Battery disconnect unit using active contactor

Abstract

The present invention relates to a battery disconnect unit using an active switch, the battery disconnect unit comprising: a main switch that supplies, to an inverter, power from a battery to drive a motor; and a precharge line connected in parallel with the main switch to precharge a DC-link capacitor, wherein the precharge line includes a precharge switch, which is a power semiconductor device, and an inductor that are connected in series with each other such that the DC-link capacitor can be precharged via periodic on-off operations of the precharge switch.

Description

Battery disconnect device using active contactor

[0001] The present invention relates to a battery disconnect device using an active contactor, and more particularly, to a battery disconnect device that can be implemented on a single substrate.

[0002] In general, in the fields of eco-friendly (electric, hydrogen, hybrid) vehicles and e-mobility, the technology to safely supply or cut off power from the battery to the motor is very important in terms of providing safety and stability.

[0003] Typically, the BDU (Battery Disconnect Unit) is placed between the battery and the motor inverter, and is composed of a contactor, a resistor for pre-charging, etc.

[0004] Figure 5 is a block diagram of a conventional BDU implementation.

[0005] Referring to FIG. 5, a conventional BDU is configured to include a main contactor (500) connected to the high voltage side of a battery (100) to supply or cut off the high voltage of the battery (100) to an inverter (200), a precharge resistor (600) and a precharge contactor (700) connected in parallel with the main contactor (500) and connected in series with each other to charge a DC-Link capacitor (300), and a low voltage side contactor (800) connected between the low voltage side of the battery (100) and the inverter (200).

[0006] In order to drive the motor (400) using the power of the battery (100) in this configuration, first, the low-voltage side contactor (800) is controlled to be closed, and the precharge contactor (700) is controlled to be closed while the main contactor (500) is open.

[0007] Therefore, the current of the high voltage side (HVDC(+)) is supplied to the DC link capacitor (300) through the precharge resistor (600) and the precharge contactor (700) to charge it.

[0008] In this precharge mode, a precharge resistor (600), which is a cement resistor, is used to limit the inrush current to ensure stable charging of the DC link capacitor (300) and subsequent motor operation.

[0009] The precharge resistor (600) is large in size, and a separate wire harness must be used to connect the precharge resistor (600), which is a cement resistor, so the overall size of the device increases.

[0010] Additionally, heat is generated in the precharge resistor (600), and a cooling system is introduced to resolve this.

[0011] When the precharge mode is completed, the precharge contactor (700) is opened and the main contactor (500) is closed so that the current of the battery (100) is supplied to the inverter (200) through the main contactor (500), and the inverter (200) is controlled to drive the motor (400) with AC current.

[0012] In order to perform the precharge mode in this way, a precharge resistor (600) was used in the past, which had the problem of increasing the size of the BDU and generating heat.

[0013] In addition, although a main contactor (500), which is a mechanical relay, is used, there were problems such as the short lifespan of the mechanical relay, the generation of operating noise, and the relatively heavy weight.

[0014] In addition, when using a precharge contactor (700), which is a mechanical relay, and a precharge resistor (600), which is a cement resistor, there was a problem that the resistor could be damaged or the mechanical relay could be damaged by fusion when an overcurrent occurred, and even when a separate sensor was added to prevent overcurrent, there was a problem that the time until the current value detected at both contact points of the precharge resistor (600) was transmitted to the upper controller and the precharge contactor (700) was controlled according to the judgment of the upper controller was delayed, which could cause damage due to overcurrent.

[0015] The problem that the present invention seeks to solve in consideration of the problems of the prior art as described above is to provide a BDU capable of precharging a DC link capacitor without using a precharge resistor.

[0016] In addition, the present invention provides a BDU that can be configured on a single printed circuit board by not using a mechanical contactor.

[0017] In addition, the present invention provides a BDU capable of protecting a circuit from the counter electromotive force of a motor without using an additional protection circuit.

[0018] In addition, the present invention provides a BDU that can simplify connection with a battery management system (BMS), which is an upper controller, and improve connectivity.

