JP2021112021A - Motor control device and motor control method - Google Patents

Abstract

To prevent the generation of a false pulse caused by noise, etc., when a motor is de-energized or stopped, in a motor control device that generates a pulse signal from a current ripple to control the motor drive.SOLUTION: A motor control device 1 has a ripple pulse conversion unit 10 that generates and outputs a pulse signal from a current ripple of a DC motor 3. The ripple pulse conversion unit 10 has a ripple detection sensitivity adjustment unit 21 that reduces the detection sensitivity of the current ripple when the DC motor 3 is de-energized or stopped. The ripple detection sensitivity adjustment unit 21 includes a motor voltage input determination unit 22 for determining a motor energized state, a ripple pulse input determination unit 23 for determining a motor operating state from the presence or absence of a ripple pulse, and an amplification adjustment unit 24 for reducing an amplification degree in the ripple pulse conversion unit 10 when the DC motor 3 is de-energized and stopped based on the determination results of the motor voltage input determination unit 22 and the ripple pulse input determination unit 23.SELECTED DRAWING: Figure 1

Description

The present invention relates to a direct current (DC) motor control technique, and more particularly to an erroneous pulse generation prevention technique in a motor control device that generates a pulse (square wave) signal from a current ripple contained in an armature current to control the drive of the motor. ..

Conventionally, so-called sensorless positioning using the current ripple generated when the contact between the brush and the commutator piece is switched has been known as a method for detecting the rotation speed and the rotation angle when controlling the operation of the brushed DC motor. For example, Patent Document 1 describes a configuration in which when the brush switches to the next commutator piece adjacent to the brush, the spike-shaped pulse output generated in the motor current is detected to detect the motor rotation speed.

On the other hand, the level of the current ripple waveform in the brushed DC motor increases or decreases in proportion to the motor current. However, since the motor current changes greatly depending on the load state of the motor, the ripple waveform also changes greatly with the load change. In addition, brush noise generated from the motor is also superimposed on the motor current. Therefore, it is not easy to extract only the current ripple from the motor current including these unstable elements.

Therefore, as in Patent Document 2, the change in the armature current is output as a voltage change signal, the current ripple component and the noise component are extracted from this voltage change signal, the noise component is removed from the signal, and only the current ripple component is extracted. A system has also been proposed in which a pulse signal is generated from a current ripple and output by extracting the signal and converting it into a digital signal. In this system, the current ripple can be extracted and pulsed with the conventional motor configuration as it is, and ripple sensing is performed without impairing the performance and characteristics of the motor.

Japanese Unexamined Patent Publication No. 2009-159674 Japanese Unexamined Patent Publication No. 2018-74662

However, even in the method as in Patent Document 2, when the motor is not operating and no current ripple is generated, static electricity, radio, surge, communication equipment, noise from other control equipment, etc. Therefore, there is a concern that the pulse may be erroneously output when a disturbance of the same frequency and voltage as the ripple waveform is input to the system. FIG. 3 is a time chart showing a motor operating state and a pulse output (ripple pulse) state. As shown in FIG. 3, when the motor is stopped (part X), the ripple pulse is not originally output. It should be, but if noise or the like is input, there is a possibility that an erroneous pulse like a broken line will occur.

When such an erroneous pulse occurs, the pulse count value may deviate, an error may occur in the rotation angle information of the motor, and the operation control of the motor may be hindered. For example, when a system such as Patent Document 2 is used for a power window motor, a deviation in pulse count leads to erroneous detection of the window position, the operating speed of the window deviates from the assumption, and the mask area of pinch detection is recognized. There was a risk of misalignment.

An object of the present invention is to prevent the generation of erroneous pulses caused by noise or the like when the motor is de-energized or stopped in a motor control device that generates a pulse signal from a current ripple to control the drive of the motor.

The motor control device of the present invention is a motor control device having a ripple pulse conversion unit that detects a current ripple included in an armature current of a DC motor and outputs the current ripple as a pulse signal, and the ripple pulse conversion unit. It is characterized in that a ripple detection sensitivity adjusting unit for lowering the detection sensitivity of the current ripple is provided when the DC motor is not energized and the DC motor is not operating.

In the present invention, the ripple detection sensitivity adjusting unit lowers the current ripple detection sensitivity when the motor is in a non-energized / stopped state. As a result, even if a disturbance due to noise or the like occurs during the non-energized / stopped period in which the pulse signal should not be generated, the occurrence of an erroneous pulse can be suppressed. Therefore, for example, even when the motor is controlled based on the pulse count, it is possible to prevent the deviation of the count value, suppress the error of the rotation angle information of the motor, and improve the control accuracy of the motor. Become.

