KR102229302B1 - Apparatus and method for cirrent sensing of dc brushed motor using shunt resistance - Google Patents

Abstract

The present invention relates to an apparatus and method for detecting a current of a DC brushed motor using a shunt resistor. The current detection device of a DC brushed motor using a shunt resistor according to an embodiment of the present invention is electrically connected to a pulse width control signal input terminal and an inverting input terminal of a pulse width control signal, respectively, to provide a pulse width control signal and an inverted pulse width control signal. The motor driving circuit that controls the driving direction and driving speed of the internal motor according to the driving method, the shunt resistance connected in series to the ground output terminal of the motor driving circuit, and the current at both ends of the shunt resistance are detected, and the feedback of the motor driving circuit is driven. It includes a motor sensing control unit that controls the driving direction and speed of the internal motor according to the voltage and the current detection value of the shunt resistor. By stabilizing the detection of the current at the ground end of the motor driving circuit and increasing the detection accuracy according to the direction determination of the motor current. , It is possible to improve the responsiveness and accuracy of the feedback current detection control method driven by feeding back the motor current.

Description

Current detection device and method of DC brushed motor using shunt resistance {APPARATUS AND METHOD FOR CIRRENT SENSING OF DC BRUSHED MOTOR USING SHUNT RESISTANCE}

The present invention relates to an apparatus and method for detecting a driving current of a motor, and in detail, by stabilizing the detection of a ground terminal current of a motor driving circuit using a shunt resistance and increasing the detection accuracy according to the direction determination of the motor current, The present invention relates to an apparatus and method for detecting a current of a DC brushed motor using a shunt resistor capable of improving the responsiveness and accuracy of a feedback current detection control method driven by feeding back a motor current.

Typically, in order to control and drive by feeding back a current such as a DC brushed motor, it is necessary to detect a driving current or a feedback current. In particular, in the case of a feedback current detection control method in which a motor current is fed back and driven, more accurate and stabilized detection circuits and devices are required.

Conventionally, as a current sensor for measuring a motor current, a hall type current sensor and a shunt resistance type current sensor are known and used. Of these, since the method using the Hall type current sensor senses the magnetism generated by the current, the detection accuracy is lower than the method using the shunt resistance when disturbed by an external magnetic field. It was lowered, and the cost of its construction was also inevitably higher.

On the other hand, in the method of using a shunt resistor, when the switching frequency is increased, there may be a signal error such as a ringing phenomenon of the switching signal. Therefore, if the detection is not performed after a stable time is secured, the detection accuracy is degraded.

Specifically, as a method of using the shunt resistor, there are a method of positioning a shunt resistor at the load end of the motor signal according to the configuration position of the shunt resistor, and a method of detecting by placing a shunt resistor at the ground end of the motor drive circuit. Since the positioning method is a method of directly measuring the actual motor current, the detection accuracy may be lower than the method of detecting by placing it at the ground end, and there is a problem in that the cost of construction is increased. On the other hand, the method of detecting by placing it at the ground end measures the absolute value of the motor current by measuring the DC link end, not the actual current value of the motor.Therefore, it is necessary to take sufficient time for the switching signal to stabilize to slightly increase its accuracy. There was a problem to be able to.

The present invention is to solve the above problems, by stabilizing the detection of the ground end current of a DC brushed motor driving circuit using a shunt resistor and increasing the detection accuracy according to the direction of the motor current, thereby feeding back the motor current to drive. An object of the present invention is to provide an apparatus and method for detecting a current of a DC brushed motor using a shunt resistor capable of improving the responsiveness and accuracy of the feedback current detection control method.

In addition to the technical problems of the present invention mentioned above, other features and advantages of the present invention will be described below or will be clearly understood by those of ordinary skill in the art from such technology and description.

A current detection device for a DC brushed motor using a shunt resistor according to an embodiment of the present invention to achieve the above object is electrically connected to a pulse width control signal input terminal and an inverting input terminal of a pulse width control signal to control the pulse width. Depending on the signal and the inverted pulse width control signal, the motor driving circuit that controls the driving direction and driving speed of the internal motor, the shunt resistance connected in series to the ground output terminal of the motor driving circuit, and the current at both ends of the shunt resistance are measured. And a motor sensing controller configured to detect and control an internal motor driving direction and speed according to a feedback driving voltage of the motor driving circuit and a current detection value of the shunt resistor.

