (ie, the wheel 8) is higher.

As shown in FIG. 4, a number (motor stage number) indicating a motor stage is assigned to each predetermined rotational position. The motor stage indicates the rotational position of the rotor 3r. In this embodiment,

motor stage numbers

1, 2, 3, 4, 5, and 6 are assigned for each electrical angle of 60 °.

The output stage is also called an energization stage, and is obtained by adding a time based on the output angle to the motor stage detected by the angle sensor 4. As will be described later, the output angle changes according to the rotational speed of the motor 3 and the target torque.

The control unit 10 performs on / off control of the semiconductor switches Q1 to Q6 of the power conversion unit 30 using the PWM signal. Thereby, the DC power supplied from the battery 2 is converted into AC power. In the present embodiment, as shown in FIG. 5, the U-phase low-side switch (semiconductor switch Q2) is PWM-controlled at the output stages 6, 1, 2, and 3. The V-phase low-side switch (semiconductor switch Q4) is PWM-controlled at the output stages 2, 3, 4, and 5, and the W-phase low-side switch (semiconductor switch Q6) is PWM-controlled at the output stages 4, 5, 6, and 1. . The stage on which PWM control is performed is determined by the energization method or the like, and is not limited to this example.

As described above, the on / off control of the low-side switch instead of the high-side switch can prevent the current generated by the regenerative operation of the motor 3 from flowing into the battery 2. In addition, when inflow of the regenerative current to the battery 2 is permitted, the high-side switch may be controlled on and off.

As shown in FIG. 5, there is a timing when the high side switch is also turned on. For example, the semiconductor switch Q1, which is a U-phase high-side switch, is turned on at predetermined time intervals in the output stages 1 and 2. Thus, heat generation of the power conversion unit 30 can be suppressed by turning on the high-side switch. Note that when a high-side switch is controlled to be turned on to prevent a current short circuit, the corresponding low-side switch (ie, in the same arm) is controlled to be off.

The accelerator position sensor 5 detects an operation amount (hereinafter referred to as “accelerator operation amount”) with respect to the accelerator of the electric vehicle 100 and transmits it to the control unit 10 as an electric signal. The accelerator operation amount corresponds to the throttle opening of the engine vehicle. The accelerator operation amount increases when the user wants to accelerate, and the accelerator operation amount decreases when the user wants to decelerate.

The assist switch 6 is a switch that is operated when the user requests assistance from the electric vehicle 100. The assist switch 6 transmits an assist request signal to the control unit 10 when operated by the user. Then, the control unit 10 controls the motor 3 to generate assist torque.

The meter (display unit) 7 is a display (for example, a liquid crystal panel) provided in the electric vehicle 100 and displays various information. The meter 7 is provided, for example, on a handle (not shown) of the electric vehicle 100. The meter 7 displays information such as the traveling speed of the electric vehicle 100, the remaining amount of the battery 2, the current time, the total traveling distance, and the remaining traveling distance. The remaining travel distance indicates how far the electric vehicle 100 can travel.

The charger 9 has a power plug (not shown) and a converter circuit (not shown) for converting an AC power supplied via the power plug into a DC power. The battery 2 is charged by the DC power converted by the converter circuit. The charger 9 is connected to the electric vehicle control device 1 through a communication network (CAN or the like) in the electric vehicle 100 so as to be communicable.

Next, the control unit 10 of the electric vehicle control device 1 will be described in detail.

As shown in FIG. 6, the control unit 10 includes a signal reception unit 11, a rotation speed calculation unit 12, and a motor control unit 13. The processing in each unit of the control unit 10 can be realized by software (program).

