CN209992647U

CN209992647U - Intelligent bypass diode module and battery pack monitoring system

Info

Publication number: CN209992647U
Application number: CN201920194384.3U
Authority: CN
Inventors: 顾建达; 刘俊
Original assignee: Wuxi Starfire Electrical Appliances Co Ltd
Current assignee: Wuxi Starfire Electrical Appliances Co Ltd
Priority date: 2019-02-13
Filing date: 2019-02-13
Publication date: 2020-01-24
Anticipated expiration: 2029-02-13

Abstract

The utility model discloses an intelligence bypass diode module and group battery monitored control system, including the bypass diode of two series connections and the RC parallel circuit of two sets of series connections in this intelligence bypass diode module, establish ties between the mid point of bypass diode and the mid point of series connection RC circuit, connect an alternating current power supply, alternating current power supply and two bypass diodes, two RC circuits constitute an "H" shape bridge, and the alternating current forces two bypass diodes to switch on in turn, end to form a signal voltage at series connection RC circuit's mid point, carry out synchronous monitoring to this signal voltage through the window comparator, can accurately judge whether opening a way of two bypass diodes, so realized the bypass diode inefficacy the online self-checking function whether, this intelligence bypass diode module has greatly improved the reliability of whole group battery.

Description

Intelligent bypass diode module and battery pack monitoring system

Technical Field

The utility model relates to a back-up source technical field, in particular to maintenance and monitored control system of series battery group.

Background

Batteries, as a backup power source, have a long history of application in various industries due to their nearly "seamless" switching (<2mS) nature. The backup power supply of relay protection equipment in a large-scale substation is as small as UPS used for office equipment (such as computers).

The backup power source, due to its "backup" identity, must have a "call-as-you-go-now" feature. Therefore, the completion status of each battery cell must be constantly monitored even in the standby state. Specifically, the system is not only responsible for real-time scanning (detecting voltage and internal resistance) of each battery unit in the battery pack, but also needs to perform maintenance work such as activation and discharge on the battery periodically. Therefore, the backup power supply and the monitoring and maintenance equipment thereof are often called a direct current backup power supply system.

In order to further improve the reliability, a scheme of connecting a bypass diode in parallel at two ends of each battery unit is also proposed in the industry to prevent the whole battery pack from being crashed when a certain battery unit suddenly fails.

If a certain battery unit has increased internal resistance or even has an open-circuit fault, the fault battery unit can be bypassed by the bypass diode, so that automatic and seamless exit is realized. At this time, the output voltage of the whole battery pack only loses the battery voltage (for example, 12V) of one unit, and then the forward voltage drop (0.7-1V) of the diode is added. This does not affect the operation in most cases.

The bypass diode is originally added to improve the reliability of the whole battery pack, but a new fault factor is introduced. Although the bypass diode has a very low probability of failure because it normally operates at a reverse voltage of more than ten volts, it is ultimately a "hazard". From a technical point of view, the monitoring systems of the prior art are "totally unknown" in case of failure, in particular open circuit, of the bypass diodes. This is not technically permissible! It is necessary to try to monitor for open circuit failure of the bypass diode.

SUMMERY OF THE UTILITY MODEL

In order to solve the problem that current bypass diode can't be detected under the failure state of opening a way, the utility model provides a can monitor self and open a way intelligent bypass diode module of inefficacy.

In order to realize the purpose, the utility model provides a technical scheme is: the utility model provides an intelligent bypass diode module of area inefficacy self-checking function, includes the bypass diode of two series connections, be connected with alternating current power supply between two bypass diodes, alternating current power supply still is connected with RC parallel circuit and the window comparator of two series connections, two bypass diodes, two RC parallel circuit and alternating current power supply constitute an H shape bridge configuration.

Further, the output end of the window comparator is connected with a microprocessor.

According to the preferable technical scheme, the alternating current power supply is connected with the microprocessor, the output waveform of the alternating current power supply is square wave, and the output frequency is 500-2 kHz.

In addition, the microprocessor is connected with a step-up transformer, and the output end of the step-up transformer is coupled with the alternating current power supply.

