Communication device and power supply monitoring device

Abstract

To provide a communication device and a power supply monitoring device capable of suppressing damage to a low-voltage drive circuit when a pulse transformer fails.SOLUTION: The communication equipment is provided with a high voltage communication equipment operated by a high voltage power supply and a low voltage communication equipment operated by a low voltage power supply, the high voltage communication equipment and the low voltage communication equipment make communication via a communication line on the way of which a pulse transformer is provided, and the low voltage communication equipment is provided with a protection resistor between the communication line and a ground potential.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a communication device and a power supply monitoring device. [Background technology]

[0002] The following Patent Document 1 discloses a safe and highly reliable battery system. This battery system includes a battery module in which a plurality of assembled batteries each having a plurality of battery cells are connected, a battery monitoring circuit provided for each assembled battery in the battery module and monitoring the state of each battery cell in the assembled battery, a microcomputer for controlling the operation of the battery monitoring circuit, a transmission signal transmission path for transmitting signals input and output between the battery monitoring circuit and the microcomputer, two pulse transformers (insulating elements) connected to the microcomputer, and a communication capacitor connected to the battery monitoring circuit, and the potential of the transmission signal transmission path is set to a floating potential relative to the potential of the microcomputer and the potential of the battery monitoring circuit. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-012080 Summary of the Invention [Problem to be solved by the invention]

[0004] The background art provides two pulse transformers (insulating elements) to electrically insulate a microcomputer, which is a low-voltage drive circuit, from a battery monitoring circuit, which is a high-voltage drive circuit. However, in the background art, if the pulse transformers fail, the microcomputer, which is a low-voltage drive circuit, may be damaged.

[0005] The present invention has been made in consideration of the above-mentioned circumstances, and aims to provide a communication device and a power supply monitoring device that can suppress damage to a low-voltage drive circuit when a pulse transformer fails. [Means for solving the problem]

[0006] In order to achieve the above object, the present invention adopts, as a first solution relating to a communication device, a communication device comprising a high-voltage communication device that operates on a high-voltage power supply and a low-voltage communication device that operates on a low-voltage power supply, wherein the high-voltage communication device and the low-voltage communication device communicate via a communication line with a pulse transformer installed in the middle, and the low-voltage communication device is provided with a protective resistor between the communication line and ground potential.

[0007] The present invention employs, as a second solution relating to a communication device, the first solution, in which a protective diode is provided between the communication line and the low-voltage power supply.

[0008] The present invention employs a third solution relating to a communication device, in the first or second solution, in which the high-voltage communication device is provided with a voltage detection circuit that detects the inter-electrode voltage of multiple battery cells that constitute the high-voltage power supply as a cell voltage, and transmits the cell voltage to the low-voltage communication device.

[0009] The present invention employs a fourth solution relating to a communication device, which is the third solution, in which the low-voltage communication device monitors the high-voltage power supply based on the cell voltage received from the high-voltage communication device.

[0010] The present invention employs a solution relating to the power supply monitoring device by providing the communication device relating to the fourth solution. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a communication device and a power supply monitoring device that can suppress damage to a low-voltage drive circuit when a pulse transformer fails. [Brief explanation of the drawings]

[0012] [Figure 1]1 is a circuit diagram showing the configuration of a power supply monitoring device A (communication device) according to one embodiment of the present invention. [Figure 2] 10 is a circuit diagram showing a modified example of a power supply monitoring device A (communication device) according to one embodiment of the present invention. FIG. [Figure 3] 1 is a circuit diagram showing a comparative example of a power supply monitoring device A (communication device) according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. 1, the power supply monitoring device A according to this embodiment includes a high-voltage power supply 1, a high-voltage communication device 2, a communication line 3, a low-voltage power supply 4, and a low-voltage communication device 5. This power supply monitoring device A is an in-vehicle device mounted on an automobile that runs using a motor (travel motor) as its power source.

[0014] As shown, the high-voltage communication device 2 includes a voltage detection circuit 2a and a high-voltage side pulse transformer 2b, while the low-voltage communication device 5 includes a low-voltage side pulse transformer 5a, a microcomputer 5b, a protective resistor 5c, and a protective diode 5d.

