JP2021197778A - Motor control device and motor control method - Google Patents

Abstract

To improve motor control accuracy by preventing a ripple detection accuracy reduction due to aging deterioration or the like in a sensorless control motor.SOLUTION: A motor control device 1 has a current detection part 11, a first smoothing circuit block 12, a gain adjustment part 13, and a ripple detection part 15, or a ripple pulse conversion part 10 further having a second smoothing circuit block 14, and extracts a current ripple from motor current to be made a digital signal, and controls a motor 3. A high-pass filter 28 extracting noise components from an adjustment signal VCA or a second smoothing signal S2 and a phase correction part 41 adjusting a phase of the adjustment signal VCA or the second smoothing signal S2 are provided to the ripple detection part 15, and a phase difference between the signals VCA and S2 and a signal after filter processing is adjusted. The ripple detection part 15 removes unnecessary noise components even if distortion or the like occurs in armature current due to aging deterioration or the like, and a ripple component signal S0 without error pulse is outputted.SELECTED DRAWING: Figure 8

Description

The present invention relates to a control technique for a direct current (DC) motor, and in particular, detects the motor rotation speed, rotation direction, etc. without using a sensing element such as a hall IC or a rotation detection member such as a rotary encoder or a tacho generator. The present invention relates to a motor control device and a motor control method.

The motor current (armature current) of a DC motor with a brush rises with an inclination according to the inductance of the motor winding when the commutator piece in contact with the brush is switched, and then depends on the difference between the power supply voltage and the countercurrent voltage. Will change. That is, the motor current is not a constant value, but is accompanied by a pulsation (ripple) corresponding to the motor rotation position. Therefore, conventionally, as a method for detecting the rotation speed and rotation angle of a DC motor with a brush, so-called sensorless positioning using the current ripple generated when the contact between the brush and the commutator piece is switched has been known. There is.

As a motor that performs such sensorless control, for example, Patent Document 1 describes a DC motor that detects the rotation speed of the motor by using the current ripple generated when the contact between the brush and the commutator piece is switched. .. Further, Patent Document 2 describes a motor control device that extracts a current ripple component from a normal motor current itself to generate a ripple pulse and detects a motor rotation speed or the like.

Japanese Unexamined Patent Publication No. 2016-77130 Japanese Unexamined Patent Publication No. 2018-74662

However, even in a motor control device as in Patent Document 2, a relatively clean ripple pulse can be obtained in the early stage of motor use, but it is abbreviated as aged deterioration such as component wear and changes in the surrounding environment (hereinafter, abbreviated as aged deterioration etc.). ) Causes distortion or spike noise to be included in the motor current, and there is a risk that an erroneous pulse will be output due to these unnecessary waveforms. For example, in the noise removal process in Patent Document 2 shown in FIG. 14, the difference C between the signal A and the original signal B that has passed through the high-pass filter 61 is taken, and the high frequency noise in the original signal is removed. However, when the motor current contains distortion components and spike noise as shown in FIG. 15A, the original signal B also contains distortion and noise as shown in FIG. 15B.

In this case, as shown in FIG. 15 (c), since the signal A that has passed through the high-pass filter 61 has a phase advance with respect to the signal B, even if the difference between the two is taken, the distortion component and the spike noise cannot be removed well. .. Therefore, as shown in FIG. 15 (d), there is a concern that the signal output through the process of FIG. 14 is also affected by distortion and spike components, and an erroneous pulse is generated. As a result, erroneous recognition may occur regarding the motor rotation speed, rotation angle, and the like, and the control accuracy of the motor may deteriorate.

An object of the present invention is to prevent a decrease in ripple detection accuracy due to deterioration over time in a sensorless control motor, and to improve the motor control accuracy.

The motor control device of the present invention is a motor control device having a ripple pulse conversion unit that detects a current ripple contained in an armature current of a DC motor and outputs the current ripple as a rectangular wave signal, and the ripple pulse conversion. The unit consists of a current detection unit that detects the armature current and outputs the change as a voltage change signal, and a first unit that extracts a current ripple component and a noise component from the voltage change signal and comprises a current ripple component and a noise component. A first smoothing unit that outputs a smoothing signal S1, a gain adjusting unit that adjusts the amplitude of the first smoothing signal S1 and outputs an adjustment signal VCA in a state where the amplitude is made uniform, and a noise component from the adjustment signal VCA. The ripple detection unit includes a ripple detection unit that removes the current ripple component and outputs the ripple component signal S0, and the ripple detection unit includes a high-pass filter that extracts noise components from the adjustment signal VCA and the high-pass filter. It is characterized by having a phase correction unit provided in parallel and adjusting the phase of the adjustment signal VCA.

