Direct-current transformer power self-balancing control system

Abstract

The invention discloses a direct-current transformer power self-balancing control system, which belongs to the technical field of direct-current self-energy taking under a direct-current power distribution network, and comprises a plurality of flyback converters, and a master-slave control framework is formed by taking the actually grounded flyback converter as a master module and taking other flyback converters as slave modules; the main module controls an MOS tube in the main module to be switched on or switched off according to the reference duty ratio; and the slave module controls on or off of an MOS tube in the slave module according to the reference duty ratio and the duty ratio correction. The master module adopts a system output voltage loop to maintain the stability of the system output voltage, the slave module input stage adopts an input grading ring to realize the sharing of the input voltage between flyback modules, and the slave module output stage adopts an output current sharing ring to improve the dynamic response effect of the system. The system can solve the problem of power distribution imbalance caused by inconsistent parameters between flyback modules.

Description

Technical Field

[0001] The present invention belongs to the technical field of direct current self-energy extraction in a direct current distribution network, and in particular relates to a direct current transformer power self-balancing control system. Background Art

[0002] Compared with traditional AC distribution networks, emerging DC distribution networks have demonstrated good energy conversion efficiency, can flexibly connect to renewable energy and equipment, avoid synchronization and reactive power compensation problems, and effectively reduce power converters, power consumption and construction costs.

[0003] Traditional AC distribution networks supply power to power equipment, most of which come from 220V low-voltage AC or uninterruptible power supply system loops. This power supply solution shows certain practical value within the framework of AC distribution networks. However, relying on 220V AC power supply in DC power grids is not the optimal solution. Instead, it introduces unnecessary complexity and increases the dependence on external AC power during the construction of DC distribution networks. In view of this, facing the problem of how to get rid of the dependence on external AC power supply when DC distribution networks supply power to secondary equipment, it is necessary to design a DC power supply system suitable for DC distribution networks.

[0004] Generally speaking, the voltage level of the DC distribution network is not less than 1.5kV, and the secondary circuit power equipment in the distribution network is mostly low-voltage DC such as 12V and 24V. The DC power supply system has the characteristics of high step-down ratio and small output power. For this special application, the Input Serise Output Parallel (ISOP) structure can be used, which can not only cleverly solve the high voltage bearing problem, but also has high reliability and redundancy.

[0005] However, in actual applications, it is impossible to ensure that the parameters of each flyback module, such as transformer ratio and leakage inductance, are completely consistent. Deviation of the parameters will inevitably lead to power distribution imbalance between the flyback modules. Summary of the invention

[0006] The object of the present invention is to provide a DC transformer power self-balancing control system, which can solve the power distribution imbalance problem caused by inconsistent parameters between flyback modules.

[0007] In order to achieve the above object, the present invention provides the following technical solutions: In a first aspect, the present invention provides a DC transformer power self-balancing control system, comprising a plurality of flyback converters, wherein the input ends of the flyback converters are connected in series, the output ends of the flyback converters are connected in parallel, the flyback converters actually grounded among the flyback converters are the main modules, and the other flyback converters not actually grounded are the slave modules; The main module features: An output voltage loop proportional-integral controller is used to obtain a main module control signal according to the output voltage of the main module and an output voltage reference value of the main module; A main module pulse width modulator, used for obtaining a reference duty cycle according to a main module control signal; The main module controls the MOS tube in the main module to turn on or off according to the reference duty cycle; The slave module features: The input voltage grading ring proportional integral controller is used to obtain the output current reference value of the slave module according to the input voltage of the slave module and the average value of the system input voltage; An output current sharing loop proportional-integral controller is used to obtain a slave module control signal according to an output current of the slave module and an output current reference value of the slave module; A slave module pulse width modulator, used for obtaining a duty cycle correction amount according to a slave module control signal; The slave module controls the MOS tube in the slave module to turn on or off according to the reference duty cycle and the duty cycle correction amount.

[0008] In combination with the first aspect, further, the calculation formula of the main module control signal is: ; in, Indicates the main module control signal, Indicates the output voltage reference value of the main module, Indicates the output voltage of the main module, Indicates the sampling ratio coefficient of the output voltage of the main module, Represents the transfer function of the output voltage loop proportional-integral controller.

