A direct current transformer power self-balancing control system

Abstract

The application discloses a DC transformer power self-balancing control system, and belongs to the technical field of DC self-energy under a DC power distribution network. The system comprises a plurality of flyback converters, wherein the flyback converter actually grounded is a master module, and other flyback converters are slave modules, thereby forming a master-slave control architecture. The master module controls MOS pipe conduction or turn-off in the master module according to a reference duty ratio. The slave module controls MOS pipe conduction or turn-off in the slave module according to the reference duty ratio and a duty ratio correction amount. The master module adopts a system output voltage loop to maintain the stability of the system output voltage. The input stage of the slave module adopts an input voltage sharing loop to realize input voltage sharing among the flyback modules. The output stage of the slave module adopts an output current sharing loop to improve the dynamic response effect of the system. The system can solve the power distribution imbalance problem caused by the inconsistency of parameters among the flyback modules.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of direct current self-energy under direct current power distribution network, and particularly relates to a direct current transformer power self-balancing control system. BACKGROUND

[0002] Compared with the traditional alternating current power distribution network, the emerging direct current power distribution network exhibits good energy conversion efficiency, can flexibly access renewable energy and equipment, avoids synchronization and reactive power compensation problems, and effectively reduces power converters, power consumption and construction costs.

[0003] The traditional alternating current power distribution network supplies power to power equipment, most of which comes from 220V low-voltage alternating current or uninterruptible power supply system loop. This power supply scheme exhibits certain practical value within the alternating current power distribution network framework. However, the method of relying on 220V alternating current power supply in the direct current power grid is not the optimal solution, but introduces unnecessary complexity and aggravates the dependence on external alternating current power in the process of building the direct current power distribution network. In view of this, in the face of the problem of how to break away from the dependence on external alternating current power supply for the direct current power distribution network to supply power to secondary equipment, a direct current power supply system suitable for the direct current power distribution network needs to be designed.

[0004] Generally, the voltage level of the direct current power distribution network is not less than 1.5kV, and the secondary loop power consumption equipment in the power distribution network is mostly low-voltage direct current such as 12V and 24V. The direct current power supply system has the characteristics of high voltage reduction ratio and small output power. For this special application occasion, the input series and output parallel (ISOP) structure can be used, which not only ingeniously solves the problem of high voltage bearing, but also has high reliability and redundancy.

[0005] However, in actual application, the transformer ratio and leakage inductance of each flyback module cannot be guaranteed to be completely consistent, and the parameter deviation will inevitably cause power distribution imbalance between the flyback modules. SUMMARY

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

[0007] To achieve the above purpose, the present application provides the following technical scheme:

[0008] In a first aspect, the present application provides a direct current transformer power self-balancing control system, which includes a plurality of flyback converters, the input ends of the flyback converters are connected in series, the output ends of the flyback converters are connected in parallel, the flyback converter actually grounded in each flyback converter is taken as a master module, and the other flyback converters not actually grounded are taken as slave modules.

[0009] The main module includes:

[0010] The output voltage loop proportional-integral controller is used to obtain the main module control signal based on the main module's output voltage and the main module's output voltage reference value;

[0011] The main module pulse width modulator is used to obtain the reference duty cycle based on the main module control signal;

[0012] The main module controls the MOSFETs within it to turn on or off based on the reference duty cycle.

[0013] The module has the following features:

[0014] The input equalizing loop proportional-integral controller is used to obtain the output current reference value of the slave module based on the input voltage of the slave module and the average value of the system input voltage;

[0015] The output current sharing loop proportional-integral controller is used to obtain the slave module control signal based on the slave module's output current and the slave module's output current reference value;

[0016] The slave module pulse width modulator is used to obtain the duty cycle correction amount based on the slave module control signal;

[0017] The module controls the MOSFETs within it to turn on or off based on the reference duty cycle and the duty cycle correction.

[0018] In conjunction with the first aspect, the calculation formula for the main module control signal is further as follows:

[0019] ;

[0020] in, Indicates the main module control signal. This indicates the reference value of the main module's output voltage. This indicates the output voltage of the main module. This represents the sampling ratio of the main module's output voltage. This represents the transfer function of the output voltage loop proportional-integral controller.