The signal receiving unit 11 receives signals that arrive at intervals corresponding to the rotation speed of the motor 3. A plurality of signals are output from the angle sensor 4 while the motor 3 rotates once. More specifically, the signal receiving unit 11 receives sensor signals (that is, rising edge signals or falling edge signals of pulse signals) output from the U-phase angle sensor 4u, the V-phase angle sensor 4v, and the W-phase angle sensor 4w. To do. In the present embodiment, the signal receiving unit 11 receives a sensor signal every time the rotor 3r of the motor 3 rotates 60 degrees in electrical angle. Therefore, the signal receiving unit 11 receives six sensor signals while the motor 3 makes one rotation at an electrical angle. As the rotational speed of the motor 3 increases, the time interval at which the sensor signal arrives decreases.

As shown in FIG. 7, the signal receiving unit 11 checks whether or not a sensor signal is received from the angle sensor 4 at every monitoring time interval Δtm. The monitor time interval Δtm is a control time interval of the motor 3, for example. The sensor signal may be received by an interrupt process from the angle sensor 4.

The monitoring time interval Δtm is shorter than the time interval of the sensor signal received by the signal receiving unit 11 when the electric vehicle 100 travels at the maximum speed, for example, 50 microseconds. More generally speaking, the monitoring time interval Δtm is shorter than the time interval of the sensor signal received by the signal receiving unit 11 when the rotation speed of the motor 3 is maximum.

Rotational speed calculation unit 12 calculates the instantaneous rotational speed of motor 3 based on the signal interval (also called inter-sensor time). Here, the signal interval is a time interval between the reception time of the first signal most recently received by the signal receiving unit 11 and the reception time of the second signal received before the first signal. is there. In the present embodiment, the second signal is a signal received immediately before the first signal. However, the second signal is not limited to this, and is a signal received two or more times before the first signal. May be.

In this embodiment, as shown in FIG. 7, the signal interval ΔT is determined by the reception time of the sensor signal S1 most recently received by the signal receiving unit 11 and the sensor signal S2 received immediately before this sensor signal S1. This is the time interval from the reception time. In this case, the rotation speed calculation unit 12 calculates the instantaneous rotation speed of the motor 3 according to Equation (1).
n = 60000 / (ΔT × Np) (1)
Here, n is the instantaneous rotational speed [rpm] of the motor 3, ΔT is the signal interval [mSec], and Np is the sensor signal received by the signal receiving unit 11 while the motor 3 makes one electrical rotation. Is a number.

In the present embodiment, the rotation speed calculation unit 12 uses a count number counted every monitoring time interval Δtm as the signal interval ΔT. When the signal receiving unit 11 has not received the sensor signal, the signal receiving unit 11 or the rotation speed calculation unit 12 increases the count number at every monitoring time interval Δtm. This count number indicates the time that has elapsed since the most recent sensor signal was received. The initial value of the count number is zero. When the signal receiving unit 11 receives the sensor signal, the count number N is reset (that is, returns to the initial value).

The rotation speed calculation unit 12 calculates the signal interval ΔT by multiplying the count number N counted between the reception of the sensor signal S1 and the reception of the sensor signal S2 by the monitoring time interval Δtm.

When measuring the signal interval by the number of counts, the rotation speed calculation unit 12 calculates the instantaneous rotation speed of the motor 3 using Equation (2).
n = 60000 / (NΔtm × Np) (2)
Here, n is an instantaneous rotational speed [rpm] of the motor 3, N is a count number counted from the reception of the sensor signal S2 to the reception of the sensor signal S1, and Δtm is a monitoring time interval [mSec]. Np is the number of sensor signals received by the signal receiver 11 while the motor 3 makes one rotation at an electrical angle.

The motor control unit 13 generates a PWM signal for causing the motor 3 to generate a desired torque based on the instantaneous rotation speed calculated by the rotation speed calculation unit 12. Then, the motor control unit 13 controls the motor 3 by transmitting the generated PWM signal to the power conversion unit 30.

In the present embodiment, the motor control unit 13 calculates a duty ratio and an output angle (energization timing) based on the instantaneous rotation speed and the target torque, and outputs a PWM signal having the calculated duty ratio at the calculated output angle. The power is output to the power conversion unit 30. Thereby, the motor 3 is controlled to generate the target torque. The generation of the PWM signal is performed every monitoring time interval, but may be performed every time the sensor signal is received or may be performed every time the motor 3 rotates once.