[0009] In combination with the first aspect, further, the calculation formula of the output current reference value of the slave module is: ; in, Indicates The output current reference value of the slave module, Indicates the system input voltage, represents the total number of flyback converters, Indicates The input voltage of a slave module, Indicates The sampling ratio coefficient of the input voltage from the module, Indicates The transfer function of the proportional-integral controller of the input voltage-equalizing loop of the slave module; The calculation formula of the slave module control signal is: ; in, Indicates A slave module control signal, Indicates The output current from the module, Indicates The sampling ratio coefficient of the output current of the slave module, Indicates The transfer function of the output current sharing loop proportional-integral controller of each slave module.

[0010] In combination with the first aspect, further, controlling the MOS tube in the slave module to be turned on or off according to the reference duty cycle and the duty cycle correction amount includes: Obtain the duty cycle of the slave module according to the reference duty cycle and the duty cycle correction value; According to the duty cycle of the slave module, the MOS tube in the slave module is controlled to be turned on or off; Among them, the calculation formula of the slave module duty cycle is: ; in, Indicates The duty cycle of the slave modules is represents the reference duty cycle, Indicates The duty cycle correction corresponding to each slave module, Represents the total number of flyback converters.

[0011] In combination with the first aspect, further, each flyback converter is provided with: An input voltage detection circuit, used for detecting an input voltage of the flyback converter; An output voltage detection circuit, used for detecting the output voltage of the flyback converter; An output current detection circuit, used for detecting the output current of the flyback converter; The power tube control circuit is used to control the MOS tube in the flyback converter to turn on or off according to the duty cycle; The primary auxiliary power supply is used to power the input voltage detection circuit and the power tube control circuit; A secondary side auxiliary power supply, used to power the output voltage detection circuit and the output current detection circuit; When the flyback converter is a master module, the duty cycle is a reference duty cycle, and when the flyback converter is a slave module, the duty cycle is a reference duty cycle and a duty cycle correction amount.

[0012] In a second aspect, the present invention provides a method for controlling power self-balancing of a DC transformer, wherein the DC transformer comprises a plurality of flyback converters, wherein the input ends of the flyback converters are connected in series, and the output ends of the flyback converters are connected in parallel, wherein the flyback converters actually grounded among the flyback converters are the main modules, and the other flyback converters not actually grounded are the slave modules, and the method comprises: Obtaining a main module control signal according to the output voltage of the main module and an output voltage reference value of the main module; According to the control signal of the main module, a reference duty cycle is obtained; According to the reference duty cycle, the MOS tube in the main module is controlled to be turned on or off; According to the input voltage of the slave module and the average value of the system input voltage, an output current reference value of the slave module is obtained; Obtaining a slave module control signal according to the output current of the slave module and an output current reference value of the slave module; Obtain duty cycle correction value according to control signal from module; According to the reference duty cycle and the duty cycle correction value, the MOS tube in the slave module is controlled to be turned on or off.

[0013] In combination with the second aspect, further, the calculation formula of the main module control signal is: ; in, Indicates the main module control signal, Indicates the output voltage reference value of the main module, Indicates the output voltage of the main module, Indicates the sampling ratio coefficient of the output voltage of the main module, Represents the transfer function of the output voltage loop proportional-integral controller.

[0014] In combination with the second aspect, further, the calculation formula of the output current reference value of the slave module is: ; in, Indicates The output current reference value of the slave module, Indicates the system input voltage, represents the total number of flyback converters, Indicates The input voltage of a slave module, Indicates The sampling ratio coefficient of the input voltage from the module, Indicates The transfer function of the proportional-integral controller of the input voltage-equalizing loop of the slave module; The calculation formula of the slave module control signal is: ; in, Indicates A slave module control signal, Indicates The output current from the module, Indicates The sampling ratio coefficient of the output current of the slave module, Indicates The transfer function of the output current sharing loop proportional-integral controller of each slave module.

[0015] In combination with the second aspect, further, controlling the MOS tube in the slave module to be turned on or off according to the reference duty cycle and the duty cycle correction amount includes: Obtain the duty cycle of the slave module according to the reference duty cycle and the duty cycle correction value; According to the duty cycle of the slave module, the MOS tube in the slave module is controlled to be turned on or off; Among them, the calculation formula of the slave module duty cycle is: ; in, Indicates The duty cycle of the slave modules is represents the reference duty cycle, Indicates The duty cycle correction corresponding to each slave module, Represents the total number of flyback converters.

