KR102625824B1 - Circuit for preventing arm short - Google Patents

Abstract

The present invention relates to a circuit for preventing arm short circuit of an inverter that supplies current to a motor for driving a vehicle. The circuit for preventing arm short circuit according to various embodiments of the present invention includes a switching element; A gate drive IC that supplies a gate control signal to the gate of the switching element; and a protection circuit connected between an output terminal through which the gate control signal is output from the gate drive IC and one side of the switching element; The protection circuit may include an arm short protection circuit disposed between the output terminal and one side of the switching element, and a thermistor connected in parallel with the arm short protection circuit.

Description

Circuit for preventing arm short {CIRCUIT FOR PREVENTING ARM SHORT}

The present invention relates to a circuit for preventing arm short circuit of an inverter that supplies current to a motor for driving a vehicle.

In general, eco-friendly vehicles such as electric vehicles (EV) and hybrid electric vehicles (HEV) have a motor for driving the vehicle, and direct current voltage from a high-voltage power source (high-voltage main battery or fuel cell) is converted into alternating current voltage. Includes an inverter that converts to

The motor is driven using current provided from the inverter. The inverter includes a plurality of switching elements that are switched in response to a pulse width modulation (PWM) signal from a motor controller and a gate driving signal from a gate driver, and converts direct current voltage from a power source into alternating current voltage. As a switching device for an inverter, a field effect transistor (FET) device, for example, a metal oxide silicon field effect transistor (MOSFET), is widely used.

Conventional gate drivers include an arm short prevention circuit to prevent damage due to an arm short phenomenon. The arm short phenomenon is a phenomenon in which a pair of FETs configured in the inverter are turned on at the same time, causing excessive current to flow, which can cause damage to the motor and gate driver.

However, the prior art requires additional components in the gate driver to configure the arm short-circuit prevention circuit, making it difficult to simplify the product package, and has problems in that it does not reflect changes in the Rds(on) value of the FET due to temperature changes.

Republic of Korea Patent Publication No. 10-0943863 (2010. 02. 17)

The present invention is intended to solve the problems described above. It has a simple structure, makes it easy to simplify the product package, and provides a circuit to prevent arm shorts that can compensate for changes in the Rds(on) value of the FET due to temperature changes. This is a technical task.

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

A circuit for preventing arm short circuit according to an embodiment of the present invention for achieving the purpose described above includes a switching element, a gate drive IC that supplies a gate control signal to the gate of the switching element, and a gate driver IC that supplies a gate control signal to the gate of the switching element. It includes a protection circuit connected between an output terminal through which a control signal is output and one side of the switching element. The protection circuit may include an arm short protection circuit disposed between the output terminal and one side of the switching element, and a thermistor connected in parallel with the arm short protection circuit.

The arm short protection circuit may include at least one resistor connected in series between the output terminal and one side of the switching element, and a diode disposed between the at least one resistor and one side of the switching element.

The thermistor may be connected in parallel with the at least one resistor.

The thermistor may be physically disposed closer to the switching element than the at least one resistor and the diode of the arm short protection circuit.

The gate control signal may be configured as pulse width modulation (PWM).

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

The circuit for preventing arm short circuit according to an embodiment of the present invention has a simple structure, making it easy to simplify the product package, and can compensate for changes in the Rds(on) value of the FET due to temperature changes.

The effects that can be obtained from the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by those skilled in the art from the description below. will be.

1 is a block diagram of an inverter gate circuit according to an embodiment of the present invention.
Figure 2 is a diagram illustrating a graph showing the change value of Rds(on) according to the temperature of the MOSFET device.
FIG. 3 is an equivalent circuit diagram of an inverter gate circuit according to an embodiment of the present invention shown in FIG. 1.

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

In order to clearly explain the present invention, parts that are not relevant to the description are omitted, and identical or similar components are assigned the same reference numerals throughout the specification.

Throughout the specification, when a part is said to be "connected" to another part, this includes not only the case where it is "directly connected," but also the case where it is "electrically connected" with another element in between. . Additionally, when a part "includes" a certain component, this means that it may further include other components 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 the other part or it may be accompanied by another part in between. In contrast, when a part is said to be "directly above" another part, it does not entail any other parts in between.

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

The terminology used herein is only intended to refer to specific embodiments and is not intended to limit the invention. As used herein, singular forms include plural forms unless phrases clearly indicate the contrary. As used in the specification, the meaning of "comprising" refers to specifying a particular characteristic, area, integer, step, operation, element and/or ingredient, and the presence or presence of another characteristic, area, integer, step, operation, element and/or ingredient. This does not exclude addition.

