Motor control device and method

Abstract

The present disclosure relates to a motor control device and method. The motor control device includes an inverter for driving a motor, a first shunt resistor connected to a first low-side switching element included in the inverter, a second shunt resistor connected to a second low-side switching element included in the inverter, a DC link shunt resistor connected in series to the inverter, and a controller for controlling the inverter based on a first current value measured through the first shunt resistor and the second shunt resistor and a second current value measured through the DC link shunt resistor.

Description

Technical Field

[0001] This disclosure relates to motor control apparatus and methods, and more specifically, to apparatus and methods for controlling a motor by measuring the current flowing through an inverter. Background Technology

[0002] Typically, in order to provide feedback on the current supplied or required to drive by a DC brush motor, etc., and then control and drive the feedback current, it is necessary to detect the drive current or feedback current. In particular, in the case of a feedback current detection and control method that feeds back the motor current and uses the feedback current for drive, it is desirable to use a more accurate and stable detection circuit or device.

[0003] Hall effect current sensors and shunt resistor current sensors are widely used as typical current sensors for measuring motor current. Among these sensors, Hall effect current sensors measure current by sensing the magnetism induced by the current. Therefore, when the sensor is subjected to external magnetic field interference, the measurement accuracy may decrease compared to shunt resistor current sensors, and the responsiveness may also degrade. Conversely, the cost of implementing this method using Hall effect current sensors inevitably increases. Summary of the Invention

[0004] To address these issues, embodiments of this disclosure provide an apparatus and method for controlling vehicle steering by controlling a removable dial.

[0005] According to one aspect of this disclosure, a motor control device is provided, comprising: an inverter for driving a motor; a first shunt resistor connected to a first low-side switching element included in the inverter; a second shunt resistor connected to a second low-side switching element included in the inverter; a DC link shunt resistor connected in series with the inverter; and a controller for controlling the inverter based on a first current value measured by the first shunt resistor and the second shunt resistor and a second current value measured by the DC link shunt resistor.

[0006] According to another aspect of this disclosure, a motor control method is provided, the method comprising the steps of: supplying power to an inverter for driving a motor; measuring a first current flowing through a first shunt resistor connected to a first low-side switching element included in the inverter and a second shunt resistor connected to a second low-side switching element included in the inverter; measuring a second current flowing through a DC link shunt resistor connected in series with the inverter; and controlling the inverter based on the measured values ​​of the first current and the second current.

[0007] According to embodiments of the present disclosure, a motor control device and method can be provided that can ensure a high duty cycle close to that of the in-line shunt resistor type by using a structure in which different conditions are applied to the associated analog-to-digital converter (ADC) when two types of shunt resistors are connected.

[0008] Furthermore, even if one type of shunt resistor fails, control can be maintained by measuring the corresponding current flowing through another type of shunt resistor. Attached Figure Description

[0009] The accompanying drawings, which are included to provide a further understanding of this disclosure and are incorporated in and constitute a part of this disclosure, illustrate various aspects of this disclosure and, together with the specification, serve to explain the principles of this disclosure. In the drawings:

[0010] Figure 1 It is a block diagram of a motor control device according to various aspects of this disclosure;

[0011] Figure 2 It is a circuit diagram used to illustrate the motor control device according to various aspects of this disclosure;

[0012] Figure 3 It is a diagram illustrating the measurement of a shunt resistor in a motor control device according to various aspects of this disclosure;

[0013] Figure 4 This is a diagram illustrating a circuit breaker included in a motor control device according to various aspects of this disclosure;

[0014] Figure 5 A motor control method according to various aspects of this disclosure is shown; and

[0015] Figure 6 It is used to explain in more detail Figure 5 The diagram shows step S530. Detailed Implementation

[0016] In the following description of examples or embodiments of this disclosure, reference will be made to the accompanying drawings, in which specific examples or embodiments that may be implemented are illustrated by way of illustration, and wherein the same reference numerals and symbols may be used to indicate the same or similar components even when the same reference numerals and symbols are shown in different drawings. Furthermore, in the following description of examples or embodiments of this disclosure, a detailed description of well-known functions and components incorporated herein will be omitted where it is determined that such detailed description may obscure the subject matter of some embodiments of this disclosure. Terms used herein, such as “comprising,” “having,” “containing,” “constituting,” “composed of,” and “formed from,” are generally intended to allow for the addition of other components unless the term is used in conjunction with the term “only.” As used herein, the singular form is intended to include the plural form unless the context clearly indicates otherwise.