[0016] In combination with the second aspect, further, each flyback converter is provided with: An input voltage detection circuit, used for detecting an input voltage of the flyback converter; An output voltage detection circuit, used for detecting the output voltage of the flyback converter; An output current detection circuit, used for detecting the output current of the flyback converter; The power tube control circuit is used to control the MOS tube in the flyback converter to turn on or off according to the duty cycle; The primary auxiliary power supply is used to power the input voltage detection circuit and the power tube control circuit; A secondary side auxiliary power supply, used to power the output voltage detection circuit and the output current detection circuit; When the flyback converter is a master module, the duty cycle is a reference duty cycle, and when the flyback converter is a slave module, the duty cycle is a reference duty cycle and a duty cycle correction amount.

[0017] Compared with the prior art, the present invention has the following beneficial effects: The DC transformer power self-balancing control system provided by the present invention can solve the power distribution imbalance problem caused by inconsistent parameters between flyback modules while solving the power supply problem of secondary power equipment in the DC distribution network, and achieve better dynamic response effect. The main module adopts the system output voltage loop to maintain the stability of the system output voltage, the input leveling loop is adopted in the input leveling loop of the slave module to realize the input voltage balancing between the flyback modules, and the output leveling loop is adopted in the output leveling loop of the slave module to improve the dynamic response effect of the system. Compared with the traditional double closed-loop control strategy, the master-slave control architecture is used to introduce the input leveling loop and the output leveling loop, which can realize the input voltage balancing between the flyback modules, achieve faster dynamic response effect, and improve the output stability. When the bus voltage disturbance or the connected load disturbance causes the input voltage of a single flyback module to increase, the output current reference value of the proportional integral controller of the input leveling loop is also increased, so that the output value of the output leveling loop is increased, thereby reducing the duty cycle of the flyback module, reducing the transmission power, and reducing the output current. The input voltage of the flyback module is adjusted through feedback, and finally the circuit input voltage balancing is maintained stable.

[0018] The DC transformer power self-balancing control system provided by the present invention adopts an input series and output parallel structure. While solving the power supply problem of secondary power equipment in the DC distribution network, it can meet the high transformation ratio requirements of input high voltage and output low voltage when the DC distribution network takes energy, reduce the voltage stress of each switching device, and make the system have higher reliability, modular redundant structure and higher power transmission capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a topological diagram of a DC transformer based on an ISOP structure provided in an embodiment of the present application; Figure 2 It is a schematic diagram of the structure of a single flyback converter of a DC transformer power self-balancing control system provided by an embodiment of the present invention; Figure 3 It is a schematic diagram of the structure of a DC transformer power self-balancing control system provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0020] The technical solution of the present application is further described in detail below in conjunction with specific implementation methods.

[0021] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and should not be construed as limitations on the present application. In the absence of conflict, the embodiments of the present application and the technical features in the embodiments may be combined with each other.

[0022] An embodiment of the present application provides a direct current transformer power self-balancing control system, including a plurality of flyback converters, wherein the input ends of the flyback converters are connected in series, and the output ends of the flyback converters are connected in parallel.

[0023] Specifically, Figure 1 As shown, each flyback converter includes a flyback transformer, an input capacitor and a MOS tube connected to the primary coil of the flyback transformer, and an output capacitor and a diode connected to the secondary coil of the flyback transformer, wherein a reverse breakdown diode is connected in parallel between the drain and source of the MOS tube.

[0024] Assume the total number of flyback converters is , Figure 1 middle, , , …, Indicates the 1st, 2nd, ..., A flyback transformer for a flyback converter, , Indicates the number of turns of the primary coil and secondary coil of each flyback transformer, , , …, Indicates the 1st, 2nd, ..., The input capacitor of the flyback converter, , , …, Indicates the 1st, 2nd, ..., A MOS tube for the flyback converter, , , …, Indicates the 1st, 2nd, ..., The reverse breakdown diode of the MOS tube of the flyback converter, , , …, Indicates the 1st, 2nd, ..., The output capacitor of the flyback converter, , , …, Indicates the 1st, 2nd, ..., The diode of the flyback converter, Represents the total input voltage of each flyback converter, that is, the system input voltage, , , …, Indicates the 1st, 2nd, ..., The input voltage of the flyback converter is represents the total output current of each flyback converter, , , …, Indicates the 1st, 2nd, ..., The output current of the flyback converter is Represents the output voltage of each flyback converter, that is, the system output voltage.

