JP4692137B2 - Control device for electric vehicle motor - Google Patents

Description

  The present invention relates to a control device that controls a motor of an electric vehicle such as an electric vehicle or an electric scooter according to a throttle operation.

  A conventional control device for an electric vehicle motor is configured as shown in FIG. 12, for example. In the figure, 1 is a motor, 2 is a motor driving force transmission mechanism that transmits the rotation of the motor 1 to the drive wheels 3 of the electric vehicle, and 4 is a battery. 5 is a throttle operated to adjust the traveling speed of the vehicle, 6 is a throttle sensor that detects the opening of the throttle 5 (throttle opening) and outputs an electrical signal proportional to the detected throttle opening; A motor control unit 7 ′ controls the motor 1 in accordance with the operation of the throttle 5. The motor control unit 7 ′ calculates the throttle opening degree detecting means 8 for detecting the throttle opening degree from the electric signal output from the throttle sensor 6, and calculates the duty ratio for the throttle opening degree detected by the throttle opening degree detecting means 8. A duty ratio calculating means 9 'and a motor driving section 10' for supplying the motor 1 with an intermittent driving current at the duty ratio calculated by the duty ratio calculating means 9 '.

  The motor drive unit 10 ′ includes a motor drive signal generation unit 11 ′ that generates a drive signal Vd including information on the duty ratio of the drive current supplied to the motor 1, and a drive necessary for rotating the motor 1 in a predetermined direction. The motor drive circuit 12 supplies the motor 1 with PWM modulation of the current with a duty ratio DF given by the drive signal Vd.

  Like the inverter circuit, the motor drive circuit 12 is composed of a bridge-type switch circuit in which each side of the bridge is configured by a switch element such as a MOSFET, and is driven from the battery 4 to the motor 1 through the switch element in an on state. Supply current.

  The motor drive signal generation means 11 ′ is calculated by the duty ratio calculation means 9 ′ to switch elements that need to be turned on in order to rotate the motor 1 in a predetermined direction among the switch elements of the motor drive circuit. By supplying a drive signal having an intermittent waveform with the duty ratio DF, the switch element of the motor drive circuit is intermittently formed, and the drive current applied to the motor 1 is converted into a PWM-modulated waveform.

  The duty ratio DF of the drive current is given by DF = Ton / T = Ton / (Ton + Toff) where T is the PWM control cycle, Ton is the time during which the drive current flows, and Toff is the time during which the drive current does not flow. It is done.

In the control device shown in FIG. 12, a duty ratio corresponding to the opening degree of the throttle 5 is calculated by the duty ratio calculating means 9 ′, and the drive current supplied from the battery 4 to the motor 1 through the motor drive circuit 12 is The rotation speed of the motor is adjusted to a magnitude commensurate with the opening of the throttle 5 by performing PWM control so as to be calculated and intermittent at a duty ratio. This type of motor control device is described in, for example, Patent Literature 1 and Patent Literature 2.
Japanese Patent Laid-Open No. 9-327101 JP 9-238402 A

  Generally, in an electric vehicle such as an electric vehicle that operates using a battery as a power source, a DC motor is used as the motor 1. In the DC motor, a large drive current flows during low-speed rotation, as can be seen from the motor drive current I versus rotational speed N characteristics shown in FIG. For this reason, when traveling at a relatively low speed by increasing the throttle opening, for example, when traveling uphill, a large drive current flows through the motor, and a large amount of heat is generated by the motor drive circuit 12 or the armature coil of the motor. When the motor is operated for a long time in this state, the switch element of the motor drive circuit and the armature coil of the motor may be thermally destroyed.

  Therefore, in the control device disclosed in Patent Document 2, when the motor overload state is detected, control is performed to limit the duty ratio of the motor drive current to a small value immediately, so that the components of the motor drive circuit And the armature coil of the motor is prevented from being thermally destroyed.

  However, as shown in Patent Document 2, if the control for limiting the duty ratio of the drive current of the motor is performed immediately when the overload state of the motor is detected, the output torque of the motor is limited. There arises a problem that the desired climbing performance cannot be obtained.

  SUMMARY OF THE INVENTION An object of the present invention is to enable a motor drive without greatly sacrificing the driving performance of the vehicle by enabling the driving to be performed while pulling out the performance of the motor as much as possible even in the driving state in which the motor is overloaded. An object of the present invention is to provide an electric vehicle motor control apparatus capable of protecting circuit components and motor armature coils.

