CN201194024Y - A battery power detection device - Google Patents

Abstract

The utility model discloses a storage battery electric quantity detection device, which comprises: the storage battery is connected with a preset load, the preset load is connected with a main control circuit for controlling the discharge of the storage battery, and the storage battery and the preset load are connected to measure the discharge signal A/ D converter, the A/D converter is connected to a single-chip microcomputer for computing digital signals and outputting the measured power value; a protection circuit is also connected between the single-chip microcomputer and the main control circuit; the single-chip microcomputer is also connected to a display for displaying the measured power value The single-chip microcomputer is also connected to the keyboard of the input control command; the device in the utility model is in the working process, after the single-chip microcomputer obtains data from the A/D converter, the actual working voltage can be calculated by various algorithms. Setting the load to measure the voltage in the storage battery has the advantages of being more accurate than measuring the voltage in the actual load and the measurement process is simple.

Description

A battery power detection device

technical field

The utility model relates to a power measuring device, in particular to a storage battery power detection device.

Background technique

At present, batteries are installed on various vehicles, such as electric bicycles, cars, etc. During driving, users need to know the actual situation of the remaining capacity of the battery, just like the driver of a car needs to know the current remaining fuel capacity.

The detection of the remaining capacity of the battery is relatively complicated, mainly using the density method, open circuit voltage method, internal resistance method and power accumulation method. Among them, the density method is not suitable for sealed batteries; the open circuit voltage method must wait until the thermodynamics reaches equilibrium before measurement is accurate, so it is not suitable for online measurement; the internal resistance method, due to the complicated relationship between the battery resistance and the remaining power of the battery, is universal. It is also relatively poor; the power accumulation method also has inaccurate measurement.

Since the battery cannot be guaranteed to be fully charged every time, when the above scheme uses the discharged power to measure the remaining capacity of the battery, factors such as battery terminal voltage, charge and discharge current, initial electro-hydraulic specific gravity, and ambient temperature need to be considered, and the measurement process is more complicated. .

Utility model content

In view of this, the utility model is to provide a storage battery power detection device to solve the above-mentioned problems of complicated measurement process and large measurement error.

In order to solve the above problems, the utility model provides a battery power detection device, including:

The storage battery is connected to a preset load, and the preset load is connected to the main control circuit for controlling the discharge of the storage battery, and the storage battery and the preset load are connected to an A/D converter for measuring discharge signals, and the A/D converter is connected to an arithmetic Signal and output the single-chip microcomputer that measures the electric value.

Preferably, a protection circuit is also connected between the single-chip microcomputer and the main control circuit.

Preferably, the single-chip microcomputer is also connected to a display for displaying the measured power value.

Preferably, the single-chip microcomputer is also connected to a keyboard for inputting control commands.

During the working process of the above-mentioned device, after the single-chip microcomputer obtains data from the A/D converter, it can calculate the actual working voltage through various algorithms. Since the voltage in the storage battery is measured through the preset load, it has the advantage of measuring the voltage in the actual load. The voltage is more accurate and the measurement process is simple.

Description of drawings

Fig. 1 is the structural diagram of device in the embodiment;

Fig. 2 is a schematic diagram of adopting BUCK structure in the main control circuit;

Fig. 3 is the circuit structure diagram of 82C54;

Fig. 4 is a structural diagram of a drive isolation circuit;

Fig. 5 is the connection schematic diagram of A/D converter and single-chip microcomputer;

Fig. 6 is the flow chart that single-chip microcomputer obtains sampling data;

FIG. 7 is a schematic diagram of the interface circuit between the microcontroller and the LCD.

Detailed ways

In order to clearly illustrate the technical solutions in the utility model, preferred embodiments are given below and detailed descriptions are given in conjunction with the accompanying drawings.

Referring to Fig. 1, Fig. 1 is a structural diagram of the device, including: an A/D converter connected to a storage battery and a preset load, the A/D conversion circuit is connected to a sequence-controlled microcontroller, and the preset load is connected to the main control circuit. A protection circuit is also added between the main control circuits; a keyboard for inputting control commands and an LCD display for displaying the remaining power of the storage battery are also connected to the single-chip microcomputer.

The main control circuit adopts IPM intelligent power module (PM800HSA060), which not only integrates IGBT switch tube and driving circuit, but also integrates perfect protection circuits, such as overvoltage protection, overcurrent protection, short circuit protection, undervoltage protection, overheat protection Etc., realize the self-protection of the components; the drive circuit is integrated in the IPM, realize the separation of the control substrate and the power substrate, and cut off the interference from the power device; highly integrated, reduce the wiring inductance; built-in interference filter, improve the work of the components reliability and anti-interference ability. Use high power resistors for discharge loads. Since the control object is current, the main circuit adopts the buck converter structure with inductive energy storage, as shown in Figure 2. L1 and D1 play the role of freewheeling and IPM protection. C1 works in discharge mode when the switch is closed, and works in charge mode when the switch is open. At the same time, the combination of C1 and L1 stabilizes the battery discharge current.