In the motor control device, the ripple detection sensitivity adjusting unit has a motor voltage input determination unit that determines the energization state of the DC motor based on the terminal voltage of the DC motor, and the ripple pulse conversion unit that outputs the motor voltage input determination unit. The DC motor is in a non-energized state based on the determination results of the ripple pulse input determination unit that determines the operating state of the DC motor based on the pulse signal, the motor voltage input determination unit, and the ripple pulse input determination unit. When it is determined that the state is stopped, an amplification degree adjusting unit that lowers the amplification degree in the ripple pulse conversion unit and lowers the detection sensitivity of the current ripple may be provided.

In this case, the motor voltage input determination unit may detect the voltages before and after the DC motor, and determine whether or not the DC motor is energized based on the voltage values of both. Further, the ripple pulse input determination unit includes a ripple pulse detection unit that separates the pulse signal into a DC component and a pulse signal, and a ripple pulse smoothing unit that converts the pulse signal separated by the ripple pulse detection unit into a DC component. And a differential amplification unit that outputs a signal when the voltage value of the pulse signal converted into a DC component by the ripple pulse smoothing unit exceeds a predetermined reference voltage may be provided.

On the other hand, the motor control method of the present invention is a motor control method that detects a current ripple contained in an armature current of a DC motor and controls the operation of the DC motor based on a pulse signal generated from the current ripple. When the DC motor is not energized and the DC motor is not operating, the detection sensitivity of the current ripple is lowered.

In the present invention, the detection sensitivity of current ripple is lowered when the motor is in a non-energized / stopped state. As a result, even if a disturbance due to noise or the like occurs during the non-energized / stopped period in which the pulse signal should not be generated, the occurrence of an erroneous pulse can be suppressed. Therefore, for example, even when the motor is controlled based on the pulse count, it is possible to prevent the deviation of the count value, suppress the error of the rotation angle information of the motor, and improve the control accuracy of the motor. Become.

According to the motor control device of the present invention, the DC motor is not energized and the DC motor is not energized in the motor control device having a ripple pulse conversion unit that generates a pulse signal from the current ripple included in the armature current of the DC motor. Since the ripple detection sensitivity adjusting unit for lowering the current ripple detection sensitivity when not in operation is provided, it is possible to suppress the occurrence of erroneous pulses even if disturbance due to noise or the like occurs during non-energization / stop. Therefore, for example, even when the motor is controlled based on the pulse count, it is possible to prevent the deviation of the count value, suppress the error of the rotation angle information of the motor, and improve the control accuracy of the motor. Become.

According to the motor control method of the present invention, the DC motor is not energized in the motor control method that controls the operation of the DC motor based on the pulse signal generated from the current ripple included in the armature current of the DC motor. Moreover, since the detection sensitivity of the current ripple is lowered when it is not operating, it is possible to suppress the occurrence of erroneous pulses even if disturbance due to noise or the like occurs when the power is off or stopped. Therefore, for example, even when the motor is controlled based on the pulse count, it is possible to prevent the deviation of the count value, suppress the error of the rotation angle information of the motor, and improve the control accuracy of the motor. Become.

It is a block diagram which shows the structure of the motor control device which is one Embodiment of this invention. It is a truth table in the ripple detection sensitivity adjustment part arranged in the motor control device of FIG. It is explanatory drawing which shows the relationship between a motor operation and a ripple pulse.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a motor control device 1 according to an embodiment of the present invention, and the motor control device 1 is applied to, for example, operation control of a motor for a power window of a vehicle. The motor control device 1 is provided with a ripple pulse conversion unit 10 that extracts the current ripple contained in the motor current (armature current) without using a Hall IC or the like and outputs it in the form of a pulse signal.

The ripple pulse conversion unit 10 is arranged on a power supply line 4 that supplies electric power from a motor driver (power supply) 2 to a brushed DC motor 3 (hereinafter, abbreviated as motor 3). A shunt resistor 5 is provided on the power supply line 4, and the ripple pulse conversion unit 10 is connected to the front and rear (motor driver 2 side and motor 3 side) of the shunt resistor 5. The motor control device 1 calculates the rotation speed, rotation direction, and the like of the motor 3 based on the pulse output (ripple pulse) from the ripple pulse conversion unit 10, and controls the operation of the motor 3.