[0021] In conjunction with the first aspect, the formula for calculating the module's output current reference value is as follows:

[0022] ;

[0023] in, Indicates the first The output current reference value of the module. Indicates the system input voltage. Indicates the total number of flyback converters. Indicates the first The input voltage of the module, Indicates the first The sampling ratio of the input voltage of each module. Indicates the first The transfer function of the proportional-integral controller of the equalizing loop from the input of the module;

[0024] The formula for calculating the module control signal is:

[0025] ;

[0026] in, Indicates the first Each module control signal, Indicates the first The output current of the module, Indicates the first The sampling ratio of the output current of the module. Indicates the first The transfer function of the proportional-integral controller of the output current sharing loop of the slave module.

[0027] In conjunction with the first aspect, further, based on the reference duty cycle and the duty cycle correction amount, controlling the on / off state of the MOSFET within the module includes:

[0028] The duty cycle of the slave module is obtained based on the baseline duty cycle and the duty cycle correction amount.

[0029] Based on the duty cycle of the slave module, control the MOS transistors inside the slave module to be turned on or off;

[0030] The formula for calculating the module duty cycle is as follows:

[0031] ;

[0032] in, Indicates the first The duty cycle of each module Indicates the baseline duty cycle. Indicates the first The duty cycle correction amount corresponding to each module This indicates the total number of flyback converters.

[0033] In conjunction with the first aspect, furthermore, each flyback converter is equipped with:

[0034] Input voltage detection circuit, used to detect the input voltage of the flyback converter;

[0035] Output voltage detection circuit, used to detect the output voltage of flyback converter;

[0036] Output current detection circuit, used to detect the output current of flyback converter;

[0037] a power tube control circuit for controlling the MOS tube to be turned on or turned off in the flyback converter according to the duty ratio;

[0038] a primary auxiliary power supply for supplying power to the input voltage detection circuit and the power tube control circuit;

[0039] a secondary auxiliary power supply for supplying power to the output voltage detection circuit and the output current detection circuit;

[0040] wherein, when the flyback converter is a master module, the duty ratio is a reference duty ratio, and when the flyback converter is a slave module, the duty ratio is the reference duty ratio and a duty ratio correction amount.

[0041] In a second aspect, the present application provides a power self-balancing control method for a DC transformer, the DC transformer comprising a plurality of flyback converters, the input ends of the flyback converters being connected in series, the output ends of the flyback converters being connected in parallel, a flyback converter actually grounded being a master module, and other flyback converters not actually grounded being slave modules, the method comprising:

[0042] obtaining a master module control signal according to an output voltage of the master module and an output voltage reference value of the master module;

[0043] obtaining a reference duty ratio according to the master module control signal;

[0044] controlling a MOS tube in the master module to be turned on or turned off according to the reference duty ratio;

[0045] obtaining an output current reference value of a slave module according to an input voltage of the slave module and an average value of system input voltages;

[0046] obtaining a slave module control signal according to an output current of the slave module and the output current reference value of the slave module;

[0047] obtaining a duty ratio correction amount according to the slave module control signal;

[0048] controlling a MOS tube in the slave module to be turned on or turned off according to the reference duty ratio and the duty ratio correction amount.

[0049] In combination with the second aspect, further, a calculation formula of the master module control signal is:

[0050] ;

[0051] wherein, the master module control signal is represented by Vm, the output voltage reference value of the master module is represented by Vmref, the output voltage of the master module is represented by Vmout, a sampling proportionality coefficient of the output voltage of the master module is represented by Kvm, and This represents the transfer function of the output voltage loop proportional-integral controller.

[0052] In conjunction with the second aspect, the formula for calculating the module's output current reference value is as follows:

[0053] ;

[0054] in, Indicates the first The output current reference value of the module. Indicates the system input voltage. Indicates the total number of flyback converters. Indicates the first The input voltage of the module, Indicates the first The sampling ratio of the input voltage of each module. Indicates the first The transfer function of the proportional-integral controller of the equalizing loop from the input of the module;

[0055] The formula for calculating the module control signal is:

[0056] ;

[0057] in, Indicates the first Each module control signal, Indicates the first The output current of the module, Indicates the first The sampling ratio of the output current of the module. Indicates the first The transfer function of the proportional-integral controller of the output current sharing loop of the slave module.

[0058] In conjunction with the second aspect, further, based on the reference duty cycle and the duty cycle correction amount, controlling the on / off state of the MOSFETs within the module includes:

[0059] The duty cycle of the slave module is obtained based on the baseline duty cycle and the duty cycle correction amount.