[0017] This document may use terms such as “first,” “second,” “A,” “B,” “(A),” or “(B)” to describe the elements of this disclosure. Each of these terms is not used to define the nature, order, sequence, or number of elements, but merely to distinguish the corresponding element from the others.

[0018] When referring to the first element as "connected to or linked to," "in contact with," or "overlapping" with the second element, it should be interpreted as meaning that not only can the first element be "directly connected to or linked to" or "directly in contact with or overlapping" the second element, but a third element can also be "inserted" between the first and second elements, or the first and second elements can be "connected to or linked to," "in contact with," or "overlapping" with each other via a fourth element. Here, the second element can be included in at least one of two or more elements that are "connected to or linked to," "in contact with," or "overlapping" with each other.

[0019] When time-related terms such as “after,” “follow,” “next,” “before,” etc., are used to describe a process or operation of an element or configuration, or a flow or step in an operation, processing, or manufacturing method, these terms may be used to describe a discontinuous or non-sequential process or operation, unless the terms “direct” or “immediate” are used together.

[0020] Furthermore, when referring to any size, relative size, etc., the numerical value or corresponding information of the component or feature (e.g., level, range, etc.) should be considered, including tolerances or error ranges that may be caused by various factors (e.g., process factors, internal or external shocks, noise, etc.), even if no relevant description is specified. In addition, the term "may" fully encompasses all the meanings of the term "can".

[0021] In the following description, the motor control device 10 according to various aspects of the present disclosure will be described with reference to the accompanying drawings.

[0022] Figure 1This is a block diagram of the motor control device 10 according to various aspects of this disclosure.

[0023] Reference Figure 1 According to various aspects of this disclosure, the motor control device 10 may include an inverter 110, a first shunt resistor 120, a second shunt resistor 130, a DC link shunt resistor 140, a controller 150, etc.

[0024] Figure 2 This is a circuit diagram illustrating the motor control device 10 according to various aspects of this disclosure.

[0025] Reference Figure 2 Inverter 110 can drive motor 20.

[0026] In some embodiments, a three-phase motor can be used as motor 20. When a three-phase motor is used, inverter 110 may include a pair of switching elements corresponding to each phase. That is, inverter 110 may include six switching elements (111, 112, 113, 114, 115, and 116). In some embodiments, metal-oxide-semiconductor field-effect transistors (MOSFETs), insulated-gate bipolar transistors (IGBTs), etc., may be used as switching elements.

[0027] refer to Figure 2 The first shunt resistor 120 can be connected to the first low-side switching element 114 included in the inverter 110. In some embodiments, where a three-phase motor is used as motor 20, the inverter 110 may include a total of six switches, i.e., two switches for each phase. In this case, the first shunt resistor 120 can be connected in series to any one of the three phases.

[0028] refer to Figure 2 The second shunt resistor 130 can be connected to the second low-side switching element 115 included in the inverter 110. In some embodiments, when a three-phase motor is used as motor 20, the second shunt resistor 130 can be connected in series to any one of the remaining two phases other than the phase to which the first shunt resistor 120 is connected.

[0029] Furthermore, the motor control device 10 may also include a third shunt resistor 160 connected to the third low-side switching element 116. Accordingly, the first current may be a current value obtained from measuring the current flowing through the first shunt resistor 120, the second shunt resistor 130, and the third shunt resistor 160, and in this case, the first current value can be obtained by adding the current values ​​flowing through the first shunt resistor 120, the second shunt resistor 130, and the third shunt resistor 160.

[0030] Figure 3This is a diagram illustrating the measurement of a shunt resistor in a motor control device according to various aspects of this disclosure.

[0031] refer to Figure 3 The motor control device 10 can measure the current through each phase of the low-side shunt resistor. Specifically, operational (OP) amplifiers (210, 210-1, and 210-2) are connected across the first shunt resistor 120, the second shunt resistor 130, and the third shunt resistor 160, respectively, and analog-to-digital converters (ADCs) (220, 220-1, and 220-2) are connected to the circuit of the OP amplifiers (210, 210-1, and 210-2). The voltages appearing across the shunt resistors are amplified by the OP amplifiers (210, 210-1, and 210-2) and then converted into digital values ​​by the ADCs (220, 220-1, and 220-2). The currents flowing through the shunt resistors (120, 130, and 160) can be obtained by dividing the converted digital voltage values ​​by the respective resistance values ​​of the shunt resistors. Furthermore, this analog-to-digital conversion of the current flowing through the low-side shunt resistor can be performed in an inactive state.