Using an external timer/counter 82C54 to provide PWM waveform has the advantages of very short period, high splitting rate, fast response speed, and less time occupied by microprocessor or single-chip microcomputer.

In order to realize the output of PWM, one counter of 82C54 is set to generate the working mode of the timing cycle required by PWM; the other counter is set to produce the working mode of modulating the pulse width, and the control terminal GATE of this counter is received by the output terminal of the previous counter OUT control, resulting in a PWM output with adjustable period and pulse width. The timing of the period depends on the resolution of the PWM output. Its relational formula is: T=2 ⁿ /f _clk ; Among them n is the digit of the resolution, is the frequency of the input clock of the counter. Taking f _clk as an example, the timing cycle for generating 8-bit resolution is 32us; if generating 16-bit resolution, the timing cycle is 18.192ms. Its hardware circuit is shown in Fig. 3.

All protection signals are sent to the interrupt input terminal of the single-chip microcomputer. The single-chip microcomputer model is 89S52. When a fault occurs, the 89S52 single-chip microcomputer is interrupted, and the PWM pulse is immediately blocked in the interrupt service program. At the same time, the corresponding fault is indicated through the LED light-emitting tube and status display for maintenance. . Its IPM gate drive isolation circuit is shown in Figure 4, which realizes the photoelectric isolation of the output PWM signal and the IPM module, and realizes the driving and level conversion functions. The high-speed optocoupler uses 6N137, the triode is 9014, and the power supply voltage is +15V. The triode converts the TTL level from the optocoupler to the +15V gate drive signal of the IPM.

A/D converter adopts AD974. AD974 is a 4-channel, 16-bit serial A/D converter. Its sampling rate can be 200KSPS. The allowable input voltage ranges are: 0~4V, 0~5V and ±10V. The schematic diagram of the connection between the A/D converter and the microcontroller is shown in Figure 5. The R/C pin is used to indicate the working state of the AD974. When it is high, it means that the AD974 is in the read state. At this time, the data can be input to the microcontroller. When it is low, it means that it is in the conversion state, and the DATA pin is used to input data to the microcontroller. DATACLK is the external clock input terminal of AD974. The SYNC pin is the synchronous port of AD974. One clock cycle before the AD974 outputs data, the SYNC terminal outputs a high pulse, which can be used to synchronize data transmission. A0 and A1 are analog input gates. V1A, V1B, V2A, V2B are analog input terminals. EXT/INT is the clock selection terminal, when its value is high, the external clock is used, otherwise the internal clock is used. PWRD is the conversion controller, connected to high level to allow conversion. CS is the AD974 chip selection signal, which is valid when its value is low. Clear the R/C bit before AD974 conversion, so that AD974 enters the conversion state, and then set R/C after the conversion is completed, so as to enter the read state. It is detected that the SYNC signal is high level, and 16-bit data can be read in sequence thereafter. Use the output of MCU P1.5 as the external working clock of AD974 to control the reading of data.

The program flow of the MCU controlling the AD974 to obtain sampling data is shown in Figure 6. After the MCU selects the channel, when the SYNC value is 1, the MCU continuously reads the data in 16 bits. After reading the data, it will be displayed through the connected LCD. The LCD adopts ZY12864D, as a graphic dot matrix liquid crystal display, which is mainly composed of a row driver/column driver and a 128*64 full dot matrix LCD screen. Graphical display can be completed, and 8*4 (16*16 dot matrix) Chinese characters can also be displayed. The LCD screen is driven by bus. The schematic diagram of its interface can be seen in Figure 7. The P2 port generates write timing signals through 74LS138 and P3.6(/WR) and P3.7(/RD), P0.0—P0. 2 Generate a control signal, write the data of the P0 port into the LCD screen, and display the status of the measurement process and the power display.

During the working process of the above-mentioned device, after the single-chip microcomputer obtains data from the A/D converter, it can calculate the actual working voltage through various algorithms. Since the working voltage of the storage battery is measured through the preset load, it has the advantage of measuring the working voltage of the actual load. The voltage is more comparable and accurate, and at the same time has the advantage of a simple measurement process.

The embodiments of the utility model have been described in detail above. For the devices described in the embodiments, any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the utility model shall be included in the utility model. within the scope of protection.

Claims (4)

1. A battery power detection device, characterized in that it comprises: the battery is connected to a preset load, the preset load is connected to a main control circuit for controlling the discharge of the battery, and the battery and the preset load are connected to measure A of the discharge signal /D converter, the A/D converter is connected to the single-chip microcomputer for calculating the digital signal and outputting the measured power value. 2 . The battery power detection device according to claim 1 , wherein a protection circuit is further connected between the single-chip microcomputer and the main control circuit. 3 . 3 . The battery power detection device according to claim 1 , wherein the single-chip microcomputer is also connected to a display for displaying the measured power value. 4 . 4. A storage battery power detection device according to claim 1, characterized in that the single-chip microcomputer is also connected to a keyboard for inputting control commands.

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