Digital power supply parallel current sharing control circuit

Abstract

The utility model discloses a parallel current-sharing control circuit for a digital power supply. The parallel current-sharing control circuit comprises a power supply module, a current amplifier, a voltage follower, a current-sharing controller, a voltage amplifier, a current-sharing control voltage Uc, a reference voltage Ur, a feedback voltage Uf, a capacitor C, a resistor R, a current-sharing bus Ub and a synchronous starting signal. The method has the beneficial effects that a constant current point is set in a program, and a constant current loop control strategy is added. On one hand, modules can be protected, and overload work is avoided; and on the other hand, when a module reaches a constant current point, the module no longer shares a load and enters a constant current loop working mode, and a program adjusts output voltages of other modules to enable the other modules to approach the constant current point with a load, so that the current sharing precision is high, and compared with a traditional average current sharing control strategy, the module can be protected after the constant current loop is added, and the service life of the module is prolonged. Damage caused by far excess of the rated load in the current sharing process is avoided. And the current sharing reliability and the module parallel current sharing precision are improved.

Description

Technical Field

[0001] The utility model relates to the technical field of parallel current sharing of power supply modules, in particular to a digital power supply parallel current sharing control circuit. Background Art

[0002] With the development of technology, there is a huge demand for high power density and high reliability DC / DC module power supplies in military and industrial production. At the same time, in high-power applications, a single module power supply can no longer meet the power level requirements, which requires multiple modules to be used in parallel. At this time, the module needs to have a current sharing function to improve the power level.

[0003] The current approach is:

[0004] 1. Use the average current method: The voltage value obtained by the output current sampling circuit of the power module output current is connected to the current sharing bus through a resistor. When the voltage value obtained by the output current sampling is greater than the voltage value on the current sharing bus, the output voltage value of the module will be lowered; when the voltage value obtained by the output current sampling is less than the voltage value on the current sharing bus, the voltage value of the module output will be increased to increase the output current of the module; using the average current method, the currents of the modules will compete with each other when they are just started, and one module will have too much current to reach overcurrent protection, or there will be two modules competing all the time, resulting in low current sharing accuracy.

[0005] 2. Use the peak current method: The voltage value obtained by the output current sampling circuit of the power module output current is connected to the current sharing bus through a diode. The module with the largest output current is the main module. The voltage on the current sharing bus is the voltage obtained by sampling the output current of the main module minus a diode voltage drop. When the power supply is started, the output current of the slave module approaches the main module, but there is a diode voltage drop between the voltage on the current sharing bus and the module. There is always a large difference between the output current of the slave module and the main module, and the accuracy is poor.

[0006] Currently, no effective solution has been proposed for the problems in the related technologies. Utility Model Content

[0007] In view of the problems in the related art, the utility model proposes a digital power supply parallel current sharing control circuit to overcome the above technical problems existing in the existing related art.

[0008] To this end, the specific technical solutions adopted by the utility model are as follows:

[0009] A digital power parallel current sharing control circuit, comprising a power module, a current amplifier, a voltage follower, a current sharing controller, a voltage amplifier, a current sharing control voltage Uc, a reference voltage Ur, a feedback voltage Uf, a capacitor C, a resistor R, a current sharing bus Ub and a synchronous start signal;

[0010] One end of the power module is connected to one end of the current amplifier, the other end of the current amplifier is connected to the positive electrode of the voltage follower, one end of the voltage follower is connected to the resistor R and the current balancing controller respectively, and the other end of the resistor R is connected to the current balancing bus Ub and the current balancing controller;

[0011] The other end of the current balancing controller generates the current balancing control voltage Uc, which is superimposed on the reference voltage Ur and connected to the positive electrode of the voltage amplifier. One end of the voltage amplifier is connected to the power module, and the negative electrode of the voltage amplifier is connected to the feedback voltage Uf and one end of the capacitor C. The other end of the capacitor C is connected to the power module, and one end of the power module is connected to the synchronous start signal.

[0012] Preferably, the sampled output current is amplified 39 times by the current amplifier to obtain the output current sampling signal Ui.

[0013] Preferably, a constant current control strategy is added.

[0014] Preferably, the voltage signal across the resistor R is sent to the module through the current sharing controller to generate a current sharing control signal Uc.

[0015] The beneficial effects of the utility model are as follows: a constant current point is set in the program, and a constant current loop control strategy is added. On the one hand, the module can be protected from overload; on the other hand, when a module reaches the constant current point, it no longer shares the load and enters the constant current loop working mode, and the program adjusts the output voltage of the remaining modules to make them close to the constant current point with high current sharing accuracy. Compared with the traditional average current sharing control strategy, the constant current loop can protect the module and avoid damage due to far exceeding the rated load during the current sharing process. The reliability of current sharing and the accuracy of module parallel current sharing are improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 It is a circuit diagram of a digital power supply parallel current sharing control circuit according to an embodiment of the utility model;

[0018] Figure 2 It is a schematic diagram of a digital power supply parallel current sharing control circuit according to an embodiment of the utility model. DETAILED DESCRIPTION

[0019] To further illustrate each embodiment, the present invention provides drawings, which are part of the disclosure of the present invention and are mainly used to illustrate the embodiments. They can be used in conjunction with the relevant descriptions in the specification to explain the operating principles of the embodiments. With reference to these contents, ordinary technicians in the field should be able to understand other possible implementation methods and advantages of the present invention. The components in the figures are not drawn to scale, and similar component symbols are generally used to represent similar components.