In addition, the current detection method of a DC brushed motor using a shunt resistor according to an embodiment of the present invention to achieve the above object is a motor driving circuit electrically connected to the pulse width control signal input terminal and the inverting input terminal of the pulse width control signal, respectively. A step of controlling the driving direction and driving speed of the internal motor according to the pulse width control signal and the inverted pulse width control signal, and driving the current at both ends of the shunt resistance connected in series to the ground output terminal of the motor driving circuit. And controlling the driving direction and speed of the internal motor according to the feedback driving voltage output from the motor driving circuit and the current detection value of the shunt resistance with the configuration of the motor sensing control unit.

As a current detection apparatus and method of a DC brushed motor using a shunt resistor according to an embodiment of the present invention having various technical characteristics as described above, the detection of the ground terminal current of the DC brushed motor driving circuit using a shunt resistor is stabilized and the motor It is possible to improve the detection accuracy according to the determination of the direction of the current.

In particular, there is an effect of improving the responsiveness and accuracy of a feedback current detection control method driven by feeding back a motor current such as a DC brushed motor.

In addition, other features and advantages of the present invention may be newly recognized through embodiments of the present invention.

1 is a circuit diagram specifically showing a current detection device for a DC brushed motor using a shunt resistor according to an embodiment of the present invention.
FIG. 2 is a view showing a driving waveform according to a current direction and a motor rotation direction of the motor driving circuit shown in FIG. 1.
3 is a flow chart for explaining a galvannealing detection method of the current detection device shown in FIG. 1.
4 is an input/output waveform diagram for driving a motor of the current detection device shown in FIG.
5 is a diagram illustrating a motor model equation applied in the direction determination process of FIG. 3.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those of ordinary skill in the art may easily implement the present invention. The present invention may be implemented in various different forms and is not limited to the embodiments described herein.

In order to clearly describe the present invention, parts irrelevant to the description have been omitted, and the same reference numerals are attached to the same or similar components throughout the specification.

Throughout the specification, when a part is said to be "connected" with another part, this includes not only "directly connected" but also "electrically connected" with another element interposed therebetween. . In addition, when a part "includes" a certain component, it means that other components may be further included rather than excluding other components unless specifically stated to the contrary.

When a part is referred to as being "on" another part, it may be directly on top of another part, or other parts may be involved in between. In contrast, when a part is referred to as being "directly above" another part, no other part is involved in between.

Terms such as first, second and third are used to describe various parts, components, regions, layers and/or sections, but are not limited thereto. These terms are only used to distinguish one part, component, region, layer or section from another part, component, region, layer or section. Accordingly, a first part, component, region, layer or section described below may be referred to as a second part, component, region, layer or section without departing from the scope of the present invention.

The terminology used herein is only for referring to specific embodiments and is not intended to limit the present invention. Singular forms as used herein also include plural forms unless the phrases clearly indicate the opposite. The meaning of "comprising" as used in the specification specifies a particular characteristic, region, integer, step, action, element and/or component, and the presence of another characteristic, region, integer, step, action, element and/or component, or It does not exclude additions.

Terms indicating a relative space such as "below" and "above" may be used to more easily describe the relationship of one part to another part shown in the drawings. These terms are intended to include other meanings or operations of the device in use together with their intended meaning in the drawings. For example, if the device in the drawing is turned over, certain parts described as being "below" other parts are described as being "above" other parts. Thus, the exemplary term “down” includes both up and down directions. The device can be rotated by 90 degrees or other angles, and terms that refer to relative space are interpreted accordingly.

Although not defined differently, all terms including technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs. Terms defined in a commonly used dictionary are additionally interpreted as having a meaning consistent with the related technical literature and the presently disclosed content, and are not interpreted in an ideal or very formal meaning unless defined.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those of ordinary skill in the art may easily implement the present invention. However, the present invention may be implemented in various different forms and is not limited to the embodiments described herein.

1 is a circuit diagram specifically showing a current detection device for a DC brushed motor using a shunt resistor according to an embodiment of the present invention.

The current detection device of the DC brushed motor shown in FIG. 1 includes a pulse width control signal (PWM) input terminal 10, a pulse width control signal inversion (PWMn) input terminal 20, a pulse width control signal (PWM) and an inverted. The motor driving circuit 100 that drives the internal motor M according to the pulse width control signal (PWMn), the shunt resistance (30, Shunt Resistance, R) connected in series to the ground output terminal of the motor driving circuit 100, and the shunt resistance It is configured to include a motor sensing control unit 200 that detects the current at both ends of the motor 30 and controls the motor driving direction and speed according to the feedback driving voltage of the motor driving circuit 100 and the current detected value of the shunt resistance R. .

