A digital control average current sharing method based on current sharing bus

Abstract

The application discloses a kind of digital control average current equalization methods based on current equalization bus, belong to current control technical field, the average current value of whole machine is obtained by the common bus circuit of multiple modules in whole machine, after average current value is amplified, compare with local current value, when local current is greater than average current value, reduce local output voltage value, and the output current of local machine is reduced;When the output voltage value of local machine is adjusted too much, output voltage gradually recovers to rated setting value;The application combines current equalization bus circuit and digital control, and the average current of multiple modules is calculated using current equalization bus technology, and the fault module can be automatically removed when the fault module occurs.Simultaneously solve the problem of module failure caused by bus voltage drop in analog average current control method, and solve the problem of slow dynamic response speed in traditional digital control method.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of current control, and particularly relates to a digital control average current equalization method based on an equalization bus. BACKGROUND

[0002] With the development of the power electronic industry and the increase of the power consumption of the whole system, multiple power modules need to work in parallel, which puts forward higher requirements for the parallel equalization precision and the equalization number of the modules.

[0003] Common equalization methods include an output impedance method, a master-slave setting method, a peak current method and an average current method. The working principle of the output load impedance method is that the greater the module output current is, the lower the output voltage is. When multiple modules are connected in parallel, the module with high output voltage cannot output more current due to the decrease of the output voltage, and then the remaining modules provide the current. However, with the increase of the current, the output voltage changes, and when the current is large, the voltage changes greatly, and the voltage stabilization precision of the module is poor. The working principle of the master-slave setting method is that multiple modules work in parallel, one of which is the master module working in the constant voltage mode, and the remaining modules work in the constant current mode with the master module as the reference. However, when the master module selected by design fails, the whole system will be paralyzed. The peak current method is that multiple modules work in parallel, and the whole system automatically selects a master module, and the remaining modules approach the master module. When the master module fails, the next master module is automatically selected. However, in the peak current method, the remaining modules can only approach the master module, and the current cannot be equal to that of the master module, so the equalization precision is poor. The average current method includes an analog control average current method and a digital control average current method. The average current values of multiple modules are obtained through a circuit or communication, and then the output voltage value is adjusted to realize the equalization of the modules.

[0004] The analog control average current method obtains the average current value through a common bus of multiple modules, compares the local current with the average current value, and then adjusts the output voltage to realize the equalization. However, when a certain module fails in the traditional control method, the average current of the whole system bus decreases, and the output voltage of the whole system is always reduced until the output voltage is reduced to the under-voltage protection point, and the whole system is protected and shut down.

[0005] The digital control average current method uses the communication technology of a digital chip to calculate the average current values of multiple analogs, compares the local current with the average current value, and then adjusts the output voltage to realize the equalization. However, the communication receiving and sending speed is slow, the average current value cannot be updated in real time, and the dynamic response performance of the whole system is poor. SUMMARY

[0006] The present application aims to provide a digital control average current equalization method based on an equalization bus to solve the problems in the background.

[0007] To achieve the above object, the present application provides the following technical solutions.

[0008] A digital control average current sharing method based on current sharing bus, which is realized by multiple current sampling modules with the same structure, and the multiple current sampling modules are connected through a common bus, the signal at the end of the common bus is the average current value of the multiple modules, the average current value of the whole machine is obtained through the common bus circuit of the multiple current sampling modules, and after the average current value is amplified, it is compared with the local current value, when the local current is greater than the average current value, the local output voltage value is reduced, and the output current of the local machine is reduced; when the output voltage value of the local machine is adjusted too much, the output voltage can gradually recover to the rated setting value, and the parallel current sharing precision of the multiple modules is realized.

[0009] Compared with the prior art, the present application has the following beneficial effects:

[0010] The present application combines the current sharing bus circuit and digital control, calculates the average current of multiple modules by using the current sharing bus technology, and automatically removes the faulty module when the faulty module appears. That is, the module failure problem caused by the bus voltage drop in the analog average current control method is solved, and the slow dynamic response speed problem in the traditional digital control method is also solved. BRIEF DESCRIPTION OF DRAWINGS

[0011] Figure 1 The digital control block diagram of the present application.

[0012] Figure 2 The circuit diagram of the present application. DETAILED DESCRIPTION

[0013] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0014] Embodiment 1:

[0015] Please refer to Figure 1 and Figure 2 , a digital control average current sharing method based on current sharing bus, the average current value of the whole machine is obtained through the common bus circuit of multiple modules in the whole machine, and after the average current value is amplified, it is compared with the local current value, when the local current is greater than the average current value, the local output voltage value is reduced, and the output current of the local machine is reduced; when the output voltage value of the local machine is adjusted too much, the output voltage gradually recovers to the rated setting value.