[0019] The battery disconnect device using the active switch of the present invention comprises a main switch that supplies power from a battery to an inverter to drive a motor, and a precharge line that is connected in parallel with the main switch to precharge a DC link capacitor, wherein the precharge line includes a precharge switch and an inductor that are power semiconductor elements that are connected in series with each other, so that the DC link capacitor can be precharged by periodic on / off of the precharge switch.

[0020] In an embodiment of the present invention, the precharge line may include a shunt resistor and a diode that are connected in series between the contact points of the precharge switch and the inductor and the low voltage side of the DC link capacitor.

[0021] In an embodiment of the present invention, the main switch is a power semiconductor device and can be mounted on the same printed circuit board as the precharge line.

[0022] In an embodiment of the present invention, the main switch or the precharge switch may include a plurality of power semiconductor elements connected in series with each other, and a parasitic diode of at least one power semiconductor element may be arranged in the reverse direction with respect to the inverter so as to block the counter electromotive force of the motor.

[0023] In an embodiment of the present invention, the gate voltage of the plurality of power semiconductor elements can be controlled so that some of them operate as resistors.

[0024] In an embodiment of the present invention, the main switch is a mechanical relay, the main switch is accommodated inside a housing, a printed circuit board on which the precharge line and the gate driver are mounted is mounted on an inner side of the housing, and the main switch can be electrically connected to the gate driver.

[0025] In an embodiment of the present invention, the printed circuit board may be divided into a low voltage region, a high voltage region, and an insulating region between the high voltage region and the high voltage region, an isolator may be arranged in the insulating region, and the high voltage region may include a precharge controller that detects the current value of the shunt resistor and controls the precharge switch according to a signal of an upper controller connected to the low voltage region side through the isolator.

[0026] In an embodiment of the present invention, the high voltage region may further include a microcontroller that communicates with the precharge controller to receive the current value of the shunt resistor and transmits it to the upper controller through the isolator together with a voltage or temperature detection value.

[0027] The present invention changes the precharge structure of a DC link capacitor using power from a battery into a configuration using a power semiconductor element and an inductor, thereby reducing the size of the circuit compared to the conventional method using a precharge resistor, and has the effect of ensuring reliability and stability by reducing heat generation.

[0028] In addition, the present invention has the effect of improving reliability and preventing noise generation compared to the case of using a conventional mechanical switch by using a power semiconductor element as a main switch.

[0029] In addition, the present invention provides a structure that can be mounted on a single printed circuit board, thereby reducing costs and facilitating maintenance and repair.

[0030] The present invention has the effect of providing a more stable and reliable circuit by detecting current and establishing overcurrent countermeasures without using a separate sensor.

[0031] In addition, the present invention has the effect of preventing damage to the circuit from the counter electromotive force of the motor without configuring an additional protection circuit.

[0032] The present invention has the effect of preventing damage caused by overcurrent by enabling faster control of the operation of a precharge switch according to detection of overcurrent.

[0033] FIG. 1 is a block diagram of a battery disconnect device using an active switch according to a preferred embodiment of the present invention.

[0034] Figure 2 is a configuration diagram illustrating a precharge switch according to a preferred embodiment of the present invention.

[0035] FIG. 3 is a block diagram of a battery cut-off device using an active switch according to another embodiment of the present invention.

[0036] Figure 4 is an example of application of the present invention.

[0037] Figure 5 is a block diagram of a conventional BDU.

[0038] - Explanation of symbols -

[0039] 10:Battery 20:Inverter

[0040] 30:DC link capacitor 40:motor

[0041] 50: Main switch 60: Shunt resistor

[0042] 70: Precharge line 71: Precharge switch

[0043] 81: Precharge controller 82: Microcontroller

[0044] 83: Gate driver 90: Housing

[0045] 91: Insert home

[0046] To fully understand the structure and effects of the present invention, preferred embodiments of the present invention will be described with reference to the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but can be implemented in various forms and can be modified in various ways. However, the description of the present embodiments is provided to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the present invention of the scope of the invention. In the accompanying drawings, components are illustrated in an enlarged size for convenience of explanation, and the proportions of each component may be exaggerated or reduced.

