CN101308196B - Current integration measuring circuit - Google Patents

Abstract

The present invention relates to a current integration measuring circuit comprising a current signal processing module, an energy calculation chip module and a reference voltage source module. The current signal processing module is a second-order active low pass filter composed of an operational amplifier LM158, precision resistors of R55, R56 and R57 and capacitors of C44, C45 and C52, and implements the filtering processing to -0.5V-+0.5V signals inputted to the chip ADE7753. The energy calculation chip module ADE7753 realizes the current integration function. The reference power supply module MAX6173 serves as a reference voltage source of the energy calculation chip module ADE7753, and divides the voltage of the reference voltage source by the precision resistors R62, R63 and R64 and then inputs the voltage to V2P ports of the energy calculation chip module ADE7753. The circuit of hardware in the invention is simple, the measuring precision is high, and the circuit can be used for battery management systems of electric automobiles and calculating the electric quantity of storage batteries.

Description

The metering circuit of current integration

Technical field

The present invention relates to be used for the current integration metering circuit of cell management system of electric automobile, battery charging and discharging equipment.

Background technology

Usually the dump energy that needs calculating accumulator in electric automobile, the battery charging and discharging equipment, current integration method are the most frequently used methods of counting cell dump energy.Calculating the most frequently used method of current integration at present is to measure electric current earlier, in software electric current is carried out integration then, and this method precision is low, and the CPU software overhead is big.As Chinese patent 03800926.9 " electric battery and battery remaining power calculating method ", mainly be integration with the computed in software energy.

Summary of the invention

The objective of the invention is to overcome the shortcoming of prior art, propose a kind of method of measuring current integration with hardware.Hardware circuit of the present invention is simple, and the measuring accuracy height has changed existing method by software engineering measurement current integration, has reduced the software work amount, has also reduced system cost simultaneously.The present invention is used for the battery management system of electric automobile, and the electric weight of calculating accumulator can improve the precision of current integration.

The present invention has utilized the energy computing function of electric weight chip.The energy computing chip needs the two paths of signals input, the first via is a current signal, and the second the tunnel is voltage signal, inserts a reference voltage source at the second road voltage signal input end, the energy that the electric weight chip is recorded just obtains current integration value AT divided by the reference voltage value of the second tunnel input.The energy calculation formula is: E=∫ UIdt, and wherein E is an energy, and U is an input voltage, and I is an input current.When being used for the voltage U of integration when being constant, $\mathrm{AT}=\frac{E}{U}=\∫\mathrm{Idt},$ Promptly can calculate the integration AT of electric current quickly and accurately by this formula.

The present invention mainly comprises: current signal processing module, energy calculation chip module, reference voltage source module.Current signal processing module directly is connected by output signal V1P with energy calculation chip module, and reference voltage source module output reference voltage REF directly receives the Voltage Reference end REF of energy computing chip.Be directly inputted to energy computing chip V2P end after reference voltage REF process precision resistance R63, the R64 of reference voltage source module output, the R62 dividing potential drop.

The signal of current sensor output through treatment conversion one-tenth-0.5V ~+the voltage signal BC+ of 0.5V.Voltage signal BC+ is input to current signal processing module.Current signal processing module is by amplifier LM158, precision resistance R55, R56, R57, and capacitor C 44, C45, C52 constitute a second-order low-pass filter.Can select the value of resistance and electric capacity in the practical application according to interference source, to obtain different filter effects.Resistance R 58 and C46 have constituted a rc filter circuit.

Energy calculation chip module is made of ADE7753 and peripheral circuit thereof.ADE7753 has the two-way analog input channel, as the current integration function time, and V1P input current signal, V2P input voltage signal.ADE7753 uses external crystal oscillation circuit, and the sample frequency of ADE7753 can reach 27.9K/S the soonest.Voltage reference of ADE7753 need of work, the voltage-reference that can use ADE7753 inside to carry also can use external voltage reference, in order to improve the sampling precision of system, has adopted external voltage reference among the present invention.ADE7753 adopts SPI communication interface and outside to carry out communication, and DIN is the DOL Data Output Line interface of Data In-Line and CPU, and DOUT is the Data In-Line interface of DOL Data Output Line and CPU, and SCLK is a clock cable, is produced the clock signal of SPI communication by CPU.

The reference voltage module is made of MAX6173 and precision resistance R62, R63, R64.MAX6173 has the precision height, the characteristics that low temperature floats.In actual use, can adopt different reference voltage modules according to the accuracy requirement of system.The reference voltage module mainly contains two effects in the present invention: the one, provide reference voltage to ADE7753, and the 2nd, through electric resistance partial pressure, give the reference voltage of the 0.1V of second channel input of ADE7753.In the input of second channel voltage is under the situation of a definite value, and current integration is exactly the integral multiple of energy value.In the present invention, current integration is exactly ten times of energy value.In the practice, can use different divider resistances, but the magnitude of voltage of input second channel must be smaller or equal to 0.5V.