[0015] The high-voltage power supply 1 is a battery pack that supplies drive power to the traction motor, and outputs high-voltage DC power having a power supply voltage of, for example, several hundred volts. This high-voltage power supply 1 is made up of multiple battery cells (unit batteries) connected in series, and the sum of the inter-electrode voltages (cell voltages) of each battery cell is the output voltage (high-voltage power supply voltage). Such a high-voltage power supply 1 is, for example, a lithium-ion battery, a fuel cell, or an all-solid-state battery.

[0016] The high-voltage communication device 2 is a communication device that operates on the high-voltage power supply 1. That is, the high-voltage communication device 2 is a circuit that operates by receiving high-voltage DC power from the high-voltage power supply 1 and has a voltage detection function and a communication function. As described above, the high-voltage communication device 2 includes the voltage detection circuit 2a and the high-voltage side pulse transformer 2b.

[0017] The voltage detection circuit 2a is an integrated circuit that detects the cell voltages by operating on the high-voltage power supply 1. The voltage detection circuit 2a sequentially detects multiple cell voltages detected for each of the multiple battery cells in the high-voltage power supply 1 in chronological order, and transmits the multiple cell voltages to the low-voltage communication device 5 as time-series voltage detection data.

[0018] The high-voltage-side pulse transformer 2b is an insulating element provided on the high-voltage communication device 2 side in the communication line 3. In other words, the high-voltage-side pulse transformer 2b is an electronic element that electromagnetically and contactlessly connects the high-voltage communication device 2 and the low-voltage communication device 5, which operate on different power sources, so that they can communicate with each other.

[0019] Specifically, this high-voltage-side pulse transformer 2b is a four-terminal element in which a primary winding and a secondary winding are magnetically coupled. One end and the other end of the primary winding of the high-voltage-side pulse transformer 2b are connected to a pair of output terminals provided in the voltage detection circuit 2a via the communication line 3. Also, one end and the other end of the secondary winding of the high-voltage-side pulse transformer 2b are connected to one end and the other end of the primary winding of the low-voltage-side pulse transformer 5a provided in the low-voltage communication device 5 via the communication line 3.

[0020] The communication line 3 is an electric wire that connects the transmitting end of the high-voltage communication device 2 and the receiving end of the low-voltage communication device 5. A high-voltage side pulse transformer 2b is provided midway on the communication line 3 on the side of the high-voltage communication device 2, and a low-voltage side pulse transformer 5a is provided midway on the side of the low-voltage communication device 5. The communication line 3, together with the high-voltage side pulse transformer 2b and the low-voltage side pulse transformer 5a, constitutes a wired communication line.

[0021] The low-voltage power supply 4 is a battery that supplies driving power to the low-voltage communication device 5, and outputs low-voltage DC power having a power supply voltage of, for example, 12 volts. This low-voltage power supply 4 operates the low-voltage communication device 5 by outputting a relatively constant low-voltage DC power of 12 volts to the low-voltage communication device 5. Such a low-voltage power supply 4 is, for example, a lead-acid battery provided in the vehicle, and its negative electrode is connected to a ground potential (GND).

[0022] The low-voltage communication device 5 is a device that operates when low-voltage DC power is supplied from the low-voltage power supply 4. This low-voltage communication device 5 monitors the high-voltage power supply 1 based on the time-series voltage detection data received from the high-voltage communication device 2 via the above-mentioned wired communication line. For example, the low-voltage communication device 5 monitors the charge state of the high-voltage power supply 1 based on the time-series voltage detection data.

[0023] The low-voltage side pulse transformer 5a is an insulating element provided on the low-voltage communication device 5 side in the communication line 3. In other words, the low-voltage side pulse transformer 5a is an electronic element that electromagnetically and contactlessly connects the low-voltage communication device 5 and the high-voltage communication device 2, which operate on different power sources, so that they can communicate with each other.

[0024] The microcomputer 5b is the main functional part of the low-voltage communication device 5 and is an integrated circuit that monitors the high-voltage power supply 1 based on a pre-stored monitoring program. That is, the microcomputer 5b monitors the high-voltage power supply 1 by processing the time-series voltage detection data received from the high-voltage communication device 2 via the wired communication line based on the monitoring program, and outputs the monitoring results to the outside.

[0025] The protective resistor 5c is a two-terminal element having a predetermined resistance value. One end of the protective resistor 5c is connected to the communication line 3. More precisely, as shown in the figure, one end of the protective resistor 5c is connected to the primary winding side (high-voltage communication device 2 side) of the low-voltage side pulse transformer 5a in the communication line 3.

