Power supply digital-analog hybrid current sharing system and multi-module parallel power supply

Abstract

The invention belongs to the technical field of power electronics, and particularly discloses a power supply digital-analog hybrid current sharing system and a multi-module parallel power supply. According to the application, an analog and digital hybrid control thought is adopted, specifically, the current sharing bus adopts an analog signal, so that the problems of dynamic response and digital signal interference of a digital communication bus are avoided, a better current sharing dynamic characteristic is realized, and a current sharing mode adopts a digital current sharing ring to realize output power supply droop adjustment; and compared with the characteristic of unstable output voltage caused by simulation droop control, the relative voltage stability of the bus is kept on the basis of achieving the same current sharing effect.

Description

Technical Field

[0001] The present application belongs to the field of power electronics technology, and more specifically, relates to a power supply digital-analog hybrid current sharing system and a multi-module parallel power supply. Background Art

[0002] In applications where multiple power modules are connected in parallel, if no measures are taken to achieve current balancing, some power modules may work in an overloaded state while others work in an unloaded state, which will greatly affect the life of the power modules and may even cause failures, thereby affecting the stability and reliability of the entire system. Therefore, current balancing measures are usually used to reduce the electrical stress of power devices related to a single power supply, thereby improving the overall operating reliability of the power supply.

[0003] Traditional power supply current sharing solutions can be mainly divided into two categories: analog and digital. Digital current sharing usually uses a digital communication bus for current sharing. Due to the limitations of communication rate and the susceptibility of high-frequency digital signals to interference, digital current sharing methods generally have poor current sharing dynamic characteristics and susceptibility to interference. Analog current sharing usually adopts a master-slave or average current sharing idea, and realizes power supply droop control current sharing through an analog current sharing bus. This method is simple, but the voltage regulation rate is poor, which may cause unstable output voltage. Therefore, it is necessary to study a current sharing method that takes into account the dynamic characteristics of current sharing and maintains bus voltage stability. Summary of the invention

[0004] In view of the defects of the prior art, the purpose of this application is to provide a power supply digital-analog hybrid current equalization system and a multi-module parallel power supply, aiming to solve the problem of poor voltage regulation rate caused by the traditional analog current equalization bus and the problem of poor current equalization dynamic characteristics and susceptibility to interference of the current equalization characteristics caused by the digital current equalization method.

[0005] The first aspect of the present application relates to a power supply digital-analog hybrid current sharing system, which is used to share the current of at least two parallel power supply modules. The current sharing system includes: at least two analog hardware circuits and at least two digital current sharing controllers; the output positive pole of each power supply module is connected to the positive power supply terminal of the load, and the output negative pole is connected to the negative power supply terminal of the load; the analog hardware circuit is connected to the output negative pole and the current sharing bus of a single power supply module, and is used to sample the voltage analog signal of the output current value of the local power supply module and the current sharing bus voltage analog signal, and output them to the digital current sharing controller. The digital current sharing controller is used to receive the voltage analog signal of the output current value of the local power supply module and the current sharing bus voltage analog signal, convert them into digital signals respectively, and use a digital current sharing loop to realize output power supply droop current sharing control.

[0006] In some implementations, the analog hardware circuit includes: a differential sampling circuit, a signal follower circuit, an ideal diode circuit, and a sampling follower circuit; The differential sampling circuit, the signal follower circuit, and the ideal diode circuit are electrically connected in sequence; The differential sampling circuit is used for differentially sampling the output current of the local power supply module; The signal follower circuit is used to realize the impedance transformation of the output current signal of the local power module; The ideal diode circuit is used to realize a unidirectional connection between the local current signal and the current sharing bus signal, thereby realizing real-time tracking of the maximum current; The input end of the sampling follower circuit is connected to the current sharing bus, and the output end is connected to the digital current sharing controller, which is used to sample and hold the current sharing bus signal.

[0007] In some implementations, the differential sampling circuit is a differential sampling circuit using an operational amplifier, one differential input port is connected to the negative output terminal of the local power module, and the other differential input port is connected to the negative power supply terminal of the load.

[0008] In some embodiments, the signal follower circuit is composed of a low-pass filter and an operational amplifier, and the inverting input terminal of the operational amplifier is connected to the output terminal of the differential sampling circuit through the low-pass filter.

