KR20180117382A - Apparatus and method for cirrent sensing of dc brushed motor using shunt resistance - Google Patents

Abstract

The present invention relates to a current detection apparatus of a DC brushed motor using shunt resistance and a method thereof. According to embodiments of the present invention, the current detection apparatus of a DC brushed motor using shunt resistance comprises: a motor driving circuit electrically connected to a pulse width control signal input terminal and a reverse input terminal of a pulse width control signal to adjust a driving direction and a driving speed of an internal motor to drive the internal motor in accordance with the pulse width control signal and a reversed pulse width control signal; shunt resistance connected to a ground output terminal of the motor driving circuit in series; and a motor sensing control unit to detect a current on both ends of the shunt resistance, and control the driving direction and speed of the internal motor in accordance with a feedback driving voltage of the motor driving circuit and a current detection value of the shunt resistance. Ground terminal current detection of the motor driving circuit is stabilized and detection accuracy is increased by direction determination of the motor current to increase response and accuracy of a feedback current detection control method of driving by feeding back the motor current.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a DC brushless motor for detecting a current in a DC brushless motor using a shunt resistor,

The present invention relates to an apparatus and method for detecting a drive current of a motor. More particularly, the present invention relates to an apparatus and method for detecting a drive current of a motor by stabilizing the ground-side current detection of a motor drive circuit using a shunt resistor, And more particularly, to an apparatus and method for detecting the current of a DC brush motor using a shunt resistor capable of improving the response and accuracy of a feedback current detection control system that feeds back the motor current.

Normally, in order to control and drive the DC brush motor or the like by feeding back the current, a driving current or a feedback current must be detected. Particularly, in the case of a feedback current detection control system that feeds back the motor current, more accurate and stable detection circuits and devices are required.

Hall current type current sensors and shunt resistor type current sensors are conventionally known as current sensors for measuring motor current. Since the method using the Hall type current sensor is a method of sensing the magnetic field generated by the current, when the external magnetic field is disturbed, the detection accuracy is lower than the method using the shunt resistance, And the cost of the construction was also increased.

On the other hand, in the method using the shunt resistor, if the switching frequency is high, there may be a signal error such as a ringing phenomenon of the switching signal.

Specifically, there is a method of using a shunt resistor, a method of placing a shunt resistor at a load end of a motor signal in accordance with a configuration position of a shunt resistor, and a method of detecting a shunt resistor at a ground terminal of a motor drive circuit. Since the method of positioning the motor is a method of directly measuring the motor current, the detection accuracy is lower than that of the method of positioning the motor at the ground level. On the other hand, in the method of detecting by detecting at the ground terminal the absolute value of the motor current is measured by measuring the DC link terminal rather than the current value of the actual motor, sufficient time is required until the switching signal is stabilized, There was a problem.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and it is an object of the present invention to provide a DC brushless motor driving circuit which stabilizes ground-side current detection of a DC brushed motor driving circuit using a shunt resistor, And an object of the present invention is to provide an apparatus and method for detecting the current of a DC brushed motor using a shunt resistor capable of improving the response and accuracy of a feedback current detection control system.

Other features and advantages of the invention will be set forth in the description which follows, or may be obvious to those skilled in the art from the description and the claims.

According to an aspect of the present invention, there is provided a DC brushless motor current detection apparatus using a shunt resistor, the apparatus comprising: a pulse width control signal input terminal; and a pulse width control signal input terminal, A shunt resistor connected in series to the ground output terminal of the motor driving circuit, and a shunt resistor connected in parallel to the ground output terminal of the motor driving circuit, And a motor sensing control unit for controlling the internal motor driving direction and speed according to the feedback drive voltage of the motor drive circuit and the current detection value of the shunt resistor.

According to another aspect of the present invention, there is provided a method of detecting a current in a brushless DC motor using a shunt resistor, the method comprising: providing a motor driving circuit, which is electrically connected to a pulse width control signal input terminal and an inverting input terminal of a pulse width control signal, Controlling the internal motor driving direction and the driving speed in accordance with the pulse width control signal and the inverted pulse width control signal, driving the shunt resistor connected in series to the ground output terminal of the motor driving circuit, And controlling the driving direction and the speed of the internal motor according to the current detection value of the shunt resistor and the feedback driving voltage output from the motor driving circuit in the configuration of the motor sensing control unit.

According to an embodiment of the present invention, there is provided an apparatus and method for detecting a current in a DC brush motor using a shunt resistor, which stabilizes the ground-side current detection of a DC brushed motor driving circuit using a shunt resistor, It is possible to enhance the detection accuracy according to the determination of the direction of the current.

