Direct current-direct current parallel system and control method thereof, charging line and charger

Abstract

The invention discloses a direct current-direct current parallel system and a control method thereof, a charging line and a charger, and belongs to the technical field of electric energy conversion, the direct current-direct current parallel system comprises any number of parallel transformation modules, two-way switch modules with the same number, a non-real-time control module and a real-time control module; the first end of each voltage transformation module is connected with the first end of the non-real-time control module, and the second end of each voltage transformation module is connected with the first end of the corresponding bidirectional switch module and the first end of the real-time control module. The second end of each bidirectional switch module is connected with the second end of the real-time control module, and the third end of each bidirectional switch module is connected with the second end of the real-time control module. According to the invention, bidirectional energy transmission is supported, circulation is effectively inhibited, and dynamic power distribution is realized.

Description

Technical Field

[0001] The present application relates to the technical field of electric energy conversion, and in particular to a DC-DC parallel system and a control method thereof, a charging cable, and a charger. Background Art

[0002] With the widespread use of mobile power supplies and chargers, users are increasingly demanding the parallel output of multiple devices. However, due to differences in output voltage, current, and power among different devices, traditional current-sharing parallel solutions are difficult to apply. Non-current-sharing parallel methods must be adopted to allow each device to share the load according to its output capacity and dynamically adjust power distribution to optimize system performance. However, existing technologies have obvious shortcomings: on the one hand, although basic parallel connection can be achieved, it cannot effectively suppress circulating current, and the non-current-sharing control capability is limited, making it impossible to dynamically adjust power distribution, resulting in modules with higher initial voltages continuously outputting higher currents, affecting system balance; on the other hand, existing technologies generally use diodes, which only support unidirectional conduction and cannot meet the needs of bidirectional energy transmission. Therefore, existing solutions are difficult to meet the requirements of high efficiency, flexibility, and reliability.

[0003] In summary, a new direct current (DC-DC) parallel system and control method are urgently needed to improve the compatibility, efficiency and reliability of the DC-DC parallel system. Summary of the Invention

[0004] The present application aims to provide a DC-DC parallel system and its control method, charging cable, and charger that can support bidirectional energy transmission, effectively suppress circulating current, and realize dynamic power distribution, which can improve the compatibility, efficiency, and reliability of the DC-DC parallel system.

[0005] To achieve the above objectives, the technical solution of this application is:

[0006] A DC-DC parallel system, comprising any number of parallel-connected transformer modules, the same number of bidirectional switch modules, a non-real-time control module, and a real-time control module;

[0007] The first end of each transformer module is connected to the first end of the non-real-time control module, and the second end of each transformer module is connected to the first end of the corresponding bidirectional switch module and the first end of the real-time control module respectively;

[0008] The second end of each bidirectional switch module is connected to the second end of the real-time control module, and the third end of each bidirectional switch module is connected.

[0009] Optionally, each voltage conversion module includes: a step-down DC-DC converter, a step-up DC-DC converter, or a step-up / step-down DC-DC converter.

[0010] Optionally, each transformer module is used to:

[0011] Obtaining updated constant voltage mode setting values ​​and constant current mode setting values ​​through a non-real-time control module;

[0012] Start output voltage;

[0013] Enter constant voltage mode, constant voltage output;

[0014] When the load current exceeds the set value of the constant current mode, it enters the constant current mode, constant current output, and voltage drops;

[0015] When the load current is less than the set value of the constant current mode, the constant current mode is exited and the constant voltage mode is entered. The output voltage recovers and the constant voltage output is maintained.

[0016] Optional, non-real-time control module for:

[0017] Obtain source and load capability information through PD protocol handshake;

[0018] Send configuration data to the transformer module and real-time control module through the communication protocol;

[0019] The setting values ​​of the constant current mode and the constant voltage mode of the parallel transformer modules are dynamically adjusted as needed to distribute the output power of the parallel transformer modules.

[0020] Optionally, the real-time control module includes: a hardware analog circuit, a micro control unit, and a digital signal processor.

[0021] Optionally, each bidirectional switch module includes: a first diode, a second diode, a third diode, a fourth diode and a first switching tube; the anode of the first diode is connected to the cathode of the second diode, and the connection midpoint is the first end of the bidirectional switch module; the cathode of the first diode is connected to the cathode of the third diode, and the anode of the second diode is connected to the anode of the fourth diode; the anode of the third diode is connected to the cathode of the fourth diode, and the connection midpoint is the third end of the bidirectional switch module, the first end of the first switching tube is connected to the connection midpoint of the first diode and the third diode, and the second end of the first switching tube is connected to the connection midpoint of the second diode and the fourth diode.