  The present invention relates to an electric vehicle that controls a motor of an electric vehicle including a battery, a motor that drives a driving wheel of the vehicle, and a throttle that is operated to adjust a traveling speed of the vehicle in accordance with an operation of the throttle. The present invention relates to a motor control device. In the present invention, motor drive signal generation means for generating a drive signal including information on the duty ratio of the drive current supplied to the motor and the duty ratio given by the drive signal are intermittent. A motor drive circuit for supplying a PWM-modulated drive current from the battery to the motor, a vehicle speed detection means for detecting the running speed of the vehicle, a temperature detection means for detecting the temperature of the motor drive circuit, and a throttle opening degree Throttle opening detection means for detecting the opening, and a first duty that increases as the throttle opening increases. A first duty ratio calculating means for calculating the tee ratio with respect to the throttle opening detected by the throttle opening detecting means, and a temperature detecting means when the vehicle speed detected by the vehicle speed detecting means is lower than a set value. As the detected temperature rises, the value tends to decrease. The lower the detected vehicle speed, the smaller the value at each temperature, and the detected temperature reaches the limit value. Second duty ratio calculating means for calculating a second duty ratio that is 0 regardless of the vehicle speed that has been detected, with respect to the temperature detected by the temperature detecting means and the vehicle speed detected by the vehicle speed detecting means. Provided. The motor drive signal generation means is configured to generate a signal including information on the smaller duty ratio of the first duty ratio and the second duty ratio as a drive signal.

  With the above configuration, when the temperature of the motor drive circuit rises while the vehicle speed is lower than the set value, the duty ratio of the motor drive current is limited. Even if an overload condition occurs, if the temperature of the motor drive circuit is low, the second duty ratio does not fall below the first duty ratio, so the motor drive current is not immediately limited, A driving current necessary for traveling of the vehicle is supplied to the motor. When the temperature of the motor drive circuit rises while the throttle opening is kept large for a long time at a low vehicle speed, the second duty ratio will eventually become smaller than the first duty ratio. The motor drive current is limited, and the components of the motor drive circuit and the armature coil of the motor are prevented from being thermally destroyed.

  In another preferred aspect of the present invention, a motor drive signal generation means, a motor drive circuit, a vehicle speed detection means, a temperature detection means, a throttle opening detection means, a throttle operation amount detection means, a first configuration configured as described above. In addition to the duty ratio calculating means and the second duty ratio calculating means, at a rate commensurate with the operation amount per unit time of the throttle detected by the throttle operation amount detecting means when the throttle is operated in the opening direction. The value tends to increase, and when the throttle is operated in the closing direction, the value tends to decrease at a rate commensurate with the throttle operation amount per unit time detected by the throttle operation amount detection means. When the operation is not performed, the third value decreases toward zero as time elapses. A third duty ratio calculating means for calculating the duty ratio by determining the limit value, and a fourth duty ratio calculating for calculating the fourth duty ratio by adding the third duty ratio to the second duty ratio. Means. In this case, the motor drive signal generation means is configured to generate a signal including information on the smaller duty ratio of the first duty ratio and the fourth duty ratio as a drive signal.

  The third duty ratio calculation means includes a correction duty ratio calculation means for calculating a correction duty ratio that increases / decreases at a predetermined rate in accordance with an increase / decrease in the operation amount per unit time of the throttle at a minute time interval, and throttle opening detection The corrected duty ratio newly calculated by the correction duty ratio calculation means when the operation of the throttle opening direction is detected from the change in the throttle opening detected by the means is added to the previously calculated correction duty ratio. When it is detected from the change in the throttle opening detected by the throttle opening detection means that the throttle is operated in the closing direction, the correction duty ratio calculation means newly calculated the correction duty ratio previously calculated. Correction duty ratio accumulating means for performing a subtraction operation from the correction duty ratio, and a fixed time Duty ratio subtracting means for subtracting a constant value from the calculation result by the correction duty ratio accumulating means every time it passes, and calculation by the duty ratio subtracting means when the calculation result by the duty ratio subtracting means is less than or equal to the set limit value The result is output as a third duty ratio, and when the calculation result by the duty ratio subtracting means exceeds the limit value, the third duty ratio output means is configured to output the limit value as the third duty ratio. Can do.

  With the above configuration, the throttle is greatly operated to accelerate the vehicle even when there is a need to limit the motor drive current because the vehicle speed is low and the temperature of the motor drive circuit is high. In this case, the third duty ratio can be increased to temporarily increase the motor drive current, so that the motor drive circuit and the armature coil of the motor are thermally destroyed without sacrificing the acceleration performance of the vehicle. Can be prevented.

  As described above, according to the present invention, when the overload state of the motor occurs, the drive current is not limited immediately, but when the temperature of the motor drive circuit rises when the vehicle speed is lower than the set value. Since the motor drive current is limited, when the motor is temporarily overloaded during climbing, etc., the motor drive current is immediately limited to prevent the vehicle's running performance from deteriorating. Therefore, the components of the motor drive circuit and the armature coil of the motor can be protected without greatly sacrificing the driving performance of the vehicle.