[0009] In some embodiments, the ideal diode circuit includes: a resistor R5, a resistor R7, an operational amplifier U1, and a diode D1; One end of the resistor R5 is connected to the output end of the signal follower circuit, and the other end is connected to the non-inverting input end of U1; One end of resistor R7 is connected to the power ground, and the other end is connected to the inverting input terminal of U1; The anode of diode D1 is connected to the output terminal of U1, and the cathode is connected to the inverting input terminal of U1 and the current sharing bus at the same time.

[0010] In some embodiments, the sampling follower circuit is composed of a low-pass filter and an operational amplifier, the non-inverting input terminal of the operational amplifier is simultaneously connected to the output terminal of the ideal diode circuit and the current sharing bus, and the output terminal is connected to the input terminal of the low-pass filter.

[0011] In some embodiments, the digital current sharing loop is specifically: using the output current of the local power module itself as the loop given, using the current sharing bus signal as feedback, and using the loop output as the bias signal of the power module output voltage, so as to achieve zero-static-error regulation between the power module output current and the current sharing signal.

[0012] In some implementations, the digital current sharing controller includes: Built-in ADC module, used to convert the two input voltage analog signals into voltage digital signals respectively; A first adder, used for performing a difference operation on two voltage digital signals; The PI controller is used to perform proportional and integral operations on the voltage digital signal difference to obtain the deviation value of the output voltage given value; The second adder is used to add the deviation value to the output voltage set value to obtain a new output voltage set value, thereby realizing droop current sharing control.

[0013] In some embodiments, the power supply is a switching power supply.

[0014] A second aspect of the present application relates to a multi-module parallel power supply, on which the power supply digital-analog hybrid current sharing system according to any embodiment of the present application is integrated.

[0015] In general, the above technical solutions conceived by this application have the following beneficial effects compared with the prior art: The present application provides a power supply digital-analog hybrid current sharing system, which adopts an analog and digital hybrid control concept. Specifically, the current sharing bus adopts an analog signal, thereby avoiding the dynamic response of the digital communication bus and the digital signal interference problem, and achieving better current sharing dynamic characteristics. The current sharing method adopts a digital current sharing loop to achieve output power droop regulation. Compared with the unstable output voltage caused by analog droop control, the relative voltage stability of the bus is maintained on the basis of achieving the same current sharing effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a control block diagram of a power supply digital-analog hybrid current sharing system provided in an embodiment of the present application.

[0017] Figure 2 It is a schematic diagram of the analog hardware circuit structure provided in an embodiment of the present application.

[0018] Figure 3 It is a schematic diagram of the structure of a digital current sharing controller provided in an embodiment of the present application. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0020] The term "and / or" in this article is a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. The symbol " / " in this article indicates that the associated objects are in an or relationship, for example, A / B means A or B.

[0021] The terms "first" and "second" in the specification and claims herein are used to distinguish different objects rather than to describe a specific order of the objects. For example, a first response message and a second response message are used to distinguish different response messages rather than to describe a specific order of the response messages.

[0022] In the embodiments of the present application, words such as "exemplary" or "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a specific way.

[0023] In the description of the embodiments of the present application, unless otherwise specified, "multiple" means two or more than two. For example, multiple processing units refer to two or more processing units, etc.; multiple elements refer to two or more elements, etc.

[0024] The embodiments of the present application are described below in conjunction with the drawings in the embodiments of the present application.

[0025] like Figure 1 As shown, the present application provides a power supply digital-analog hybrid current balancing system for balancing the current of at least two parallel power supply modules (U101 and U102), wherein the current balancing system comprises: at least two analog hardware circuits and at least two digital current balancing controllers; the output positive pole of each power supply module is connected to the positive power supply terminal of the load (U103), and the output negative pole is connected to the negative power supply terminal of the load (U103).

[0026] The analog hardware circuit is connected to the output negative pole and the current sharing bus of a single power module, and is used to sample the voltage analog signal of the output current value of the local power module and the voltage analog signal of the current sharing bus, and output them to the digital current sharing controller.

[0027] The digital current sharing controller is used to receive the voltage analog signal of the output current value of the local power module and the current sharing bus voltage analog signal, convert them into digital signals respectively, and use a digital current sharing loop to realize output power droop current sharing control.