[0022] A control method for a DC-DC parallel system, applied to any one of the DC-DC parallel systems described above, comprising:

[0023] Step S1: Obtain the capability information of the source and load through the PD protocol handshake, designate one of the transformer modules as the master module and the remaining transformer modules as slave modules;

[0024] Step S2: respectively setting the set value CC of the constant current mode and the set value CV of the constant voltage mode of the parallel transformer modules, all modules start running, and the main module enters the constant voltage mode to control the output voltage;

[0025] Step S3: Determine whether the load current is greater than the set value of the constant current mode of the main module. If so, proceed to step S5; if not, proceed to step S4;

[0026] Step S4: the master module outputs voltage, the bidirectional switch of the slave module is disconnected, and the slave module does not output; return to step S3;

[0027] Step S5: The main module enters the constant current mode, and the output voltage of the main module begins to drop;

[0028] Step S6: When the output voltage of the master module drops below the set value of the constant voltage mode of the slave module, the bidirectional switch of the slave module is turned on, the slave module starts to output current, and the slave module enters the constant voltage mode, and the output voltage is controlled by the slave module;

[0029] Step S7: If the load current continues to increase and becomes greater than the sum of the constant current mode settings of the master module and the slave module, the slave module enters the constant current mode and the output voltage continues to drop.

[0030] Step S8: When the load current decreases to a value greater than the set value of the constant current mode of the master module but less than the sum of the set values ​​of the constant current modes of the master module and the slave module, the slave module exits the constant current mode and enters the constant voltage mode, and the output voltage is controlled by the slave module;

[0031] Step S9: The load current continues to decrease until it is less than the set value of the constant current mode of the master module. The master module exits the constant current mode and enters the constant voltage mode. The master module pulls up the output voltage. When the output voltage is higher than the set value of the constant voltage mode of the slave module, the bidirectional switch of the slave module is disconnected and the slave module stops outputting.

[0032] Optionally, the main module includes: a voltage transformation module with a large source or load capacity, a voltage transformation module with a small source or load capacity, and a module that successfully shakes hands first.

[0033] Optionally, the set value of the constant voltage mode of the master module is higher than the set value of the constant voltage mode of the slave module.

[0034] Optionally, the setting values ​​of the constant current mode and the constant voltage mode of the master module and each slave module are selected according to needs.

[0035] A charging cable comprising: n+1 ports and a DC-DC parallel system as described in any one of the above descriptions; the first end of the n+1th port is connected to the second end of the DC-DC parallel system, and the first ends of the 1st to nth ports are respectively connected to the first end of the DC-DC parallel system.

[0036] Optionally, the first end of the (n+1)th port is connected to the third end of each bidirectional switch module, and the second end of the (n+1)th port is connected to the third end of the non-real-time control module;

[0037] The first ends of the 1st to nth ports are respectively connected to the third ends of the corresponding voltage transformation modules, and the second ends of the 1st to nth ports are connected to the second end of the non-real-time control module.

[0038] Optionally, the third end of the (n+1)th port is connected to the load, and the third ends of the 1st to nth ports are connected to the source.

[0039] Optionally, the third end of the (n+1)th port is connected to a source, and the third ends of the 1st to nth ports are connected to a load.

[0040] Optionally, the n+1 ports are USB ports.

[0041] A charger comprising: a plug, an AC-DC conversion system, a battery, n+1 ports, and a DC-DC parallel system as described above;

[0042] The first ends of the 1st to nth ports are connected to the first end of the DC-DC parallel system, and the first end of the (n+1th) port is connected to the second end of the DC-DC parallel system; the third ends of one or more of the 1st to nth ports are connected to the first end of the AC-DC conversion system, the third ends of one or more of the 1st to nth ports are connected to the first end of the battery, and the first end of the plug is connected to the second end of the AC-DC conversion system.

[0043] Optionally, the first end of the (n+1)th port is connected to the third end of each bidirectional switch module, and the second end of the (n+1)th port is connected to the third end of the non-real-time control module;

[0044] The first ends of the 1st to nth ports are respectively connected to the third ends of the corresponding voltage transformation modules, and the second ends of the 1st to nth ports are connected to the second end of the non-real-time control module.

[0045] Optionally, the (n+1)th port is a USB port.

[0046] The DC-DC parallel system and its control method, charging cable, and charger of the present application have n transformer modules connected in parallel for output, and can intelligently distribute the output current according to the input capability difference of the corresponding input source of each DC-DC transformer module. When lightly loaded, the first transformer module outputs, while the remaining transformer modules do not output and are disconnected from the output to prevent backflow of circulating current. When heavily loaded, the remaining transformer modules are connected in real time to provide additional output, thereby achieving optimized parallel operation under the condition of asymmetric input source capability. By adopting a bidirectional switch, the problem of limited energy flow caused by the use of unidirectional conducting devices in traditional parallel circuits is effectively solved. When the bidirectional switch is turned off, it has a bidirectional voltage blocking capability, forming a circulating current suppression mechanism that can effectively prevent energy backflow between DC-DC transformer modules with different input source capabilities. At the same time, the bidirectional switch is designed to have a hysteresis characteristic, which can prevent the bidirectional switch from repeatedly switching between on and off when the difference in output voltage is close to 0.