[0025] In this embodiment, the flyback converter that is actually grounded among the flyback converters is the master module, and the other flyback converters that are not actually grounded are slave modules, forming a master-slave control architecture. The master module and the slave module are collectively referred to as a flyback module.

[0026] Specifically, Figure 1 As shown, suppose The flyback converter is the main module, the 1st to the A flyback converter is a slave module.

[0027] In this embodiment, the main module is provided with: An output voltage loop proportional-integral controller is used to obtain a main module control signal according to the output voltage of the main module and an output voltage reference value of the main module; A main module pulse width modulator, used for obtaining a reference duty cycle according to a main module control signal; The main module controls the MOS tube in the main module to turn on or off according to the reference duty cycle.

[0028] The output voltage loop proportional-integral controller obtains the main module control signal according to the output voltage of the main module and the output voltage reference value of the main module, and forms a system output voltage loop in the main module.

[0029] Specifically, Figure 3 As shown, Represents the output voltage loop proportional-integral controller, Represents the main module pulse width modulator, Indicates the output voltage of the main module, that is, the system output voltage. Indicates the output voltage reference value of the main module, Indicates the sampling ratio coefficient of the output voltage of the main module, Indicates the main module control signal, Indicates the reference duty cycle. Figure 1 and Figure 3 , Output connection The gate, that is, according to control On or off.

[0030] The calculation formula of the main module control signal is: ; in, Indicates the main module control signal, Indicates the output voltage reference value of the main module, Indicates the output voltage of the main module, Indicates the sampling ratio coefficient of the output voltage of the main module, Represents the transfer function of the output voltage loop proportional-integral controller.

[0031] In this embodiment, the slave module is provided with: The input voltage grading ring proportional integral controller is used to obtain the output current reference value of the slave module according to the input voltage of the slave module and the average value of the system input voltage; An output current sharing loop proportional-integral controller is used to obtain a slave module control signal according to an output current of the slave module and an output current reference value of the slave module; A slave module pulse width modulator, used for obtaining a duty cycle correction amount according to a slave module control signal; The slave module controls the MOS tube in the slave module to turn on or off according to the reference duty cycle and the duty cycle correction amount.

[0032] The input voltage grading loop proportional-integral controller obtains the output current reference value of the slave module according to the input voltage of the slave module and the average value of the system input voltage, and forms an input voltage grading loop at the input stage of the slave module.

[0033] The output current sharing loop proportional-integral controller obtains the slave module control signal according to the output current of the slave module and the output current reference value of the slave module, and forms an output current sharing loop at the output stage of the slave module.

[0034] Specifically, Figure 3 As shown, , , …, Indicates the 1st, 2nd, ..., The input voltage balancing loop proportional integral controller of the slave module, , , …, Indicates the 1st, 2nd, ..., The output current sharing loop proportional integral controller of the slave module is , , …, Indicates the 1st, 2nd, ..., A slave module pulse width modulator, represents the total number of flyback converters, Indicates the system input voltage, , , …, Indicates the 1st, 2nd, ..., The input voltage of the flyback converter is 1, 2, ..., The input voltage of a slave module, , , …, Indicates the 1st, 2nd, ..., The output current reference value of the slave module, , , …, Indicates the 1st, 2nd, ..., The output current of the flyback converters, i.e., the output current of the 1st, 2nd, ..., The output current from the module, , , …, Indicates the 1st, 2nd, ..., The sampling ratio coefficient of the input voltage from the module, , , …, Indicates the 1st, 2nd, ..., The sampling ratio coefficient of the output current of the slave module, , , …, Indicates the 1st, 2nd, ..., A slave module control signal, , , …, Indicates the 1st, 2nd, ..., The duty cycle correction corresponding to each slave module.

[0035] The calculation formula of the output current reference value of the slave module is: ; in, Indicates The output current reference value of the slave module, Indicates the system input voltage, represents the total number of flyback converters, Indicates The input voltage of a slave module, Indicates The sampling ratio coefficient of the input voltage from the module, Indicates The transfer function of the proportional-integral controller of the input balancing loop of the slave module.