The calculation of the duty ratio and the output angle will be described in detail with reference to FIGS. The motor control unit 13 acquires the target torque by searching the torque map M1 using the accelerator operation amount received from the accelerator position sensor 5 and the instantaneous rotation speed calculated by the rotation speed calculation unit 12. Here, the torque map M1 is a map showing the relationship among the accelerator operation amount, the rotational speed of the motor 3, and the target torque of the motor 3, as shown in FIG.

Next, the motor control unit 13 acquires the duty ratio by searching the duty ratio map M2 using the target torque acquired from the torque map M1 and the instantaneous rotation speed calculated by the rotation speed calculation unit 12. . Here, the duty ratio map M2 is a map showing the relationship among the target torque of the motor 3, the rotational speed of the motor 3, and the duty ratio of the PWM signal, as shown in FIG. 9B.

Further, the motor control unit 13 acquires the output angle by searching the output angle map M3 using the target torque acquired from the torque map M1 and the instantaneous rotation speed calculated by the rotation speed calculation unit 12. Here, the output angle map M3 is a map showing the relationship among the target torque of the motor 3, the rotational speed of the motor 3, and the output angle of the PWM signal, as shown in FIG. 9C.

When the control unit 10 controls the power conversion unit 30 using a plurality of energization methods (for example, 120 ° energization method and 180 ° energization method), the duty ratio map M2 and the output angle map M3 correspond to each energization method. Used. That is, when the 120 ° energization method is used, the duty ratio and the output angle are obtained using the duty ratio map and the output angle map for the 120 ° energization method, and when the 180 ° energization method is used, the 180 ° energization method is used. The duty ratio and the output angle are acquired using the duty ratio map and the output angle map.

The PWM signal having the duty ratio acquired as described above is output to the power conversion unit 30 at the output angle acquired as described above, and the semiconductor switches Q1 to Q6 are on / off controlled. Thereby, the motor 3 is controlled to generate a desired torque.

Next, the instantaneous correction of the duty ratio by the motor control unit 13 will be described in detail with reference to FIG. 10 and FIG.

The motor control unit 13 corrects the duty ratio of the PWM signal based on the instantaneous rotation speed when the change amount of the instantaneous rotation speed calculated by the rotation speed calculation unit 12 is equal to or greater than a specified value. As will be described in detail later, the duty ratio is corrected so that the output voltage of the inverter (power conversion unit 30) becomes a value corresponding to the instantaneous rotation speed. That is, the duty ratio is corrected so that the output voltage of the inverter becomes a value corresponding to the motor induced voltage.

In the example shown in FIG. 10, until time t1, the difference between the output voltage of the inverter and the motor induced voltage (voltage induced by the rotation of the motor 3) (hereinafter simply referred to as “voltage difference”) was V0. Thereafter, the instantaneous rotational speed decreased instantaneously from time t1, and the amount of decrease in the instantaneous rotational speed reached the specified value Δn1 at time t2. As a result of the motor induced voltage decreasing with the decrease in the instantaneous rotational speed, the voltage difference temporarily increases between times t1 and t2, as shown in FIG.

However, when the amount of decrease in the instantaneous rotational speed reaches the specified value Δn1, the motor control unit 13 corrects the duty ratio of the PWM signal based on the instantaneous rotational speed. By driving the inverter with the PWM signal having the corrected duty ratio, as shown in FIG. 10, the output voltage of the inverter is lowered, so that the voltage difference is reduced (the voltage difference is V1 in the steady state). Since the voltage difference is suppressed from increasing by instantaneously correcting the duty ratio in this way, a current that matches the target torque flows to the motor 3 and the output torque can be prevented from becoming excessive.