The ripple pulse conversion unit 10 is provided with a current detection unit 11, a first smoothing circuit 12, a gain adjustment unit 13, a second smoothing circuit 14, a ripple detection unit 15, and a digital signal conversion unit 16. The current detection unit 11 detects the voltage difference (voltage drop) before and after the shunt resistor 5 to detect the motor drive current, and outputs the change as a voltage change signal. This voltage change signal is sent from the first smoothing circuit 12 to the gain adjusting unit 13 → the second smoothing circuit 14 → the ripple detection unit 15, and the noise component is removed from the voltage change signal and only the current ripple component is extracted. The extracted current ripple component is converted into a pulse signal corresponding to the encoder output by the digital signal conversion unit 16, and a ripple pulse is generated and output.

In the pulse signal formed by the ripple pulse conversion unit 10, each pulse corresponds to the switching of contact between the brush and the commutator piece. Since the number of brushes and commutator pieces is predetermined for each motor, the rotation speed of the motor 3 can be calculated by counting the pulses. That is, the rotation speed of the motor 3 is detected from the current ripple in the motor current without using a rotation detection member such as a Hall IC. At that time, the ripple pulse conversion unit 10 can extract the ripple from the motor current with the conventional motor configuration as it is.

On the other hand, the motor control device 1 according to the present invention is further provided with a ripple detection sensitivity adjusting unit 21 that adjusts the sensitivity for detecting current ripple from the motor current. The ripple detection sensitivity adjusting unit 21 includes a motor voltage input determining unit 22, a ripple pulse input determining unit 23, and an amplification degree adjusting unit 24, and when the motor 3 is not energized and is not operating, The amplification degree in the ripple pulse conversion unit 10 is lowered to lower the detection sensitivity of the current ripple.

As shown in FIG. 1, the motor voltage input determination unit 22 detects the voltages VA and VB (motor terminal voltage) before and after the motor 3, respectively, and based on the voltage values of both, the energized state (whether or not energized) is applied to the motor 3. ) Is determined. The ripple pulse input determination unit 23 determines the operating state (whether it is rotating or stopped) of the motor 3 from the presence or absence of the ripple pulse. The amplification degree adjustment unit 24 adjusts the amplification degree in the gain adjustment unit 13 (gain control) based on the outputs from the motor voltage input determination unit 22 and the ripple pulse input determination unit 23, and adjusts the current ripple detection sensitivity.

In this case, the ripple pulse input determination unit 23 separates the ripple pulse output from the ripple pulse conversion unit 10 into a DC component (DC component) and a pulse signal by the ripple pulse detection unit 25 and the ripple pulse detection unit 25. The voltage values of the ripple pulse smoothing section 26 that converts the pulsed signal into a DC component and the pulse signal converted into a DC component by the ripple pulse smoothing section exceed a predetermined reference voltage (Bias voltage: Voff). It is provided with a differential amplification unit 27 that outputs a signal in some cases.

Further, when the motor 3 is in the non-energized state and the ripple pulse is not continuously generated, the amplification degree adjusting unit 24 considers that the motor 3 is in the stopped state and lowers the amplification degree of the ripple pulse conversion unit 10. It works and reduces the ripple detection sensitivity. As a result, even if there is a disturbance input, the ripple pulse conversion unit 10 does not generate a pulse corresponding to the disturbance input, and the generation of an erroneous pulse due to the disturbance is suppressed. FIG. 2 is a truth table of the ripple detection sensitivity adjusting unit 21, and the ripple detection sensitivity adjusting unit 21 adjusts the gain of the ripple pulse conversion unit 10 by the following processing.

(1) In the case of motor energization / steady rotation When the motor 3 is in a steady rotation in the energized state, either the terminal voltage VA or VB of the motor 3 becomes "H (Hi)". Here, it is set to "VA: H, VB: L (Low)" at the time of CW rotation and "VA: L, VB: H" at the time of CCW rotation. Therefore, in the case of energization / steady rotation, the output D (output of NAND33) after passing through NOT 31 and 32 becomes "H" in both CW rotation and CCW rotation. That is, when the motor 3 is energized, the output from the motor voltage input determination unit 22 becomes “H”.

On the other hand, a ripple pulse (hereinafter abbreviated as RP) is input from the ripple pulse conversion unit 10 to the ripple pulse input determination unit 23. In the ripple pulse input determination unit 23, the RP output may be fixed at “H” when RP is not generated. Therefore, first, the ripple pulse detection unit 25 using a differentiating circuit converts the ripple pulse into a DC component and a pulse signal. Sort. Next, the pulse signal obtained by the ripple pulse detection unit 25 is converted into a DC component by the ripple pulse smoothing unit 26. The output A of the ripple pulse smoothing unit 26 is input to the differential amplification unit 27, and the output B is generated based on the relationship with a predetermined Bias voltage (Voff).