[0032] It should be noted that this method for measuring the current flowing through a shunt resistor is merely one example of a possible method; therefore, embodiments of this disclosure are not limited to this specific method, as long as the current flowing through the shunt resistor can be measured. For example, methods for measuring the current flowing through a shunt resistor can utilize typical techniques.

[0033] When using two low-side shunt resistors, after measuring the current associated with the phase connected to the low-side shunt resistors, the current in any phase not connected to the low-side shunt resistors can be measured by using the principle that the sum of the currents flowing through the three phases is zero.

[0034] For example, if the third shunt resistor 160 is not connected to the line through which the current Iw flows, the currents (Iu and Iv) flowing through the lines to which the first shunt resistor 120 and the second shunt resistor 130 are respectively connected can be measured first. That is, the current Iu flowing through the first shunt resistor 120 and the current Iv flowing through the second shunt resistor 130 can be measured first. Then, the current Iw can be measured using the following Equation 1.

[0035] [Equation 1]

[0036] Iu+Iv+Iw=0

[0037] Return to reference Figure 2 The DC link shunt resistor 130 can be connected in series with the inverter 110.

[0038] Therefore, the motor control device 10 can measure the current through each phase of the DC link shunt resistor 140. In the same manner as measuring the current through the aforementioned low-side shunt resistor, with the OP amplifier 210-3 connected across the DC link shunt resistor 140 and the ADC 220-3 connected to the OP amplifier 210-3, the current flowing through the DC link shunt resistor 140 can be measured by: amplifying the voltage appearing across the DC link shunt resistor 140 using the OP amplifier 210-3; converting the amplified voltage to a digital voltage value using the ADC 220-3; and then dividing the converted digital voltage value by the resistance value of the DC link shunt resistor 140. Furthermore, this analog-to-digital conversion of the current flowing through the DC link shunt resistor 140 can be performed under effective operating conditions.

[0039] In addition, such as Figure 2 As shown, with the low-side shunt resistor and the DC link shunt resistor 140 connected together, and the two low-side shunt resistors connected in series, the current in the remaining phase can be calculated by replacing the zeros in Equation 1 with the second current value, which corresponds to the current value in each phase.

[0040] As described above, according to embodiments of this disclosure, since one or more low-side shunt resistors and DC link shunt resistors 140 have different corresponding conditions related to analog-to-digital conversion, a duty cycle utilization close to 99% of the duty cycle utilization in the in-line shunt resistor type can be ensured by using this configuration including low-side shunt resistors and DC link shunt resistors 140.

[0041] The controller 150 can control the inverter 110 based on a first current value obtained by adding the measured values ​​of the current flowing through the first shunt resistor 120, the second shunt resistor 130 and the third low-side switching element 116, and a second current value obtained by measuring the current flowing through the DC link shunt resistor.

[0042] The controller 150 can compare a first current value with a second current value, and can control the inverter 110 when the first current value matches the second current value. Since the first current value and the second current value are obtained only in the same circuit using different measurement methods, typically, the measured first current value and the measured second current value can be the same.

[0043] The controller 150 can compare a first current value with a second current value, and when the first current value matches the second current value, it can control the inverter 110. In this case, the controller 150 can compare the first current value and the second current value, or compare each of the first current value and the second current value for each phase separately.

[0044] When the controller 150 compares the first current with the second current, the controller 150 can determine whether each component or assembly is working properly, and in particular, monitor whether the shunt resistor connected to a specified location is working properly.

[0045] Specifically, when the first current and the second current are mismatched, the controller 150 can control the inverter 110 based on the duty cycle of the circuit including the inverter 110 using either the first current or the second current. Since the first shunt resistor 120 and the second shunt resistor 130 can form a low-side shunt resistor, this can guide the current in each phase of the motor 20 to be measured, thus allowing a predetermined duty cycle to exist. Furthermore, the DC link shunt resistor can also guide the current in each phase of the motor 20 to be measured, thus allowing a duty cycle different from that of the low-side shunt resistor. Therefore, the controller 150 can pre-store the predetermined duty cycle that exists when each shunt resistor operates individually and compare the stored duty cycle with the duty cycle in the current state.

[0046] For example, when the low-side shunt resistor and the DC link shunt resistor 140 are operating normally, the duty cycle of the circuit including these components can reach 100%. However, if at least one of these components fails, the resulting duty cycle can be less than 100% and represent a specific value. The controller 150 can compare each of the duty cycles of the low-side shunt resistor and the DC link shunt resistor with the specific value, determine that one or more of these shunt resistors matching the specific value are operating normally, and control the inverter 110 based on the current measured through the one or more shunt resistors determined to be operating normally.