The same applies when the instantaneous rotation speed increases. In the example shown in FIG. 10, the voltage difference was V1 until time t3. Thereafter, the instantaneous rotation speed increased instantaneously from time t3, and the increase amount of the instantaneous rotation speed reached the specified value Δn2 at time t4. As the instantaneous rotational speed increases, the motor induced voltage also increases. As a result, the voltage difference temporarily decreases between times t3 and t4.

However, when the increase amount of the instantaneous rotational speed reaches the specified value Δn2, the motor control unit 13 corrects the duty ratio of the PWM signal based on the instantaneous rotational speed. By driving the inverter with the PWM signal having the corrected duty ratio, as shown in FIG. 10, the output voltage of the inverter rises, so that the voltage difference increases (the voltage difference becomes V2 in the steady state). As a result, a current that matches the target torque flows through the motor 3, and the output torque can be suppressed from becoming too small.

In the present embodiment, the specified value Δn1 and the specified value Δn2 are determined by the amount of change in the count number. For example, in FIG. 7, the count number counted between the sensor signal S1 and the sensor signal S2 is more than a specified value (or less) than the count number counted between the sensor signal S2 and the sensor signal S3. In this case, instantaneous correction of the duty ratio is performed.

Next, a method for instantaneously correcting the duty ratio by linear interpolation will be described with reference to FIG. A characteristic line L indicating the relationship between the instantaneous rotation speed and the corrected duty ratio is used. The characteristic line L is a straight line connecting the points A and B. Here, the point A is a point defined by the lower limit value X1 of the rotation speed range R centering on the average rotation speed Nav and the duty ratio Y1 corresponding to the instantaneous rotation speed of the lower limit value X1. The average rotation speed Nav is a rotation speed calculated from the time for which the motor 3 rotates once. Point B is a point defined by an upper limit value X2 of the rotation speed range R and a duty ratio Y2 corresponding to the instantaneous rotation speed of the upper limit value X2.

The duty ratios Y1 and Y2 are acquired from the duty ratio map M2. That is, the duty ratio Y1 is obtained by searching the duty ratio map M2 using the instantaneous rotation speed at the lower limit value X1 and the target torque at that time, and the duty ratio Y2 is obtained by calculating the instantaneous rotation speed at the upper limit value X2. Then, it is acquired by searching the duty ratio map M2 using the target torque at that time.

For the rotation speed range R, the following relational expression holds.
X1 = Nav−f (3)
X2 = Nav + f (4)
Here, f is the fluctuation range of the instantaneous rotation speed of the motor 3.

The fluctuation range f is the maximum value at which the instantaneous rotational speed deviates from the average rotational speed Nav due to the condition of the road surface on which the electric vehicle 100 travels, the accuracy of the angle sensor 4, and the like. The fluctuation range f is, for example, 500 rpm. Thus, by defining the rotation speed range R in consideration of the fluctuation range f of the instantaneous rotation speed of the motor 3, even when the instantaneous rotation speed fluctuates greatly due to changes in road surface conditions, the accuracy of the angle sensor 4, etc. The linear interpolation can be performed to correct the duty ratio instantaneously.

The characteristic line L is updated every time the average rotation speed is calculated by the rotation speed calculation unit 12. That is, every time the average rotation speed is calculated, the rotation speed range R is updated, and the duty ratios corresponding to the instantaneous rotation speeds of the lower limit value and the upper limit value of the rotation speed range R are respectively set in the torque map M1 and the duty ratio map M2. The characteristic straight line L is updated by obtaining using. Thereby, linear interpolation using the characteristic straight line L suitable for the running state of the electric vehicle 100 can be performed, and the accuracy of instantaneous correction of the duty ratio can be maintained high.

Note that the characteristic line L may be updated in accordance with the change in the accelerator operation amount received from the accelerator position sensor 5. Thereby, the duty ratio can be corrected with higher accuracy.