Particularly, there is an effect that the response and accuracy of the feedback current detection control system that drives the DC brush motor by feedback of the motor current can be improved.

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

FIG. 1 is a circuit diagram showing a current detecting device of a DC brush motor using a shunt resistor according to an embodiment of the present invention.
2 is a diagram showing driving waveforms according to the current direction and the motor rotation direction of the motor driving circuit shown in FIG.
3 is a flowchart for explaining a method of detecting a current of the current detecting device shown in FIG.
4 is an input / output waveform diagram for driving a motor of the current detecting device shown in FIG.
FIG. 5 is a diagram illustrating a motor model expression applied in the direction determination process of FIG.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings, which will be readily apparent to those skilled in the art to which the present invention pertains. The present invention may be embodied in many different forms and is not limited to the embodiments described herein.

In order to clearly illustrate the present invention, parts not related to the description are omitted, and the same or similar components are denoted by the same reference numerals throughout the specification.

Throughout the specification, when a part is referred to as being "connected" to another part, it includes not only "directly connected" but also "electrically connected" with another part in between . Also, when an element is referred to as "comprising ", it means that it can include other elements as well, without departing from the other elements unless specifically stated otherwise.

If any part is referred to as being "on" another part, it may be directly on the other part or may be accompanied by another part therebetween. In contrast, when a section is referred to as being "directly above" another section, no other section is involved.

The terms first, second and third, etc. are used to describe various portions, components, regions, layers and / or sections, but are not limited thereto. These terms are only used to distinguish any moiety, element, region, layer or section from another moiety, moiety, region, layer or section. Thus, a first portion, component, region, layer or section described below may be referred to as a second portion, component, region, layer or section without departing from the scope of the present invention.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms as used herein include plural forms as long as the phrases do not expressly express the opposite meaning thereto. Means that a particular feature, region, integer, step, operation, element and / or component is specified and that the presence or absence of other features, regions, integers, steps, operations, elements, and / It does not exclude addition.

Terms indicating relative space such as "below "," above ", and the like may be used to more easily describe the relationship to other portions of a portion shown in the figures. These terms are intended to include other meanings or acts of the apparatus in use, as well as intended meanings in the drawings. For example, when inverting a device in the figures, certain portions that are described as being "below" other portions are described as being "above " other portions. Thus, an exemplary term "below" includes both up and down directions. The device can be rotated by 90 degrees or rotated at different angles, and terms indicating relative space are interpreted accordingly.

Unless otherwise defined, 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 this invention belongs. Commonly used predefined terms are further interpreted as having a meaning consistent with the relevant technical literature and the present disclosure, and are not to be construed as ideal or very formal meanings unless defined otherwise.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

FIG. 1 is a circuit diagram showing a current detecting device of a DC brush motor using a shunt resistor according to an embodiment of the present invention.

1 includes a pulse width control signal PWM input 10, an inverted PWMn input 20 of a pulse width control signal, a pulse width control signal PWM, A motor driving circuit 100 for driving the internal motor M in accordance with the pulse width control signal PWMn, a shunt resistor 30 connected to the ground output terminal of the motor driving circuit 100, And a motor sensing control unit 200 for detecting the both ends of the motor 30 and controlling the motor driving direction and speed according to the feedback drive voltage of the motor drive circuit 100 and the current detection value of the shunt resistor R .

The motor driving circuit 100 is connected to the pulse width control signal PWM input terminal 10 and the inverted PWMn input terminal 20 of the pulse width control signal and outputs the pulse width control signal PWM and the inverted pulse width And receives the control signal PWMn. The motor driving circuit 100 controls the driving direction and the 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 and AL, respectively, and outputs the pulse width control signal PWM and the inverted pulse width control signal PWMn And supplies 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 is configured to include two switching elements AH and BH constituting the upper arm and four switching elements D1, D2, D3 and D4, And devices (BL, AL).

The two switching elements AH and BH constituting the upper arm of the motor driving circuit 100 are connected to the positive direct current bus and the two switching elements BL and AL constituting the lower arm are connected to the ground direct current bus do.

Here, the two switching elements AH and BH constituting the upper arm and the two switching elements BL and AL constituting the lower arm are switching elements using a wide band gap semiconductor, and SiC MOSFETs (SiC: Silicon Carbide, A silicon carbide), a gallium nitride (GaN), or a diamond semiconductor (C) as a main material.

