KR102607987B1 - Pre-charge Relay Driver in Battery Disconnected Unit - Google Patents

Abstract

This disclosure relates to a precharge relay driver of a battery separation unit, and the technical problem to be solved is to reduce power loss of the precharge switch by reliably increasing the gate voltage above the threshold voltage at once when the precharge switch is turned on. The goal is to provide a precharge relay driver for a removable battery disconnect unit. To this end, the present disclosure provides a battery separation unit including a main relay connected between the battery and the inverter, a precharge switch connected in parallel to the main relay and connected between the battery and the inverter, and a capacitor connected in parallel to the inverter, The precharge relay driver that drives the switch includes a PWM integrated circuit that outputs a first pulse-width modulation (PWM) signal to drive the precharge switch; A pulse transformer connected to the PWM integrated circuit and converting the first PWM signal to output a second PWM signal; a rectifier connected to a pulse transformer to rectify the second PWM signal and output a gate signal; and a voltage limiter connected between the rectifier and the precharge switch to output a gate signal after the voltage rises to the threshold.

Description

Pre-charge Relay Driver in Battery Disconnected Unit}

This disclosure relates to a precharge relay driver of a battery disconnect unit.

Generally, an electric vehicle includes a main relay, a pre-charge relay, and a pre-charge resistor that are installed between the high-voltage battery and the inverter/motor to selectively supply power. Here, the precharge relay performs a precharge process immediately before applying high voltage power from the high voltage battery to the inverter, thereby preventing a high inrush current from occurring when the main relay is connected. This inrush current occurs in proportion to the voltage of the high-voltage battery and the capacitor capacity of the inverter input terminal, and can act as a major factor in shortening the lifespan of the inverter and capacitor. Therefore, conventionally, the capacitor of the inverter is charged through the precharge relay and the precharge resistor before connecting the main relay to limit the generation of inrush current due to the voltage difference.

For example, with regard to the precharge relay, according to Publication Patent No. 2018-0056175, “Power relay assembly for electric vehicles and driving method thereof,” the input voltage is chopping and used as a flyback/forward converter. A method of transmitting a control signal to a precharge drive is known.

However, this method has the problem of increasing the withstand voltage of the switching element and generating a lot of ringing noise due to the characteristics of many flyback/forward converters, affecting electro magnetic interference (EMI). Additionally, since there is no feedback control circuit for the output voltage, there is a problem in stabilizing the voltage of the driving signal section; Moreover, when selecting a switch drive integrated circuit, the frequency and duty ratio must be variable.

In addition, as an example, according to registered patent 10-1314114 "Power relay assembly driving device and method thereof" and registered patent 10-1776341 "main relay failure diagnosis method of eco-friendly vehicle", most of the systematic details about the battery separation unit itself It only discloses an over-driving method and does not disclose a specific driving circuit.

A photodiode integrated circuit is sometimes used for isolation to directly drive the IGBT switch, but this requires two integrated circuits to increase the gate driving voltage and a large turn-on loss due to the low driving current capacity of the photodiode integrated circuit. It is expensive and has poor long-term reliability.

The above-described information disclosed in the background technology of this invention is only for improving understanding of the background of the present invention, and therefore may include information that does not constitute prior art.

The problem to be solved according to the present disclosure is to provide a precharge relay driver for a battery separation unit that can eliminate power loss of the precharge switch by reliably increasing the gate voltage to above the threshold voltage at once when the precharge switch is turned on. is to provide.

The problem to be solved according to the present disclosure is to provide a precharge relay driver of a battery disconnect unit that has a constant output voltage for turning on the precharge switch even if the input voltage input to the PWM integrated circuit (i.e., driving driver) changes. .

The precharge relay driver of the exemplary battery separation unit according to the present disclosure includes a main relay connected between the battery and the inverter, a precharge switch connected in parallel to the main relay and connected between the battery and the inverter, and a capacitor connected in parallel to the inverter. In the battery separation unit, the precharge relay driver driving the precharge switch includes: a PWM integrated circuit that outputs a first pulse-width modulation (PWM) signal to drive the precharge switch; A pulse transformer connected to the PWM integrated circuit and converting the first PWM signal to output a second PWM signal; a rectifier connected to a pulse transformer to rectify the second PWM signal and output a gate signal; And it may include a voltage limiter that is connected between the rectifier and the precharge switch and outputs a gate signal after the voltage rises to the threshold.

The pulse transformer includes a primary winding and a secondary winding, and the ratio of the primary winding to the secondary winding may be 1:2 to 3:8.