In this embodiment, linear interpolation is performed using the characteristic straight line L connecting the points A and B, and the duty ratio is corrected. That is, as shown in FIG. 11, the value of the characteristic line L corresponding to the instantaneous rotation speed Nm calculated by the rotation speed calculation unit 12 is obtained as the corrected duty ratio. Linear interpolation is performed every time the rotational speed calculation unit 12 calculates the instantaneous rotational speed.

As described above, in the electric vehicle control device 1 according to the present embodiment, the signal receiving unit 11 is a sensor signal output from the angle sensor 4 while the motor 3 makes one rotation, and the rotation speed of the motor 3. The rotation speed calculation unit 12 calculates the instantaneous rotation speed of the motor 3 based on the signal interval ΔT between the sensor signal S1 and the sensor signal S2, and receives a sensor signal that arrives at an interval according to the motor control unit. 13 corrects the duty ratio of the PWM signal based on the instantaneous rotational speed when the calculated change amount of the instantaneous rotational speed is equal to or greater than a specified value. The duty ratio is corrected so that the output voltage of the power conversion unit 30 (inverter) becomes a value corresponding to the instantaneous rotation speed (that is, the motor induced voltage). That is, the duty ratio of the PWM signal is instantaneously corrected according to instantaneous fluctuations in the rotation speed of the motor 3 so that the voltage difference between the inverter and the motor induced voltage does not deviate from the value based on the target torque. To. Thereby, according to this embodiment, even if it is a case where a rotational speed fluctuates instantaneously with the external force added to the motor 3 according to a road surface state, the fluctuation | variation of the output torque of the motor 3 is suppressed, and appropriate motor control is performed. It can be performed.

<Electric vehicle control method>
Next, an example of the electric vehicle control method according to the present embodiment will be described with reference to the flowchart of FIG. It is assumed that the count number has been initialized in advance.

The signal receiving unit 11 determines whether or not the monitor time interval Δtm has elapsed (step S11). When the monitoring time interval Δtm has elapsed (S11: Yes), it is determined whether a sensor signal has been received from the angle sensor 4 (step S12). When the sensor signal is not received (S12: No), the count number is increased by 1 (step S13), and the process returns to step S11.

On the other hand, when the sensor signal is received (S12: Yes), the rotation speed calculation unit 12 calculates the instantaneous rotation speed of the motor 3 based on the count number counted between the sensor signal S1 and the sensor signal S2. (Step S14). Then, the rotation speed calculation unit 12 resets the count number to an initial value (step S15). The count number may be reset at any timing of steps S15 to S19.

Next, the motor control unit 13 obtains the duty ratio and output angle of the PWM signal based on the instantaneous rotation speed calculated in step S14 and the accelerator operation amount received from the accelerator position sensor 5 (step S16). Specifically, as described with reference to FIG. 8, the duty ratio and output angle of the PWM signal are obtained by using the torque map M1, the duty ratio map M2, and the output angle map M3.

Next, the motor control unit 13 determines whether or not the amount of change in the instantaneous rotation speed calculated in step S14 is equal to or greater than a specified value (step S17). In this step, for example, the current count (the count between the sensor signal S1 and the sensor signal S2) is greater than the previous count (the count between the sensor signal S2 and the sensor signal S3). This is done by determining whether it is greater (or less) than a specified value.

If the change amount of the instantaneous rotation speed is equal to or greater than the specified value (S17: Yes), the duty ratio obtained in step S16 is corrected (step S18). The correction in this step is performed by, for example, linear interpolation using the characteristic line L described above. Thereafter, the PWM signal having the corrected duty ratio is transmitted to the inverter to control the motor 3 (step S19).

On the other hand, when the change amount of the instantaneous rotational speed is less than the specified value (S17: No), the process proceeds to step S19 without correcting the duty ratio, and the PWM signal having the duty ratio obtained in step S16 is transmitted to the inverter.