[0026] The other end of this protective resistor 5c is connected to the negative electrode (ground potential) of the low-voltage power supply 4. Such protective resistor 5c has the function of suppressing (preventing) damage caused by application of high voltage to the low-voltage communication device 5 in the event of insulation breakdown of the high-voltage-side pulse transformer 2b. In other words, since the other end of protective resistor 5c is connected to the negative electrode of the low-voltage power supply 4, it has the function of suppressing the voltage at one end to a constant voltage.

[0027] The protective diode 5d is a two-terminal element that limits the direction of current flow to one direction. The protective resistor 5c has a cathode terminal connected to the communication line 3 and an anode terminal connected to the positive electrode of the low-voltage power supply 4. The protective diode 5d is a well-known silicon diode. Like the protective resistor 5c described above, the protective diode 5d suppresses (prevents) damage to the low-voltage communication device 5 in the event of dielectric breakdown of the high-voltage-side pulse transformer 2b.

[0028] That is, since the anode terminal of the protective diode 5d is connected to the positive electrode of the low-voltage power supply 4, the voltage of the cathode terminal is maintained at a relatively low voltage obtained by adding its own forward voltage to the positive electrode of the low-voltage power supply 4. Therefore, the protective diode 5d suppresses (prevents) the voltage on the low-voltage communication device 5 side of the communication line 3 from becoming a high voltage.

[0029] Here, in the power supply monitoring device A of this embodiment, in order to suppress (prevent) the voltage on the low-voltage communication device 5 side of the communication line 3 from becoming a high voltage, a protective diode 5d is provided in addition to the protective resistor 5c.

[0030] However, either the protective resistor 5c or the protective diode 5d, for example, only the protective resistor 5c, may be provided. That is, in the power supply monitoring device A according to this embodiment, the low-voltage communication device 5 described above may be replaced with a low-voltage communication device 5A shown in the circuit diagram of FIG.

[0031] Next, the operation of the power supply monitoring device A according to this embodiment will be described with reference to the circuit diagram of FIG.

[0032] Here, Figure 3 shows a reference example of a power supply monitoring device A (communication device) according to this embodiment, and shows a communication device and power supply monitoring device equipped with a low-voltage communication device 5S in which the protective resistor 5c and protective diode 5d have been removed from the low-voltage communication device 5 described above.

[0033] In such a low-voltage communication device 5S, as shown in the figure, if breakdown occurs in the high-voltage-side pulse transformer 2b provided on the high-voltage communication device 2 side of the communication line 3, the absence of a protective resistor 5c and a protective diode 5d means that high-voltage time-series voltage detection data close to the high-voltage DC power supplied to the voltage detection circuit 2a by the high-voltage power supply 1 is applied to the primary winding of the low-voltage-side pulse transformer 5a. As a result, there is a risk that the low-voltage-side pulse transformer 5a and the microcomputer 5b will be damaged or destroyed by the high voltage.

[0034] In contrast, the low-voltage communication device 5 in this embodiment is provided with a protective resistor 5c and a protective diode 5d, which suppresses (prevents) high-voltage time-series voltage detection data from being applied to the primary winding of the low-voltage-side pulse transformer 5a. That is, the protective resistor 5c and the protective diode 5d suppress (prevent) the voltage applied to the primary winding of the low-voltage-side pulse transformer 5a from becoming a high voltage.

[0035] As described above, the communication device (power supply monitoring device A) of this embodiment is a communication device that includes a high-voltage communication device 2 that operates on a high-voltage power supply 1 and a low-voltage communication device 5 that operates on a low-voltage power supply 4, and the high-voltage communication device 2 and the low-voltage communication device 5 communicate via a communication line 3 that has a high-voltage side pulse transformer 2b and a low-voltage side pulse transformer 5a (pulse transformer) installed along the way, and the low-voltage communication device 5 has a protective resistor 5c installed between the communication line 3 and the negative electrode (ground potential) of the low-voltage power supply 4.

[0036] According to this embodiment, a protective resistor 5c is provided between the communication line 3 and the negative electrode (ground potential) of the low-voltage power supply 4 in the low-voltage communication device 5, so that a communication device power supply monitoring device A can be provided that can suppress damage to the low-voltage drive circuit 5 in the event of insulation breakdown (failure) of the high-voltage side pulse transformer 2b (pulse transformer).