[0060] Based on the duty cycle of the slave module, control the MOS transistors inside the slave module to be turned on or off;

[0061] The formula for calculating the module duty cycle is as follows:

[0062] ;

[0063] in, Indicates the first The duty cycle of each module Indicates the baseline duty cycle. denotes the duty cycle correction amount corresponding to the denotes the total number of flyback converters.

[0064] In combination with the second aspect, further, each flyback converter is provided with:

[0065] an input voltage detection circuit for detecting the input voltage of the flyback converter;

[0066] an output voltage detection circuit for detecting the output voltage of the flyback converter;

[0067] an output current detection circuit for detecting the output current of the flyback converter;

[0068] a power tube control circuit for controlling the conduction or turn-off of the MOS tube in the flyback converter according to the duty cycle;

[0069] a primary side auxiliary power supply for powering the input voltage detection circuit and the power tube control circuit;

[0070] a secondary side auxiliary power supply for powering the output voltage detection circuit and the output current detection circuit;

[0071] wherein when the flyback converter is a master module, the duty cycle is the reference duty cycle, and when the flyback converter is a slave module, the duty cycle is the reference duty cycle plus the duty cycle correction amount.

[0072] Compared with the prior art, the present application has the following advantages:

[0073] The DC transformer power self-balancing control system provided by the present application can solve the power supply problem of secondary power equipment in a DC power distribution network, and can also solve the power distribution imbalance problem caused by inconsistent parameters between flyback modules, and achieve better dynamic response effect. The master module uses a system output voltage loop to maintain the stability of the system output voltage, the input stage of the slave module uses an input voltage equalization loop to achieve equal distribution of input voltages between flyback modules, and the output stage of the slave module uses an output current equalization loop to improve the dynamic response effect of the system. Compared with the traditional double closed-loop control strategy, the master-slave control architecture, the input voltage equalization loop and the output current equalization loop can achieve equal distribution of input voltages between flyback modules and achieve faster dynamic response effect, and improve the stability of the output. 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, and then the duty cycle of the flyback module decreases, the transmission power decreases, and the output current decreases. Through feedback, the input voltage of the flyback module is adjusted, and finally the circuit input voltage is maintained stable.

[0074] ​The DC transformer power self-balancing control system provided by the application has an input series connection and an output parallel connection structure, can solve the power supply problem of secondary power equipment in a DC power distribution network, can meet the high transformation ratio requirement of high input voltage and low output voltage when power is taken from the DC power distribution network, can reduce the voltage stress of each switching device, and can make the system have high reliability, a modular redundant structure and high power transmission capacity. BRIEF DESCRIPTION OF DRAWINGS

[0075] Figure 1 is a DC transformer topology diagram based on an ISOP structure provided by an embodiment of the application;

[0076] Figure 2 is a single flyback converter structure diagram of a DC transformer power self-balancing control system provided by an embodiment of the application;

[0077] Figure 3 is a structure diagram of a DC transformer power self-balancing control system provided by an embodiment of the application. DETAILED DESCRIPTION

[0078] The technical solutions of the application will be further described in detail below with reference to specific implementation manners.

[0079] The embodiments of the application will be described in detail below, and examples of the embodiments are shown in the drawings, in which the same or similar reference signs represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the drawings are exemplary and are only used to explain the application and cannot be understood as a limitation on the application. The technical features in the embodiments of the application and the embodiments can be combined with each other without conflict.

[0080] The DC transformer power self-balancing control system provided by an embodiment of the application 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.

[0081] Specifically, as shown in Figure 1 , each flyback converter comprises a flyback transformer, an input capacitor and a MOS tube connected with a primary coil of the flyback transformer, and an output capacitor and a diode connected with a secondary coil of the flyback transformer, wherein a reverse breakdown diode is connected in parallel between the drain and the source of the MOS tube.

[0082] Let the total number of flyback converters be , Figure 1 in , , …, represent the flyback transformers of the 1st, 2nd, …, th flyback converters, , This indicates the number of turns in the primary and secondary coils of each flyback transformer. , … Indicates the 1st, 2nd, ... The input capacitor of the flyback converter , … Indicates the 1st, 2nd, ... The MOSFETs of the flyback converter , … Indicates the 1st, 2nd, ... The reverse breakdown diode of the MOSFET in the flyback converter , … Indicates the 1st, 2nd, ... The output capacitor of the flyback converter , … Indicates the 1st, 2nd, ... The diodes of the flyback converter This represents the total input voltage of all flyback converters, i.e., the system input voltage. , … Indicates the 1st, 2nd, ... The input voltage of a flyback converter This represents the total output current of each flyback converter. , … Indicates the 1st, 2nd, ... The output current of the flyback converter This represents the output voltage of each flyback converter, i.e., the system output voltage.