More specifically, in the present invention, the two switching elements AH and BH constituting the upper arm and the two switching elements BL and AL constituting the lower arm are controlled and driven by the complementary bipolar switching method Can be proposed.

The shunt resistor 30 is disposed between a ground direct current bus and a node to which a current from the motor M flows. When a current flows from the motor M, a voltage difference occurs across the shunt resistor 30, So that a phase current can be generated by the voltage difference.

The motor sensing control unit 200 detects a current at both ends of the shunt resistor 30 and controls the motor driving direction and speed according to the feedback drive voltage of the motor drive circuit 100 and the current detection value of the shunt resistor 30. [ And a sensing control unit (200).

Specifically, the motor sensing control unit 200 is configured to detect a current at both ends of the shunt resistor 30 and output a current value signal indicative of a detected value of a phase current corresponding to a voltage difference between the both ends. The current value signal at this time can be used for the purpose of protecting the motor driving circuit 100 from an overcurrent or controlling the motor sensing control unit 200. [

In particular, the motor sensing control unit 200 detects the phase current detection value according to the correct feedback drive voltage according to the driving speed and the voltage difference across the shunt resistor 30, together with the driving direction of the internal motor M Thus, a more accurate detection result can be obtained by supplementing the detection disadvantage at the ground level.

In particular, the motor sensing control unit 200 of the present invention controls the duty ratio Duty of the feedback drive voltage, which is the final output according to the control of the internal motor M, when the phase current detection value corresponding to the voltage difference across the shunt resistor 30 is detected. (For example, 50%) or more, the phase current value is detected at the peak point of the output waveform counter.

When the phase current detection value is detected, if the duty ratio of the feedback driving voltage is less than a preset reference ratio (for example, 50%), phase currents are detected at the minimum value of the output waveform counter at a Velley point .

Accordingly, the motor sensing control unit 200 according to the present invention minimizes the timing of detecting the phase current value during the period when the ringing phenomenon occurs, determines the current direction by the motor voltage method, So that the value can be calculated. Here, the duty ratio may be a ratio of a time at which the current flows to a time at which no current flows.

2 is a diagram showing driving waveforms according to the current direction and the motor rotation direction of the motor driving circuit shown in FIG.

2 (a), in the motor driving circuit 100, two switching elements AH and BH constituting the upper arm and two switching elements BL and AL constituting the lower arm are connected by a complementary bipolar switching method The internal motor M is driven in the first direction (forward direction) in accordance with the switching operation of the first upper switching element AH constituting the upper arm and the first lower switching element AL constituting the lower arm, As shown in Fig.

Referring to FIG. 2B, the switching operation of the second lower switching element AL constituting the lower arm and the first upper switching element BH constituting the upper arm causes the internal motor M to operate in the reverse direction And can be rotationally driven in two directions.

At this time, the motor sensing control unit 200 detects both ends of the shunt resistor 30 and receives the feedback drive voltage of the motor drive circuit 100 to drive the internal motor M together with the drive direction of the internal motor M It is possible to obtain a more accurate detection result by complementing the detection disadvantage at the ground level by detecting the accurate feedback drive voltage according to the speed and the phase current detection value according to the voltage difference across the shunt resistor 30. [

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

As described above, in the motor driving circuit 100, the internal motor M is rotationally driven in the forward direction in accordance with the switching drive of the first upper side switching device AH and the first lower side switching device AL, Since the internal motor M is rotationally driven in the reverse direction by the switching operation of the element AL and the first upper switching element BH, the motor driving circuit 100 is driven through the motor sensing control unit 200, The feedback control voltage may be input to perform the feedback control (S10).

3 and 4, when the duty ratio of the feedback drive voltage, which is the final output according to the control of the internal motor M, is lower than a preset reference ratio (for example, 50%) or less, and judges whether it is less than 50% (S20).

If the duty ratio of the feedback drive voltage is equal to or greater than a predetermined reference ratio (for example, 50%), the phase current PO of the shunt resistor 30 at the peak point PO of the output waveform counter in the peak period (POS) (S30).

On the other hand, when the phase current detection value of the shunt resistor R is detected, if the duty ratio of the feedback driving voltage is less than a preset reference ratio (for example, 50%), the output in the Velley section And the phase current of the shunt resistor 30 is detected at the vale point VO which is the minimum value of the waveform counter (S40).

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

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

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, according to the apparatus and method for detecting the DC brush motor using the shunt resistor according to the present invention, it is possible to stabilize the ground-side current detection of the DC brushed motor driving circuit using the shunt resistor, It is possible to enhance the detection accuracy according to the present invention.