The other motor control device of the present invention is 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 rectangular wave signal. The pulse conversion unit consists of a current detection unit that detects the armature current and outputs the change as a voltage change signal, and extracts a current ripple component and a noise component from the voltage change signal, and comprises a current ripple component and a noise component. The first smoothing unit that outputs the first smoothing signal S1, the gain adjusting unit that adjusts the amplitude of the first smoothing signal S1 and outputs the adjustment signal VCA in a state where the amplitude is made uniform, and the adjustment signal VCA. A second smoothing portion that corrects distortion and outputs a second smoothing signal S2 having a constant center value and a uniform amplitude, and a ripple component by removing a noise component from the second smoothing signal S2 and extracting only a current ripple component. A ripple detection unit that outputs a signal S0 is provided, and the ripple detection unit includes a high-pass filter that extracts a noise component from the second smoothing signal S2, and a high-pass filter that is provided in parallel with the high-pass filter and that is the second smoothing signal S2. It is characterized by having a phase correction unit for adjusting the phase.

In the present invention, the motor control device is provided with a current detection unit, a first smoothing unit, a gain adjusting unit, a ripple detecting unit, or a second smoothing unit between the gain adjusting unit and the ripple detecting unit. A ripple pulse conversion unit is provided, and the current ripple is converted into a digital signal from the motor current and extracted to control the motor. At that time, the ripple detection unit has a high-pass filter that extracts noise components from the adjustment signal VCA output from the gain adjustment unit or the second smoothing signal S2 output from the second smoothing unit, and the adjustment signal VCA or the adjustment signal VCA. A phase correction unit for adjusting the phase of the second smoothing signal S2 is provided, and the phase difference between the adjustment signal VCA or the second smoothing signal S2 and the signal after high-pass filter processing is adjusted. As a result, even if the armature current contains distortion components and spike components due to deterioration over time, noise components including distortion are extracted from the adjustment signal VCA and the second smoothing signal S2 using a high-pass filter. Based on the generated noise component and the original waveform, unnecessary noise component is removed and only the necessary waveform is extracted. As a result, it is possible to suppress the generation of the ripple component signal S0 whose waveform is distorted due to the distortion component or the like, and the ripple component signal S0 having a waveform without fear of erroneous pulse output is output from the ripple detection unit.

In the motor control device, the phase correction unit may correct the phase shift that occurs between the adjustment signal VCA or the second smoothing signal S2 and the signal that has passed through the high-pass filter. Further, a differential that removes a noise component from the adjustment signal VCA or the second smoothing signal S2 by taking the difference between the signal that has passed through the high-pass filter and the signal that has passed through the phase correction unit in the ripple detection unit. An amplification unit may be provided. It is also possible to further provide the ripple detection unit with a digital signal conversion unit that converts the ripple component signal S0 into a digital signal.

On the other hand, the motor control method of the present invention is 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. , The armature current is detected, the change is output as a voltage change signal, the current ripple component and the noise component are extracted from the voltage change signal, and the first smoothing signal S1 composed of the current ripple component and the noise component is output. , The amplitude of the first smoothing signal S1 is adjusted, the adjustment signal VCA in a state where the amplitude is made uniform is output, the noise component is removed from the adjustment signal VCA, and only the current ripple component is extracted to extract the ripple component signal S0. Is output, a noise component is extracted from the adjustment signal VCA using the high-pass filter, and a signal corrected for the phase shift generated between the adjustment signal VCA and the signal passing through the high-pass filter is generated to generate a phase. Based on the corrected signal and the signal passed through the high-pass filter, the noise component is removed from the adjustment signal VCA, only the current ripple component is extracted, and the ripple component signal S0 is output.

Further, 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. , The armature current is detected, the change is output as a voltage change signal, the current ripple component and the noise component are extracted from the voltage change signal, and the first smoothing signal S1 composed of the current ripple component and the noise component is output. , The amplitude of the first smoothing signal S1 is adjusted, the adjustment signal VCA in a state where the amplitude is made uniform is output, the distortion of the adjustment signal VCA is corrected, and the second smoothing of the uniform amplitude having a constant center value is performed. The signal S2 is output, the noise component is removed from the second smoothing signal S2, only the current ripple component is extracted, the ripple component signal S0 is output, and the noise component is extracted from the second smoothing signal S2 using a high-pass filter. At the same time, a signal corrected for the phase shift generated between the second smoothing signal S2 and the signal passed through the high-pass filter is generated, and the phase-corrected signal and the signal passed through the high-pass filter are combined. Based on this, it is characterized in that the noise component is removed from the second smoothing signal S2, only the current ripple component is extracted, and the ripple component signal S0 is output.

In the present invention, each step of the current detection step, the first smoothing step, the gain adjustment step, the ripple detection step, or further, the second smoothing step is performed between the gain adjustment step and the ripple detection step. The current ripple is converted into a digital signal from the motor current and extracted to control the motor. At that time, in the ripple detection step, a noise component is extracted from the adjustment signal VCA output in the gain adjustment step or the second smoothing signal S2 output in the second smoothing section step using a high-pass filter, and at the same time. A signal that corrects the phase shift that occurs between the adjustment signal VCA or the second smoothing signal S2 and the signal that has passed through the high-pass filter is generated, and the adjustment signal VCA or the second smoothing signal S2 and the signal after high-pass filter processing are generated. Adjust the phase difference with. Then, based on the phase-corrected signal and the signal that has passed through the high-pass filter, the noise component is removed from the adjustment signal VCA and the second smoothing signal S2, and only the current ripple component is extracted. As a result, even if the armature current contains distortion components and spike components due to deterioration over time, noise components including distortion are extracted from the adjustment signal VCA and the second smoothing signal S2 using a high-pass filter. Based on the generated noise component and the original waveform, unnecessary noise component is removed and only the necessary waveform is extracted. As a result, it is possible to suppress the generation of the ripple component signal S0 whose waveform is distorted due to the distortion component or the like, and the ripple component signal S0 having a waveform without fear of erroneous pulse output is output from the ripple detection unit.