  According to the second aspect of the present invention, even when the vehicle speed is low and the temperature of the motor drive circuit is high, it is necessary to limit the drive current of the motor. When the throttle is greatly operated for acceleration, the motor drive current can be temporarily increased, so that the motor drive circuit and the armature coil of the motor are destroyed without sacrificing the acceleration performance of the vehicle. The advantage is that it can be prevented.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows the configuration of the first embodiment of the present invention. In FIG. 1, parts that are the same as the parts of the control device shown in FIG. In FIG. 1, 1 is a motor, 2 is a motor driving force transmission mechanism that transmits the rotation of the motor 1 to driving wheels 3 of an electric vehicle, 4 is a battery, 5 is a throttle that is operated to adjust the traveling speed of the vehicle, A throttle sensor 6 detects the opening degree of the throttle 5 (throttle opening degree) and outputs an electric signal proportional to the detected throttle opening degree.

  Reference numeral 8 denotes a throttle opening degree detecting means for detecting the throttle opening degree from an electric signal output from the throttle sensor 6. Reference numeral 9 denotes a value which increases as the throttle opening degree increases as shown in FIG. The first duty ratio calculating means calculates the first duty ratio DF1 with respect to the throttle opening detected by the throttle detecting means 8. The throttle opening means the amount of displacement of a throttle (accelerator grip, accelerator pedal, accelerator lever, etc.) that is a member operated to adjust the vehicle speed.

  The first duty ratio calculated by the first duty ratio calculating means is the same as the duty ratio calculated by the duty ratio calculating means 9 'of the conventional control device. Reference numeral 10 denotes a motor drive unit that supplies the motor 1 with an intermittent drive current calculated at the duty ratio calculated by the first duty ratio calculation unit 9. The motor drive unit 10 is information on the duty ratio of the drive current supplied to the motor 1. And a motor drive signal generation means 11 for generating a drive signal Vd including the PWM signal, and a drive current necessary for rotating the motor 1 in a predetermined direction is PWM-modulated with a duty ratio DF given by the drive signal Vd and supplied to the motor 1 And a motor drive circuit 12 for performing the above operation.

  The motor drive circuit 12 is composed of a bridge-type switch circuit in which each side of the bridge is configured by switch elements that can be turned on and off, such as MOSFETs and IGBTs, as in a normal inverter circuit. A drive current is supplied to the motor 1 through a certain switch element.

  The motor drive signal generation means 11 generates a drive signal to be given to a switch element that needs to be turned on when a drive current is supplied to the motor 1 among the switch elements of the motor drive circuit. When the motor drive circuit 12 is composed of a bridge-type switch circuit, the motor drive signal generation unit 11 turns on one switch element selected from a plurality of switch elements constituting the upper side of the bridge of the switch circuit. And a drive signal for turning on another switch element selected from a plurality of switch elements constituting the lower side of the bridge, and at least one of the pair of drive signals is generated. Is an intermittent waveform with the duty ratio DF calculated by the duty ratio calculation means 9. As a result, a drive current having an intermittent waveform with the duty ratio DF calculated by the duty ratio calculation means 9 is passed from the battery 4 to the motor 1 through the motor drive circuit 12.

  Of the above components, the portions other than the motor drive signal generating means 11 are configured in the same manner as in the conventional control device. In the present invention, in addition to the conventional configuration, a rotary encoder 20 that generates a pulse each time the rotation shaft of the motor 1 rotates by a minute angle, and a vehicle speed (vehicle traveling speed) are detected from the output of the rotary encoder 20. Vehicle speed detection means 21, temperature detection means 22 for detecting the temperature of the motor drive circuit 12, vehicle speed detected by the vehicle speed detection means 21, and the temperature of the motor drive circuit detected by the temperature detection means 22 are second. The second duty ratio calculating means 23 for calculating the duty ratio DF2 is provided, and the second duty ratio DF2 is input to the motor drive signal generating means 11 together with the first duty ratio DF1.

  In the embodiment shown in FIG. 1, a throttle opening degree detection means 8, a first duty ratio calculation means 9, a motor drive unit 10 including a motor drive signal generation means 11 and a motor drive circuit 12, and a vehicle speed detection means 21. The temperature detection means 22 and the second duty ratio calculation means 23 constitute the motor control unit 7.

  The vehicle speed detection means 21 calculates the vehicle speed from the interval at which the rotary encoder 20 generates pulses and the reduction ratio of the motor driving force transmission mechanism 2. When the motor drive force transmission mechanism 2 is provided with a transmission having a variable speed ratio, an output signal of a sensor for detecting the speed ratio of the transmission is given to the vehicle speed detecting means 21.

  The temperature detection means 22 is means for acquiring information on the temperature of the switch element of the motor drive circuit 12, and this temperature detection means 22 detects the temperature of the heat sink to which the switch element constituting the motor drive circuit 12, for example, is attached. And an A / D converter that converts the output of the temperature sensor into a digital signal.