According to the above driving method, even when the rotation speed fluctuates instantaneously due to the external force applied to the motor 3 according to the road surface state, the fluctuation of the output torque of the motor 3 is suppressed and appropriate motor control is performed. be able to.

In the above processing flow, the count number is used, but the signal interval may be calculated using the reception time of the sensor signal to calculate the instantaneous rotation speed. Further, when the sensor signal is not received (S12: No), the duty ratio may be acquired from the duty ratio map M2 using the latest accelerator operation amount and the instantaneous rotation speed calculated last time. Then, the characteristic straight line L may be updated using the acquired duty ratio, or the PWM signal transmitted to the power conversion unit 30 may be updated.

In some electric vehicles, the motor 3 directly drives the wheels 8 (a so-called direct drive system), and a so-called hub damper is not provided. The present invention can also be applied to such an electric vehicle. In this case, it is preferable that the motor control unit 13 gradually increase the duty ratio of the PWM signal when the electric vehicle 100 is started (at the time of low rotation) as shown in FIG. Thereby, even if it is a case of a direct drive system, the electric vehicle 100 can be started smoothly.

At least a part of the electric vehicle control device 1 (control unit 10) described in the above-described embodiment may be configured by hardware or software. When configured by software, a program for realizing at least a part of the functions of the control unit 10 may be stored in a recording medium such as a flexible disk or a CD-ROM, and read and executed by a computer. The recording medium is not limited to a removable medium such as a magnetic disk or an optical disk, but may be a fixed recording medium such as a hard disk device or a memory.

Further, a program that realizes at least a part of functions of the control unit 10 may be distributed via a communication line (including wireless communication) such as the Internet. Further, the program may be distributed in a state where the program is encrypted, modulated or compressed, and stored in a recording medium via a wired line such as the Internet or a wireless line.

Based on the above description, those skilled in the art may be able to conceive additional effects and various modifications of the present invention, but the aspects of the present invention are not limited to the individual embodiments described above. . You may combine suitably the component covering different embodiment. Various additions, modifications, and partial deletions can be made without departing from the concept and spirit of the present invention derived from the contents defined in the claims and equivalents thereof.

DESCRIPTION OF SYMBOLS 1 Electric vehicle control apparatus 2 Battery 3 Motor 3r Rotor 4 Angle sensor 4u U-phase angle sensor 4v V-phase angle sensor 4w W-phase angle sensor 5 Accelerator position sensor 6 Assist switch 7 Meter 8 Wheel 9 Charger 10 Control part 11 Signal receiving part 12 rotational speed calculation unit 13 motor control unit 20 storage unit 30 power conversion unit 100 electric vehicle f fluctuation range L characteristic straight line M1 torque map M2 duty ratio map M3 output angle map Nav average rotational speed Q1, Q2, Q3, Q4, Q5 Q6 Semiconductor switch R Rotational speed range S1, S2, S3 Sensor signal