According to the motor control device of the present invention, it has a ripple pulse conversion unit including a current detection unit, a first smoothing unit, a gain adjustment unit, and a ripple detection unit, and a current ripple is digitized and extracted from the motor current. In the motor control device that controls the motor, the ripple detection unit is provided with a high-pass filter that extracts noise components from the adjustment signal VCA output from the gain adjustment unit and a phase correction unit that adjusts the phase of the adjustment signal VCA. Therefore, the phase difference between the adjustment signal VCA and the signal after high-pass filter processing can be adjusted, and ripple detection is possible even if the armature current contains distortion components or spike components due to deterioration over time. In the section, it is possible to remove unnecessary noise components including distortion and extract only the necessary waveform. As a result, it is possible to suppress the generation of the ripple component signal S0 whose waveform is distorted due to the distortion component or the like in the ripple detection unit, and the ripple component signal S0 having a waveform without fear of erroneous pulse output is output from the ripple detection unit. It becomes possible to do. As a result, it is possible to prevent a decrease in the ripple detection accuracy due to the influence of aging deterioration and the like, and it is possible to improve the motor control accuracy.

Further, according to another motor control device of the present invention, it has a ripple pulse conversion unit including a current detection unit, a first smoothing unit, a gain adjustment unit, a second smoothing unit, and a ripple detection unit, and is used in the motor current. In the motor control device that controls the motor by converting the current ripple into a digital signal and controlling the motor, the ripple detection unit adjusts the phase of the high-pass filter that extracts the noise component from the second smoothing signal S2 and the phase of the second smoothing signal S2. Since the phase correction unit is provided, the phase difference between the second smoothing signal S2 and the signal after high-pass filter processing can be adjusted, and the armature current contains distortion components and spike components due to aging deterioration and the like. Even so, the ripple detection unit can remove unnecessary noise components including distortion and extract only the necessary waveform. As a result, it is possible to suppress the generation of the ripple component signal S0 whose waveform is distorted due to the distortion component or the like in the ripple detection unit, and the ripple component signal S0 having a waveform without fear of erroneous pulse output is output from the ripple detection unit. It becomes possible to do. As a result, it is possible to prevent a decrease in the ripple detection accuracy due to the influence of aging deterioration and the like, and it is possible to improve the motor control accuracy.

On the other hand, according to the motor control method of the present invention, a current detection step, a first smoothing step, a gain adjustment step, and a ripple detection step are provided, and by carrying out each step, the current ripple is converted into a digital signal from the motor current. In the ripple detection step in the motor control method that controls the motor by extracting the noise component from the adjustment signal VCA output in the gain adjustment step, the noise component is extracted using the high-pass filter and passed through the adjustment signal VCA and the high-pass filter. A signal that corrects the phase shift that occurs between the signal and the signal is generated, and the phase difference between the adjustment signal VCA and the signal after high-pass filter processing is adjusted. Therefore, the adjustment signal VCA and the signal after high-pass filter processing are adjusted. Even if the armature current contains distortion components and spike components due to deterioration over time, unnecessary noise components including distortion can be removed in the ripple detection step. It is possible to remove and extract only the necessary waveform. As a result, it is possible to suppress the generation of the ripple component signal S0 whose waveform is distorted due to the distortion component or the like in the ripple detection step, and it is possible to generate the ripple component signal S0 having a waveform without fear of erroneous pulse output. It becomes. As a result, it is possible to prevent a decrease in the ripple detection accuracy due to the influence of aging deterioration and the like, and it is possible to improve the motor control accuracy.

Further, according to another motor control method of the present invention, a current detection step, a first smoothing step, a gain adjustment step, a second smoothing step, and a ripple detection step are provided, and by carrying out each step, the motor current is generated. In the ripple detection step in the motor control method in which the current ripple is converted into a digital signal and extracted from the inside to control the motor, the noise component is extracted from the second smoothing signal S2 using a high-pass filter, and the second smoothing signal S2 A signal that corrects the phase shift that occurs between the signal that has passed through the high-pass filter is generated, and the phase difference between the second smoothing signal S2 and the signal that has been processed by the high-pass filter is adjusted. The phase difference between S2 and the signal after high-pass filter processing can be adjusted, and even if the armature current contains distortion components and spike components due to deterioration over time, distortion occurs in the ripple detection step. It is possible to remove unnecessary noise components including, etc., and extract only the necessary waveform. As a result, it is possible to suppress the generation of the ripple component signal S0 whose waveform is distorted due to the distortion component or the like in the ripple detection step, and it is possible to generate the ripple component signal S0 having a waveform without fear of erroneous pulse output. It becomes. As a result, it is possible to prevent a decrease in the ripple detection accuracy due to the influence of aging deterioration and the like, and it is possible to improve the motor control accuracy.