[0083] In this embodiment, the flyback converters that are actually grounded are designated as master modules, and the other flyback converters that are not actually grounded are designated as slave modules, forming a master-slave control architecture. The master module and slave modules are collectively referred to as flyback modules.

[0084] Specifically, such as Figure 1 As shown, let the first... The flyback converter is the main module, from the 1st to the 2nd... Each flyback converter is a slave module.

[0085] In this embodiment, the main module includes:

[0086] The output voltage loop proportional-integral controller is used to obtain the main module control signal based on the main module's output voltage and the main module's output voltage reference value;

[0087] a main module pulse width modulator, configured to obtain a reference duty cycle according to a main module control signal;

[0088] The main module controls the conduction or turn-off of a MOS transistor in the main module according to the reference duty cycle.

[0089] An output voltage loop proportional integral controller obtains the main module control signal according to an output voltage of the main module and an output voltage reference value of the main module, and forms an output voltage loop of the system in the main module.

[0090] Specifically, as shown in Figure 3 , denotes an output voltage loop proportional integral controller, denotes a main module pulse width modulator, denotes an output voltage of the main module, i.e., an output voltage of the system, denotes an output voltage reference value of the main module, denotes a sampling proportional coefficient of the output voltage of the main module, denotes a main module control signal, denotes a reference duty cycle. In combination with Figure 1 and Figure 3 , the output end of is connected to the gate of , i.e., according to to control to conduct or turn off.

[0091] The calculation formula of the main module control signal is:

[0092] ;

[0093] wherein, denotes a main module control signal, denotes an output voltage reference value of the main module, denotes an output voltage of the main module, denotes a sampling proportional coefficient of the output voltage of the main module, denotes a transfer function of an output voltage loop proportional integral controller.

[0094] In the embodiment, the slave module is provided with:

[0095] an input voltage loop proportional integral controller, configured to obtain an output current reference value of the slave module according to an input voltage of the slave module and an average value of a system input voltage;

[0096] an output current loop proportional integral controller, configured to obtain a slave module control signal according to an output current of the slave module and the output current reference value of the slave module;

[0097] The slave module pulse width modulator is used to obtain the duty cycle correction amount based on the slave module control signal;

[0098] The module controls the MOSFETs within it to turn on or off based on the reference duty cycle and the duty cycle correction.

[0099] The input equalizing loop proportional-integral controller obtains the output current reference value of the slave module based on the average value of the slave module's input voltage and the system input voltage, and forms an input equalizing loop at the input stage of the slave module.

[0100] The output current sharing loop proportional-integral controller obtains the slave module control signal based on the slave module's output current and the slave module's output current reference value, and forms an output current sharing loop at the slave module's output stage.

[0101] Specifically, such as Figure 3 As shown, , … Indicates the 1st, 2nd, ... A proportional-integral controller for the input equalizing loop of the module. , … Indicates the 1st, 2nd, ... A proportional-integral controller for the output current sharing loop of the module. , … Indicates the 1st, 2nd, ... A pulse width modulator module, Indicates the total number of flyback converters. Indicates the system input voltage. , … Indicates the 1st, 2nd, ... The input voltages of the flyback converters, i.e., the 1st, 2nd, ..., The input voltage of the module, , … Indicates the 1st, 2nd, ... The output current reference value of the module. , … Indicates the 1st, 2nd, ... The output current of each flyback converter, i.e., the 1st, 2nd, ..., The output current of the module, , … Indicates the 1st, 2nd, ... The sampling ratio of the input voltage of each module. , , …, denotes the sampling proportional coefficient of the output current of the 1st, 2nd, …, , , …, denotes the 1st, 2nd, …, slave module control signal, , , …, denotes the 1st, 2nd, …, duty cycle correction amount corresponding to the slave module.

[0102] The calculation formula of the output current reference value of the slave module is:

[0103] ;

[0104] wherein, denotes the output current reference value of the 1st, slave module, denotes the system input voltage, denotes the total number of flyback converters, denotes the input voltage of the 1st, slave module, denotes the sampling proportional coefficient of the input voltage of the 1st, slave module, denotes the transfer function of the input voltage sharing ring proportional integral controller of the 1st, slave module.