[0020] According to an embodiment of the utility model, a digital power supply parallel current sharing control circuit is provided.

[0021] Embodiment 1;

[0022] like Figure 1-2 As shown, the digital power parallel current sharing control circuit according to the embodiment of the utility model includes a power module, a current amplifier, a voltage follower, a current sharing controller, a voltage amplifier, a current sharing control voltage Uc, a reference voltage Ur, a feedback voltage Uf, a capacitor C, a resistor R, a current sharing bus Ub and a synchronous start signal;

[0023] One end of the power module is connected to one end of the current amplifier, the other end of the current amplifier is connected to the positive electrode of the voltage follower, one end of the voltage follower is connected to the resistor R and the current balancing controller respectively, and the other end of the resistor R is connected to the current balancing bus Ub and the current balancing controller;

[0024] The other end of the current balancing controller generates the current balancing control voltage Uc, which is superimposed on the reference voltage Ur and connected to the positive electrode of the voltage amplifier. One end of the voltage amplifier is connected to the power module, and the negative electrode of the voltage amplifier is connected to the feedback voltage Uf and one end of the capacitor C. The other end of the capacitor C is connected to the power module, and one end of the power module is connected to the synchronous start signal.

[0025] The core controller used in the module is ADP32F035. The sampled output current is amplified 39 times to obtain the output current sampling signal Ui, which is then connected to one end of the current-sharing resistor R through a voltage follower. The other end of R is connected to the current-sharing bus. The voltage follower can improve the circuit's anti-interference ability. The voltage signal at both ends of R generates a current-sharing control signal Uc through the current-sharing control circuit and is sent to the DSP. Two modules with an output current of 36A are connected in parallel, and the total current I out=72A. The constant current control strategy is added to the program, the output voltage is lowered, and the load no longer increases with the total load. The program compensates the output voltage of other modules, allowing other modules to share more loads and approach the constant current point. The current sharing error is within 2A, achieving an ideal current sharing effect.

[0026] Embodiment 2:

[0027] like Figure 1-2 As shown, the sampled output current is amplified 39 times by the current amplifier to obtain the output current sampling signal Ui, and a constant current control strategy is added. The voltage signal at both ends of the resistor R is sent to the module through the current equalizing controller to generate a current equalizing control signal Uc.

[0028] In summary, with the help of the above technical solution of the utility model, the constant current point is set in the program and the constant current loop control strategy is added. On the one hand, the module can be protected to avoid overload; on the other hand, when a module reaches the constant current point, it no longer shares the load and enters the constant current loop working mode, and the program adjusts the output voltage of the remaining modules to make it close to the constant current point with high current sharing accuracy. Compared with the traditional average current sharing control strategy, the constant current loop can protect the module and avoid damage due to far exceeding the rated load during the current sharing process. The reliability of current sharing and the accuracy of parallel module current sharing are improved.

[0029] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A digital power supply parallel current sharing control circuit, characterized in that: It includes a power module, a current amplifier, a voltage follower, a current sharing controller, a voltage amplifier, a current sharing control voltage Uc, a reference voltage Ur, a feedback voltage Uf, a capacitor C, a resistor R, a current sharing bus Ub and a synchronous start signal; One end of the power module is connected to one end of the current amplifier, the other end of the current amplifier is connected to the positive electrode of the voltage follower, one end of the voltage follower is connected to the resistor R and the current balancing controller respectively, and the other end of the resistor R is connected to the current balancing bus Ub and the current balancing controller; The other end of the current balancing controller generates the current balancing control voltage Uc, which is superimposed on the reference voltage Ur and connected to the positive electrode of the voltage amplifier. One end of the voltage amplifier is connected to the power module, and the negative electrode of the voltage amplifier is connected to the feedback voltage Uf and one end of the capacitor C. The other end of the capacitor C is connected to the power module, and one end of the power module is connected to the synchronous start signal.

2. A digital power parallel current sharing control circuit according to claim 1, characterized in that: The sampled output current is amplified 39 times by the current amplifier to obtain an output current sampling signal Ui.

3. A digital power parallel current sharing control circuit according to claim 1, characterized in that: When a module reaches the constant current point 36A during the current sharing process, the module enters the constant current loop mode.

4. A digital power parallel current sharing control circuit according to claim 1, characterized in that: The voltage signal at both ends of the resistor R is sent to the module through the current sharing controller to generate a current sharing control signal Uc.

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