[0036] The calculation formula of the slave module control signal is: ; in, Indicates A slave module control signal, Indicates The output current from the module, Indicates The sampling ratio coefficient of the output current of the slave module, Indicates The transfer function of the output current sharing loop proportional-integral controller of each slave module.

[0037] In this embodiment, according to the reference duty cycle and the duty cycle correction amount, controlling the MOS tube in the slave module to turn on or off specifically includes: Obtain the duty cycle of the slave module according to the reference duty cycle and the duty cycle correction value; According to the duty cycle of the slave module, the MOS tube in the slave module is controlled to be turned on or off.

[0038] Specifically, Figure 3 As shown, , , …, Indicates the 1st, 2nd, ..., The duty cycle of the slave module. Figure 1 and Figure 3 , , , …, The output of After the output of , , …, The gate of , , …, and After superposition, obtain , , …, ,according to , , …, control , , …, On or off.

[0039] The calculation formula of the slave module duty cycle is: ; in, Indicates The duty cycle of the slave modules is represents the reference duty cycle, Indicates The duty cycle correction corresponding to each slave module, Represents the total number of flyback converters.

[0040] The DC transformer power self-balancing control system provided in this embodiment can solve the power supply problem of secondary power equipment in the DC distribution network, while solving the power distribution imbalance problem caused by inconsistent parameters between flyback modules, and achieve better dynamic response effect.

[0041] Specifically, the master module uses the system output voltage loop to maintain the stability of the system output voltage, the slave module input stage uses the input voltage equalization loop to realize the input voltage equalization between the flyback modules, and the slave module output stage uses the output current equalization loop to improve the dynamic response effect of the system. Compared with the traditional dual closed-loop control strategy, the master-slave control architecture is used to introduce the input voltage equalization loop and the output current equalization loop, which can realize the input voltage equalization between the flyback modules, achieve a faster dynamic response effect, and improve the output stability. When the bus voltage disturbance or the connected load disturbance causes the input voltage of a single flyback module to increase, the output current reference value of the input voltage equalization loop proportional integral controller also increases, so that the output value of the output current equalization loop increases, thereby reducing the duty cycle of the flyback module, reducing the transmission power, and reducing the output current. The input voltage of the flyback module is adjusted through feedback, and finally the circuit input voltage equalization is maintained stable.

[0042] In this embodiment, the number of turns of the primary coil of each flyback transformer is the same, and the number of turns of the secondary coil of each flyback transformer is the same. The input voltage-sharing proportional-integral controller of each slave module is the same, the sampling proportional coefficient of the input voltage of each slave module is the same, and the transfer function of the input voltage-sharing proportional-integral controller of each slave module is the same. The output current-sharing proportional-integral controller of each slave module is the same, the sampling proportional coefficient of the output current of each slave module is the same, and the transfer function of the output current-sharing proportional-integral controller of each slave module is the same.

[0043] In a possible embodiment, each flyback converter is provided with: An input voltage detection circuit, used for detecting an input voltage of the flyback converter; An output voltage detection circuit, used for detecting the output voltage of the flyback converter; An output current detection circuit, used for detecting the output current of the flyback converter; The power tube control circuit is used to control the MOS tube in the flyback converter to turn on or off according to the duty cycle; The primary auxiliary power supply is used to power the input voltage detection circuit and the power tube control circuit; A secondary side auxiliary power supply, used to power the output voltage detection circuit and the output current detection circuit; When the flyback converter is a master module, the duty cycle is a reference duty cycle, and when the flyback converter is a slave module, the duty cycle is a reference duty cycle and a duty cycle correction amount.

[0044] In this embodiment, each flyback converter is further provided with: The analog / digital converter is used to perform analog-to-digital conversion on the input voltage, output voltage, and output current of the main module.

[0045] like Figure 2 As shown, taking the first slave module as an example, Figure 2 In the resistor ,capacitance ,diode To form an RCD absorption circuit, Indicates the load resistance of the first slave module. Figure 2 MOS tubes are omitted Reverse breakdown diode.

[0046] Specifically, the main module has: An input voltage detection circuit is used to detect the input voltage of the main module; An output voltage detection circuit is used to detect the output voltage of the main module; Output current detection circuit, used to detect the output current of the main module; Analog / digital converter, used for analog-to-digital conversion of input voltage, output voltage and output current of the main module; The power tube control circuit is used to control the MOS tube in the main module to turn on or off according to the reference duty cycle; Primary auxiliary power supply, used to power the input voltage detection circuit; The secondary side auxiliary power supply is used to power the output voltage detection circuit and the output current detection circuit.