On the basis of the technical scheme, the midpoint of the series RC circuit is connected with a window comparator. Two output ends of the window comparator drive two light-emitting diodes on one hand to serve as local indications of states of the two bypass diodes; and on the other hand, the state information of the two bypass diodes is provided to the outside through the communication interface.

As an additional function, the microprocessor of the present invention can also sample the battery voltage in real time. Namely, the utility model discloses still in the integrated back-up power supply system, the function is patrolled and examined to each battery cell's of series connection group battery voltage.

As a preferred scheme, the power supply of all parts of the utility model can be directly taken from the battery unit connected with the module in parallel by a switch type voltage-stabilized power supply circuit with wide input range.

In addition, the first diode and the second diode are arranged in the main shell, other circuits are arranged in the auxiliary shell, and a heat insulation baffle is arranged between the main shell and the auxiliary shell.

In the above technical solution, preferably, a heat dissipation bottom plate is disposed at the bottom of the main housing.

In the technical scheme, the auxiliary shell is provided with a status indicator light, and the status indicator light is connected with the microprocessor.

Additionally, the utility model provides a group battery intelligent monitoring system, including a plurality of parallelly connected above-mentioned group battery intelligent monitoring module, the microprocessor of group battery intelligence bypass diode module is connected with 485 drive circuit, 485 drive circuit's output is connected with the transformer, the output and the 485 bus connection of transformer, be connected with host computer and monitor terminal on the 485 bus.

In this system, it is preferable that a plurality of flywheel diodes are further connected to the 485 driving circuit.

The utility model discloses beneficial effect for prior art is: according to the intelligent bypass diode module, the two bypass diodes are forced to be alternately switched on and switched off through the two bypass diodes connected in series and an alternating current power supply, and whether the bypass diodes are opened or not is judged by matching with a set of specially designed circuits such as a window comparator, so that the function of online failure self-checking of the bypass diodes is realized, and the reliability of the battery pack connected in series in a backup power supply system is improved to the greatest extent. Due to the fact that the microprocessor is added, the voltage inspection function of the battery unit of the series battery pack in the backup power supply system is integrated, and the bus type communication function is achieved easily.

Drawings

FIG. 1 is a schematic diagram of a main measurement circuit of an intelligent bypass diode module;

FIG. 2 is a functional block diagram of the overall configuration of the intelligent bypass diode module;

FIG. 3 is a voltage waveform of point O in the series RC circuit at normal times for two bypass diodes;

FIG. 4 is a block diagram of an intelligent bypass diode module;

FIG. 5 is a diagram of the internal connections of an intelligent bypass diode module;

FIG. 6 is a schematic diagram of a series battery monitoring system formed from intelligent bypass diode modules;

FIG. 7 is a 485 communication schematic diagram of data driven by transformer isolation after Manchester encoding.

Detailed Description

The following describes the present invention with reference to the accompanying drawings. It should be noted that the description of the embodiments is provided to help understanding of the present invention, but the present invention is not limited thereto. In addition, the technical features related to the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

An intelligent bypass diode module is shown in fig. 1. Two bypass diodes PD1 and PD2 connected in series are connected between the positive and negative poles of each battery cell, and the positive pole of PD1 is connected to the negative pole of PD 2. There are two further series connected RC parallel circuits R1(C1), R2 (C2). An alternating current power supply ME, a resistor R3, a resistor R4, a light-emitting diode VD, a comparator A1 and a comparator A2 are connected between a connection point of PD1 and PD2 and a connection point of R1(C1) and R2 (C2). The junction O of R1(C1) and R2(C2) is connected to the window comparator through a resistor R0. Two output ends of the window comparator are connected with two light emitting diodes LD1 and LD 2.

In fig. 1, ME is an independent ac power supply for measurement, and in this embodiment, the output waveform of the ac power supply is a square wave, and the output frequency is 500 to 2 kHz. The function is to force the two bypass diodes PD1, PD2 to be alternately switched on and off. If both bypass diodes are normal, an equal amount of charge will be obtained on the capacitors C1, C2, and the level of the midpoint O is close to half the battery voltage.