It is a block diagram which shows the structure of the motor control device which is Embodiment 1 of this invention. This is an example of an output signal from the current detection unit. It is explanatory drawing which shows the processing in the 1st control voltage generation circuit. It is explanatory drawing which shows the processing in the 1st variable component smoothing circuit. It is explanatory drawing which shows the processing in a CV inverting circuit. It is explanatory drawing which shows the processing in an automatic gain adjustment circuit. It is explanatory drawing which shows the processing in the 2nd smoothing circuit block. It is explanatory drawing which shows the processing in a ripple detection part. It is explanatory drawing which shows the structure of the phase correction part provided in the ripple detection part. It is explanatory drawing about the noise removal processing of the motor current containing a distortion component and a spike component by aged deterioration in this embodiment, (a) is an example of a motor current waveform containing a distortion component and a spike component, (b). ) Is the original signal waveform of the processing in the ripple detection unit of FIG. 8, (c) is the waveform of the signal A and the signal B in the ripple detection unit of FIG. 8, and (d) is generated based on the signal of (c) in the subsequent stage. The output signals are shown respectively. It is explanatory drawing which shows the processing in a digital signal conversion part. It is a block diagram which shows the structure of the motor control device which is Embodiment 2 of this invention. It is explanatory drawing which shows the process in the ripple detection part in the motor control device of FIG. It is explanatory drawing which shows the noise removal processing process of the motor control apparatus used for the motor which performs sensorless control. It is explanatory drawing about the noise removal processing of the motor current containing a distortion component and a spike component by aged deterioration, etc., (a) is an example of the voltage change signal waveform of the motor current containing a distortion component and a spike component, (b). ) Show the original signal waveform in the process of FIG. 14, (c) shows the waveforms of the signal A and the signal B in the process of FIG. 14, and (d) shows the ripple pulse generated based on the signal of (c). ..

(Embodiment 1)
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 the first embodiment of the present invention. The motor control device 1 is applied to, for example, operation control of a DC motor used as a drive source of a power window (opening / closing body) of an automobile, and uses a Hall IC or the like to reduce current ripple included in a motor current (armature current). It extracts without any problem, outputs it in the form of a rectangular wave, and calculates the rotation speed and rotation direction of the motor.

The motor control device 1 is provided with a ripple pulse conversion unit 10, and the current ripple detection method of the present invention is carried out by the ripple pulse conversion unit 10. The ripple pulse conversion unit 10 is arranged on the power supply line 4 that supplies electric power from the power supply 2 to the brushed DC (direct current) 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 (power supply 2 side and motor 3 side) of the shunt resistor 5.

As shown in FIG. 1, the ripple pulse conversion unit 10 includes a current detection unit 11, a first smoothing circuit block (first smoothing unit: signal smoothing unit) 12, a gain adjusting unit 13, and a second in order from the shunt resistance 5 side. It is composed of each functional block of a smoothing circuit block (second smoothing unit) 14, a ripple detection unit 15, and a digital signal conversion unit 16. In the ripple pulse conversion unit 10, the current detection unit 11 detects the voltage difference (voltage drop) before and after the shunt resistance 5 to detect the motor drive current, and outputs the change as a voltage change signal. This voltage change signal is sent to each functional block of the first smoothing circuit block 12 and below (gain adjustment unit 13 → second smoothing circuit block 14 → ripple detection unit 15), and only the current ripple component is extracted from the voltage change signal. Ripple. Then, the extracted current ripple component is converted into a pulse signal corresponding to the encoder output by the digital signal conversion unit 16 and output, and the rotation speed of the motor 3 is detected based on this pulse signal.

Hereinafter, the processing in each functional block in the ripple pulse conversion unit 10 will be described step by step. As described above, the current detection unit 11 captures the voltage difference before and after the shunt resistor 5 and outputs it as a voltage change signal (current detection step). FIG. 2 is an example of an output signal from the current detection unit 11. The current detection unit 11 outputs the voltage difference before and after the shunt resistor 5 in a differentially amplified form with reference to the bias voltage Voff1 based on the power supply voltage. As shown in FIG. 2, the voltage change signal includes a noise component and a current ripple component, and the voltage signal in this state is output from the current detection unit 11, and the first smoothing circuit block 12 Will be sent to.

The first smoothing circuit block 12 is provided with a first control voltage (CV: Control Voltage) generating circuit 21 and a first variable component smoothing circuit 22. From the voltage change signal of FIG. 2, a current ripple component and a noise component are provided. Is extracted (first smoothing step). FIG. 3 is an explanatory diagram showing processing in the first control voltage generation circuit 21, and FIG. 4 is an explanatory diagram showing processing in the first variable component smoothing circuit 22. By using the low pass filter 23, the first control voltage generation circuit 21 extracts the center value of the current ripple component as the change component of the motor drive current from the voltage change signal (FIG. 2) input from the current detection unit 11. (Fv (t) in FIG. 3), output as the first control voltage CV1 (first control voltage generation step).