The rectifier may include a half-wave voltage doubler rectifier circuit.

The voltage limiter includes a bipolar transistor with a collector-emitter connected between the rectifier and the gate of the precharge switch; A Zener diode connected between the base of the bipolar transistor and the source of the precharge switch; A resistor connected between the collector and base of a bipolar transistor; and a capacitor connected between the emitter of the bipolar transistor and the source of the precharge switch.

It may further include a voltage regulator connected to the PWM integrated circuit.

The voltage regulator includes a bipolar transistor with a collector and emitter connected to the input and output terminals of a PWM integrated circuit; A first voltage dividing resistor connected between the input terminal of the PWM integrated circuit and the base of the bipolar transistor; a first voltage dividing resistor and a second voltage dividing resistor connected to the base of the bipolar transistor; And it may include a Zener diode connected between the second voltage dividing resistor and the ground terminal.

Among the voltage regulators, the emitter of the bipolar transistor may be connected to the primary winding of the pulse transformer.

Among the voltage regulators, the emitter of the bipolar transistor may further include a freewheel diode connected to the primary winding of the pulse transformer.

The present disclosure can provide a precharge relay driver of a battery separation unit that can eliminate power loss of the precharge switch by reliably increasing the gate voltage above the threshold voltage at once when the precharge switch is turned on.

The present disclosure can provide a precharge relay driver of a battery disconnect unit whose output voltage for turning on the precharge switch is constant even if the input voltage input to the PWM integrated circuit (i.e., driving driver) changes.

1A and 1B are block diagrams showing the configuration and basic concept of an exemplary battery separation unit according to the present disclosure.
2A and 2B are block diagrams and main waveform diagrams showing the configuration of a precharge relay driver of an exemplary battery separation unit according to the present disclosure.
Figure 3 is a block diagram showing the configuration of a precharge relay driver of a battery separation unit according to an example of the present disclosure.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings.

The present disclosure is provided to more completely explain the present invention to those skilled in the art, and the following examples may be modified in various other forms, and the scope of the present invention is limited to the following examples. It is not limited. Rather, these embodiments are provided to make the disclosure more faithful and complete, and to fully convey the spirit of the invention to those skilled in the art.

Additionally, as used herein, the term “and/or” includes any one and all combinations of one or more of the corresponding listed items. In addition, the meaning of "connected" in this specification refers not only to the case where member A and member B are directly connected, but also to the case where member C is interposed between member A and member B to indirectly connect member A and member B. do.

The terms used herein are used to describe specific embodiments and are not intended to limit the invention. As used herein, the singular forms include the plural forms unless the context clearly indicates otherwise. Additionally, when used herein, “comprise, include,” and/or “comprising, including” refer to mentioned features, numbers, steps, operations, members, elements, and/or groups thereof. It specifies the presence and does not exclude the presence or addition of one or more other shapes, numbers, movements, members, elements and/or groups.

Although the terms first, second, etc. are used herein to describe various members, parts, regions, layers and/or parts, these members, parts, regions, layers and/or parts are limited by these terms. It is obvious that this cannot be done. These terms are used only to distinguish one member, component, region, layer or section from another region, layer or section. Accordingly, a first member, component, region, layer or portion described below may refer to a second member, component, region, layer or portion without departing from the teachings of the present invention.

Additionally, the PWM integrated circuit and/or other related devices or components according to the present disclosure may be implemented using any suitable hardware, firmware (e.g., custom semiconductor), software, or a suitable combination of software, firmware, and hardware. there is. For example, various components of a PWM integrated circuit and/or other related devices or components according to the present disclosure may be formed on one integrated circuit chip or on separate integrated circuit chips. Additionally, the various components of the PWM integrated circuit can be implemented on flexible printed circuit film, a tape carrier package, a printed circuit board, or formed on the same substrate as the PWM integrated circuit.

1A and 1B are block diagrams showing the configuration and basic concept of an exemplary battery separation unit 10 according to the present disclosure.

As shown in FIG. 1A, the exemplary battery disconnect unit 10 includes a pair of main relays 14 (positive side main relay ( 14) and a precharge switch 15 connected in parallel to the negative side main relay 14) and the main relay 14 (positive side main relay 14) and connected between the battery 11 and the inverter 12. And it may include a capacitor 16 connected in parallel to the inverter 12. In some examples, the battery separation unit 10 includes a current sensor 17 installed on the positive side high current line to sense the current, a precharge resistor 18 connected between the precharge switch 15 and the inverter 12, and It may further include a safety plug 19 (fuse) installed between the plurality of batteries 11.