In this case, the Bias voltage is set so that the output A> Voff when several tens of pulses or more (for example, 20 pulses or more) are continuously generated in order to separate the disturbance from the normal operation time. Therefore, in the energization / steady rotation, since the RP is continuously output for several tens of pulses or more, the output A of the ripple pulse smoothing unit 26 becomes larger than the Bias voltage, and the output B of the differential amplification unit 27 becomes “H”. ".

Output D: "H" is input to the amplification degree adjusting unit 24 from the motor voltage input determination unit 22, output B: "H" is input from the differential amplification unit 27, and inputs E and C of the NAND 34 are input by NOT 35 and 36. They are "L" and "L", respectively. Therefore, the output F of the NAND 34 becomes "H", and the output G of the NOT 37 becomes "L". As a result, the gate of the transistor (switching element) 38 becomes “L”, and the collector side P of the transistor 38 becomes open. As a result, gain control is not performed on the gain adjusting unit 13, ripple pulse detection is performed at a normal amplification degree, and drive control of the motor 3 is performed.

(2) In the case of motor de-energization / coasting rotation Strictly speaking, an induced voltage is generated in the motor 3 even when the motor 3 is not energized but coasting rotation, and the terminal being monitored. Either the voltage VA or VB is "H". However, the induced voltage at that time is very small as compared with the case of energization and steady rotation. Therefore, in the ripple detection sensitivity adjusting unit 21, when VA and VB are less than a predetermined voltage, the value is set to “L”. As a result, "H" and "H" are input to the NAND 33 via NOT 31 and 32, and in the case of non-energized / coasting rotation, the output D is "L" in both CW rotation and CCW rotation. Become.

On the other hand, during coasting rotation, RP of several tens of pulses or more that is continuous to some extent is input to the ripple pulse input determination unit 23, unlike when stopped. Therefore, in the case of non-energized / coasting rotation, the output A becomes larger than the Bias voltage, and the output B of the differential amplification unit 27 becomes “H”. Output D: "L" is input from the motor voltage input determination unit 22 to the amplification degree adjustment unit 24, output B: "H" is input from the differential amplification unit 27, and inputs E and C of the NAND 34 are input by NOT 35 and 36. They are "H" and "L", respectively. Therefore, the output F of the NAND 34 is “H”, the output G of the NOT 37 is “L”, and the collector side P of the transistor 38 is open. As a result, the gain control of the gain adjusting unit 13 is not performed, and the drive control (ripple pulse detection) of the motor 3 is performed at a normal amplification degree.

(3) In the case of non-energization / reversal of the motor When the rotation of the motor 3 is restrained during steady rotation and then the energization is turned off, the motor 3 may reverse due to the reaction of the motor mechanism. In this case, either the terminal voltage VA or VB is "H", but as in the case of non-energization / coasting, the induced voltage at that time is smaller than that during steady rotation, so the ripple detection sensitivity is adjusted. In part 21, VA and VB are treated as "L". As a result, "H" and "H" are input to the NAND 33 via NOT 31 and 32, and the output D becomes "L" in both the CW rotation and the CCW rotation in the case of non-energization / reverse rotation.

Further, even during reverse rotation, the ripple pulse input determination unit 23 is input with RP of several tens of pulses or more that are continuous to some extent, so that the output B of the differential amplification unit 27 is the same as in the case of non-energization / coasting. It becomes "H". Then, the output D: "L" is input from the motor voltage input determination unit 22 and the output B: "H" is input from the differential amplification unit 27 to the amplification degree adjusting unit 24, as in the case of non-energization / coasting. , The inputs E and C of the NAND 34 are "H" and "L" by NOT35 and 36, respectively. Therefore, the output F of the NAND 34 is "H", the output G of the NOT 37 is "L", the collector side P of the transistor 38 is open, and the gain control for the gain adjusting unit 13 is not performed.

(4) When the motor is not energized / stopped When the motor 3 is stopped without being energized, VA and VB are set to “L”. As a result, "H" and "H" are input to the NAND 33 via NOT 31 and 32, and the output D becomes "L" in the case of non-energization / stop. Further, when stopped, continuous RP is not input to the ripple pulse input determination unit 23. Therefore, in the case of stop, the output A becomes smaller than the Bias voltage, and the output B of the differential amplification unit 27 becomes “L”.