[0028] In some embodiments, Figure 2 As shown, the analog hardware circuit includes: a differential sampling circuit, a signal follower circuit, an ideal diode circuit and a sampling follower circuit; The differential sampling circuit, the signal follower circuit, and the ideal diode circuit are electrically connected in sequence; The differential sampling circuit is used for differentially sampling the output current of the local power supply module; The signal follower circuit is used to realize the impedance transformation of the output current signal of the local power module; The ideal diode circuit is used to realize a unidirectional connection between the local current signal and the current sharing bus signal, thereby realizing real-time tracking of the maximum current; The input end of the sampling follower circuit is connected to the current sharing bus, and the output end is connected to the digital current sharing controller, which is used to sample and hold the current sharing bus signal.

[0029] In some embodiments, Figure 2 As shown, the differential sampling circuit is a differential sampling circuit using an operational amplifier, one differential input port is connected to the negative output terminal of the local power module, and the other differential input port is connected to the negative power supply terminal of the load. Optionally, the differential sampling circuit is composed of resistors R1, R2, R4, R6 and an operational amplifier U2.

[0030] In some embodiments, Figure 2 As shown, the signal follower circuit is composed of a low-pass filter and an operational amplifier, and the inverting input terminal of the operational amplifier is connected to the output terminal of the differential sampling circuit through the low-pass filter. Optionally, the signal follower circuit is composed of a resistor R3, a capacitor C1 and an operational amplifier U3. The resistor R3 and the capacitor C1 form a low-pass filter.

[0031] In some embodiments, Figure 2 As shown, the ideal diode circuit includes: a resistor R5, a resistor R7, an operational amplifier U1 and a diode D1; one end of the resistor R5 is connected to the output end of the signal follower circuit, and the other end is connected to the non-inverting input end of U1; one end of the resistor R7 is connected to the power ground, and the other end is connected to the inverting input end of U1; the anode of the diode D1 is connected to the output end of U1, and the cathode is connected to the inverting input end of U1 and the current sharing bus at the same time.

[0032] In some embodiments, Figure 2 As shown, the sampling follower circuit is composed of a low-pass filter and an operational amplifier, the non-inverting input terminal of the operational amplifier is connected to the output terminal of the ideal diode circuit and the current sharing bus at the same time, and the output terminal is connected to the input terminal of the low-pass filter. Optionally, the sampling follower circuit is composed of a resistor R8, a capacitor C2 and an operational amplifier U4. The resistor R8 and the capacitor C2 form a low-pass filter. ADCIN1 represents the bus voltage sampling signal, which is output to the digital current sharing control for analog-to-digital conversion.

[0033] In some embodiments, the digital current sharing loop is specifically: using the output current of the local power module itself as the loop given, using the current sharing bus signal as feedback, and using the loop output as the bias signal of the power module output voltage, so as to achieve zero-static-error regulation between the power module output current and the current sharing signal.

[0034] In some embodiments, Figure 3 As shown, the digital current sharing controller includes: a built-in ADC module, used to convert two input voltage analog signals into voltage digital signals respectively; a first adder, used to make a difference between the two voltage digital signals; a PI controller, used to scale and integrate the voltage digital signal difference to obtain a deviation value of the output voltage given value; a second adder, used to superimpose the deviation value on the output voltage given value to obtain a new output voltage given value, thereby realizing droop current sharing control.

[0035] In some implementations, the power supply is a switching power supply, and a 1+1 or N+1 parallel redundant working mode can be used to improve the power supply reliability of the system.

[0036] The digital current sharing controller can be implemented by MCU or DSP.

[0037] The rated given value of the output voltage of each power module is initialized to be consistent. For example, if the rated output of the power module is +12V, the voltage given value is uniformly set to +12V by default.

[0038] A second aspect of the present application relates to a multi-module parallel power supply, on which the power supply digital-analog hybrid current sharing system according to any embodiment of the present application is integrated.

[0039] It should be understood that expressions such as "including" and "may include" that may be used in the present application indicate the existence of the disclosed functions, operations, or constituent elements, and do not limit one or more additional functions, operations, and constituent elements. In the present application, terms such as "including" and / or "having" may be interpreted as indicating specific characteristics, numbers, operations, constituent elements, components, or combinations thereof, but may not be interpreted as excluding the existence or possibility of adding one or more other characteristics, numbers, operations, constituent elements, components, or combinations thereof.