In this case, the slope of the ripple waveform is determined by the relationship between the inductance of the motor and the current change when the brush straddles the commutator piece. Therefore, the cutoff frequency fc1 of the low-pass filter 23 for extracting fv (t) is between the frequency component due to the motor inductance and the ripple frequency component at the time of motor lock, in consideration of the motor specifications, installation conditions, and the like. It will be decided as appropriate. The first control voltage CV1 extracted by the first control voltage generation circuit 21 is output to the first variable component smoothing circuit 22 and the gain adjusting unit 13.

In the first variable component smoothing circuit 22, the current ripple component (+ noise component) is obtained from the voltage change signal obtained by the current detection unit 11 using the first control voltage CV1 obtained by the first control voltage generation circuit 21. Extract. That is, by taking the difference between the voltage change signal of FIG. 2 (FIG. 4 (a)) and the first control voltage CV1 (FIG. 4 (c)), the fluctuation component (change component) of the motor drive current is taken from the voltage change signal. Is removed, and the current ripple component (+ noise component) is extracted (FIG. 4 (e)).

Further, in the first variable component smoothing circuit 22, as shown in FIGS. 4 (b) and 4 (d), the voltage levels (of the waveform) between the voltage change signal and the first control voltage CV1 are used by using the bias voltages Vref1 and Vref2. Height) is adjusted. As a result, only the current ripple component and the noise component are extracted, and the first smoothing signal S1 as shown in FIG. 4 (e) is output (first variable component smoothing step). As shown in FIG. 4 (e), since the center level of the waveform of the first smoothing signal S1 is constant, the subsequent waveform shaping process becomes easy and the certainty thereof is improved.

As shown in FIG. 4 (e), the signal obtained by the first variable component smoothing circuit 22 is accompanied by an amplitude change due to a change in the motor current. Therefore, next, the gain adjusting unit 13 waveform-shapes the signal of FIG. 4 (e) into a signal having a uniform swing width (gain adjustment step). The gain adjustment unit 13 is provided with a CV inverting circuit (control voltage inverting circuit) 24 and an automatic gain adjustment circuit 25. FIG. 5 is an explanatory diagram showing processing in the CV inverting circuit 24, and FIG. 6 is an automatic gain adjustment. It is explanatory drawing which shows the processing in a circuit 25. The gain adjusting unit 13 adjusts as shown in FIG. 6 (c) by the inverting first control voltage CV1'of the opposite phase inverted by the CV inverting circuit 24 and the first smoothing signal S1 from the first variable component smoothing circuit 22. The signal VCA is created.

As shown in FIG. 5, in the CV inversion circuit 24, the top and bottom of the first control voltage CV1 input from the first control voltage generation circuit 21 are inverted, and the inverted first control voltage CV1'is output (control voltage inversion). Step). The automatic gain adjustment circuit 25 equalizes the amplitude of the first smoothing signal S1 by multiplying the first smoothing signal S1 by the inverted first control voltage CV1'. That is, by multiplying the first smoothing signal S1 and the inverted first control voltage CV1'in which the waveforms of the first control voltage CV1 are upside down, a small voltage is applied to a portion having a large amplitude and a large voltage is applied to a portion having a small amplitude. A voltage is applied to each, and an adjustment signal VCA having a uniform amplitude is output as shown in FIG. 6 (c) (gain adjustment step). As a result, the level of the current ripple component is made uniform, and the certainty of waveform processing is improved.

The adjustment signal VCA obtained by the gain adjustment unit 13 is sent to the second smoothing circuit block 14 and smoothed again (second smoothing step). As shown in FIG. 6 (c), although the amplitude of the adjustment signal VCA is made uniform, this time, the entire adjustment signal VCA is curved along with the change of the inverted first control voltage CV1'. Therefore, in order to correct it into a linear signal having a constant center value, a smoothing process is performed by the second smoothing circuit block 14. The second smoothing circuit block 14 is provided with a second control voltage generation circuit 26 and a second variable component smoothing circuit 27, and the same processing as that of the first smoothing circuit block 12 is executed.

FIG. 7 is an explanatory diagram showing processing in the second smoothing circuit block 14. As shown in FIG. 7B, also in the second smoothing circuit block 14, the second control voltage generation circuit 26 creates the second control voltage CV2 from the adjustment signal VCA (second control voltage generation step). Then, the second fluctuation component smoothing circuit 27 creates the second smoothing signal S2 of FIG. 7 (c) from the second control voltage CV2 and the adjustment signal VCA input from the gain adjustment unit 13. That is, the second smoothing signal S2 having a uniform amplitude as shown in FIG. 7 (c) is obtained by subtracting the second control voltage CV2 (FIG. 7 (b)) shown by the alternate long and short dash line from the waveform of FIG. 7 (a). Is formed (second variable component smoothing step).