[0037] Furthermore, in the communication device (power supply monitoring device A) according to this embodiment, a protective diode 5d is provided between the communication line 3 and the positive electrode of the low-voltage power supply 4. Therefore, according to this embodiment, it is possible to more reliably suppress damage to the low-voltage drive circuit 5 in the event of dielectric breakdown (failure) of the high-voltage side pulse transformer 2b (pulse transformer), compared to the case where only the protective resistor 5c is provided.

[0038] Furthermore, in the communication device (power supply monitoring device A) according to this embodiment, the high-voltage communication device 2 includes a voltage detection circuit 2a that detects the inter-electrode voltage of a plurality of battery cells that make up the high-voltage power supply 1 as a cell voltage, and transmits the cell voltage to the low-voltage communication device 5 via the communication line 3. According to this embodiment, in a configuration that includes the high-voltage communication device 2 that detects the cell voltage of the high-voltage power supply 1, it is possible to suppress damage to the low-voltage drive circuit 5 in the event of insulation breakdown (failure) of the high-voltage side pulse transformer 2b (pulse transformer).

[0039] Furthermore, in the communication device (power supply monitoring device A) according to this embodiment, the low-voltage communication device 5 monitors the high-voltage power supply 1 based on the cell voltage of each battery cell received from the high-voltage communication device 2. According to this embodiment, in a configuration including the low-voltage communication device 5 that monitors the high-voltage power supply 1 based on the cell voltage, it is possible to suppress damage to the low-voltage drive circuit 5 in the event of dielectric breakdown (failure) of the high-voltage side pulse transformer 2b (pulse transformer).

[0040] Furthermore, the power supply monitoring device A according to this embodiment includes the above-mentioned communication device. Therefore, this embodiment can provide a power supply monitoring device A that can suppress damage to the low-voltage drive circuit 5 in the event of dielectric breakdown (failure) in the high-voltage side pulse transformer 2b (pulse transformer).

[0041] The present invention is not limited to the above-described embodiment, and the following modifications are possible.

[0042] (1) In the above embodiment, the high-voltage communication device 2 is described as having a voltage detection circuit 2a, but the present invention is not limited to this. That is, the function of the high-voltage communication device 2 is not limited to the function of detecting the cell voltages of the multiple battery cells that make up the high-voltage power supply 1. The present invention is applicable to high-voltage communication devices having various functions.

[0043] (2) In the above embodiment, the low-voltage communication device 5 monitors the high-voltage power supply 1 based on the cell voltage of each battery cell received from the high-voltage communication device 2. However, the present invention is not limited to this. In other words, the function of the low-voltage communication device 5 is not limited to monitoring the high-voltage power supply 1 based on the cell voltage.

[0044] (3) In the above embodiment, the circuit configuration including at least the protective resistor 5c among the protective resistor 5c and the protective diode 5d has been described, but the present invention is not limited to this. For example, only the protective diode 5d may be provided as needed.

[0045] (4) In the above embodiment, a circuit configuration using a well-known silicon diode as the protection diode 5d has been described, but the present invention is not limited to this. For example, a voltage regulator diode may be used as the protection diode 5d instead of a silicon diode. [Explanation of symbols]

[0046] A, A1 Power monitoring device 1 High voltage power supply 2. High-voltage communication equipment 2a Voltage detection circuit 2b High-voltage side pulse transformer (pulse transformer) 3. Communication lines 4 Low voltage power supply 5.5A low voltage communication device 5a Low-voltage side pulse transformer (pulse transformer) 5b microcontroller 5c protection resistor 5d Protection diode

Claims

1. A communication device comprising a high-voltage communication device that operates on a high-voltage power supply and a low-voltage communication device that operates on a low-voltage power supply, wherein the high-voltage communication device and the low-voltage communication device communicate with each other via a communication line that has a pulse transformer installed midway, The low-voltage communication device is characterized in that a protective resistor is provided between the communication line and ground potential.

2. 2. The communication device according to claim 1, further comprising a protective diode provided between the communication line and the low-voltage power supply.

3. The communication device according to claim 1 or 2, characterized in that the high-voltage communication device includes a voltage detection circuit that detects inter-electrode voltages of a plurality of battery cells that constitute the high-voltage power supply as cell voltages, and transmits the cell voltages to the low-voltage communication device.

4. The communication device according to claim 3 , wherein the low-voltage communication device monitors the high-voltage power supply based on the cell voltage received from the high-voltage communication device.

5. A power supply monitoring device comprising the communication device according to claim 4.

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