[0047] The controllers corresponding to the main module include: An output voltage loop proportional-integral controller is used to obtain a main module control signal according to the output voltage of the main module and an output voltage reference value of the main module; The main module pulse width modulator is used to obtain a reference duty cycle according to the main module control signal.

[0048] Combination Figure 1 , Figure 2 and Figure 3 , the power tube control circuit of the main module is connected The gate of the main module power tube control circuit is based on Output control On or off.

[0049] Specifically, the slave module has: An input voltage detection circuit, used to detect the input voltage of the slave module; An output voltage detection circuit, used to detect the output voltage of the slave module; An output current detection circuit, used to detect the output current of the slave module; Analog / digital converter, used for analog-to-digital conversion of input voltage, output voltage and output current of the slave module; The power tube control circuit is used to control the MOS tube in the slave module to turn on or off according to the reference duty cycle and the duty cycle correction value; Primary auxiliary power supply, used to power the input voltage detection circuit; The secondary side auxiliary power supply is used to power the output voltage detection circuit and the output current detection circuit.

[0050] The controllers corresponding to the slave modules include: The input voltage grading ring proportional integral controller is used to obtain the output current reference value of the slave module according to the input voltage of the slave module and the average value of the system input voltage; An output current sharing loop proportional-integral controller is used to obtain a slave module control signal according to an output current of the slave module and an output current reference value of the slave module; The slave module pulse width modulator is used to obtain a duty cycle correction amount according to a slave module control signal.

[0051] Among them, the power tube control circuit controls the MOS tube in the slave module to be turned on or off according to the reference duty cycle and the duty cycle correction amount, specifically including: the power tube control circuit superimposes the reference duty cycle and the duty cycle correction amount, obtains the slave module duty cycle, and controls the MOS tube in the slave module to be turned on or off according to the slave module duty cycle.

[0052] Combination Figure 1 , Figure 2 and Figure 3 , connect the power tube control circuit of the module , , …, The gate of the main module's power tube control circuit will , , …, Output , , …, and Output After superposition, obtain , , …, ,according to , , …, control , , …, On or off.

[0053] The DC transformer power self-balancing control system provided in this embodiment adopts an input series and output parallel structure. While solving the power supply problem of secondary power equipment in the DC distribution network, it can meet the high transformation ratio requirements of input high voltage and output low voltage when the DC distribution network draws energy, reduce the voltage stress of each switching device, and make the system have higher reliability, modular redundant structure and higher power transmission capacity.

[0054] The embodiment of the present application provides a method for self-balancing power of a DC transformer, wherein the DC transformer includes a plurality of flyback converters, wherein the input ends of the flyback converters are connected in series, and the output ends of the flyback converters are connected in parallel, wherein the flyback converters actually grounded among the flyback converters are the main modules, and the other flyback converters not actually grounded are the slave modules, and the method includes: Obtaining a main module control signal according to the output voltage of the main module and an output voltage reference value of the main module; According to the control signal of the main module, a reference duty cycle is obtained; According to the reference duty cycle, the MOS tube in the main module is controlled to be turned on or off; According to the input voltage of the slave module and the average value of the system input voltage, an output current reference value of the slave module is obtained; Obtaining a slave module control signal according to the output current of the slave module and an output current reference value of the slave module; Obtain duty cycle correction value according to control signal from module; According to the reference duty cycle and the duty cycle correction value, the MOS tube in the slave module is controlled to be turned on or off.

[0055] In this embodiment, the calculation formula of the main module control signal is: ; in, Indicates the main module control signal, Indicates the output voltage reference value of the main module, Indicates the output voltage of the main module, Indicates the sampling ratio coefficient of the output voltage of the main module, Represents the transfer function of the output voltage loop proportional-integral controller.

[0056] The calculation formula of the output current reference value of the slave module is: ; in, Indicates The output current reference value of the slave module, Indicates the system input voltage, represents the total number of flyback converters, Indicates The input voltage of a slave module, Indicates The sampling ratio coefficient of the input voltage from the module, Indicates The transfer function of the proportional-integral controller of the input balancing loop of the slave module.