[0105] The calculation formula of the slave module control signal is:

[0106] ;

[0107] wherein, denotes the 1st, slave module control signal, denotes the output current of the 1st, slave module, denotes the sampling proportional coefficient of the output current of the 1st, slave module, denotes the transfer function of the output current sharing ring proportional integral controller of the 1st, slave module.

[0108] In the embodiment, according to the reference duty cycle and the duty cycle correction amount, the MOS tube in the slave module is turned on or turned off, which specifically includes:

[0109] According to the reference duty cycle and the duty cycle correction amount, the slave module duty cycle is obtained;

[0110] According to the slave module duty cycle, the MOS tube in the slave module is turned on or turned off.​

[0111] Specifically, as shown in Figure 3 , , , …, represent the first, second, …, slave module duty cycles. In combination with Figure 1 and Figure 3 , , , …, outputs are superimposed on the output of , the input , , …, gate, that is , , …, and superimposed, to obtain , , …, , according to , , …, control , , …, on or off.

[0112] The calculation formula of the slave module duty cycle is:

[0113] ;

[0114] Among them, represents the first slave module duty cycle, represents the reference duty cycle, represents the duty cycle correction amount corresponding to the first slave module, represents the total number of flyback converters.

[0115] The direct current transformer power self-balancing control system provided by the embodiment can solve the power supply problem of secondary power equipment in the direct current power distribution network, solve the power distribution imbalance problem caused by inconsistent parameters between flyback modules, and achieve better dynamic response effect.

[0116] Specifically, 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 voltage sharing loop to realize the input voltage sharing among flyback modules, and the slave module output stage adopts an output current sharing loop to improve the dynamic response effect of the system. Compared with the traditional double closed-loop control strategy, the input voltage sharing loop and the output current sharing loop are introduced by using the master-slave control architecture, so that the input voltage sharing among flyback modules can be realized, the dynamic response effect is faster, and the stability of the output is improved. 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 sharing loop proportional integral controller also increases, so that the output value of the output current sharing loop increases, and then the duty cycle of the flyback module decreases, the transmission power decreases, and the output current decreases. Through feedback, the input voltage of the flyback module is adjusted, and finally the input voltage sharing stability of the circuit is maintained.

[0117] In the 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 loop 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 loop proportional integral controller of each slave module is the same. The output current sharing loop 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 loop proportional integral controller of each slave module is the same.

[0118] In one possible embodiment, each flyback converter is provided with:

[0119] an input voltage detection circuit for detecting the input voltage of the flyback converter;

[0120] an output voltage detection circuit for detecting the output voltage of the flyback converter;

[0121] an output current detection circuit for detecting the output current of the flyback converter;

[0122] a power tube control circuit for controlling the conduction or turn-off of the MOS tube in the flyback converter according to the duty cycle;

[0123] a primary side auxiliary power supply for supplying power to the input voltage detection circuit and the power tube control circuit;

[0124] a secondary side auxiliary power supply for supplying power to the output voltage detection circuit and the output current detection circuit;

[0125] wherein 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 the reference duty cycle and a duty cycle correction amount.

[0126] In the embodiment, each flyback converter is further provided with:

[0127] Analog / digital converter, for analog-digital conversion of the input voltage, output voltage and output current of the main module.

[0128] As shown in Figure 2 , taking the first slave module as an example, Figure 2 , the resistance , the capacitor , and the diode form an RCD absorption circuit, , which represents the load resistance of the first slave module. Figure 2 The reverse breakdown diode of the MOS tube is omitted.

[0129] Specifically, the main module is provided with:

[0130] An input voltage detection circuit for detecting the input voltage of the main module;

[0131] An output voltage detection circuit for detecting the output voltage of the main module;

[0132] An output current detection circuit for detecting the output current of the main module;

[0133] An analog / digital converter for analog-digital conversion of the input voltage, output voltage and output current of the main module;

[0134] A power tube control circuit for controlling the conduction or turn-off of the MOS tube in the main module according to the reference duty ratio;

[0135] A primary side auxiliary power supply for powering the input voltage detection circuit;

[0136] A secondary side auxiliary power supply for powering the output voltage detection circuit and the output current detection circuit.

[0137] The controller corresponding to the main module comprises:

[0138] An output voltage loop proportional-integral controller for obtaining a main module control signal according to the output voltage of the main module and the output voltage reference value of the main module;

[0139] A main module pulse width modulator for obtaining a reference duty ratio according to the main module control signal.