The present invention has just finished the integration of power in energy chip inside, CPU only need read the result of integration in the energy chip, just can obtain the current integration result through simple operation, so just significantly reduce the software work amount, also improve the precision of current integration simultaneously.

Description of drawings

Fig. 1 is that system module connects block diagram;

Fig. 2 is a current signal treatment circuit schematic diagram;

Fig. 3 is that energy calculates the chip circuit schematic diagram;

Fig. 4 is the reference voltage source circuit schematic diagram;

Embodiment

Fig. 1 is that system module of the present invention connects block diagram.The present invention includes current signal processing module, energy calculation chip module, reference voltage source module three parts.Current signal processing module directly is connected by output signal V1P with energy calculation chip module, and reference voltage source module output reference voltage REF directly receives the Voltage Reference end REF of energy computing chip.Be directly inputted to energy computing chip V2P end after reference voltage REF process precision resistance R63, the R64 of reference voltage source module output, the R62 dividing potential drop.

Shown in Figure 2 is current signal processing module.The signal BC+ that enters current signal processing module be one-0.5V ~+voltage signal of 0.5V.Therefore no matter which type of current sensor of front end, need only its output signal is converted to-0.5V ~+voltage signal of 0.5V after, just can be directly and the current signal processing module interface.Concrete connected mode is: amplifier LM158, resistance R 55, R56, R57 capacitor C 45, C44, C52 have constituted a second order active low-pass filter.BC+ directly receives resistance R 55, and resistance R 56 and capacitor C 44 are received in the output of resistance R 55, and capacitor C 44 connects 1 pin of LM158, and the output of resistance R 56 connects 3 pins and the capacitor C 45 of amplifier LM158.2 pin connecting resistance R57 and the capacitor C 52 of amplifier LM158, resistance R 57 output pins are connected with capacitor C 52 output pins, and resistance R 57 outputs connect 1 pin of amplifier LM158, and the output of capacitor C 52 connects 1 pin of amplifier LM158.The 1 pin connecting resistance R58 of amplifier LM158, resistance R 58 output signal V1P.Signal V1P is by capacitor C 46 ground connection, and synchronous signal V1P is input to energy calculation chip module.Since the signal of filtering be one-0.5V ~+voltage signal of 0.5V, so the power supply of amplifier LM158 needs a dual-supply voltage, among the present invention uses+5V and-5V voltage powers for amplifier LM158.Capacitor C 53, C54 are the filter capacitors of amplifier LM158 power supply.Resistance R 58 is by C46 ground connection, and resistance R 58 outputs connect the pin 4 of ADE7753, and resistance R 58, capacitor C 46 constitute a simple RC filter at the output terminal of second-order active filter device.

Figure 3 shows that energy calculation chip module.U25 is energy computing chip ADE7753, and U25 has two input channel pins 4 and pin 7, and when using the energy integral function, what pin 4 was imported is current signal, and what pin 7 was imported is voltage signal.Pin 9 is energy chip reference voltage input.Pin two is that energy chip digital power input end, pin 3 are energy chip analog power input ends.Pin one 5, pin one 6 connect external crystal oscillation circuit.Pin one 4 is that interruption output, pin one 7 are sheet choosing ends of ADE7753, and low level is effective.Pin one 8, pin one 9, pin two 0 are the SPI communication terminals of ADE7753, and DI0 is the data input pin of energy computing chip, and DO0 is the data output end of energy chip, and SCLK0 is the clock signal terminal of energy chip, produce the communication clock signal by host CPU.Concrete connected mode is: the digital power of pin two is by capacitor C 48, C49 ground connection, and the analog power of pin 3 is by capacitor C 51, C50 ground connection.Pin 9 is by capacitor C 57, C60 ground connection.Pin one 5, pin one 6 meets external crystal-controlled oscillation X2, and the two ends of crystal oscillator X2 are by capacitor C 61, C62 ground connection.