  The second duty ratio calculation means 23 shows a tendency that the value decreases as the temperature detected by the temperature detection means 22 increases when the vehicle speed detected by the vehicle speed detection means is lower than the set value. The lower the detected vehicle speed, the smaller the value at each temperature, and when the detected temperature reaches the limit value, the second duty ratio DF2 is 0 regardless of the detected vehicle speed. Calculation is performed on the temperature detected by the temperature detection means 22 and the vehicle speed detected by the vehicle speed detection means 21.

  The set value of the vehicle speed is a value that gives a lower limit value of a rotational speed region that can normally travel without causing an overload condition of the motor even when the throttle opening is increased, and is set to 15 km / h, for example. In other words, when the vehicle speed is equal to or higher than the set value, the motor is normally overloaded even when the throttle is opened at a large value (if left as it is, the temperature of the switch element of the motor drive circuit and the armature coil When the vehicle speed is lower than the set value, the motor becomes overloaded when the throttle is opened and the temperature of the switch element of the motor drive circuit and The temperature of the armature coil exceeds the allowable value.

  Normally, as the switch element constituting the motor drive circuit 12, since an element having a current capacity corresponding to the rated value of the motor drive current is used, the motor drive current exceeds the rated value and the motor is overloaded. When the temperature of the armature coil exceeds the allowable value, the temperature of the switch element of the motor drive circuit also exceeds the allowable limit value. Therefore, by detecting the temperature of the switch element constituting the motor drive circuit 12, it is possible to obtain information as to whether or not the temperature of the armature coil exceeds the allowable value.

  The second duty ratio DF2 is obtained by searching a map for the temperature detected by the temperature detection means 22 and the vehicle speed detected by the vehicle speed detection means 21 and performing an interpolation calculation. The map for calculating the second duty ratio DF2 is a table in which the relationship among the temperature of the motor drive circuit 12, the vehicle speed, and the second duty ratio DF2 is summarized in the form of a table. The drive current is limited to such a value that the switch element of the motor drive circuit 12 and the armature coil of the motor 1 are not likely to be thermally destroyed when the throttle is operated in a low state of less than A duty ratio value that can be calculated is created so as to be calculated with respect to the vehicle speed and the temperature of the motor drive circuit.

  A configuration example of the second duty ratio calculation map used in this embodiment is shown in FIG. In the example shown in FIG. 5, the set value of the vehicle speed is set to 15 km / h, and the limit value of the switch element of the motor drive circuit 12 is set to 80 ° C. In this example, for example, when the vehicle speed is 5 km / h and the temperature of the motor drive circuit is 60 ° C., the value of the second duty ratio DF2 is 46%.

  The motor drive signal generation means 11 is configured to generate a signal including information on the smaller duty ratio of the first duty ratio DF1 and the second duty ratio DF2 as the drive signal Vd. In the present embodiment, the motor drive signal generation means 11 has a waveform drive signal (in order to turn on the switch element) that is intermittent at the smaller duty ratio of the first duty ratio DF1 and the second duty ratio DF2. Is provided to the control terminal of each switch element of the motor drive circuit 12.

  The vehicle speed detection means 21, temperature detection means 22, first duty ratio calculation means 9, second duty ratio calculation means 23, and motor drive signal generation means 11 shown in FIG. 1 cause the microprocessor to execute a predetermined program. It is constituted by.

  The microprocessor configures the first duty ratio calculation means 9 by executing processing for calculating the first duty ratio DF1 with respect to the throttle opening at a minute time interval. FIG. 2 shows an algorithm of processing executed by the microprocessor to constitute the first duty ratio calculating means 9. In this processing, first, in step S001, the output of the throttle sensor is converted into a digital value. The output of the A / D converter is read to detect the throttle opening, and in step S002, the first duty ratio DF1 that changes as shown in FIG. 3 with respect to the throttle opening is calculated. The calculation of the first duty ratio may be a map calculation or an arithmetic expression.

The microprocessor also calculates the vehicle travel speed from the output pulse generation interval or frequency of the rotary encoder 20 at a minute time interval, and constitutes the second duty ratio calculation means 23 each time the vehicle travel speed is calculated. Process. FIG. 4 shows an algorithm of a process executed by the microprocessor at a minute time interval for calculating the second duty ratio. In this process, first, the vehicle speed is detected in step S101, and the motor drive circuit is detected in step S102. The output of the A / D converter that converts the output of the temperature sensor that detects the temperature into a digital value is read to detect the temperature of the motor drive circuit. In step S103, the second duty ratio calculation map created as shown in FIG. 5 and stored in the ROM of the microprocessor is searched for the vehicle speed and the temperature of the motor drive circuit, and interpolated to the searched value. By performing the calculation, the second duty ratio DF2 is calculated. For example, when the vehicle speed is 5 km / h and the temperature of the motor drive circuit 12 is 60 ° C., the calculation result of the second duty ratio DF2 is 46%.