[0140] In combination Figure 1 , Figure 2 and Figure 3 , the gate of the power tube control circuit of the main module is connected , and the power tube control circuit of the main module controls the conduction or turn-off according to the output control .

[0141] Specifically, the slave module is provided with:

[0142] an input voltage detection circuit for detecting the input voltage of the slave module;

[0143] an output voltage detection circuit for detecting the output voltage of the slave module;

[0144] an output current detection circuit for detecting the output current of the slave module;

[0145] an analog / digital converter for analog-digital conversion of the input voltage, the output voltage and the output current of the slave module;

[0146] a power tube control circuit for controlling the on or off of the MOS tube in the slave module according to the reference duty ratio and the duty ratio correction amount;

[0147] a primary side auxiliary power supply for supplying power to the input voltage detection circuit;

[0148] a secondary side auxiliary power supply for supplying power to the output voltage detection circuit and the output current detection circuit.

[0149] the controller corresponding to the slave module comprises:

[0150] an input voltage equalization loop proportional integral controller for obtaining 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;

[0151] an output current equalization loop proportional integral controller for obtaining the slave module control signal according to the output current of the slave module and the output current reference value of the slave module;

[0152] a slave module pulse width modulator for obtaining the duty ratio correction amount according to the slave module control signal.

[0153] The power tube control circuit controls the on or off of the MOS tube in the slave module according to the reference duty ratio and the duty ratio correction amount specifically comprises: the power tube control circuit superimposes the reference duty ratio and the duty ratio correction amount to obtain the slave module duty ratio, and controls the on or off of the MOS tube in the slave module according to the slave module duty ratio.

[0154] In combination with Figure 1 , Figure 2 and Figure 3 , the gate of the power tube control circuit of the slave module is connected to , , , the power tube control circuit of the master module outputs , , , , , , and outputted After superimposition, acquire , , According to , , Control , , Turn on or turn off.

[0155] The direct-current transformer power self-balancing control system provided by the embodiment adopts an input series connection and output parallel connection structure, can solve the power supply problem of secondary power equipment in a direct-current power distribution network, can meet the high transformation ratio requirement of high input voltage and low output voltage when power is taken from the direct-current power distribution network, can reduce the voltage stress of each switching device, and can make the system have high reliability, modular redundancy structure and higher power transmission capacity.

[0156] The embodiment of the application provides a direct-current transformer power self-balancing control method, the direct-current transformer comprises a plurality of flyback converters, the input ends of the flyback converters are connected in series, the output ends of the flyback converters are connected in parallel, an actually grounded flyback converter in each flyback converter is taken as a master module, and other flyback converters not actually grounded are taken as slave modules, and the method comprises the following steps:

[0157] According to the output voltage of the master module and the output voltage reference value of the master module, a master module control signal is acquired;

[0158] According to the master module control signal, a reference duty cycle is acquired;

[0159] According to the reference duty cycle, MOS tubes in the master module are controlled to turn on or turn off;

[0160] 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 acquired;

[0161] According to the output current of the slave module and the output current reference value of the slave module, a slave module control signal is acquired;

[0162] According to the slave module control signal, a duty cycle correction amount is acquired;

[0163] According to the reference duty cycle and the duty cycle correction amount, MOS tubes in the slave module are controlled to turn on or turn off.

[0164] In the embodiment, the calculation formula of the master module control signal is as follows:

[0165] ;

[0166] Wherein, represents the master module control signal, This indicates the reference value of the main module's output voltage. This indicates the output voltage of the main module. This represents the sampling ratio of the main module's output voltage. This represents the transfer function of the output voltage loop proportional-integral controller.

[0167] The formula for calculating the module's output current reference value is:

[0168] ;

[0169] in, Indicates the first The output current reference value of the module. Indicates the system input voltage. Indicates the total number of flyback converters. Indicates the first The input voltage of the module, Indicates the first The sampling ratio of the input voltage of each module. Indicates the first The transfer function of the proportional-integral controller of the input equalizing loop of the module.

[0170] The formula for calculating the module control signal is:

[0171] ;

[0172] in, Indicates the first Each module control signal, Indicates the first The output current of the module, Indicates the first The sampling ratio of the output current of the module. Indicates the first The transfer function of the proportional-integral controller of the output current sharing loop of the slave module.

[0173] In this embodiment, controlling the on / off state of the MOS transistor within the module based on the reference duty cycle and the duty cycle correction amount includes:

[0174] The duty cycle of the slave module is obtained based on the baseline duty cycle and the duty cycle correction amount.