As shown in FIG. 7C, the second smoothing signal S2 contains a current ripple component and a noise component. Therefore, the ripple detection unit 15 extracts only the current ripple component from the second smoothing signal S2 (ripple detection step). FIG. 8 is an explanatory diagram showing processing in the ripple detection unit 15. In this case, since the noise component has a higher frequency than the current ripple component, only the noise component is first extracted from the second smoothing signal S2 (FIG. 8A) using the high-pass filter 28 (noise component extraction step). (FIG. 8 (b)). At this time, the cutoff frequency fc2 of the high-pass filter 28 is set between the frequency component of the rising and falling times of the current ripple component due to the motor inductance and the frequency component of the noise component after appropriate verification according to the system specifications. ..

After extracting only the noise component from the second smoothing signal S2, it is inverted and combined with the second smoothing signal S2. That is, the noise component is removed from the second smoothing signal S2 by inputting the second smoothing signal S2 and the antiphase signal of the noise component to the differential amplifier circuit (differential amplification unit) 29 and taking the difference between the two. The ripple component signal S0 is amplified to form and output the ripple component signal S0 in which only the current ripple component is manifested (FIG. 8 (d)). As a result, a signal containing only the current ripple component as shown in FIG. 8D is extracted from the voltage change signal shown in FIG. 2 (current ripple component extraction step). By removing the noise component from the second smoothing signal S2 in this way, it is possible to extract only the current ripple component from the motor current without blunting the waveform of the current ripple.

On the other hand, as described above, when distortion or spike noise is included in the motor current due to deterioration over time or the like, distortion or noise is also included in the second smoothing signal S2. As a result, even if the difference between the signal after the high-pass filter processing and the original signal is taken by the ripple detection unit 15, the distortion component and the spike noise cannot be removed well. Therefore, in the motor control device 1, a phase correction unit 41 for adjusting the phase of the second smoothing signal S2 is arranged in parallel with the high-pass filter 28 in front of the differential amplifier circuit 29, and the signal passes through the high-pass filter 28. The phase shift that occurs between A and the second smoothing signal S2 is corrected.

Here, the AC coupling circuit 42 as shown in FIG. 9 is used as the phase correction unit 41. The phase correction unit 41 has a configuration including a capacitor C, a resistor R, and a buffer operational amplifier OP, advances the phase of the second smoothing signal S2 in the same manner as the high-pass filter 28, and outputs the phase to the differential amplifier circuit 29 (signal). B). That is, the phase correction unit 41 advances the phase of the second smoothing signal S2 so that the phase of the second smoothing signal S2 whose phase is advanced by the high-pass filter 28 and the original second smoothing signal S2 are the same. Output. As a result, signals A and B having the same phase based on the second smoothing signal S2 are input to the differential amplifier circuit 29. The phase adjustment amount of the phase correction unit 41 can be appropriately controlled by changing the C and R values of the AC coupling circuit 42.

10A and 10B are explanatory views regarding noise removal processing in the ripple detection unit 15, where FIG. 10A is an example of a voltage change signal waveform of a motor current including a distortion component and a spike component, and FIG. 10B is a voltage of FIG. 10A. The waveform of the second smoothing signal S2 input from the change signal to the ripple detection unit 15 via the previous stage processing, (c) is the waveform of the signal A and signal B in the ripple detection unit 15 of FIG. 8, and (d) is (c). ) Is generated based on the signal of), and the output C (ripple component signal S0) from the differential amplification circuit 29 is shown. As shown in FIG. 10 (c), in the ripple detection unit 15 in the present embodiment, the signals A and B input to the differential amplifier circuit 29 are the same as both signals in FIG. 15 (c) as a result of phase correction. Unlike, the waveforms of distortion and spike noise are aligned.

Therefore, in the ripple detection unit 15, distortion components and spike components are removed by the differential amplifier circuit 29, and unnecessary components as shown in FIG. 15D remain in the output C of the differential amplifier circuit 29. However, the ripple component signal S0 is in the state as shown in FIG. 10 (d) in which the influence of the distortion component and the spike component is removed. That is, the ripple detection unit 15 extracts unnecessary components with the high-pass filter 28 and subtracts them from the original waveform phase-corrected by the AC coupling circuit 42, thereby absorbing the disturbance of the waveform due to aging deterioration and the like. , Only the required waveform is extracted. As a result, in the digital signal conversion unit 16 in the subsequent stage, it is possible to prevent erroneous pulse generation due to the influence of distortion components and spike components, prevent deterioration of ripple detection accuracy due to the influence of aging deterioration, etc., and improve motor control accuracy. Is possible.

The phase of the high-pass filter 28 changes even in a signal without deterioration over time. In that case, the second smoothing signal S2 contains peculiar noise such as a distortion component and a spike component. However, noise with a relatively uniform waveform is superimposed. Therefore, even if the signal with the advanced phase is synthesized by the differential amplifier circuit 29, noise that affects the pulse generation in the subsequent stage does not remain.

After extracting only the current ripple component in this way, it is sent to the digital signal conversion unit 16 to be converted into a digital signal (digital signal conversion step). FIG. 11 is an explanatory diagram showing processing in the digital signal conversion unit 16. In the digital signal conversion unit 16, the phase shift unit 31 slightly shifts the phase of the ripple component signal S0 (FIG. 11A) sent from the ripple detection unit 15 (phase shift signal creation step). Then, in the comparator 32, the original ripple component signal S0 and the signal S0'with a slight phase shift are compared and converted into a pulse signal as shown in FIG. 11D.