[0057] The calculation formula of the slave module control signal is: ; in, Indicates A slave module control signal, Indicates The output current from the module, Indicates The sampling ratio coefficient of the output current of the slave module, Indicates The transfer function of the output current sharing loop proportional-integral controller of each slave module.

[0058] In this embodiment, according to the reference duty cycle and the duty cycle correction amount, controlling the MOS tube in the slave module to turn on or off includes: Obtain the duty cycle of the slave module according to the reference duty cycle and the duty cycle correction value; According to the duty cycle of the slave module, the MOS tube in the slave module is controlled to be turned on or off.

[0059] The calculation formula of the slave module duty cycle is: ; in, Indicates The duty cycle of the slave modules is represents the reference duty cycle, Indicates The duty cycle correction corresponding to each slave module, Represents the total number of flyback converters.

[0060] In a possible embodiment, each flyback converter is provided with: An input voltage detection circuit, used for detecting an input voltage of the flyback converter; An output voltage detection circuit, used for detecting the output voltage of the flyback converter; An output current detection circuit, used for detecting the output current of the flyback converter; The power tube control circuit is used to control the MOS tube in the flyback converter to turn on or off according to the duty cycle; The primary auxiliary power supply is used to power the input voltage detection circuit and the power tube control circuit; A secondary side auxiliary power supply, used to power the output voltage detection circuit and the output current detection circuit; When the flyback converter is a master module, the duty cycle is a reference duty cycle, and when the flyback converter is a slave module, the duty cycle is a reference duty cycle and a duty cycle correction amount.

[0061] In this embodiment, each flyback converter is further provided with: The analog / digital converter is used to perform analog-to-digital conversion on the input voltage, output voltage, and output current of the main module.

[0062] The DC transformer power self-balancing control method provided in the embodiment of the present application has the corresponding beneficial effects of the DC transformer power self-balancing control system.

[0063] The above are only preferred implementations of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A DC transformer power self-balancing control system, comprising a plurality of flyback converters, wherein the input ends of the flyback converters are connected in series, and the output ends of the flyback converters are connected in parallel, wherein: The flyback converter that is actually grounded among the flyback converters is the master module, and the other flyback converters that are not actually grounded are slave modules; The main module features: An output voltage loop proportional-integral controller is used to obtain a main module control signal according to the output voltage of the main module and an output voltage reference value of the main module; A main module pulse width modulator, used for obtaining a reference duty cycle according to a main module control signal; The main module controls the MOS tube in the main module to turn on or off according to the reference duty cycle; The slave module features: The input voltage grading ring proportional integral controller is used to obtain the output current reference value of the slave module according to the input voltage of the slave module and the average value of the system input voltage; An output current sharing loop proportional-integral controller is used to obtain a slave module control signal according to an output current of the slave module and an output current reference value of the slave module; A slave module pulse width modulator, used for obtaining a duty cycle correction amount according to a slave module control signal; The slave module controls the MOS tube in the slave module to turn on or off according to the reference duty cycle and the duty cycle correction amount.

2. The DC transformer power self-balancing control system according to claim 1, characterized in that: The calculation formula of the main module control signal is: ； in, Indicates the main module control signal, Indicates the output voltage reference value of the main module, Indicates the output voltage of the main module, Indicates the sampling ratio coefficient of the output voltage of the main module, Represents the transfer function of the output voltage loop proportional-integral controller.

3. The DC transformer power self-balancing control system according to claim 1, characterized in that: The calculation formula of the output current reference value of the slave module is: ； in, Indicates The output current reference value of the slave module, Indicates the system input voltage, represents the total number of flyback converters, Indicates The input voltage of a slave module, Indicates The sampling ratio coefficient of the input voltage from the module, Indicates The transfer function of the proportional-integral controller of the input voltage-equalizing loop of the slave module; The calculation formula of the slave module control signal is: ； in, Indicates A slave module control signal, Indicates The output current from the module, Indicates The sampling ratio coefficient of the output current of the slave module, Indicates The transfer function of the output current sharing loop proportional-integral controller of each slave module.

4. The DC transformer power self-balancing control system according to claim 1, characterized in that: According to the reference duty cycle and the duty cycle correction amount, controlling the MOS tube in the slave module to turn on or off includes: Obtain the duty cycle of the slave module according to the reference duty cycle and the duty cycle correction value; According to the duty cycle of the slave module, the MOS tube in the slave module is controlled to be turned on or off; Among them, the calculation formula of the slave module duty cycle is: ； in, Indicates The duty cycle of the slave modules is represents the reference duty cycle, Indicates The duty cycle correction corresponding to each slave module, Represents the total number of flyback converters.