[0175] Based on the duty cycle of the slave module, control the MOS transistors within the slave module to turn on or off.

[0176] The formula for calculating the module duty cycle is:

[0177] ;

[0178] in, denotes the duty cycle of the th slave module, denotes the reference duty cycle, denotes the duty cycle correction amount corresponding to the th slave module, denotes the total number of flyback converters.

[0179] In one possible embodiment, each flyback converter is provided with:

[0180] an input voltage detection circuit for detecting the input voltage of the flyback converter;

[0181] an output voltage detection circuit for detecting the output voltage of the flyback converter;

[0182] an output current detection circuit for detecting the output current of the flyback converter;

[0183] a power tube control circuit for controlling the conduction or turn-off of the MOS tube in the flyback converter according to the duty cycle;

[0184] a primary side auxiliary power supply for powering the input voltage detection circuit and the power tube control circuit;

[0185] a secondary side auxiliary power supply for powering the output voltage detection circuit and the output current detection circuit;

[0186] wherein when the flyback converter is a master module, the duty cycle is the reference duty cycle, and when the flyback converter is a slave module, the duty cycle is the reference duty cycle plus the duty cycle correction amount.

[0187] In this embodiment, each flyback converter is further provided with:

[0188] an analog / digital converter for analog-to-digital conversion of the input voltage, output voltage and output current of the master module.

[0189] The DC transformer power self-balancing control method provided by the embodiments of the present application has the corresponding beneficial effects of the DC transformer power self-balancing control system.

[0190] The above is only the preferred embodiment of the present application, and it should be noted that for those skilled in the art, without departing from the technical principles of the present application, a number of improvements and modifications can be made, and these improvements and modifications should be considered as the protection scope of the present application.

Claims

1. A direct current transformer power self-balancing control system comprising a plurality of flyback converters, input terminals of each flyback converter being connected in series, output terminals of each flyback converter being connected in parallel, characterized in that, The actual ground flyback converter in each flyback converter is a master module, and other flyback converters not actually grounded are slave modules; The master module is provided with: An output voltage loop proportional integral controller, configured to obtain a master module control signal according to an output voltage of the master module and an output voltage reference value of the master module; A master module pulse width modulator, configured to obtain a reference duty cycle according to the master module control signal; The master module controls the conduction or turn-off of a MOS transistor in the master module according to the reference duty cycle; The slave module is provided with: An input voltage equalization loop proportional integral controller, configured to obtain an output current reference value of the slave module according to an input voltage of the slave module and a system input voltage average value; An output current loop proportional integral controller, configured to obtain a slave module control signal according to an output current of the slave module and the output current reference value of the slave module; A slave module pulse width modulator, configured to obtain a duty cycle correction amount according to the slave module control signal; The slave module controls the conduction or turn-off of a MOS transistor in the slave module according to the reference duty cycle and the duty cycle correction amount.

2. The DC transformer power self-balancing control system of claim 1, wherein, The calculation formula of the master module control signal is: ； wherein, represents a master module control signal, represents an output voltage reference value of the master module, represents an output voltage of the master module, represents a sampling proportional coefficient of the output voltage of the master module, represents a transfer function of an output voltage loop proportional-integral controller.

3. The DC-DC converter power self-balancing control system of claim 1, wherein, The calculation formula of the output current reference value of the slave module is: ； in, Indicates the first The output current reference value of the module. Indicates the system input voltage. Indicates the total number of flyback converters. Indicates the first The input voltage of the module, Indicates the first The sampling ratio of the input voltage of each module. Indicates the first The transfer function of the proportional-integral controller of the equalizing loop from the input of the module; The calculation formula of the slave module control signal is: ； wherein, represents the output current of the nth slave module, represents the output current of the nth slave module, represents the sampling proportional factor of the output current of the nth slave module, represents the transfer function of the output current loop proportional-integral controller of the nth slave module. ​​​​ 4. The DC-DC converter power self-balancing control system of claim 1, wherein, The control of the conduction or turn-off of the MOS transistor in the slave module according to the reference duty cycle and the duty cycle correction amount includes: Obtaining a slave module duty cycle according to the reference duty cycle and the duty cycle correction amount; Controlling the conduction or turn-off of the MOS transistor in the slave module according to the slave module duty cycle; The calculation formula of the slave module duty cycle is: ； in, Indicates the first The duty cycle of each module Indicates the baseline duty cycle. Indicates the first The duty cycle correction amount corresponding to each module This indicates the total number of flyback converters.