[0016] The average current value of the whole machine of the embodiment 2 is obtained by a plurality of current sampling modules with the same structure, the plurality of current sampling modules are connected by a common bus, and the signal at the end of the common bus is the average current value of the plurality of modules.

[0017] The current sampling module of the embodiment 3 comprises a current sharing bus circuit and a current sharing line current sampling circuit, the input end of the current sharing bus circuit is connected with the current signal ADCIN1 of the machine, the output end of the current sharing bus circuit is connected with the input end of the current sharing line current sampling circuit, and the output end of the current sharing line current sampling circuit is connected with the AD sampling port ADCIN2 of the single-chip microcomputer.

[0018] The current sharing bus circuit of the embodiment 4 comprises an operational amplifier N1A, a resistor R1, a capacitor C1, a resistor R2, a resistor R3 and a capacitor C2, the input end IN+ of the operational amplifier N1A is connected with the resistor R1 and the capacitor C1, the input end IN- of the operational amplifier N1A is connected with the resistor R2 and the output end OUT of the operational amplifier N1A, the other end of the capacitor C1 is grounded, the other end of the resistor R2 is connected with the resistor R3 and the capacitor C2, the other end of the resistor R3 is connected with the other end of the capacitor C2 and the ground end, the power supply end V+ of the operational amplifier N1A is connected with a 3.3V voltage, and the ground end V- of the operational amplifier N1A is connected with the ground end.

[0019] The current sharing line current sampling circuit comprises an operational amplifier N1B, a resistor R4, a resistor R5, a capacitor C3, a resistor R6 and a capacitor C4, one end of the resistor R4 is connected with the resistor R2 and the capacitor C2, the other end of the resistor R4 is connected with the capacitor C3 and the input end IN+ of the operational amplifier N1B, the input end IN- of the operational amplifier N1B is connected with the resistor R5 and the resistor R6, the other end of the resistor R5 is connected with the other end of the capacitor C3 and the ground end, the other end of the resistor R6 is connected with the output end OUT of the operational amplifier N1B, a capacitor C5 and a resistor R7, the other end of the resistor R7 is connected with the AD sampling port ADCIN2 of the single-chip microcomputer, the other end of the capacitor C5 is grounded, the other end of the capacitor C6 is grounded, the power supply end V+ of the operational amplifier N1B is connected with a 3.3V voltage, and the ground end V- of the operational amplifier N1B is connected with the ground end.

[0020] The working principle is as follows:

[0021] As Figure 2As shown, the design uses the common bus circuit of N current sampling modules (hereinafter referred to as modules) to obtain the average current value of the whole machine. The local current of module 1 is filtered by resistor R1 and capacitor C1 and then input to the non-inverting input terminal of operational amplifier N1A. The inverting input terminal and the output terminal of operational amplifier N1A are directly connected, forming a voltage follower, which realizes the buffering and isolation of the local current value. The output terminal voltage of operational amplifier N1A is equal to the local current value of module 1. The signal filtered by resistor R2, resistor R3 and capacitor C2 is connected to the common bus terminal. The bus terminals of multiple modules (module 1 to module N) are connected together, and the signal of the common bus terminal is the average current value of multiple modules. The average current value is filtered by resistor R3 and capacitor C3 and then input to the non-inverting input terminal of operational amplifier N1B. In order to improve the adjustment accuracy of the output voltage and further improve the current sharing accuracy, the average current is amplified by operational amplifier N1B, and the amplification multiple is resistor R6 / resistor R5. The voltage signal output by operational amplifier N1B is connected to the AD sampling port (ADCIN2) of the single-chip microcomputer, and the collected signal is the current sharing line voltage AD2, hereinafter referred to as AD2. The single-chip microcomputer realizes digital control and adjustment of the output voltage according to the sampling voltage of the AD port.

[0022] The local current signal ADCIN1 is amplified by the same scale (amplification multiple is R6 / R5), and the amplified voltage signal is referred to as AD1. AD2 and AD1 are compared. When the local current is greater than the average current, that is, the AD1 voltage signal is greater than the AD2 voltage signal, the output voltage reference value VRef of the local machine is reduced, the output voltage value Vout is reduced, the local output current is reduced, and the output currents of the remaining modules are increased. When the output voltage is reduced too much, resulting in that the local output current is less than the average current, that is, the AD1 voltage signal is less than the AD2 voltage signal, the output voltage reference is gradually restored, the output voltage reference value VRef is increased, and the output voltage is restored to the voltage reference setting value.