In this way, the operating mode of the battery separation unit 10 may operate including a precharging mode, a discharging mode, and a charging mode. The precharging mode is a mode in which the capacitor 16 is initially charged through the precharge switch 15 to prevent damage to the inverter 12 due to high voltage inrush current when the relay is driven. The discharge mode is a mode in which the main relay 14 is driven to supply high power to the inverter 12. The charging mode is a mode in which the fast charging main relay 14 operates to rapidly charge with direct current voltage. In some examples, the precharge switch 15 serves to initially charge the capacitor 16 to prevent high voltage inrush current. Since this disclosure relates to the precharge relay driver 100 that drives the precharge switch 15, the operation of the main relay 14 is not described in detail.

In some examples, the precharge switch 15 receives a system input voltage (e.g., 12V, 400 ms), and the precharge relay driver 100 connects the precharge switch 15 (e.g., IGBT: Insulated-gate bipolar transistor).

Meanwhile, as shown in FIG. 1B, the driving voltage of the precharge switch 15 can receive an approximately 12V pulse signal (amplitude of approximately several hundred ms) as input. Then, the input signal is chopped at a high frequency of tens to hundreds of kHz by the precharge relay driver 100 to create a PWM (Pulse Width Modulation) signal, and then a galvanic isolation element (e.g., The signal may be converted by the transformer 120). At this time, the PWM signal can be amplified by the turns ratio (turn ratio) of the transformer 120. Subsequently, the high-frequency PWM signal can be restored again by the rectifier circuit and applied to the gate-source terminal of the precharge switch 15.

FIGS. 2A and 2B are block diagrams and main waveform diagrams showing the configuration of the precharge relay driver 100 of the exemplary battery disconnect unit 10 according to the present disclosure.

As shown in FIG. 2A, the precharge relay driver 100 of the exemplary battery disconnect unit 10 according to the present disclosure includes a PWM integrated circuit 110 connected between the power input terminal 111 and the precharge switch 15. ), a pulse transformer 120, a rectifier 130, and a voltage limiter 140.

The PWM integrated circuit 110 may receive power from the power input terminal 111 to drive the precharge switch 15 and output a first pulse-width modulation (PWM) signal through an internal circuit. In some examples, the PWM integrated circuit 110 includes a bias circuit 112 that is connected to the power input terminal 111 to generate a reference voltage (Vref), an oscillator 113, a reference voltage section 114, an oscillator 113, and It may include a PWM generator 115 connected to the reference voltage unit 114 to generate a PWM signal, a controller 116 connected to the PWM generator 115, and a current buffer 117 connected to the controller 116. In some examples, a deadtime control terminal 118a may be connected to the oscillator 113, a frequency control terminal 118b (device) may be connected to the oscillator 113, and a PWM generator 115 and a reference voltage section ( 114) may be connected to a duty ratio control terminal (element) 118c. In some examples, current buffer 117 may include a pair of bipolar transistors (Q1, Q2). In some examples, the current buffer 117 includes a first transistor (Q1) having a collector, an emitter, and a base, a second transistor (Q2) having a collector, an emitter, and a base, and the first and second transistors ( The bases of Q1 and Q2) may be connected to the controller 116, and the emitters and collectors of the first and second transistors (Q1 and Q2) may be connected to each other. In some examples, the collector terminal 117a of the first transistor Q1, the emitter terminal 117c of the second transistor Q2, and the emitter-collector terminal 117b of the first and second transistors Q1 and Q2. ) may be provided. In some examples, the PWM integrated circuit 110 may include KIA494, a bipolar linear integrated circuit (voltage-mode PWM controller IC) from KEC, Inc.

The pulse transformer 120 is connected to the PWM integrated circuit 110 and can convert the first PWM signal into a second PWM signal and output it. In some examples, pulse transformer 120 may include a primary winding (n1) and a secondary winding (n2), and the ratio of the primary winding (n1) to the secondary winding (n2) is approximately 1:2 to It may be approximately 3:8. In practice, the driving voltage (gate voltage) of the precharge switch 15 is determined by the turns ratio (turn ratio) of the PWM integrated circuit 110 and/or the voltage regulator 250 and the pulse transformer 120, so the turns ratio is changed. It can be. In some examples, the input terminal of the primary winding (n1) of the pulse transformer 120 may be connected to the emitter-collector terminal 117b of the PWM integrated circuit 110, and the primary winding (n1) of the pulse transformer 120 may be connected to the emitter-collector terminal 117b of the PWM integrated circuit 110. ) may be connected to the emitter terminal 117c of the PWM integrated circuit 110. In some examples, a resistor (R1) and a capacitor (C1) may be connected in series between the emitter-collector terminal (117b) and the input terminal (111) of the primary winding (n1) to remove the direct current component and transmit only the alternating current component. there is.