Fig. 4 is a reference voltage source module.U26 is the reference voltage source MAX6173 of MAXIM company, and output voltage is 2.5V, and its precision is 0.06%, and temperature coefficient is that 3ppm (40 ℃～+ 125 ℃) pin two is a voltage input end, and pin two connects+the 5V power supply, at power supply termination capacitor C 55, C56.。Pin 4 is earth terminals.Pin 6 is output terminals of MAX6173, output 2.5V.The output terminal of U26 is directly received the REF end of energy computing chip.It is 0.1% that resistance R 63, R64, R62 adopt precision, temperature coefficient is the precision resistance of 10ppm, obtain the voltage V2P of a 0.1V after 6 pins output process precision resistance R63, the R64 of U26, the R62 dividing potential drop, voltage V2P is directly inputted to 7 pins of energy computing chip U25.Concrete connected mode is: pin two meets power supply+5V, simultaneously by capacitor C 55, and C56 ground connection.Pin 6 output signal REF are input to resistance R 63, and R63 meets R64, and R64 is by resistance R 62 ground connection, and the pin 7 of energy calculation chip module is directly received in the output of resistance R 64.The pin 5 of energy chip ADE7753, pin 6, pin one 7, pin 8, pin one 0 direct ground connection.

Claims (6)

1. a current integration metering circuit is characterized in that described circuit comprises current signal processing module, energy computing chip ADE7753 and reference voltage source module; Current signal processing module is to the first via input current signal I of energy computing chip ADE7753, reference voltage source module is to the second road input reference voltage signal U of energy computing chip ADE7753, and wherein reference voltage signal is a fixed voltage value U who produces by the outside reference voltage source; Utilize the function of energy computing chip ADE7753 internal calculation energy,, just obtain the integrated value AT of electric current, that is: the magnitude of voltage U of the energy value E that reads from energy computing chip ADE7753 inside divided by the second tunnel input

E＝∫UIdt，

When being used for the voltage U of integration when being constant,

Described current signal processing module is connected by output signal V1P with energy computing chip ADE7753, and the reference voltage source module output reference voltage is directly received the Voltage Reference end REF of energy computing chip ADE7753; Be directly inputted to the V2P end of energy computing chip ADE7753 after reference voltage process precision resistance R63, the R64 of reference voltage source module output, the R62 dividing potential drop.

2. current integration metering circuit according to claim 1 is characterized in that described current signal processing module by amplifier LM158, precision resistance R55, R56 and R57, the second order active low-pass filter that capacitor C 44, C45 and C52 constitute; Energy computing chip ADE7753 realizes the current integration function; The reference power supply module is input to the V2P port of energy computing chip ADE7753 by the reference voltage source of chip MAX6173 as energy computing chip ADE7753 after precision resistance R62, R63, R64 are to the reference voltage source dividing potential drop; Current signal processing module to be input to energy computing chip ADE7753-signal of 0.5V-+0.5V carries out Filtering Processing.

3. current integration metering circuit according to claim 1, it is characterized in that in the current signal processing module, the signal BC+ that enters current signal processing module directly receives resistance R 55, resistance R 56 and capacitor C 44 are received in the output of resistance R 55, resistance R 56 and capacitor C 44 parallel connections, capacitor C 44 connects 1 pin of amplifier LM158, and the output of resistance R 56 connects 3 pins and the capacitor C 45 of amplifier LM158; 2 pin connecting resistance R57 and the capacitor C 52 of amplifier LM158, resistance R 57 and capacitor C 52 parallel connections, resistance R 57 outputs connect 1 pin of amplifier LM158, and the output of capacitor C 52 connects 1 pin of amplifier LM158; The 1 pin connecting resistance R58 of amplifier LM158, resistance R 58 output signal V1P; Signal V1P is by capacitor C 46 ground connection, and synchronous signal V1P is input to energy calculation chip module.

4. current integration metering circuit according to claim 1, the digital power that it is characterized in that 2 pins of energy computing chip ADE7753 passes through capacitor C 48, C49 ground connection, the analog power of 3 pins is by capacitor C 51, C50 ground connection, and 9 pins are by capacitor C 57 and capacitor C 60 ground connection; 15 pins and 16 pins meet external crystal-controlled oscillation X2, and the two ends of crystal oscillator X2 are by capacitor C 61 and C62 ground connection; 5 pins of energy computing chip ADE7753,6 pins, 17 pins, 8 pins and the direct ground connection of 10 pins.

5. current integration metering circuit according to claim 1, it is characterized in that reference voltage source module is chip MAX6173,2 pins of chip MAX6173 meet power supply+5V, simultaneously by capacitor C 55, C56 ground connection, 6 pin output signal REF are input to resistance R 63, resistance R 63 connecting resistance R64, resistance R 64 is by resistance R 62 ground connection, and 7 pins of energy computing chip ADE7753 are directly received in the output of resistance R 64.

6. current integration metering circuit according to claim 1 is characterized in that the resistance of resistance R 55, R56 and the R57 of second order active low-pass filter circuit, and the appearance value of capacitor C 44, C45 and C52 is selected according to interference source.

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