[0040] In addition, in the present application, the expression "and / or" includes any and all combinations of the associated listed words. For example, the expression "A and / or B" may include A, may include B, or may include both A and B.

[0041] In the description of the embodiments of the present application, it should be noted that, unless otherwise clearly specified and limited, the term "connection" should be understood in a broad sense. For example, "connection" can be a detachable connection or a non-detachable connection; it can be a direct connection or an indirect connection through an intermediate medium.

[0042] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A power supply digital-analog hybrid current sharing system, characterized in that: Used to balance the current of at least two parallel power modules, the current balancing system includes: at least two analog hardware circuits and at least two digital current balancing controllers; The positive output of each power module is connected to the positive power supply terminal of the load, and the negative output is connected to the negative power supply terminal of the load; The analog hardware circuit is connected to the output negative electrode and the current sharing bus of a single power module, and is used to sample the voltage analog signal of the output current value of the local power module and the voltage analog signal of the current sharing bus, and output it to the digital current sharing controller. The digital current sharing controller is used to receive the voltage analog signal of the output current value of the local power module and the current sharing bus voltage analog signal, convert them into digital signals respectively, and use a digital current sharing loop to realize output power droop current sharing control.

2. The current balancing system according to claim 1, characterized in that: The analog hardware circuit comprises: a differential sampling circuit, a signal following circuit, an ideal diode circuit and a sampling following circuit; The differential sampling circuit, the signal follower circuit, and the ideal diode circuit are electrically connected in sequence; The differential sampling circuit is used for differentially sampling the output current of the local power supply module; The signal follower circuit is used to realize the impedance transformation of the output current signal of the local power module; The ideal diode circuit is used to realize a unidirectional connection between the local current signal and the current sharing bus signal, thereby realizing real-time tracking of the maximum current; The input end of the sampling follower circuit is connected to the current sharing bus, and the output end is connected to the digital current sharing controller, which is used to sample and hold the current sharing bus signal.

3. The current balancing system according to claim 2, characterized in that: The differential sampling circuit is a differential sampling circuit using an operational amplifier, one differential input port is connected to the negative output terminal of the local power module, and the other differential input port is connected to the negative power supply terminal of the load.

4. The current balancing system according to claim 2, characterized in that: The signal follower circuit is composed of a low-pass filter and an operational amplifier, and the inverting input end of the operational amplifier is connected to the output end of the differential sampling circuit through the low-pass filter.

5. The current balancing system according to claim 2, characterized in that: The ideal diode circuit includes: a resistor R5, a resistor R7, an operational amplifier U1 and a diode D1; One end of the resistor R5 is connected to the output end of the signal follower circuit, and the other end is connected to the non-inverting input end of U1; One end of resistor R7 is connected to the power ground, and the other end is connected to the inverting input terminal of U1; The anode of diode D1 is connected to the output terminal of U1, and the cathode is connected to the inverting input terminal of U1 and the current sharing bus at the same time.

6. The current balancing system according to claim 2, characterized in that: The sampling follower circuit is composed of a low-pass filter and an operational amplifier. The non-inverting input end of the operational amplifier is connected to the output end of the ideal diode circuit and the current sharing bus at the same time, and the output end is connected to the input end of the low-pass filter.

7. The current balancing system according to claim 6, characterized in that: The digital current sharing loop specifically takes the output current of the local power module itself as the loop given, takes the current sharing bus signal as feedback, and takes the loop output as the bias signal of the power module output voltage, so as to achieve zero-static-error regulation between the power module output current and the current sharing signal.

8. The current balancing system according to claim 1, characterized in that: The digital current sharing controller comprises: Built-in ADC module, used to convert the two input voltage analog signals into voltage digital signals respectively; A first adder, used for performing a difference operation on two voltage digital signals; The PI controller is used to perform proportional and integral operations on the voltage digital signal difference to obtain the deviation value of the output voltage given value; The second adder is used to add the deviation value to the output voltage set value to obtain a new output voltage set value, thereby realizing droop current sharing control.

9. The current balancing system according to any one of claims 1 to 8, characterized in that: The power supply is a switching power supply.

10. A multi-module parallel power supply, characterized in that: A power supply digital-analog hybrid current sharing system as described in any one of claims 1 to 9 is integrated thereon.

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