5. The DC transformer power self-balancing control system according to claim 1, characterized in that: Each flyback converter is equipped with: An input voltage detection circuit, used for detecting an input voltage of the flyback converter; An output voltage detection circuit, used for detecting the output voltage of the flyback converter; An output current detection circuit, used for detecting the output current of the flyback converter; The power tube control circuit is used to control the MOS tube in the flyback converter to turn on or off according to the duty cycle; The primary auxiliary power supply is used to power the input voltage detection circuit and the power tube control circuit; A secondary side auxiliary power supply, used to power the output voltage detection circuit and the output current detection circuit; When the flyback converter is a master module, the duty cycle is a reference duty cycle, and when the flyback converter is a slave module, the duty cycle is a reference duty cycle and a duty cycle correction amount.

6. A method for controlling power self-balancing of a DC transformer, wherein the DC transformer comprises a plurality of flyback converters, the input ends of the flyback converters are connected in series, and the output ends of the flyback converters are connected in parallel, wherein: The flyback converter that is actually grounded among the flyback converters is a master module, and the other flyback converters that are not actually grounded are slave modules. The method includes: Obtaining a main module control signal according to the output voltage of the main module and an output voltage reference value of the main module; According to the control signal of the main module, a reference duty cycle is obtained; According to the reference duty cycle, the MOS tube in the main module is controlled to be turned on or off; Obtaining an output current reference value of the slave module according to the input voltage of the slave module and the average value of the system input voltage; Obtaining a slave module control signal according to the output current of the slave module and an output current reference value of the slave module; Obtain duty cycle correction value according to control signal from module; According to the reference duty cycle and the duty cycle correction value, the MOS tube in the slave module is controlled to be turned on or off.

7. The DC transformer power self-balancing control method according to claim 6, characterized in that: The calculation formula of the main module control signal is: ； in, Indicates the main module control signal, Indicates the output voltage reference value of the main module, Indicates the output voltage of the main module, Indicates the sampling ratio coefficient of the output voltage of the main module, Represents the transfer function of the output voltage loop proportional-integral controller.

8. The DC transformer power self-balancing control method according to claim 6, characterized in that: The calculation formula of the output current reference value of the slave module is: ； in, Indicates The output current reference value of the slave module, Indicates the system input voltage, represents the total number of flyback converters, Indicates The input voltage of a slave module, Indicates The sampling ratio coefficient of the input voltage from the module, Indicates The transfer function of the proportional-integral controller of the input voltage-equalizing loop of the slave module; The calculation formula of the slave module control signal is: ； in, Indicates A slave module control signal, Indicates The output current from the module, Indicates The sampling ratio coefficient of the output current of the slave module, Indicates The transfer function of the output current sharing loop proportional-integral controller of each slave module.

9. The DC transformer power self-balancing control method according to claim 6, characterized in that: According to the reference duty cycle and the duty cycle correction amount, controlling the MOS tube in the slave module to turn on or off includes: Obtain the duty cycle of the slave module according to the reference duty cycle and the duty cycle correction value; According to the duty cycle of the slave module, the MOS tube in the slave module is controlled to be turned on or off; Among them, the calculation formula of the slave module duty cycle is: ； in, Indicates The duty cycle of the slave modules is represents the reference duty cycle, Indicates The duty cycle correction corresponding to each slave module, Represents the total number of flyback converters.

10. The DC transformer power self-balancing control method according to claim 6, characterized in that: Each flyback converter is equipped with: An input voltage detection circuit, used for detecting an input voltage of the flyback converter; An output voltage detection circuit, used for detecting the output voltage of the flyback converter; An output current detection circuit, used for detecting the output current of the flyback converter; The power tube control circuit is used to control the MOS tube in the flyback converter to turn on or off according to the duty cycle; The primary auxiliary power supply is used to power the input voltage detection circuit and the power tube control circuit; A secondary side auxiliary power supply, used to power the output voltage detection circuit and the output current detection circuit; When the flyback converter is a master module, the duty cycle is a reference duty cycle, and when the flyback converter is a slave module, the duty cycle is a reference duty cycle and a duty cycle correction amount.

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