In this case, the comparator 32 outputs a signal in the form of, for example, H when the signal S0 is large and L when the signal S0'is large among the signal S0 and the signal S0'. Therefore, as shown in FIG. 11 (c), "H" is output because S0> S0'in the section P, and "L" is output because S0 <S0'in the section Q, and the change in the ripple component signal S0. A rectangular wavy pulse signal corresponding to is formed and output (digital conversion step).

In the rectangular wave signal generated in this way, 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, it is possible to detect the rotation speed of the motor 3 from the current ripple in the motor current without using a rotation detection member such as a Hall IC. At that time, in the apparatus / method of the present invention, it is not necessary to increase the current ripple by changing the magnetic pole pitch or the like, and the ripple extraction can be performed with the conventional motor configuration as it is. Therefore, ripple sensing can be performed without impairing the performance and characteristics of the motor and without increasing the motor noise and heat generation. Furthermore, precise filters and delicate cutoff settings are not required, and problems such as pulse non-output and delay can be prevented.

(Embodiment 2)
Next, as the second embodiment, the motor control device 51 which does not have the above-mentioned second smoothing circuit block 14 will be described. FIG. 12 is a block diagram showing the configuration of the motor control device 51 according to the second embodiment of the present invention, and FIG. 13 is an explanatory diagram showing signal processing by the ripple detection unit 15 in the motor control device 51. Similar to the first embodiment, the motor control device 51 is also provided with a ripple pulse conversion unit 52, and the current ripple detection method of the present invention is carried out by the ripple pulse conversion unit 52. The same parts as those of the motor control device 1 of the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

As shown in FIG. 12, in the motor control device 51, the second smoothing circuit block 14 in the previous motor control device 1 is not provided, and the ripple detection unit 15 is arranged after the gain adjustment unit 13. .. As described above, the second smoothing circuit block 14 corrects the adjustment signal VCA obtained by the gain adjustment unit 13 into a linear signal having a constant center value (see FIG. 7). On the other hand, although the adjustment signal VCA has a curved shape as a whole, it does not bend too much when viewed at an enlarged scale (see FIG. 13), and the amplitude is made uniform by the gain adjustment unit 13. There is. Therefore, it is often possible to remove the noise component by the high-pass filter without further smoothing. Therefore, in the motor control device 51 of the embodiment, the second smoothing circuit block 14 is omitted, and the adjustment signal VCA output from the gain adjustment unit 13 is input to the ripple detection unit 15, and the noise component is removed and the ripple component is extracted. It is carried out. The ripple pulse conversion unit 52 performs the same processing as the ripple pulse conversion unit 10 of the first embodiment except that the adjustment signal VCA is input to the ripple detection unit 15 to perform signal processing.

FIG. 13 is an explanatory diagram showing processing in the ripple detection unit 15 of the motor control device 51, in which the ripple detection unit 15 removes a noise component from the adjustment signal VCA by a high-pass filter 28. On the other hand, in this case as well, as described above, the phase difference between the original signal and the filtered signal makes it impossible to successfully remove the distortion component and spike noise due to aging deterioration. Therefore, also in the ripple detection unit 15 of the embodiment, the phase correction unit 41 is provided in parallel with the high-pass filter 28 to adjust the phase of the adjustment signal VCA. In this case, the same AC coupling circuit 42 as in FIG. 9 is used for the phase correction unit 41. As a result, the phase shift that occurs between the signal A that has passed through the high-pass filter 28 and the adjustment signal VCA is corrected, and the waveforms of the signals A and B that are input to the differential amplifier circuit 29 are aligned as in FIG. , Distortion component and spike component are removed.

As described above, also in the motor control device 51, the phase correction unit 41 is provided in the ripple detection unit 15, the phase of the adjustment signal VCA output from the gain adjustment unit 13 is adjusted, and the adjustment signal VCA and the signal after the filter processing thereof are adjusted. The signal is processed so that there is no phase difference between the signal and the signal. As a result, similarly to the motor control device 1 of the first embodiment, the ripple detection unit 15 can extract only the necessary waveform while absorbing the disturbance of the waveform due to aged deterioration or the like. As a result, in the digital signal conversion unit 16 in the subsequent stage, it is possible to prevent erroneous pulse generation due to the influence of distortion components and spike components, prevent deterioration of ripple detection accuracy due to the influence of aging deterioration, etc., and improve motor control accuracy. Is possible.

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 motor control function in the above-mentioned motor control device is not a hardware-like configuration like the ripple pulse conversion unit 10, but it is also possible to substitute / realize these functions on software.