At this time, the output D: "L" is input to the amplification degree adjusting unit 24 from the motor voltage input determination unit 22, the output B: "L" is input from the differential amplification unit 27, and the inputs E and C of the NAND 34 are NOT35. , 36 are "H" and "H", respectively. Therefore, the output F of the NAND 34 is "L", and the output G of the NOT 37 is "H". Then, at this time, the gate of the transistor 38 becomes "H", and the collector side P of the transistor 38 conducts with the emitter side and is grounded to become "L". As a result, the gain control voltage of the gain adjusting unit 13 becomes “L”, and the amplification degree is lowered. As a result, the sensitivity of the ripple pulse conversion unit 10 is lowered, and even if noise or the like is input to the part X in FIG. 3X (when the motor is stopped), the generation of an erroneous pulse as shown by the broken line can be suppressed.

As described above, in the motor control device 1 of the present invention, when the motor 3 is in the non-energized / stopped state, the current ripple is generated by the ripple pulse conversion unit 10 that extracts the current ripple contained in the motor current and outputs the ripple pulse. By providing the ripple detection sensitivity adjusting unit 21 that lowers the detection sensitivity, it is possible to suppress the occurrence of erroneous pulses even if disturbance due to noise or the like occurs during the ripple pulse non-occurrence period. Therefore, for example, even when the motor is controlled based on the pulse count, it is possible to prevent the deviation of the count value, suppress the error of the rotation angle information of the motor, and improve the control accuracy of the motor. Become. Therefore, by using the control device for the power window motor as in the present embodiment, it is possible to prevent erroneous detection of the window position due to the deviation of the pulse count. As a result, the control accuracy of the power window is improved, and the control accuracy such as the operating speed of the window and the pinch detection is also improved.

It goes without saying that the present invention is not limited to the above-described embodiment and can be variously modified without departing from the gist thereof.
For example, the functions of the motor control device described above are not hardware-like configurations such as the ripple pulse conversion unit 10 and the ripple detection sensitivity adjustment unit 21, but these functions can be replaced or realized on software. be.

The motor control device according to the present invention not only controls the operation of a power window motor, but also transmits a pulse from a motor drive current of other in-vehicle electric devices such as wipers and power seats, household electric products using a brushed motor, and the like. It can be widely applied to devices that use detection technology.

1 Motor control device 2 Motor driver 3 Brushed DC motor 4 Power supply line 5 Shunt resistance 10 Ripple pulse conversion unit 11 Current detection unit 12 1st smoothing circuit 13 Gain adjustment unit 14 2nd smoothing circuit 15 Ripple detection unit 16 Digital signal conversion unit 21 Ripple detection sensitivity adjustment unit 22 Motor voltage input judgment unit 23 Ripple pulse input judgment unit 24 Amplification degree adjustment unit 25 Ripple pulse detection unit 26 Ripple pulse smoothing unit 27 Differential amplification unit 31 NOT
32 NOT
33 NAND
34 NAND
35 NOT
36 NOT
37 NOT
38 transistor

Claims (5)

A motor control device having a ripple pulse converter that detects a current ripple contained in an armature current of a DC motor and outputs the current ripple as a pulse signal.
The ripple pulse conversion unit
A motor control device comprising a ripple detection sensitivity adjusting unit that lowers the detection sensitivity of the current ripple when the DC motor is not energized and the DC motor is not operating. In the motor control device according to claim 1,
The ripple detection sensitivity adjustment unit
A motor voltage input determination unit that determines the energized state of the DC motor based on the terminal voltage of the DC motor,
A ripple pulse input determination unit that determines the operating state of the DC motor based on the pulse signal output from the ripple pulse conversion unit, and a ripple pulse input determination unit.
When the DC motor is determined to be in a non-energized state and a stopped state based on the determination results of the motor voltage input determination unit and the ripple pulse input determination unit, the amplification degree in the ripple pulse conversion unit is reduced to obtain the above. A motor control device including an amplification degree adjusting unit that lowers the detection sensitivity of current ripple. In the motor control device according to claim 2,
The motor voltage input determination unit is a motor control device, which detects voltages before and after the DC motor, and determines whether or not the DC motor is energized based on the voltage values of both. In the motor control device according to claim 2,
The ripple pulse input determination unit
A ripple pulse detector that separates the pulse signal into a DC component and a pulse signal,
A ripple pulse smoothing unit that converts the pulse signal separated by the ripple pulse detection unit into a DC component, and a ripple pulse smoothing unit.
A motor control device including a differential amplification unit that outputs a signal when the voltage value of a pulse signal converted into a DC component by the ripple pulse smoothing unit exceeds a predetermined reference voltage. .. A motor control method that detects a current ripple included in the armature current of a DC motor and controls the operation of the DC motor based on a pulse signal generated from the current ripple.
A motor control method, characterized in that the detection sensitivity of the current ripple is lowered when the DC motor is not energized and the DC motor is not operating.

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