[0047] When using three low-side shunt resistors, i.e., when the first to third shunt resistors are connected, even if any one of these shunt resistors malfunctions, the current of the corresponding faulty phase can be calculated using Equation 1 above. Therefore, in order to identify a circuit including such low-side shunt resistors as having a fault in the low-side shunt resistors, the malfunction of two or more low-side shunt resistors can be identified as a fault in the low-side shunt resistors.

[0048] One or more first currents can be obtained by measuring the current flowing through the first shunt resistor 120, the current flowing through the second shunt resistor 130, and the current flowing through the third shunt resistor 160.

[0049] The controller 150 can control the inverter 110 based on the measured current of each phase. In one embodiment, the controller 150 can receive steering command values ​​from a steering control system (not shown) for controlling the steering of the vehicle, and send a control signal for controlling the power of the motor 20 to the inverter 110 to execute the steering command. Here, the control signal can be a pulse width modulation (PWM) signal. Alternatively, the control signal can be transmitted to the inverter 110 via a gate driver that alternately outputs high-level and low-level signals at a predetermined frequency.

[0050] Figure 4 This is a diagram illustrating a circuit breaker such as a phase-out (PCO) switch included in a motor control device according to various aspects of this disclosure.

[0051] Reference Figure 4 The motor control device 10 may also include a circuit breaker such as a phase-out (PCO) switch, which is connected between the output terminal of the inverter 110 and the input terminal of the motor 20, and is capable of transmitting the drive current generated by the inverter 110 to the motor 20 or cutting off the transmission of the drive current by switching on or off.

[0052] Specifically, the PCO switch can operate in either the on or off state, and when the PCO switch is in the on state, it transmits drive current from the inverter 110 to the motor 20. Furthermore, when the PCO switch is in the off state, it can cut off the transmission of drive current from the inverter 110 to the motor 20.

[0053] When the controller 150 malfunctions, the PCO switch can cut off the drive current. Specifically, under normal operating conditions, the PCO switch can operate in the ON state and transmit drive current from the inverter 110 to the motor 20. Furthermore, when the controller 150 malfunctions, the PCO switch can operate in the OFF state and cut off the transmission of drive current from the inverter 110 to the motor 20. For example, when the inverter 110 is short-circuited and provides an overcurrent as drive current, the PCO switch can cut off the transmission of drive current to the motor 20.

[0054] A microcontroller unit (MCU) can be implemented as controller 150. The microcontroller unit (MCU) may include at least one or more of the following: one or more processors, memory, storage devices, user interfaces for input, and user interfaces for output, all communicating with each other via a bus. Furthermore, the microcontroller unit (MCU) may also include a network interface for accessing a network. The processor may be a CPU or a semiconductor element or device capable of executing processing instructions stored in memory and / or storage devices. Memory and storage devices may include various types of volatile / non-volatile storage media. For example, memory may include ROM and RAM.

[0055] The following describes a motor control method using a motor control device 10 capable of performing all the above-described embodiments and examples.

[0056] Figure 5 This is a flowchart illustrating a motor control method according to various aspects of this disclosure.

[0057] Reference Figure 5 The motor control method according to various aspects of this disclosure may include: a power supply step, in step S510, supplying power to an inverter 110 for driving a motor 20; a current measurement step, in step S520, measuring a first current flowing through a first shunt resistor 120 connected to a first low-side switching element 114 and a second shunt resistor 130 connected to a second low-side switching element 115 included in the inverter 110, and measuring a second current flowing through a DC link shunt resistor connected in series with the inverter 110; and an inverter control step, in step S530, controlling the inverter 110 based on the measured values ​​of the first current and the second current.

[0058] Figure 6 It is used to explain in more detail Figure 5 The diagram shows step S530.

[0059] Reference Figure 6 In step S610, the motor control device 10 can measure the first current. Specifically, the motor control device 10 can also measure the current flowing through the third shunt resistor 160 connected to the third low-side switching element 116 of the inverter 110.

[0060] In this case, the current measured by the third shunt resistor 160 can be included in the first current. That is, the first current value can be obtained by adding the current flowing through the first shunt resistor 120, the current flowing through the second shunt resistor 130, and the current flowing through the third shunt resistor 160.

[0061] In step S620, the motor control device 10 can measure the second current flowing through the DC link shunt resistor 140 connected in series with the inverter 110 and obtain the second current value.

[0062] In step S630, the motor control device 10 can determine whether the first current value and the second current value match each other.

[0063] When the first current value and the second current value match each other ("Yes" in step S630), in step S640, the motor control device 10 can control the inverter 110 based on the first current value or the second current.