[0047] Terms such as "first" and "second" may be used to describe various components, but the components should not be limited by these terms. These terms may only be used to distinguish one component from another. For example, without departing from the scope of the present invention, a "first component" may be referred to as a "second component," and similarly, a "second component" may also be referred to as a "first component." Furthermore, singular expressions include plural expressions unless the context clearly dictates otherwise. Terms used in the embodiments of the present invention may be interpreted as having meanings commonly known to those of ordinary skill in the art, unless otherwise defined.

[0048] Hereinafter, a battery cut-off device using an active switch according to an embodiment of the present invention will be described in detail with reference to the drawings.

[0049]

[0050] FIG. 1 is a block diagram of a battery disconnect device using an active switch according to a preferred embodiment of the present invention.

[0051] Referring to FIG. 1, the present invention is configured to include a main switch (50) connecting a high voltage side (HVDC(+)) of a battery (10) and one side (INV(+)) of an inverter (20), a precharge line (70) including a first diode (D1), a precharge switch (71) and an inductor (L) connected in parallel with the main switch (50), and a shunt resistor (60) and a second diode (D2) connecting a contact point of the precharge switch (71) and the inductor (L) and the other side (INV(-)) of the inverter (20).

[0052] The structure described above is mounted on a single printed circuit board (PCB), and the printed circuit board (PCB) has connection terminals arranged on one side to which the high voltage side connection terminal of the battery (10), the inverter (20), and both ends of the DC link capacitor (30) are respectively connected.

[0053] In the above inverter (20), a DC link capacitor (30) and a motor (40) are connected in parallel.

[0054] Hereinafter, the configuration and operation of the battery cut-off device using the active switch of the present invention configured as described above will be described in more detail.

[0055] First, in the present invention, both the main switch (50) and the precharge switch (71) can use power semiconductor elements rather than mechanical relays. Power semiconductor elements, for example, SiC MOSFETs (Metal Oxide Semiconductor Field Effect Transistors) or IGBTs (Insulated Gate Bipolar Transistors), can be used.

[0056] In a preferred embodiment of the present invention, it is preferable that the power semiconductor device uses a SiC MOSFET.

[0057] As another example of the present invention, the main switch (50) may use a mechanical relay, and an example in which the main switch (50) is a mechanical relay will be described in more detail later.

[0058] By changing the configuration of the main switch (50) and the precharge switch (71) to power semiconductor elements, the present invention can be implemented on a single printed circuit board (PCB).

[0059] At this time, in the past, a precharge resistor, which is a cement resistor, was used to control power for charging the DC link capacitor in the precharge mode, but in the present invention, the precharge resistor is not used, so that the present invention can be mounted on a single printed circuit board.

[0060] Specifically, the present invention controls the main switch (50) to be in an open state in the precharge mode, and the precharge switch (71) to be repeatedly closed and open according to a set frequency.

[0061] At this time, the second diode (D2) enables the inertial current generated in the inductor (L) to be supplied to the DC link capacitor (30). The second diode (D2) may use a Schottky diode, etc.

[0062] When the above precharge switch (71) is closed, current flows, which is charged in the inductor (L), and when the precharge switch (71) is switched to the open state, the energy supply is stopped, and the energy charged in the inductor (L) is supplied to the DC link capacitor (30), thereby performing the precharge operation.

[0063] That is, the present invention enables a precharge operation to be performed by supplying a lower current to the DC link capacitor (30) without using a precharge resistor as in the prior art.

[0064] Additionally, the precharge current can be limited by setting the gate voltage of the precharge switch (71) to be equal to the threshold voltage or to be 10 to 20% larger than the threshold voltage.

[0065] After performing the precharge operation in this manner, the precharge switch (71) is switched to an open state, the main switch (50) is switched to a closed state, power from the battery (10) is supplied to the inverter (20), and the inverter (20) is controlled to supply current to the motor (40).

[0066] The present invention can mount both the precharge line (70) and the main switch (50) on a single printed circuit board, thereby reducing the size and manufacturing cost, and ensuring ease of maintenance and repair.