In some examples, a first diode D1 is connected between the collector terminal 117a and the emitter-collector terminal 117b of the current buffer 117 (that is, the anode of the first diode D1 is connected to the emitter terminal). -connected to the collector terminal (117b), and the cathode of the first diode (D1) is connected to the collector terminal (117a), and between the emitter-collector terminal (117b) and the emitter terminal (117c) a second diode ( D2) may be connected (that is, the anode of the second diode D2 is connected to the emitter terminal 117c, and the cathode of the second diode D2 is connected to the emitter-collector terminal 117b). That is, the first and second diodes D1 and D2 may be freewheeling diodes that feed back energy from the primary winding n1 of the pulse transformer 120.

The rectifier 130 is connected to the pulse transformer 120 and can rectify the second PWM signal to output a gate signal. In some examples, rectifier 130 may include a half-wave voltage doubler rectifier circuit. In some examples, the rectifier 130 includes a capacitor C2 connected to the secondary winding n2 of the pulse transformer 120, a diode D3 connected to the capacitor C2, and a capacitor C2 and a diode D3. It may include a Zener diode (ZD1) connected between the node and the ground terminal, and a capacitor (C3) connected between the diode (D3) and the ground terminal. Here, the anode of diode D3 may be connected to capacitor C2 and the cathode of diode D3 may be connected to capacitor C3. Additionally, the anode of the Zener diode ZD1 may be connected to the ground terminal, that is, the emitter (or source) of the precharge switch 15. Here, the capacitor C3 and Zener diode ZD1 restore the direct current component from the PWM signal transmitted to the secondary winding n2.

The voltage limiter 140 is connected between the rectifier 130 and the precharge switch 15, so that the gate signal can be output after the voltage rises to the threshold. In some examples, voltage limiter 140 may include or be referred to as a voltage regulator. In some examples, the voltage limiter 140 includes a bipolar transistor (Q3) whose collector-emitter is connected between the rectifier 130 and the gate of the precharge switch 15, the base of the bipolar transistor (Q3), and the precharge switch ( 15), the zener diode (ZD2) connected between the source of the bipolar transistor (Q3), the resistor (R2) connected between the collector and base of the bipolar transistor (Q3), and the emitter of the bipolar transistor (Q3) and the source of the precharge switch (15). It may include a capacitor (C4) connected to. In some examples, the emitter of bipolar transistor Q3 may be connected to the cathode of diode D3 and the collector of bipolar transistor Q3 may be connected to the base of precharge switch 15. The base of the bipolar transistor Q3 may be connected to the cathode of the Zener diode ZD2, and the anode of the Zener diode ZD2 may be connected to the emitter of the precharge switch 15. A resistor (R2) may be connected between the emitter and base of the bipolar transistor (Q3). In addition, a resistor (R3) may be connected between the gate and emitter (source) of the precharge switch 15.

By using the voltage limiter 140, the gate voltage (Vgate) of the precharge switch 15 increases in the form of a single step rather than in the form of multiple steps, as shown in FIG. 2B, thereby reducing power loss. It can be prevented. The voltage limiter 140 does not output the gate signal until a certain voltage, that is, the voltage of the Zener diode (ZD2) rises. In other words, the voltage limiter 140 outputs a gate signal in the form of a step to the precharge switch 15 after the voltage of the Zener diode (ZD2) rises, so that the collector-emitter voltage (VCE) and collector current (IC) is also output in the form of a single step, so no power loss occurs.

FIG. 3 is a block diagram showing the configuration of the precharge relay driver 200 of the battery separation unit according to the present disclosure. The example precharge relay driver 200 shown in FIG. 3 may be similar except that it further includes a voltage regulator 250 compared to the example precharge relay driver 100 shown in FIG. 2A. .

As shown in FIG. 3 , the exemplary precharge relay driver 200 may further include a voltage regulator 250 coupled to the PWM integrated circuit 110 . In some examples, the voltage regulator 250 includes a bipolar transistor (Q3) whose collector and emitter are connected to the input terminal 111 and the output terminal of the PWM integrated circuit 110, and the input terminal 111 of the PWM integrated circuit 110 and the bipolar transistor Q3. A first dividing resistor (R4) connected between the base of the transistor (Q4), a second dividing resistor (R5) connected between the first dividing resistor (R4) and the base of the bipolar transistor (Q4), and a second dividing resistor (R5) ) and a zener diode (ZD3) connected between the ground terminal. In some examples, the anode of Zener diode ZD3 may be connected to the ground terminal, and the cathode of Zener diode ZD3 may be connected to the second voltage dividing resistor R5.