[0064] When the first current value and the second current value do not match (No in step S630), in step S650, the motor control device 10 can determine whether one or more of the shunt resistors are malfunctioning based on the duty cycle. Here, the duty cycle can represent the conduction ratio of the circuit including the inverter 110, i.e., the power supply for supplying power to the inverter 110 and the circuit including the motor 20 driven by the inverter 110. Furthermore, the malfunction of one or more of the shunt resistors can be determined based on a predetermined duty cycle maintained by the low-side shunt resistor and a duty cycle of another value maintained by the DC link shunt resistor 140.

[0065] When all shunt resistors are functioning correctly, the corresponding duty cycle can be higher than the first two duty cycles. Therefore, at the highest duty cycle, all shunt resistors are functioning correctly, and the functioning of each shunt resistor can be determined by the predetermined duty cycle present when the low-side shunt resistors are functioning correctly and the duty cycle of another value present when the DC link shunt resistor 140 is functioning correctly.

[0066] According to the embodiments described herein, a motor control device and method can be provided that can ensure a high duty cycle close to that in the in-line shunt resistor type by using a structure in which different conditions are applied to the associated analog-to-digital converter (ADC) when two types of shunt resistors are connected.

[0067] Furthermore, even if one type of shunt resistor fails, control can be maintained by measuring the corresponding current flowing through another type of shunt resistor.

[0068] The above description is provided to enable those skilled in the art to implement and use the technical ideas of this disclosure, and is given in the context of a particular application and its requirements. Various modifications, additions, and substitutions to the described embodiments will be apparent to those skilled in the art, and the general principles defined herein can be applied to other embodiments and applications without departing from the spirit and scope of this disclosure. The above description and drawings provide examples of the technical ideas of this disclosure for illustrative purposes only. That is, the disclosed embodiments are intended to illustrate the scope of the technical ideas of this disclosure. Therefore, the scope of this disclosure is not limited to the embodiments shown, but is consistent with the widest scope conforming to the claims. The scope of protection of this disclosure should be interpreted based on the appended claims, and all technical ideas within the scope of their equivalents should be interpreted as being included within the scope of this disclosure.

[0069] Cross-references to related applications

[0070] This application claims priority to Korean Patent Application 10-2020-0150129, filed on November 11, 2020, with the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety.

Claims

1. A motor control device, the motor control device comprising: An inverter used to drive a motor; A first shunt resistor is connected to a first low-side switching element included in the inverter. A second shunt resistor is connected to a second low-side switching element included in the inverter; DC link shunt resistor, wherein the DC link shunt resistor is connected in series with the inverter; as well as A controller is configured to control the inverter based on a first current value measured through the first shunt resistor and the second shunt resistor and a second current value measured through the DC link shunt resistor, wherein the controller compares the first current value with the second current value and controls the inverter when the first current value and the second current value match each other.

2. The motor control device according to claim 1, wherein, When the first current value and the second current value do not match each other, the controller controls the inverter by either the first current or the second current based on the duty cycle of the circuit including the inverter.

3. The motor control device according to claim 1, further comprising a third shunt resistor connected to a third low-side switching element included in the inverter.

4. The motor control device according to claim 3, wherein, The first current value is obtained based on measurements taken from the first shunt resistor, the second shunt resistor, and the third shunt resistor.

5. The motor control device according to claim 1, further comprising a phase-disconnect switch connected between the output terminal of the inverter and the input terminal of the motor, and capable of transmitting the drive current generated by the inverter to the motor or cutting off the transmission of the drive current by switching on or off.

6. A motor control method, the motor control method comprising the following steps: The power supply step involves supplying power to the inverter used to drive the motor; The current measurement step involves measuring a first current flowing through a first shunt resistor connected to a first low-side switching element and a second shunt resistor connected to a second low-side switching element included in the inverter, and measuring a second current flowing through a DC link shunt resistor connected in series with the inverter. as well as The inverter control steps are based on a first current value measured by the first shunt resistor and the second shunt resistor and a second current value measured by the DC link shunt resistor to control the inverter, wherein the first current value is compared with the second current value, and the inverter is controlled when the first current value and the second current value match each other.

7. The motor control method according to claim 6, wherein, In the inverter control step, when the first current value and the second current value do not match each other, the inverter is controlled by either the first current or the second current based on the duty cycle of the circuit including the inverter.

8. The motor control method according to claim 6, wherein, The first current value includes a measurement of a third shunt resistor connected to a third low-side switching element included in the inverter.

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