  The microprocessor also executes the processing shown in FIG. 6 at a minute time interval to constitute the motor drive signal generation means 11. In this process, the first duty ratio DF1 and the second duty ratio DF2 are compared in step S201, and when the first duty ratio DF1 is smaller than the second duty ratio DF2, the process proceeds to step S202 and the first duty ratio DF1 is increased. A drive signal having an intermittent waveform with a duty ratio DF1 is applied to the control terminal of a predetermined switch element of the motor drive circuit 12. As a result of comparing the first duty ratio DF1 and the second duty ratio DF2, when it is determined that the second duty ratio DF2 is equal to or less than the first duty ratio DF1, the process proceeds to step S203 and the second duty ratio DF2 is A drive signal having an intermittent waveform with a duty ratio DF2 is applied to a predetermined switch element of the motor drive circuit 12.

  For example, when the calculation result of the first duty ratio DF1 is 50% and the calculation result of the second duty ratio DF2 is 46%, the motor drive signal generation unit 11 uses the second duty ratio DF2 (= 46%). A drive signal having an intermittent waveform is applied to a predetermined switch element of the motor drive circuit.

  The motor drive circuit 12 turns on and off a predetermined switch element in accordance with a drive signal supplied from the motor drive signal generation means 11 to form a drive current supplied from the battery 4 to the armature coil of the motor 1 as a PWM modulated waveform. Then, a drive current having an average value corresponding to the throttle opening is supplied to the armature coil of the motor 1.

  If comprised as mentioned above, when the rotational speed of a motor falls at the time of hill-climbing driving, the drive current of a motor can be restrict | limited and it can prevent that the component of a motor drive circuit and the armature coil of a motor are thermally destroyed. . Also, when the motor overload condition occurs, the drive current is not immediately limited, and when the vehicle speed is lower than the set value and the throttle is opened widely, the motor drive circuit temperature rises. Since the drive current is limited, when the motor is temporarily overloaded during climbing, etc., it prevents the motor drive current from being immediately limited to reduce the vehicle running performance. Therefore, the components of the motor drive circuit and the armature coil of the motor can be protected from thermal destruction without greatly sacrificing the driving performance of the vehicle.

  In the above embodiment, not only when traveling on an uphill, but also when traveling on flat ground, the motor drive current is limited, so the acceleration performance of the vehicle may be reduced. FIG. 7 shows the configuration of the second embodiment of the present invention that can prevent the occurrence of such a problem. In this embodiment, in addition to the configuration of the embodiment shown in FIG. 1, the throttle operation amount detection means 25 for detecting the operation amount per unit time of the throttle, and when the acceleration operation is performed by the driver Third duty ratio calculating means for calculating the third duty ratio DF3 with respect to the operation amount per unit time of the throttle in order to correct the second duty ratio and suppress the deterioration of the acceleration performance of the vehicle. 26 and fourth duty ratio calculating means 27 for calculating the fourth duty ratio DF4 by adding the third duty ratio DF3 to the second duty ratio DF2.

  The third duty ratio DF3 calculated by the third duty ratio calculating means 26 shows different values when the throttle is operated in the opening direction and when the throttle is operated in the closing direction. The third duty ratio DF3 calculated in the present embodiment increases at a rate commensurate with the operation amount per unit time of the throttle detected by the throttle operation amount detection means when the throttle is operated in the opening direction. When the throttle is operated in the closing direction, the value tends to decrease at a rate commensurate with the throttle operation amount per unit time detected by the throttle operation amount detection means. Further, when the throttle is not operated, the value tends to decrease toward 0 with the passage of time. The third duty ratio is calculated so as not to exceed a set limit value in order to prevent an excessive value when the throttle is continuously operated in the opening direction.

  In the example shown in the figure, the third duty ratio calculating means 26 calculates a correction duty ratio that increases or decreases at a predetermined rate according to increase or decrease of the operation amount per unit time of the throttle as shown in FIG. When it is detected from the change in the throttle opening detected by the correction duty ratio calculation means 28 and the throttle opening detection means 8 that the throttle is opened, the correction duty ratio calculation means 28 is newly added. The calculated correction duty ratio is added to the previously calculated correction duty ratio, and when it is detected from the change in the throttle opening detected by the throttle opening detection means 8 that the throttle is closed, the correction duty ratio is corrected. Calculation for subtracting the corrected duty ratio newly calculated by the ratio calculating means 28 from the previously calculated corrected duty ratio The correction duty ratio accumulating means 29 to be performed, the duty ratio subtracting means 30 for subtracting a constant value from the calculation result by the correction duty ratio accumulating means 29 every time a fixed time elapses, and the limit in which the calculation result by the duty ratio subtraction means is set When the value is less than or equal to the value and when negative, the calculation result by the duty ratio subtraction means is output as the third duty ratio DF3, and when the calculation result by the duty ratio subtraction means exceeds the limit value, the limit value is output as the third duty ratio. It is comprised with the 3rd duty ratio output means 31 output as DF3.