[0067] The present invention includes a shunt resistor (60) between the contact point of the precharge switch (71) and the inductor (L) and the second diode (D2), and current detection using the shunt resistor (60) is possible.

[0068] Accordingly, the present invention enables detection of current and switching control using the detected current without adding a current sensor to each of the precharge switch (71) and the main switch (50).

[0069] The current value detected in the shunt resistor (60) is provided to a controller (not shown in the drawing), and the controller can be applied to control the main switch (50) or the precharge switch (71).

[0070] That is, when overcurrent is detected, the main switch (50) or precharge switch (71) can be opened depending on the operating mode to prevent damage to the circuit caused by overcurrent.

[0071] Figure 2 is an exemplary configuration diagram of a precharge switch (71) according to a preferred embodiment of the present invention.

[0072] The precharge switch (71) can use at least two SiC MOSFETs connected in series, and in particular, can be configured so that the drain / source directions are connected in opposite directions.

[0073] This can block the current generated by the counter electromotive force of the motor (40) by using the parasitic diode component of the SiC MOSFET.

[0074] In addition, various controls can be performed using multiple precharge switches (71). For example, the current supplied to the DC link capacitor (30) can be more precisely controlled by differentiating the gate voltage of the precharge switch (71).

[0075] Additionally, one precharge switch (71) can be used to reduce current like a resistor, and another precharge switch can be turned on and off to perform precharge mode.

[0076] In this way, the present invention can be applied in various ways by applying a plurality of precharge switches (71), and has the feature of being able to easily change and provide a control method that meets the field of application or customer needs.

[0077] In Fig. 2, an example in which a plurality of precharge switches (71) are configured on a precharge line (70) is illustrated and described, but a plurality of main switches (50) can also be provided to provide various control methods, and damage to the circuit caused by the counter electromotive force of the motor (40) can be prevented.

[0078] Figure 3 is a block diagram of a BDU according to another embodiment of the present invention.

[0079] Referring to FIG. 3, the present invention may include a precharge controller (81) that controls the on / off of the precharge switch (71), a microcontroller (82) that checks various status information and communicates with an upper controller through a communication line, and a gate driver (83) that drives the main switch (50).

[0080] Here, the upper controller may be a battery management system (BMS).

[0081] As previously explained, the present invention is mounted on a single PCB, and the microcontroller (82) and precharge controller (81) can also be mounted together on the same PCB.

[0082] The precharge controller (81) includes a gate driver (81a) that drives a precharge switch (71) as shown in the drawing, and may include a current detection unit (82b) that detects the current of the shunt resistor (60).

[0083] The above gate driver (81a) can control the operating state of the precharge switch (71) according to the precharge enable signal of the upper controller, and when overcurrent is detected in the current detection unit (82b), the gate driver (81a) controls the precharge switch (71) to an open state, thereby protecting the circuit from overcurrent.

[0084] In addition, the precharge controller (81) and the microcontroller (82) are capable of communicating with each other through I2C communication, and the current value of the shunt resistor (60) detected by the precharge controller (81) is transmitted to the microcontroller (82), and the microcontroller (82) can transmit the detected values ​​including the received current value to the upper controller.

[0085] The upper controller can check the detection values ​​and control the main switch (50) and precharge switch (71).

[0086] In this configuration, the printed circuit board (PCB) on which the present invention is mounted has a low voltage region (LV) for communication connection with the upper controller, and a high voltage region (HV) for the part on which the present invention is mounted.

[0087] An isolation area (IA) is located between the low voltage area (LV) and the high voltage area (LV).

[0088] That is, by dividing a single PCB into a low voltage area (LV), an insulation area (IA), and a high voltage area (HV), various circuit damages caused by voltage in the high voltage area can be prevented.

[0089] Detection values ​​can be transmitted between the above microcontroller (82) and the upper controller through a single communication line. The detection value at this time includes the current value of the shunt resistor (60) described above, and detection values ​​detected by various sensors (sensors for temperature and voltage detection) can be collected by the microcontroller (82) and transmitted to the upper controller through a single communication line.