Claims

A signal receiving unit that receives a plurality of signals output from the rotational position sensor during one rotation of the motor that drives the load and that arrives at an interval corresponding to the rotational speed of the motor;
Based on the signal interval between the reception time of the first signal most recently received by the signal receiving unit and the reception time of the second signal received before the first signal, the instantaneous moment of the motor A rotation speed calculation unit for calculating the rotation speed;
A motor control unit that generates a PWM signal based on the instantaneous rotation speed, transmits the PWM signal to a power conversion unit that supplies AC power to the motor, and controls the motor;
When the amount of change in the instantaneous rotation speed is equal to or greater than a specified value, the motor control unit determines the duty ratio of the PWM signal based on the instantaneous rotation speed, and the output voltage of the power conversion unit depends on the instantaneous rotation speed. A drive device characterized in that the correction is made so as to obtain a correct value.
2. The driving apparatus according to claim 1, wherein the motor control unit corrects the duty ratio by linear interpolation using a characteristic straight line indicating a relationship between the instantaneous rotation speed and the corrected duty ratio.
3. The driving apparatus according to claim 2, wherein the linear interpolation is performed every time the instantaneous rotation speed is calculated.
The characteristic line is
A first point defined by a lower limit value of a rotation speed range centered on an average rotation speed calculated from a time during which the motor makes one rotation, and a duty ratio corresponding to the lower limit value;
3. The drive device according to claim 2, wherein the drive device is a straight line connecting an upper limit value of the rotation speed range and a second point defined by a duty ratio corresponding to the upper limit value.
The drive device according to claim 4, wherein the rotation speed range is determined in consideration of a fluctuation range of an instantaneous rotation speed of the motor.
The driving apparatus according to claim 4, wherein the characteristic straight line is updated each time the average rotation speed is calculated.
The rotation speed calculation unit is configured to multiply the count number counted for each monitoring time interval from when the second signal is received until the first signal is received by multiplying the signal by the monitoring time interval. The driving apparatus according to claim 1, wherein the interval is calculated.
The rotation speed calculation unit calculates the instantaneous rotation speed according to the following equation when the second signal is a signal received immediately before the first signal. The drive device described.
n = 60000 / (ΔT × Np)
Here, n is the instantaneous rotational speed [rpm], ΔT is the signal interval [mSec], and Np is the number of the signals received by the signal receiving unit while the motor makes one electrical rotation. Is a value indicating
The motor control unit searches a duty ratio map indicating a relationship among the target torque of the motor, the rotational speed of the motor, and the duty ratio of the PWM signal, using the target torque of the motor and the instantaneous rotational speed. The drive device according to claim 1, wherein the duty ratio is acquired by performing the operation.
The load is a wheel of an electric vehicle,
2. The driving apparatus according to claim 1, wherein the motor control unit gradually increases a duty ratio of the PWM signal when the electric vehicle is started when the motor directly drives the wheels.
2. The driving apparatus according to claim 1, wherein the signal received by the signal receiving unit is a rising edge signal or a falling edge signal of a pulse signal output from a rotational position sensor provided in the motor. .
2. An electric vehicle according to claim 1, further comprising a drive device in which the load is a wheel of the electric vehicle.
The electric vehicle according to claim 12, wherein the wheel and the motor are mechanically connected without a clutch.
A signal receiving unit that receives a plurality of signals output from the rotational position sensor while the motor driving the load makes one rotation and that arrives at an interval corresponding to the rotational speed of the motor;
The rotation speed calculation unit is based on a signal interval between the reception time of the first signal most recently received by the signal reception unit and the reception time of the second signal received before the first signal. Calculating the instantaneous rotational speed of the motor;
A motor control unit that generates a PWM signal based on the instantaneous rotation speed, and transmits the PWM signal to a power conversion unit that supplies AC power to the motor to control the motor, and
When the amount of change in the instantaneous rotation speed is equal to or greater than a specified value, the motor control unit determines the duty ratio of the PWM signal based on the instantaneous rotation speed, and the output voltage of the power conversion unit depends on the instantaneous rotation speed. The driving method is characterized in that the correction is made so that the value becomes the same.
A signal receiving unit that receives a plurality of signals output from the rotational position sensor while the motor driving the load makes one rotation and that arrives at an interval corresponding to the rotational speed of the motor;
The rotation speed calculation unit is based on a signal interval between the reception time of the first signal most recently received by the signal reception unit and the reception time of the second signal received before the first signal. Calculating the instantaneous rotational speed of the motor;
A motor control unit that generates a PWM signal based on the instantaneous rotation speed, and transmits the PWM signal to a power conversion unit that supplies AC power to the motor to control the motor; A driving program,
When the amount of change in the instantaneous rotation speed is equal to or greater than a predetermined value, the motor control unit determines the duty ratio of the PWM signal based on the instantaneous rotation speed, and the output voltage of the power conversion unit according to the instantaneous rotation speed. A drive program characterized by correcting the value so as to obtain a correct value.