[0023] When M modules in N modules have no output due to failure, the voltage value AD2 processed by the common bus terminal at this time is I total / N, which is not the average current I total / (N-M) of the actual normal working modules. AD1 and AD2*N / (N-M) are compared. When the AD1 voltage signal is greater than the AD2*N / (N-M) voltage signal, the output voltage reference value VRef of the local machine is reduced, the output voltage value Vout is reduced, the local output current is reduced, and the output currents of the remaining modules are increased.

[0024] The digital control average current sharing method based on the current sharing bus proposed in the patent can automatically exclude faulty modules, has good dynamic response performance, and has high parallel current sharing.

[0025] It will be obvious to a person skilled in the art that the application is not limited to the details of the foregoing exemplary embodiments and can be implemented in other concrete forms without departing from the spirit or essential characteristics of the application. The embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the application being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. No reference signs in the claims should be considered as limiting the scope of the claims to the identity of the reference signs therein.

[0026] Furthermore, it should be understood that although the description is made on the basis of the embodiments, not every embodiment contains only one independent technical solution, and the description of the specification is only for the sake of clarity, and those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that those skilled in the art can understand.

Claims

1. A digital control method for average current sharing based on a current sharing bus, characterized in that, The specific method is as follows: the average current value of the whole machine is obtained through the common bus circuit of multiple circuit modules in the whole machine. The average current value of the whole machine is obtained through multiple current sampling modules with the same structure. The multiple current sampling modules are connected through a common bus. The signal at the common bus terminal is the average current value of multiple circuit modules. The current sampling module includes a current sharing bus circuit and a current sharing line current sampling circuit. The input terminal of the current sharing bus circuit is connected to the local current signal ADCIN1. The output terminal of the current sharing bus circuit is connected to the input terminal of the common bus and the current sharing line current sampling circuit. The output terminal of the current sharing line current sampling circuit is connected to the microcontroller's AD sampling port ADCIN2. After the average current value of the whole machine is amplified, it is compared with the current value of the machine itself. When the current of the machine itself is greater than the average current value, the output voltage of the machine is reduced, and the output current of the machine is reduced. When the output voltage of this machine is adjusted too high, the output voltage gradually returns to the rated setting value; When M out of N circuit modules fail and have no output, if the current of the machine is greater than the average current value of the modules that are actually working normally, the output voltage of the machine will be reduced. The average current value is AD2*N / (NM), where AD2 is the current value output by the current sampling circuit of the current sharing line.

2. The digital control average current sharing method based on a current sharing bus according to claim 1, characterized in that, The current sharing bus circuit includes an operational amplifier N1A, a resistor R1, a capacitor C1, a resistor R2, a resistor R3, and a capacitor C2. The local current signal ADCIN1 is connected to one end of the resistor R1. The input terminal IN+ of the operational amplifier N1A is connected to the other end of the resistor R1 and one end of the capacitor C1. The input terminal IN- of the operational amplifier N1A is connected to one end of the resistor R2 and the output terminal OUT of the operational amplifier N1A. The other end of the capacitor C1 is grounded. The other end of the resistor R2 is connected to one end of the resistor R3 and one end of the capacitor C2. The other end of the resistor R3 is connected to the other end of the capacitor C2 and the ground terminal.

3. The digital control average current sharing method based on a current sharing bus according to claim 2, characterized in that, The current sampling circuit includes an operational amplifier N1B, resistors R4 and R5, capacitors C3 and R6, and capacitor C4. One end of resistor R4 is connected to the other end of resistor R2 and one end of capacitor C2. The other end of resistor R4 is connected to one end of capacitor C3 and the input terminal IN+ of operational amplifier N1B. The input terminal IN- of operational amplifier N1B is connected to one end of resistor R5 and one end of resistor R6. The other end of resistor R5 is connected to the other end of capacitor C3 and ground. The other end of resistor R6 is connected to the output terminal OUT of operational amplifier N1B, one end of capacitor C5, and one end of resistor R7. The other end of resistor R7 is connected to the microcontroller's AD sampling port ADCIN2 and one end of capacitor C6. The other end of capacitor C5 and the other end of capacitor C6 are grounded.

4. The digital control average current sharing method based on a current sharing bus according to claim 3, characterized in that, The input terminal IN- and output terminal OUT of the operational amplifier N1A are directly connected to form a voltage follower.

5. The digital control average current sharing method based on a current sharing bus according to claim 4, characterized in that, The operational amplifiers N1A and N1B have the same model number.

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