The motor driving circuit 100 is connected to a pulse width control signal (PWM) input terminal 10 and a pulse width control signal inversion (PWMn) input terminal 20, respectively, and a pulse width control signal (PWM) and an inverted pulse width. Each control signal (PWMn) is received. Accordingly, the motor driving circuit 100 controls the driving direction and driving speed of the internal motor M according to the pulse width control signal PWM and the inverted pulse width control signal PWMn.

To this end, the motor driving circuit 100 changes the switching states of the plurality of switching elements (AH, BL, BH, AL), respectively, to provide each of the pulse width control signal PWM and the inverted pulse width control signal PWMn. It is configured to convert into an AC signal and supply the load to the internal motor (M). Here, the internal motor M may be a DC brushed motor.

The motor driving circuit 100 of the present embodiment comprises two switching elements (AH, BH) constituting the upper arm, four reflux diodes (D1, D2, D3, D4), and two switching elements constituting the lower arm. It may be configured with elements BL and AL.

In the motor driving circuit 100, two switching elements (AH, BH) constituting the upper arm are connected to a positive DC bus, and two switching elements (BL, AL) constituting the lower arm are connected to a ground DC bus. do.

Here, the two switching elements (AH, BH) constituting the upper arm and the two switching elements (BL, AL) constituting the lower arm are switching elements using a wide bandgap semiconductor, and are SiC MOSFETs (SiC: Silicon Carbide, Silicon carbide), or gallium nitride (GaN), or a switching element formed of a semiconductor made of a diamond mode (C) as a main material.

In more detail, in the present invention, the switching method of the two switching elements (AH, BH) constituting the upper arm and the two switching elements (BL, AL) constituting the lower arm can be controlled and driven by the Complementary Bipolar Switching method. It can be suggested as a case.

The shunt resistor 30 is disposed between the ground DC bus and the node through which the current from the motor M flows, and when the current from the motor M flows, a voltage difference between both ends of the shunt resistor 30 occurs. The phase current can be generated by the voltage difference.

The motor sensing controller 200 detects the current at both ends of the shunt resistor 30, and controls the motor driving direction and speed according to the feedback driving voltage of the motor driving circuit 100 and the current detection value of the shunt resistor 30. It is configured to include the sensing control unit 200.

Specifically, the motor sensing control unit 200 is configured to detect a current across the shunt resistor 30 and output a current value signal indicating a detection value of a phase current according to a voltage difference between both ends. The current value signal at this time may be used for purposes such as controlling the motor sensing controller 200 or protecting the motor driving circuit 100 from overcurrent.

In particular, the motor sensing control unit 200 detects an accurate feedback driving voltage according to the driving speed along with the driving direction (direction of the motor current) of the internal motor M and a phase current detection value according to the voltage difference between both ends of the shunt resistor 30. By doing so, it is possible to derive more accurate detection results by supplementing the detection disadvantages at the ground stage.

In particular, when the motor sensing control unit 200 in the present invention detects the phase current detection value according to the voltage difference across the shunt resistor 30, the duty ratio of the feedback driving voltage, which is the final output according to the control of the internal motor M, is If Ratio) is more than a preset reference ratio (eg 50%), each phase current value is detected at the peak point of the output waveform counter.

And, when detecting the phase current detection value, if the duty ratio of the feedback driving voltage is less than a preset reference ratio (for example, 50%), each phase current is detected at the Valley point, the minimum value of the output waveform counter. .

Accordingly, the motor sensing control unit 200 in the present invention minimizes the timing of detecting the phase current value during the period in which the ringing phenomenon occurs, and the detected phase current detection value determines the current direction by the motor voltage method to determine the minimum current. Make it possible to calculate the value. Here, the duty ratio may be a ratio of a time in which current flows to a time in which no current flows.

FIG. 2 is a view showing a driving waveform according to a current direction and a motor rotation direction of the motor driving circuit shown in FIG. 1.

Referring to FIG. 2(a), in the motor driving circuit 100, two switching elements (AH, BH) constituting the upper arm and two switching elements (BL, AL) constituting the lower arm are a Complementary Bipolar Switching method. It is controlled and driven in the first direction in which the internal motor M is in the forward direction according to the switching drive of the first upper switching element AH constituting the upper arm and the first lower switching element AL constituting the lower arm. It can be driven to rotate.