In fact, since C1 and C2 are also discharged, the level of the midpoint O is periodically changed around half the cell voltage value as shown in fig. 3. But this does not affect the elucidation of the detection principle below.

If the upper tube PD1 is open, the midpoint O level will rise because C1 cannot be charged, otherwise the PD2 is open and the midpoint O level will fall. VD is a light emitting diode, and here the window voltage required by the window comparator is generated by its forward voltage drop of around 2V (e.g. green light emitting tube).

(for convenience of description, it is assumed that the voltage of the battery cell is 12V in the following description)

If the midpoint O level is higher than 7V, the output of the comparator a1 is low, the indicator lamp LD1 lights up, and is isolated (different levels) by the diode ID1 and output from the IO1 line for the microprocessor to sense the open state of the PD 1.

If the midpoint O level is lower than 5V, the output of the comparator a2 is low, the indicator lamp LD2 lights up, and is isolated (different levels) by the diode ID2 and output from the IO2 line for the microprocessor to sense the open state of the PD 2.

As shown in fig. 2, the output end of the window comparator is connected to a microprocessor MCU, which is powered by the battery unit, in this embodiment, the MUC employs a single chip microcomputer with model STC15W408 AS.

The detection ac power ME is generated by two output pins Wo1 and Wo2 of the microprocessor in a push-pull output manner. And then is isolated and coupled between two middle points of an alternating current power supply ME in the figure 2 through a 1:2 booster transformer. Thus, the requirement of independent (non-common ground) feeding can be met. If an H-bridge drive is additionally arranged between the MCU and the transformer, the 1:1 transformer which is convenient to purchase can be selected, and the load of the MCU of the microprocessor can be reduced.

Referring to fig. 2, the interfaces between the two state outputs of the window comparator and the MCU are S1 and S2, and the battery voltage sampling interface is Ai. The R7 and R8 divide the voltage of the 12V battery into 4V, and the voltage is sampled and converted by a microprocessor powered by 5V.

Whether the bypass diode is in an open circuit state or not can be accurately reflected through the detection result of the window comparator, the detection frequency is high, the detection is in an online state, the normal work of the battery pack cannot be influenced, and the reliability of the battery pack is greatly improved.

As shown in fig. 4 and 5, two bypass diodes are arranged in the main casing 1, other circuits are arranged in the auxiliary casing 2, a heat insulation baffle 3 is arranged between the main casing 1 and the auxiliary casing 2, the auxiliary casing 2 is partially designed into a separate space, and a diode open circuit measuring circuit, a battery voltage sampling circuit, an intelligent processing and communication circuit and the like are arranged inside the auxiliary casing and are collectively called as a measuring unit. The measurement unit is placed in a separate space (spaced apart from the body space) to facilitate the heat generating die away from the two bypass diodes.

Further, a heat dissipation bottom plate 4 is arranged at the bottom of the main casing 1. The heat radiation base plate 4 does not extend to the measurement cell space of the sub-body housing 2. This is to keep the measuring unit as far away as possible from the heating element of the diode core.

In the above technical solution, the sub-housing 2 is provided with a status indicator lamp 21.

The connecting wire used between the diode and the measuring circuit adopts a high temperature resistant wire, the wire diameter is 0.5mm, and the outer diameter of the insulating layer is 2 mm. And the electrode plates of the double diodes are connected by pressure welding, so that the conductivity and the connection strength are ensured.

In addition, on the basis of above-mentioned intelligent bypass diode module, the utility model also provides a group battery intelligent monitoring system, as shown in fig. 6, this system includes a plurality of parallelly connected above-mentioned intelligent bypass diode modules, and the microprocessor of intelligent bypass diode module is connected with 485 drive circuit, 485 drive circuit's output is connected with the transformer, the output and the 485 bus connection of transformer, 485 bus connection has special monitor terminal.

Because the intelligent monitoring module of the battery pack adopts 'on-site' power supply of the voltage of the battery unit, the intelligent monitoring module has the greatest advantages of convenient wiring and no need of wiring for power supply on site. But this "self-powered" mode also brings with it a problem: the modules are not grounded, so 485 communications must be isolated. The 485 communication isolation scheme of the present invention will be specifically described below.