Terms indicating relative space, such as “below” and “above,” can be used to more easily describe the relationship of one part shown in the drawing to another part. These terms are intended to include other meanings or operations of the device in use along with the meaning intended in the drawings. For example, if the device in the drawing is turned over, some parts described as being “below” other parts will be described as being “above” other parts. Accordingly, the exemplary term “down” includes both upward and downward directions. The device can be rotated 90° or at other angles, and terms indicating relative space are interpreted accordingly.

Although not defined differently, all terms including technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art in the technical field to which the present invention pertains. Terms defined in commonly used dictionaries are further interpreted as having meanings consistent with related technical literature and currently disclosed content, and are not interpreted in ideal or very formal meanings unless defined.

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

The present invention provides a circuit to prevent the arm short phenomenon of FET, a switching element used to control motor AC current in eco-friendly vehicles such as electric vehicles (EV) and hybrid electric vehicles (HEV). This is what I want to do.

1 is a block diagram of an inverter gate circuit according to an embodiment of the present invention.

Referring to FIG. 1, an inverter gate circuit according to an embodiment of the present invention may include a gate drive IC 200, a gate drive circuit 300, and a switching element 400. According to one embodiment, the inverter gate circuit is mounted on one gate driving board and can be mounted on an eco-friendly vehicle such as an electric vehicle (EV) or a hybrid electric vehicle (HEV).

The inverter gate circuit may be a device that converts the form of electrical energy that powers an electric vehicle or hybrid electric vehicle. The inverter gate circuit includes an arm short protection circuit that stops the operation of the switching element 400 when an arm short phenomenon occurs in the switching element 400, and a temperature protection circuit to compensate for changes in the characteristics of the switching element 400 due to temperature changes. May include a compensation circuit.

The gate drive IC 200 may include a first terminal (IN) and a second terminal (FAULT) connected to a microcomputer (not shown). The gate drive IC 200 receives a gate drive signal, for example, a PWM signal, from the microcomputer through the first terminal (IN). The gate drive IC 200 senses the voltage of the arm short protection circuit of the gate drive circuit 300 and the voltage of the switching element 400, and determines whether there is an arm short based on the sensed results. When it is determined that an arm short has occurred, the gate drive IC 200 outputs a fault signal through the second terminal (FAULT). The fault signal output through the second terminal (FAULT) is transmitted to an external microcomputer, and the microcomputer can block (stop) the supply of the gate driving signal (PWM signal) in response to the fault signal.

The gate drive IC 200 amplifies the gate driving signal input through the first terminal (IN) and outputs the amplified gate driving signal through the third terminal (OUT). The third terminal (OUT) is connected to the gate 401 of the switching element 400. The gate driving circuit 300 may include at least one resistor 307 between the third terminal (OUT) of the gate drive IC 200 and the gate 401 of the switching element 400.

In addition, the gate drive IC 200 may further include a fourth terminal (Vcc) into which a Vcc voltage, for example, 12V, is input, and a fifth terminal (COM) connected to a ground voltage.

The switching device 400 may be a field effect transistor (FET) device, for example, a metal oxide silicon field effect transistor (MOSFET). Two switching elements 400 may be connected in series up and down to form one arm. According to one embodiment, the switching element 400 may have a total of three arms connected in parallel to form a three-phase inverter circuit. This is to convert high-voltage direct current power into three-phase alternating current (AC) of U, V, and W in order to control a three-phase alternating current motor. The illustrated example represents only one switching element 400 among arbitrary arms configured in the inverter gate circuit according to an embodiment of the present invention.

The gate driving circuit 300 is an arm short protection circuit, and is connected in series to a plurality of series resistors 301 and 302 and a plurality of series resistors 301 and 302 connected to the third terminal (OUT) of the gate drive IC 200. It may include a connected diode 305. The cathode of the diode 305 may be connected to one side 410 of the switching element 400, for example, the source terminal of the switching element 400.

Figure 2 is a diagram illustrating a graph showing the change value of Rds(on) according to the temperature of the MOSFET device.

Referring to FIG. 2, it can be seen that the Rds(on) value of the MOSFET device widely used as the switching device 400 is not constant depending on the temperature. Accordingly, embodiments of the present invention include a temperature compensation circuit. That is, as shown in FIG. 1, the gate driving circuit 300 further includes a thermistor (TH) as a temperature compensation circuit.

The thermistor TH may be connected in parallel with any one of the plurality of series resistors 301 and 302 constituting the arm short protection circuit, for example, the resistor 301 directly connected to the diode 305. By being placed relatively close to the switching element 400, the thermistor (NTC) can compensate for temperature changes resulting from the operation of the switching element 400 as much as possible.