Referring to FIG. 2(b), according to the switching drive of the second lower switching element AL constituting the lower arm and the first upper switching element BH constituting the upper arm, the internal motor M is reversed. It can be driven to rotate in two directions.

At this time, the motor sensing control unit 200 detects the current at both ends of the shunt resistor 30, receives the feedback driving voltage of the motor driving circuit 100, and drives it together with the driving direction of the internal motor M (the direction of the motor current). By detecting the accurate feedback driving voltage according to the speed and the phase current detection value according to the voltage difference between both ends of the shunt resistor 30, it is possible to derive a more accurate detection result by supplementing the detection disadvantage at the ground terminal.

FIG. 3 is a flowchart illustrating a method of detecting a galvanic current of the current detection device shown in FIG. 1. 4 is an input/output waveform diagram for driving a motor of the current detection device shown in FIG. 1.

As described above, in the motor driving circuit 100, the internal motor M is driven to rotate in the forward direction according to the switching driving of the first upper switching element AH and the first lower switching element AL, and the second lower switching Since the internal motor M is driven to rotate in the second direction, which is the reverse direction, according to the switching drive of the element AL and the first upper switching element BH, the motor driving circuit 100 through the motor sensing control unit 200 Feedback control may be performed by receiving the feedback driving voltage of (S10).

At this time, as shown in FIGS. 3 and 4, the motor sensing control unit 200 sets the duty ratio of the feedback driving voltage, which is the final output according to the control of the internal motor M, to a preset reference ratio (for example, 50%) or more or less than or not detected and determined (S20).

And if the duty ratio of the feedback driving voltage is more than a preset reference ratio (for example, 50%), the phase current of each shunt resistor 30 at the peak point (PO) of the output waveform counter in the peak period (POS) The value is detected (S30).

On the other hand, when detecting the phase current detection value of the shunt resistor (R), if the duty ratio of the feedback driving voltage is less than a preset reference ratio (e.g. 50%), the output within the Valley section (POS) The phase current of each shunt resistor 30 is detected at the belly point VO, which is the minimum value of the waveform counter (S40).

5 is a diagram illustrating a motor model equation applied in the direction determination process of FIG. 3.

Referring to FIG. 5, the absolute value of the phase current value detected in S30 or S40 is then extracted (S50). For example, the motor sensing controller 200 extracts an absolute value of at least one of a feedback driving voltage and a phase current detection value of the shunt resistor 30, which is a final output according to the control of the internal motor M.

Subsequently, the absolute value of the phase current is applied to the motor model equation to determine the rotation and driving direction of the internal motor M (S60).

As described above, the current detection apparatus and method of a DC brushed motor using a shunt resistor according to the present invention stabilizes the detection of the ground terminal current of a DC brushed motor driving circuit using a shunt resistor and determines the direction of the motor current. It is possible to increase the detection accuracy according to the

In particular, an effect of improving the responsiveness and accuracy of a feedback current detection control method that is driven by feeding back a motor current such as a DC brushed motor can be expected.

Those skilled in the art to which the present invention pertains, since the present invention may be implemented in other specific forms without changing the technical spirit or essential features thereof, the embodiments described above are illustrative in all respects and should be understood as non-limiting. Only do it. The scope of the present invention is indicated by the claims to be described later rather than the detailed description, and all changes or modified forms derived from the meaning and scope of the claims and their equivalent concepts should be interpreted as being included in the scope of the present invention. .

100: motor driving circuit 200: motor sensing control unit

Claims (10)