As shown in fig. 7, the 485 communication isolation scheme of the present invention is transformer isolation. The optical coupling isolation scheme and the magnetic isolation chip of ADI company which are commonly used in the market are not adopted. The reason is that: 1. the utility model adopts a self-powered scheme of simplifying field wiring, and the power supply is each battery unit in the battery pack in the backup power supply system; 2. the bypass diode is connected to prevent the failure of individual battery units, so that the module can fail along with the failure of the battery units; 3. the problem that must be solved is how to automatically disengage from the bus without "straining" other nodes on the entire bus when the 485 communication node fails. The transformer isolation coupling is the best coupling scheme!

However, transformer coupling also has a fatal disadvantage: that is, the signal to be transmitted must be purely ac!

Therefore, the utility model discloses to the unipolar non-return to zero (TTL) signal of microprocessor serial ports output, Manchester's coding has been carried out. Each byte is split into two manchester codes of the byte, and then the two manchester codes are driven by a 485 chip. Because the 485 driving chip is in differential output, the Manchester code signal is in pure alternating current through differential output.

Due to the adoption of 485 drive, the anti-interference capability is higher, so that a higher baud rate, such as 57600bps, can be adopted, and the reduction of the communication efficiency caused by Manchester coding can be compensated. The higher baud rate also enables the isolation transformer to be smaller in size. The utility model adopts a permalloy iron core transformer.

D1 to D4 in fig. 7 are intended to be added to the safety driving of the communication isolation transformer. Because of the bus drive of the 485 chip, the inside of the device is in a push-pull structure, but not in an H-bridge structure, and a freewheeling diode is not arranged. Therefore, four diodes are externally connected and used for absorbing the recoil voltage caused by the leakage inductance of the primary inductor of the transformer.

485 communication is carried out in a transformer isolation coupling mode, so that the anti-interference capability of the whole monitoring system is enhanced, a high baud rate is easy to use, and the communication efficiency is improved.

The embodiments of the present invention have been described in detail with reference to the accompanying drawings, but the present invention is not limited to the described embodiments. It will be apparent to those skilled in the art that various changes, modifications, substitutions and alterations can be made in the embodiments without departing from the principles and spirit of the invention, and the scope of the invention is to be accorded the full scope of the claims.

Claims

1. An intelligent bypass diode module, characterized in that: the high-voltage direct current power supply comprises two bypass diodes which are connected in series, an alternating current power supply is connected between the two bypass diodes, the alternating current power supply is further connected with two RC parallel circuits which are connected in series and a window comparator, and the two bypass diodes, the two RC parallel circuits and the alternating current power supply form an H-shaped bridge structure.

2. The intelligent bypass diode module of claim 1, wherein: and the output end of the window comparator is connected with a microprocessor.

3. The intelligent bypass diode module of claim 1, wherein: the alternating current power supply is connected with the microprocessor, the output waveform of the alternating current power supply is a square wave, and the output frequency is 500-2 kHz.

4. The intelligent bypass diode module of claim 3, wherein: the microprocessor is connected with a step-up transformer, and the output end of the step-up transformer is coupled with the alternating current power supply.

5. The intelligent bypass diode module of claim 1, wherein: the two bypass diodes are arranged in the main shell, other circuits are arranged in the auxiliary shell, and a heat insulation baffle is arranged between the main shell and the auxiliary shell.

6. The intelligent bypass diode module of claim 5, wherein: and a status indicator lamp is arranged on the auxiliary shell and is connected with the microprocessor.

7. The intelligent bypass diode module of claim 5, wherein: the bottom of the main shell body is provided with a heat dissipation bottom plate.

8. A battery pack monitoring system, characterized by: the intelligent bypass diode module comprises a plurality of intelligent bypass diode modules connected in parallel, a 485 driving circuit is connected to a microprocessor in each intelligent bypass diode module, a transformer is connected to the output end of the 485 driving circuit, the output end of the transformer is connected with a 485 bus, and the 485 bus can be connected with a special monitoring terminal.

9. The battery pack monitoring system according to claim 8, wherein: and the 485 driving circuit is also connected with a plurality of freewheeling diodes.