5. The DC-DC converter power self-balancing control system of claim 1, wherein, Each flyback converter is provided with: An input voltage detection circuit, configured to detect an input voltage of the flyback converter; An output voltage detection circuit, configured to detect an output voltage of the flyback converter; An output current detection circuit, configured to detect an output current of the flyback converter; A power transistor control circuit, configured to control the conduction or turn-off of a MOS transistor in the flyback converter according to a duty cycle; A primary side auxiliary power supply, configured to supply power to the input voltage detection circuit and the power transistor control circuit; A secondary side auxiliary power supply, configured to supply power to the output voltage detection circuit and the output current detection circuit; When the flyback converter is the master module, the duty cycle is the reference duty cycle, and when the flyback converter is the slave module, the duty cycle is the reference duty cycle and the duty cycle correction amount.

6. A method for controlling power self-balancing of a DC transformer, the DC transformer comprising a plurality of flyback converters, input terminals of the flyback converters being connected in series, output terminals of the flyback converters being connected in parallel, the method comprising: determining a voltage difference between the input terminals of the flyback converters; and adjusting a voltage of the output terminals of the flyback converters based on the voltage difference. The actual ground flyback converter in each flyback converter is a master module, and other flyback converters not actually grounded are slave modules, and the method includes: Obtaining a master module control signal according to an output voltage of the master module and an output voltage reference value of the master module; Obtaining a reference duty cycle according to the master module control signal; Controlling the conduction or turn-off of a MOS transistor in the master module according to the reference duty cycle; Obtaining an output current reference value of the slave module according to an input voltage of the slave module and a system input voltage average value; Obtaining a slave module control signal according to an output current of the slave module and the output current reference value of the slave module; Obtaining a duty cycle correction amount according to the slave module control signal; Controlling the conduction or turn-off of a MOS transistor in the slave module according to the reference duty cycle and the duty cycle correction amount.

7. The DC-DC converter power self-balancing control method according to claim 6, wherein, The calculation formula of the master module control signal is: ； wherein, represents a master module control signal, represents an output voltage reference value of the master module, represents an output voltage of the master module, represents a sampling proportional coefficient of the output voltage of the master module, represents a transfer function of an output voltage loop proportional-integral controller.

8. The DC-DC converter power self-balancing control method of claim 6, wherein, The calculation formula of the output current reference value of the slave module is: ； in, Indicates the first The output current reference value of the module. Indicates the system input voltage. Indicates the total number of flyback converters. Indicates the first The input voltage of the module, Indicates the first The sampling ratio of the input voltage of each module. Indicates the first The transfer function of the proportional-integral controller of the equalizing loop from the input of the module; The calculation formula of the slave module control signal is: ； in, Indicates the first Each module control signal, Indicates the first The output current of the module, Indicates the first The sampling ratio of the output current of the module. Indicates the first The transfer function of the proportional-integral controller of the output current sharing loop of the slave module.

9. The DC-DC converter power self-balancing control method of claim 6, wherein, According to the reference duty ratio and the duty ratio correction amount, the MOS tube in the slave module is controlled to be turned on or turned off, comprising: According to the reference duty ratio and the duty ratio correction amount, the slave module duty ratio is obtained; According to the slave module duty ratio, the MOS tube in the slave module is controlled to be turned on or turned off; The calculation formula of the slave module duty ratio is: ； wherein, denotes the duty cycle of the i-th slave module, denotes the duty cycle of the i-th slave module, denotes the reference duty cycle, denotes the duty cycle of the i-th slave module, denotes the duty cycle correction amount corresponding to the i-th slave module, denotes the total number of flyback converters.

10. The DC-DC converter power self-balancing control method of claim 6, wherein, Each flyback converter is provided with: An input voltage detection circuit for detecting the input voltage of the flyback converter; An output voltage detection circuit for detecting the output voltage of the flyback converter; An output current detection circuit for detecting the output current of the flyback converter; A power tube control circuit for controlling the MOS tube in the flyback converter to be turned on or turned off according to the duty ratio; A primary side auxiliary power supply for supplying power to the input voltage detection circuit and the power tube control circuit; A secondary side auxiliary power supply for supplying power to the output voltage detection circuit and the output current detection circuit; When the flyback converter is a master module, the duty ratio is the reference duty ratio, and when the flyback converter is a slave module, the duty ratio is the reference duty ratio and the duty ratio correction amount.

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