  In this case, the motor drive signal generation unit 11 is configured to generate a signal including information on the smaller duty ratio of the first duty ratio and the fourth duty ratio as a drive signal.

  FIG. 9 shows an algorithm of processing that is executed by the microprocessor every time a minute time elapses in order to calculate the third duty ratio DF3. In the case of this algorithm, first, in step S301, an input signal (throttle opening) from an A / D converter that performs A / D conversion on the output of the throttle sensor is read, and the throttle opening read this time and the previous time are read. The throttle operation amount per unit time is detected from the difference from the read throttle opening. Next, in step S302, the correction duty ratio is calculated with respect to the throttle operation amount per unit time using a map that gives a relationship between the correction duty ratio and the throttle operation amount per unit time as shown in FIG. To do. When the map shown in FIG. 8 is used, when the throttle operation amount per unit time is 40%, the correction duty ratio is 10%.

  Next, in step S303, it is determined whether the throttle is operated in the opening direction (accelerating side) or in the closing direction. As a result, when it is determined that the throttle is operated in the opening direction, the process proceeds to step S304, and the corrected duty ratio calculated in step S302 is added to the previous third duty ratio calculation result (initial value is 0). Is added. If it is determined in step S303 that the throttle is operated in the closing direction, the process proceeds to step S305, and the corrected duty calculated in step S302 from the previous third duty ratio calculation result (initial value is 0). Subtract the ratio. Next, in step S306, every time the unit time elapses, a certain period of time is subtracted from the calculation result in step S304 or S305. When the throttle is no longer operated, the third duty ratio DF3 is decreased by the subtraction performed in step S306 and eventually becomes 0%.

  In order to prevent the third duty ratio from becoming an excessive value, in step S307, the calculation result in step S306 is compared with a preset limit value of the third duty ratio. When the calculation result in step S308 is larger than the limit value, the process proceeds to step S308, where the limit value is output as the third duty ratio DF3, and then the third duty ratio output this time in step S309 is set as the previous third duty ratio. This process ends.

  In step S307, when it is determined that the calculation result in step S306 is equal to or less than the limit value, the process proceeds to step S310, where it is determined whether the calculation result in step S306 is negative, and the calculation result in step S306. Is determined to be negative, the third duty ratio DF3 is set to 0 in step S311, and then the process proceeds to step S309 to set the third duty ratio output this time as the previous third duty ratio. In step S310, when it is determined that the calculation result in step S306 is positive, the process proceeds to step S312 and the calculation result in step S306 is output as the third duty ratio DF3, and the process proceeds to step S309 and is output this time. After the third duty ratio is set to the previous third duty ratio, this process is terminated.

  Here, as a specific example, assuming that the throttle is opening, the previous third duty ratio (initial value 0%) is 0%, the correction duty ratio is 10%, and the third duty ratio per unit time. Assuming that the value to be subtracted from the calculated value is 0.1%, the limit value of the third duty ratio is 30%, and the third duty ratio is calculated every 10 msec, the calculation result of the third duty ratio Is 0% + 10% -0.1% = 9.9%. After 10 msec, this value becomes the previous third duty ratio. If the calculation result of the corrected duty ratio after 10 msec is 15%, the calculation result of the third duty ratio after 10 msec is 9.9% + 15% −0.1% = 24.8%. The value becomes the value of the previous third duty ratio. If the calculation result of the correction duty ratio after 20 msec is 8%, the calculation result of the third duty ratio after 20 msec is 24.8% + 8% −0.1% = 32.7%. Since this value exceeds the limit value of 30%, the calculation result of the third duty ratio is 30%. After 30 msec, this value becomes the previous third duty ratio. Thereafter, the same calculation is repeated.

  When the throttle is closing, the correction duty ratio is subtracted from the previous third duty ratio, and then a value obtained by subtracting a constant value for each unit time is set as the third duty ratio. When the calculation result of the third duty ratio becomes negative, the third duty ratio is set to zero. For example, assuming that the previous third duty ratio is 20%, the correction duty ratio is 8%, the value to be subtracted every unit time is 0.1%, and the third duty ratio is calculated every 10 msec. The calculation result of the third duty ratio is 20% -8% -0.1% = 11.9%. After 10 msec, this value becomes the previous third duty ratio. If the calculation result of the correction duty ratio after 10 msec is 12%, the calculation result of the third duty ratio after 10 msec is 11.9% −12% −0.1% = − 0.2%. Since this value is negative, the calculation result of the third duty ratio is 0%. In 20 msec, the same calculation is repeated with this value as the value of the previous third duty ratio.