In some examples, the emitter of the bipolar transistor Q4 of the voltage regulator 250 may be connected to the primary winding n1 of the pulse transformer 120 through a diode D1. That is, the emitter of the bipolar transistor Q4 may be connected to the cathode of the diode D1, and the primary winding n1 of the transformer 120 may be connected to the anode of the diode D1.

In this way, in the precharge relay driver 200 according to the present disclosure, the output voltage for turning on the precharge switch 15 may be constant even if the input voltage input to the PWM integrated circuit 110 changes. For example, even if the input voltage input to the PWM integrated circuit 110 varies from approximately 7V to approximately 18V, the operating voltage for turning on the precharge switch 15 is constant.

What has been described above is only one embodiment for implementing the precharge relay driver of the exemplary battery separation unit according to the present disclosure, and the present invention is not limited to the above embodiment, but is as claimed in the following patent claims. Likewise, it will be said that the technical spirit of the present invention exists to the extent that anyone with ordinary knowledge in the field to which the present invention pertains can make various modifications without departing from the gist of the present invention.

10: Battery separation unit
11: battery 12; inverter
13: motor 14: main relay
15: precharge switch 16: capacitor
17: Current sensor 18: Precharge resistor
19: Safety plug 100; Precharge relay driver
110; PWM integrated circuit 111; Power input terminal
112; bias circuit 113; oscillator
114; Reference voltage unit 115; PWM generator
116; controller 117; current buffer
Q1, Q2; bipolar transistor
117a; collector terminal 117b; Emitter-collector terminal
117c; emitter terminal 118a; dead control terminal
118b; frequency control terminal 118c; Duty ratio control terminal
120; pulse transformer n1; Primary winding
n2; secondary winding 130; rectifier
140; voltage limiter 250; voltage regulator

Claims (8)

A battery separation unit including a main relay connected between the battery and the inverter, a precharge switch connected in parallel to the main relay and connected between the battery and the inverter, and a capacitor connected in parallel to the inverter, wherein the precharge switch drives the precharge switch. Charge relay driver
A PWM integrated circuit that outputs a first pulse-width modulation (PWM) signal to drive a precharge switch;
A pulse transformer connected to the PWM integrated circuit and converting the first PWM signal to output a second PWM signal;
a rectifier connected to a pulse transformer to rectify the second PWM signal and output a gate signal; and
It includes a voltage limiter connected between the rectifier and the precharge switch to output a gate signal after the voltage rises to the threshold,
The voltage limiter includes a bipolar transistor with a collector-emitter connected between the rectifier and the gate of the precharge switch;
A Zener diode connected between the base of the bipolar transistor and the source of the precharge switch;
A resistor connected between the collector and base of a bipolar transistor; and
A precharge relay driver in a battery disconnect unit comprising a capacitor connected between the emitter of the bipolar transistor and the source of the precharge switch. According to claim 1,
A precharge relay driver of a battery disconnect unit, wherein the pulse transformer includes a primary winding and a secondary winding, and the ratio of the primary winding to the secondary winding is 1:2 to 3:8. According to claim 1,
The rectifier is a precharge relay driver of the battery separation unit, including a half-wave voltage doubler rectifier circuit. delete According to claim 1,
A precharge relay driver in a battery disconnect unit, further comprising a voltage regulator coupled to the PWM integrated circuit. According to claim 5,
The voltage regulator is
A bipolar transistor with a collector and emitter connected to the input and output terminals of a PWM integrated circuit;
A first voltage dividing resistor connected between the input terminal of the PWM integrated circuit and the base of the bipolar transistor;
a first voltage dividing resistor and a second voltage dividing resistor connected to the base of the bipolar transistor; and
A precharge relay driver of a battery disconnect unit, comprising a Zener diode connected between a second voltage dividing resistor and a ground terminal. According to claim 6,
Among the voltage regulators, the emitter of the bipolar transistor is connected to the primary winding of the pulse transformer, and the precharge relay driver of the battery separation unit. According to claim 7,
A precharge relay driver of a battery separation unit, further comprising a freewheel diode connected to the emitter of a bipolar transistor in the voltage regulator and the primary winding of the pulse transformer.