[0090] At this time, communication can use SPI (Serial Peripheral Interface), but various known serial communications can be used.

[0091] In this way, the present invention provides detection values ​​from the high-voltage side BDU to the upper controller through communication, thereby greatly simplifying the line compared to the conventional method of providing the detection results of each sensor to the upper controller.

[0092] In addition, enable signals, supply voltages, etc. between the low voltage side (LV) and the high voltage side (HV) are provided in an isolated manner. An isolator (symbol omitted) using an optical signal can be used as the isolation method.

[0093] Figure 4 is an example of application of the present invention.

[0094] Referring to FIG. 4, the present invention may be a mechanical relay with a main switch (50).

[0095] With the main switch (50) fixed to the housing (90), the inner side of the housing (90) includes an insertion groove (91) into which a printed circuit board (PCB) on which the present invention is mounted can be inserted and fixed.

[0096] In this way, the present invention can insert and fix a printed circuit board including a precharge line (70) including the precharge switch (71) described above, a precharge controller (81), a microcontroller (82), and a gate driver (83) into the inner side of a housing (90) through an insertion groove (91), and can operate a main switch (50) according to a gate drive enable signal from an external upper controller.

[0097] In this configuration, the printed circuit board (PCB) is exposed from the inner side of the housing (90) to the upper side, which has the advantage of being easy to maintain and repair.

[0098] Conversely, this means that the main switch (50), which is a mechanical relay with a relatively short lifespan, is easy to maintain and repair.

[0099] The main switch (50), which is a mechanical relay, is driven by the gate driver (83), and can be easily maintained by replacing the main switch (50) and electrically connecting it to the gate driver (83).

[0100] While the embodiments of the present invention have been described above, they are merely exemplary, and those skilled in the art will understand that various modifications and equivalent embodiments are possible. Therefore, the true scope of technical protection of the present invention should be defined by the following claims.

[0101]

[0102] The present invention relates to a design technology for mounting a BDU on a single PCB using the laws of nature, and has industrial applicability.

Claims

1. A main switch that supplies power from the battery to the inverter to drive the motor; and Including a precharge line that is connected in parallel with the above main switch to precharge the DC link capacitor, The above precharge line includes a precharge switch and an inductor, which are power semiconductor devices connected in series with each other. A battery disconnect device characterized in that the DC link capacitor is precharged by periodic on / off of the precharge switch.

2. In paragraph 1, In the above precharge line, A battery disconnect device including a diode disposed between the contacts of the precharge switch and the inductor and the connection terminal of the DC link capacitor.

3. In paragraph 2, A battery disconnect device further comprising a shunt resistor disposed between the contacts of the precharge switch and the inductor and the diode.

4. In paragraph 2, The above main switch, It is a power semiconductor device, A battery disconnect device characterized in that it is mounted on the same printed circuit board as the above precharge line.

5. In paragraph 4, The above main switch or the above precharge switch, Multiple power semiconductor devices are connected in series with each other, A battery disconnect device characterized in that at least one parasitic diode of a power semiconductor element is arranged in the reverse direction with respect to the inverter to block the counter electromotive force of the motor.

6. In paragraph 5, A plurality of the above power semiconductor devices, A battery disconnect device characterized in that the gate voltage is controlled so that some of the elements act as resistors.

7. In paragraph 2, The above main switch, It is a mechanical relay, A battery disconnect device characterized in that the main switch is housed within the housing, and the printed circuit board on which the precharge line and the gate driver are mounted is mounted on the inner side of the housing.

8. In any one of paragraphs 4 to 7, The above printed circuit board, It is divided into a low voltage region, a high voltage region, and an insulation region between the high voltage region and the high voltage region, An isolator is placed in the above insulation area, A battery disconnect device including a precharge controller that detects the current value of the shunt resistor in the high voltage region and controls the precharge switch according to a signal from an upper controller connected to the low voltage region side through the isolator.

9. In paragraph 8, In the above high voltage area, A battery disconnect device further comprising a microcontroller that communicates with the precharge controller to receive the current value of the shunt resistor and transmits it to the upper controller through the isolator together with a voltage or temperature detection value.

Images