  In the case of the algorithm shown in FIG. 9, the throttle operation amount detection means 25 is configured by step S301, and the corrected duty ratio calculation means is configured by step S302. In addition, the corrected duty ratio accumulating unit 29 is configured by steps S303 to S305, and the duty ratio subtracting unit 30 is configured by step S306. Further, the third duty ratio output means 31 is configured by steps S307 to S312.

  FIG. 10 shows an algorithm of processing to be executed by the microprocessor every time the third duty ratio is output in order to configure the fourth duty ratio calculation means 27. In this processing, The fourth duty ratio DF4 is calculated by adding the third duty ratio to the duty ratio. For example, if the calculation result of the second duty ratio is 46% and the calculation result of the third duty ratio is 19.9%, the calculation result of the fourth duty ratio is 46% + 19.9% = 65.9%. It becomes.

  FIG. 11 shows a process executed by the microprocessor every minute time in order to configure the motor drive signal generating means 11. In this process, the first duty ratio DF1 and the fourth duty ratio are changed in step S501. The duty ratio DF4 is compared. When the first duty ratio DF1 is smaller than the fourth duty ratio DF4, the process proceeds to step S502, and a drive signal having a waveform intermittent at the first duty ratio DF1 is given to the motor drive circuit 12 in advance. To the control terminal of the switch element. As a result of comparing the first duty ratio DF1 and the fourth duty ratio DF4, when it is determined that the fourth duty ratio DF4 is equal to or less than the first duty ratio DF1, the process proceeds to step S503 and the fourth duty ratio DF4 is A drive signal having an intermittent waveform with a duty ratio DF4 is applied to a predetermined switch element of the motor drive circuit 12.

  For example, when the calculation result of the first duty ratio is 80% and the calculation result of the fourth duty ratio is 65.9%, the calculation result of the fourth duty ratio is set as the duty ratio of the drive current, and this duty ratio is calculated. A drive signal having an intermittent waveform at 65.9% is output.

  When the control as described above is performed, the fourth duty ratio is increased when the throttle is opened, and the motor drive current that is output is increased. It is possible to prevent the acceleration performance from being reduced due to the drive current being limited when the vehicle speed becomes equal to or lower than the set value while the temperature of the engine is rising. In addition, after the fixed time has elapsed, the third duty ratio becomes 0% and the fourth duty ratio becomes equal to the second duty ratio, so that the motor drive current is limited, and the motor drive circuit 12 and the motor 1 are prevented from being thermally destroyed.

It is the block diagram which showed the structure of the 1st Embodiment of this invention. It is the flowchart which showed the algorithm of the process which a microprocessor performs in order to comprise the 1st duty ratio calculating means in the 1st Embodiment of this invention. It is the graph which showed an example of the relationship between the 1st duty ratio and throttle opening. It is the flowchart which showed the algorithm of the process which a microprocessor performs in order to comprise the 2nd duty ratio calculating means in the 1st Embodiment of this invention. It is the graph which showed an example of the relationship between a vehicle speed, the temperature of a motor drive circuit, and a 2nd duty ratio. It is the flowchart which showed the algorithm of the process which a microprocessor performs in order to comprise a motor drive signal production | generation means in the 1st Embodiment of this invention. It is the block diagram which showed the structure of the 2nd Embodiment of this invention. It is the graph which showed the relationship between the correction | amendment duty ratio calculated in 2nd Embodiment, and the throttle operation amount per unit time. It is the flowchart which showed the algorithm of the process which a microprocessor performs in order to comprise the 3rd duty ratio calculating means in 2nd Embodiment. It is the flowchart which showed the algorithm of the process which a microprocessor performs in order to comprise the 4th duty ratio calculating means in 2nd Embodiment. It is the flowchart which showed the algorithm of the process which a microprocessor performs in order to comprise a motor drive signal production | generation means in 2nd Embodiment. It is the block diagram which showed the structure of the conventional motor control apparatus for electric vehicles. It is the graph which showed the relationship between the drive current of a motor, and rotational speed.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Motor 2 Motor drive force transmission mechanism 3 Drive wheel 4 Battery 5 Throttle 6 Throttle sensor 7 Motor control part 8 Throttle opening degree detection means 9 1st duty ratio calculation means 10 Motor drive part 11 Motor drive signal generation means 12 Motor drive circuit DESCRIPTION OF SYMBOLS 20 Rotary encoder 21 Vehicle speed detection means 22 Temperature detection means 23 2nd duty ratio calculation means 25 Throttle operation amount detection means 26 Third duty ratio calculation means 27 Fourth duty ratio calculation means 28 Correction duty ratio calculation means 29 Correction duty Ratio accumulating means 30 Duty ratio subtracting means 31 Third duty ratio output means