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

1 Motor control device 2 Power supply 3 Brushed DC motor 4 Power supply line 5 Shunt resistance 10 Ripple pulse conversion unit 11 Current detection unit 12 1st smoothing circuit block (1st smoothing unit)
13 Gain adjustment unit 14 2nd smoothing circuit block (2nd smoothing unit)
15 Ripple detection unit 16 Digital signal conversion unit 21 1st control voltage generation circuit 22 1st variable component smoothing circuit 23 Low-pass filter 24 CV inverting circuit 25 Automatic gain adjustment circuit 26 2nd control voltage generation circuit 27 2nd variable component smoothing circuit 28 High-pass filter 29 Differential amplifier circuit (differential amplifier)
31 Phase shift unit 32 Comparator 41 Phase correction unit 42 AC coupling circuit 51 Motor control device 52 Ripple pulse conversion unit 61 High-pass filter CV1 First control voltage CV1'Inverted first control voltage CV2 Second control voltage S0 Ripple component signal S0' Shift signal S1 First smoothing signal S2 Second smoothing signal VCA Adjustment signal Voff1 Bias voltage Vref1 Bias voltage Vref2 Bias voltage fc1 Cutoff frequency fc2 Cutoff frequency

Claims (6)

A motor control device having a ripple pulse converter that detects a current ripple contained in the armature current of a DC motor and outputs the current ripple as a square wave signal.
The ripple pulse conversion unit is
A current detector that detects the armature current and outputs the change as a voltage change signal.
A first smoothing unit that extracts a current ripple component and a noise component from the voltage change signal and outputs a first smoothing signal S1 composed of the current ripple component and the noise component.
A gain adjustment unit that adjusts the amplitude of the first smoothing signal S1 and outputs an adjustment signal VCA in a state where the amplitude is made uniform.
A ripple detection unit that removes a noise component from the adjustment signal VCA, extracts only a current ripple component, and outputs a ripple component signal S0 is provided.
The ripple detection unit includes a high-pass filter that extracts noise components from the adjustment signal VCA, and a phase correction unit that is provided in parallel with the high-pass filter and adjusts the phase of the adjustment signal VCA. .. A motor control device having a ripple pulse converter that detects a current ripple contained in the armature current of a DC motor and outputs the current ripple as a square wave signal.
The ripple pulse conversion unit is
A current detector that detects the armature current and outputs the change as a voltage change signal.
A first smoothing unit that extracts a current ripple component and a noise component from the voltage change signal and outputs a first smoothing signal S1 composed of the current ripple component and the noise component.
A gain adjustment unit that adjusts the amplitude of the first smoothing signal S1 and outputs an adjustment signal VCA in a state where the amplitude is made uniform.
A second smoothing section that corrects the distortion of the adjustment signal VCA and outputs a second smoothing signal S2 having a constant amplitude and a uniform amplitude.
A ripple detection unit that removes a noise component from the second smoothing signal S2, extracts only a current ripple component, and outputs a ripple component signal S0 is provided.
The ripple detection unit is characterized by having a high-pass filter that extracts a noise component from the second smoothing signal S2 and a phase correction unit that is provided in parallel with the high-pass filter and adjusts the phase of the second smoothing signal S2. Motor control device. In the motor control device according to claim 1 or 2.
The phase correction unit is a motor control device that corrects a phase shift that occurs between the adjustment signal VCA or the second smoothing signal S2 and a signal that has passed through the high-pass filter. In the motor control device according to any one of claims 1 to 3.
The ripple detection unit takes a difference between the signal that has passed through the high-pass filter and the signal that has passed through the phase correction unit, thereby removing a noise component from the adjustment signal VCA or the second smoothing signal S2. A motor control device characterized by having a unit. A motor control method that detects a current ripple contained 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.
The armature current is detected, and the change is output as a voltage change signal.
The current ripple component and the noise component are extracted from the voltage change signal, and the first smoothing signal S1 composed of the current ripple component and the noise component is output.
The amplitude of the first smoothing signal S1 is adjusted, and the adjustment signal VCA in a state where the amplitude is made uniform is output.
The noise component is removed from the adjustment signal VCA, only the current ripple component is extracted, and the ripple component signal S0 is output.
The phase was corrected by extracting the noise component from the adjustment signal VCA using the high-pass filter and generating a signal corrected for the phase shift generated between the adjustment signal VCA and the signal passing through the high-pass filter. A motor control method comprising removing a noise component from the adjustment signal VCA, extracting only a current ripple component, and outputting a ripple component signal S0 based on the signal and a signal that has passed through the high-pass filter. A motor control method that detects a current ripple contained 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.
The armature current is detected, and the change is output as a voltage change signal.
The current ripple component and the noise component are extracted from the voltage change signal, and the first smoothing signal S1 composed of the current ripple component and the noise component is output.
The amplitude of the first smoothing signal S1 is adjusted, and the adjustment signal VCA in a state where the amplitude is made uniform is output.
The distortion of the adjustment signal VCA is corrected, and a uniform amplitude second smoothing signal S2 having a constant center value is output.
The noise component is removed from the second smoothing signal S2, only the current ripple component is extracted, and the ripple component signal S0 is output.
A noise component is extracted from the second smoothing signal S2 using a high-pass filter, and a signal that corrects the phase shift generated between the second smoothing signal S2 and the signal that has passed through the high-pass filter is generated to generate a phase. Based on the corrected signal and the signal passed through the high-pass filter, the noise component is removed from the second smoothing signal S2, only the current ripple component is extracted, and the ripple component signal S0 is output. Motor control method.

Images