In particular, according to various embodiments of the present invention, the thermistor TH may be configured to be physically placed as close to the switching element 400 as possible to compensate for temperature changes in the switching element 400 as accurately as possible. For example, the thermistor TH may be placed physically closest to the switching element 400 among the components constituting the gate driving circuit 300. For example, the thermistor TH is physically closer to the switching element 400 than other components constituting the gate driving circuit 300 (e.g., a plurality of series resistors 301 and 302, and diode 305). can be placed.

Meanwhile, according to another embodiment of the present invention, the switching element 400 is composed of a modular MOSFET and may internally include a thermistor (TH). For example, the thermistor (TH) may be built into the switching element 400 composed of modular MOSFETs. In this case, the built-in thermistor (TH) included in the switching element 400 can directly compensate for the change in the on-resistance value due to the temperature change of the switching element 400.

Meanwhile, the other side 420 of the switching element 400, for example, the drain terminal of the switching element 400, may be connected to the sixth terminal (Vs) of the gate drive IC 200. The gate driving circuit 300 may include a capacitor 311 disposed between the drain terminal of the switching element 400 and the seventh terminal CS of the gate drive IC 200.

FIG. 3 is an equivalent circuit diagram of an inverter gate circuit according to an embodiment of the present invention shown in FIG. 1.

Referring to FIG. 3, in an embodiment of the present invention, even if the size of Vds changes at a constant current depending on temperature, the thermistor (TH) compensates for the temperature change, so that the voltage applied to Vcs is constant. Therefore, the present invention can set a constant current threshold, for example, 7 V, regardless of temperature changes, and detect arm short based on the set threshold. Therefore, the present invention can increase the reliability of the arm short prevention operation, and there are no additional components other than the addition of the thermistor (TH), which has the effect of facilitating simplification of the product package.

Those skilled in the art to which the present invention pertains should understand that the present invention can be implemented in other specific forms without changing its technical idea or essential features, and that the embodiments described above are illustrative in all respects and not restrictive. Just do it. The scope of the present invention is indicated by the claims 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 construed as being included in the scope of the present invention. .

In a hardware implementation, the processing units may include one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field-programmable gate arrays (FPGAs), processors, It may be implemented in a controller, microcontroller, microprocessor, other electronic unit designed to perform the functions described herein, or a combination thereof.

What has been described above includes examples of one or more embodiments. Of course, not all possible combinations of components or methods can be described for the purposes of describing the above-described embodiments, and those skilled in the art will recognize that many additional combinations and substitutions of the various embodiments are possible. Accordingly, the described embodiments are intended to include all alternatives, modifications and alterations that fall within the spirit and scope of the appended claims. Moreover, to the extent the term “comprises” is used in the description or claims, such term shall be similar to “consisting of” as the term “consisting of” is interpreted when used as a transitional word in the claims. It is included in this way.

Moreover, as used in this application, the terms "component", "module", "system", etc. refer to computer-related components such as, but not limited to, hardware, firmware, a combination of hardware and software, software, or software running on the computer. It contains entities. For example, but not limited to, a component may be a process running on a processor, a processor, an object, an executable thread of execution, a program, and/or a computer. As an example, both an application running on a computing device and the computing device may be components. One or more components may reside within a process and/or thread of execution, and a component may be centralized on one computer and/or distributed between two or more computers. Additionally, these components can execute from various computer-readable media storing various data structures. Components follow a signal with one or more data packets (e.g., data from a local system, another component of a distributed system, and/or a component that interacts via a network, such as the Internet, with other systems by signal). etc. can be communicated by local and/or remote processes.

200: Gate drive IC
300: Gate driving circuit
400: switching element

Claims (6)

switching element;
A gate drive IC that supplies a gate control signal to the gate of the switching element; and
a protection circuit connected between an output terminal through which the gate control signal is output from the gate drive IC and one side of the switching element;
The protection circuit includes a female short protection circuit disposed between the output terminal and one side of the switching element and a thermistor connected in parallel with the female short protection circuit,
The arm short protection circuit is
at least one resistor connected in series between the output terminal and one side of the switching element; and
A circuit for preventing arm short circuit including a diode disposed between the at least one resistor and one side of the switching element. delete According to claim 1,
The thermistor is
A circuit for preventing arm short circuit connected in parallel with the at least one resistor. According to claim 3,
The thermistor is
A circuit for preventing arm short circuits that is physically disposed closer to the switching element than the at least one resistor and the diode of the arm short protection circuit. According to claim 1,
The gate control signal is a circuit for preventing arm short circuit consisting of a PWM (pulse width modulation) signal. delete

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