A motor driving circuit electrically connected to an input terminal of a pulse width control signal and an inverting input terminal of a pulse width control signal, respectively, to control and drive an internal motor driving direction and a driving speed according to the pulse width control signal and the inverted pulse width control signal;
A shunt resistance connected in series to the ground output terminal of the motor driving circuit; And
A motor sensing controller configured to detect currents at both ends of the shunt resistor and control the driving direction and speed of the internal motor according to a feedback driving voltage of the motor driving circuit and a current detection value of the shunt resistor; and
The motor driving circuit,
Consisting of having two switching elements constituting the upper arm, four reflux diodes, and two switching elements constituting the lower arm,
Two switching elements constituting the upper arm are connected to a positive DC bus, and two switching elements constituting the lower arm are connected to a ground DC bus, and the pulse width control signal and the inverted pulse width control signal A current detection device for a DC brushed motor using a shunt resistor configured to convert each into an AC signal and supply it to the internal motor. delete The method of claim 1, wherein the two switching elements constituting the upper arm and the two switching elements constituting the lower arm,
It is configured to be switched and driven in a complementary bipolar switching method, and a semiconductor made mainly of SiC MOSFET (SiC: Silicon Carbide), or gallium nitride (GaN), or diamond mode (C) using a bandgap semiconductor. DC brushed motor current detection device using a shunt resistor, characterized in that the switching element formed of. The method of claim 1, wherein the shunt resistance is
A shunt resistor that is disposed between the ground DC bus and a node through which current from the internal motor flows, so that when a current from the internal motor flows, a voltage difference occurs at both ends and a phase current can be generated by the voltage difference at both ends. DC brushed motor current detection device using The method of claim 1, wherein the motor sensing control unit,
When detecting the phase current detection value according to the voltage difference across the shunt resistor, if the duty ratio of the feedback driving voltage, which is the final output according to the internal motor control, is more than a preset reference ratio, each phase current value is detected at the peak point of the output waveform counter. ,
When the duty ratio of the feedback driving voltage is less than the reference ratio, each phase current is detected at the belly point, which is the minimum value of the output waveform counter,
A current detection device for a DC brushed motor using a shunt resistor that minimizes the timing of detecting the phase current value during the period when the ringing phenomenon occurs The method of claim 1, wherein the motor driving circuit,
Consisting of having two switching elements constituting the upper arm, four reflux diodes, and two switching elements constituting the lower arm, the two switching elements constituting the upper arm are connected to the positive DC bus, The two switching elements constituting the lower arm are connected to a ground DC bus,
In accordance with the switching driving of the first upper switching element constituting the upper arm and the first lower switching element constituting the lower arm, the internal motor is driven to rotate in a first direction, which is a positive direction,
The internal motor rotates in a second direction, which is a reverse direction, according to switching driving of the second lower switching element constituting the lower arm and the first upper switching element constituting the upper arm,
The motor sensing control unit receives the feedback driving voltage of the motor driving circuit and detects the feedback driving voltage according to the driving speed along with the driving direction (direction of the motor current) of the internal motor. Detection device. A step of driving by controlling the driving direction and driving speed of the internal motor according to the pulse width control signal and the inverted pulse width control signal with a configuration of a motor driving circuit electrically connected to the pulse width control signal input terminal and the inverting input terminal of the pulse width control signal. ;
Detecting a current at both ends of a shunt resistance connected in series to a ground output terminal of the motor driving circuit; And
Controlling the driving direction and speed of the internal motor according to a feedback driving voltage output from the motor driving circuit and a current detection value of the shunt resistor with a motor sensing control unit configuration; and
In the step of driving by adjusting the driving direction and the driving speed of the internal motor,
In the motor drive circuit structure comprising two switching elements constituting the upper arm, four reflux diodes, and two switching elements constituting the lower arm, the two switching elements constituting the upper arm are positive DC bus To connect with,
The two switching elements constituting the lower arm are connected to a ground DC bus, converting each of the pulse width control signal and the inverted pulse width control signal into an AC signal, and supplying it to the internal motor. DC brushed motor current detection method using delete The method of claim 7,
In the step of controlling the driving direction and speed of the internal motor,
When detecting the phase current detection value according to the voltage difference across the shunt resistor, if the duty ratio of the feedback driving voltage, which is the final output according to the internal motor control, is more than a preset reference ratio, each phase current value is detected at the peak point of the output waveform counter. ,
When the duty ratio of the feedback driving voltage is less than the reference ratio, each phase current is detected at the belly point, which is the minimum value of the output waveform counter,
Current detection method of a DC brushed motor using a shunt resistor that minimizes the timing of detecting a phase current value during a period when a ringing phenomenon occurs The method of claim 7,
In the step of controlling the driving direction and speed of the internal motor,
Causing the internal motor to rotate in a first direction, which is a positive direction, according to switching driving of a first upper switching element constituting the upper arm and a first lower switching element constituting the lower arm;
Causing the internal motor to rotate in a second direction, which is a reverse direction, according to switching driving of the second lower switching element constituting the lower arm and the first upper switching element constituting the upper arm; And
Current detection of a DC brushed motor using a shunt resistor comprising the step of receiving a feedback driving voltage of the motor driving circuit and detecting a feedback driving voltage according to a driving speed together with a driving direction (direction of motor current) of the internal motor Way.

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