Particularly, it is expected that the response and accuracy of the feedback current detection control system that drives the DC brush motor by feedback of the motor current can be improved.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims and their equivalents. Only. It is intended that the present invention covers the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents. .

100: motor driving circuit 200: motor sensing control part

Claims (10)

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 to adjust the driving direction and the driving speed of the internal motor according to the pulse width control signal and the inverted pulse width control signal;
A shunt resistor connected in series to a ground output terminal of the motor driving circuit; And
And a motor sensing control unit for detecting a current at both ends of the shunt resistor and controlling the internal motor driving direction and speed according to a feedback drive voltage of the motor drive circuit and a current detection value of the shunt resistor, Current detector of the motor. The motor drive circuit according to claim 1,
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 line, 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 And supplies the AC signal to the internal motor, wherein the shunt resistor is configured to supply the AC signal to the internal motor. 3. The switching regulator according to claim 2, wherein the two switching elements constituting the upper arm and the two switching elements constituting the lower arm comprise:
(SiC), gallium nitride (GaN), or diamond mode (C) based bandgap semiconductors, which can be switched and driven by a complementary bipolar switching method. Wherein the switching element is a switching element formed by a shunt resistor. The shunt resistor according to claim 2,
A shunt resistor which is disposed between the ground direct current bus and a node to which a current flows from the internal motor and generates a voltage difference between both ends when a current flows from the internal motor, A DC brushless motor current detection device using a DC brushless motor. The motor control device according to claim 2,
When the duty ratio of the feedback drive voltage, which is the final output according to the internal motor control, is equal to or greater than a predetermined reference ratio when detecting the phase current detection value according to the voltage difference across the shunt resistor, the 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, detecting phase currents at the minimum value of the output waveform counter,
A current detection device of a DC brushed motor using a shunt resistor that minimizes a timing for detecting a phase current value during a period in which a ringing phenomenon occurs. The motor drive circuit according to claim 2,
Two switching elements constituting the upper arm, four reflux diodes, and two switching elements constituting the lower arm, wherein 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 the ground direct current bus,
The internal motor is driven to rotate in the first direction in the forward direction in accordance with the switching operation 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 second direction opposite to the first direction by the switching operation 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 a feedback driving voltage of the motor driving circuit and detects a feedback driving voltage corresponding to the driving speed together with the driving direction of the internal motor Detection device. Driving the internal motor driving direction and driving speed according to the pulse width control signal and the inverted pulse width control signal in a motor driving circuit configuration electrically connected to the pulse width control signal input terminal and the inverting input terminal of the pulse width control signal, respectively ;
Detecting a current at both ends of a shunt resistor connected in series to a ground output terminal of the motor driving circuit; And
And controlling the driving direction and the speed of the internal motor according to a feedback drive voltage output from the motor drive circuit and a current detection value of the shunt resistor in the configuration of the motor sensing control unit. Current detection method. 8. The method of claim 7,
In the step of driving by adjusting the internal motor driving direction and the driving speed,
The two switching elements constituting the upper arm in the motor driving circuit structure constituted by the two switching elements constituting the upper arm, the four reflux diodes and the two switching elements constituting the lower arm are connected to the positive polarity direct current bus Lt; / RTI >
And the two switching elements constituting the lower arm are connected to the ground direct current bus so that each of the pulse width control signal and the inverted pulse width control signal is converted into an AC signal and supplied to the internal motor, A method of detecting a current in a DC brushed motor using the method. 9. The method of claim 8,
Controlling the driving direction and speed of the internal motor,
When the duty ratio of the feedback drive voltage, which is the final output according to the internal motor control, is equal to or greater than a predetermined reference ratio when detecting the phase current detection value according to the voltage difference across the shunt resistor, the 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, detecting phase currents at the minimum value of the output waveform counter,
A method of detecting a current in a DC brushed motor using a shunt resistor that minimizes a timing for detecting a phase current value during a period in which a ringing phenomenon occurs. 9. The method of claim 8,
Controlling the driving direction and speed of the internal motor,
Causing the internal motor to be rotationally driven in a forward direction in accordance with a switching drive of a first upper switching element constituting the upper arm and a first lower switching element constituting a lower arm;
Causing the internal motor to be rotationally driven in a second direction opposite to that of the second lower switching element constituting the lower arm and the first upper switching element constituting the upper arm; And
And detecting a feedback driving voltage corresponding to a driving speed together with a driving direction of the internal motor (direction of the motor current) by receiving a feedback driving voltage of the motor driving circuit, and detecting a current of the DC brush motor using the shunt resistor Way.

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