Claims (3)

An electric vehicle motor for controlling the motor of an electric vehicle according to the operation of the throttle, comprising: a battery; a motor for driving a driving wheel of the vehicle; and a throttle operated to adjust a traveling speed of the vehicle. A control device of
Motor drive signal generating means for generating a drive signal including information on a duty ratio of a drive current supplied to the motor;
A motor drive circuit for supplying a drive current modulated by PWM so as to be intermittent at a duty ratio given by the drive signal from the battery to the motor;
Vehicle speed detection means for detecting the traveling speed of the vehicle;
Temperature detecting means for detecting the temperature of the motor drive circuit;
Throttle opening detection means for detecting the throttle opening as the throttle opening;
First duty ratio calculating means for calculating a first duty ratio that increases as the throttle opening increases with respect to the throttle opening detected by the throttle opening detecting means;
When the vehicle speed detected by the vehicle speed detection means is lower than a set value, the value tends to decrease as the temperature detected by the temperature detection means increases, and as the detected vehicle speed is lower When the detected temperature reaches a limit value and the detected temperature reaches a limit value, the second duty ratio that becomes 0 regardless of the detected vehicle speed is the temperature detected by the temperature detecting means. Second duty ratio calculating means for calculating the vehicle speed detected by the vehicle speed detecting means;
Comprising
The motor drive signal generation means is configured to generate a signal including information on a smaller duty ratio of the first duty ratio and the second duty ratio as the drive signal;
A control apparatus for an electric vehicle motor. An electric vehicle motor for controlling the motor of an electric vehicle according to the operation of the throttle, comprising: a battery; a motor for driving a driving wheel of the vehicle; and a throttle operated to adjust a traveling speed of the vehicle. A control device of
Motor drive signal generating means for generating a drive signal including information on a duty ratio of a drive current supplied to the motor;
A motor drive circuit for supplying a drive current modulated by PWM so as to be intermittent at a duty ratio given by the drive signal from the battery to the motor;
Vehicle speed detection means for detecting the traveling speed of the vehicle;
Temperature detecting means for detecting the temperature of the motor drive circuit;
Throttle opening detection means for detecting the throttle opening as the throttle opening;
Throttle operation amount detection means for detecting an operation amount per unit time of the throttle;
First duty ratio calculating means for calculating a first duty ratio that increases as the throttle opening increases with respect to the throttle opening detected by the throttle opening detecting means;
When the vehicle speed detected by the vehicle speed detection means is lower than a set value, the value tends to decrease as the temperature detected by the temperature detection means increases, and as the detected vehicle speed is lower When the detected temperature reaches a limit value and the detected temperature reaches a limit value, the second duty ratio that becomes 0 regardless of the detected vehicle speed is the temperature detected by the temperature detecting means. Second duty ratio calculating means for calculating the vehicle speed detected by the vehicle speed detecting means;
When the throttle is operated in the opening direction, the value tends to increase at a rate commensurate with the throttle operation amount per unit time detected by the throttle operation amount detection means, and the throttle is closed. When operated, the value tends to decrease at a rate commensurate with the throttle operation amount per unit time detected by the throttle operation amount detection means. When the throttle operation is not performed, the time elapses. A third duty ratio calculating means for calculating a third duty ratio, the value of which decreases as the value decreases toward zero, by determining the limit value;
A fourth duty ratio calculating means for calculating a fourth duty ratio by adding a third duty ratio to the second duty ratio;
Comprising
The motor drive signal generating means is configured to generate a signal including information on a smaller duty ratio of the first duty ratio and the fourth duty ratio as the drive signal;
A control apparatus for an electric vehicle motor. The third duty ratio calculating means includes:
Correction duty ratio calculating means for calculating a correction duty ratio that increases or decreases at a predetermined rate according to increase or decrease of the operation amount per unit time of the throttle at a minute time interval;
The correction duty ratio newly calculated by the correction duty ratio calculation means when the operation of the throttle in the opening direction is detected from the change in the throttle opening detected by the throttle opening detection means. The correction duty ratio calculation means is newly added when it is detected that the throttle is operated in the closing direction from the change in the throttle opening detected by the throttle opening detection means. Correction duty ratio accumulating means for performing a calculation for subtracting the correction duty ratio calculated in the above from the correction duty ratio calculated last time;
Duty ratio subtracting means for subtracting a constant value from the calculation result by the correction duty ratio accumulating means each time a fixed time elapses;
When the calculation result by the duty ratio subtraction means is less than or equal to a set limit value and when it is negative, the calculation result by the duty ratio subtraction means is output as a third duty ratio, and the calculation result by the duty ratio subtraction means is the limit value. A third duty ratio output means for outputting the limit value as a third duty ratio when exceeding the value;
The control apparatus for an electric vehicle motor according to claim 2, comprising:

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