[0047] Furthermore, the set value CC of the constant current mode and the set value CV of the constant voltage mode are rewritten by the real-time control module and the non-real-time control module, and they work together to realize dynamic power distribution. Regardless of whether it is a one-to-n or n-to-one charging situation, non-uniform dynamic power distribution can be realized to ensure rapid power rebalancing and complete system-level non-real-time power optimization and allocation, thereby significantly improving the compatibility, safety and operating efficiency of the parallel system of multiple mobile power supplies or chargers, and is especially suitable for parallel scenarios of heterogeneous devices with different output voltages, currents and powers.

[0048] In order to make the above features and advantages of the application more obvious and easy to understand, the following embodiments are given and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 This is a module diagram of the DC-DC parallel system provided in this application.

[0050] Figure 2 This is a control logic diagram of a single transformer module.

[0051] Figure 3 Module diagram of the DC-DC parallel system 1 provided in this application when n=2

[0052] Figure 4 Schematic diagram of the bidirectional switch hysteresis loop turn-on and turn-off.

[0053] Figure 5 This is a circuit diagram of the first specific embodiment of the DC-DC parallel system proposed in this application.

[0054] Figure 6 This is a circuit diagram of the second specific embodiment of the DC-DC parallel system proposed in this application.

[0055] Figure 7 This is a circuit diagram of the third specific embodiment of the DC-DC parallel system proposed in this application.

[0056] Figure 8 This is a control logic diagram of the non-real-time control module.

[0057] Figure 9 This is a flow chart of the control method for the DC-DC parallel system provided in this application.

[0058] Figure 10 Schematic diagram of the waveforms of the voltage and current of two parallel transformer modules in this application as the load current changes.

[0059] Figure 11 This is a waveform diagram of the voltage and current changing with the load current when two parallel transformer modules dynamically distribute the output current in this application.

[0060] Figure 12 This is a schematic structural diagram of the first specific embodiment of the charging cable provided in this application.

[0061] Figure 13 This is a schematic structural diagram of the first specific embodiment of the charger provided in this application. DETAILED DESCRIPTION

[0062] To make the purpose and technical solutions of the embodiments of the present application clearer, the technical solutions of the embodiments of the present application will be clearly and completely described below in conjunction with the drawings of the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the described embodiments of the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0063] This application provides a DC-DC parallel system 1, see Figure 1 , Figure 1 The module diagram of the DC-DC parallel system 1 provided in this application includes: n parallel transformer modules, n bidirectional switch modules, a non-real-time control module 131 and a real-time control module 132. Specifically, the n parallel transformer modules include: a first transformer module 111 to an nth transformer module 11n, and the n bidirectional switch modules include: a first bidirectional switch module 121 to an nth bidirectional switch module 12n.

[0064] The first end of the n transformer modules is connected to the first end of the non-real-time control module 131, and the second end of the nth transformer module is connected to the first end of the nth bidirectional switch module and the first end of the real-time control module 132 respectively; the nth transformer module outputs a voltage V n .

[0065] The second ends of the n bidirectional switch modules are connected to the second end of the real-time control module 132 , and the third ends of the n bidirectional switch modules are connected.

[0066] As an example, the first end of the nth port is connected to the third end of the nth transformer module, and the second ends of the n ports are respectively connected to the second ends of the non-real-time control module 131 .

[0067] As an example, the first end of the (n+1)th port is connected to the third ends of the n bidirectional switch modules respectively, and the second end of the (n+1)th port is connected to the third end of the non-real-time control module 131 .

[0068] Specifically, the n+1 ports include: a first port 2 to an n+1th port n+2.

[0069] As an example, the first port 2 to the n-th port n+1 are connected to sources respectively, and the n+1-th port n+2 is connected to a load.

[0070] As another example, the first port 2 to the n-th port n+1 are connected to the load respectively, and the n+1-th port n+2 is connected to the source.

[0071] As an example, the n parallel-connected transformation modules each include a DC-DC converter, and the DC-DC transformation module may include a step-down DC-DC converter, a step-up DC-DC converter, or a step-up / step-down DC-DC converter.

[0072] As examples, a step-down DC-DC converter has an output voltage less than or equal to the input voltage; a boost DC-DC converter has an output voltage greater than or equal to the input voltage; and a buck-boost DC-DC converter has an output voltage that can be either greater than or less than the input voltage. The types and power ratings of the n parallel-connected transformer modules are selected based on specific requirements. For example, the first transformer module 111 is a buck-boost DC-DC converter, and the second through n-th transformer modules 112 through 11n are boost DC-DC converters. Alternatively, all n parallel-connected transformer modules are buck-boost DC-DC converters.

[0073] As an example, n parallel-connected transformer modules operate in a constant voltage mode or a constant current mode.

[0074] As an example, see Figure 2 , Figure 2 This is a schematic diagram of the control logic of a single transformer module. The control logic of n parallel transformer modules includes:

[0075] Obtaining updated constant voltage mode setting value CV and constant current mode setting value CC through the non-real-time control module 131;

[0076] The transformer module starts outputting voltage;

[0077] Enter constant voltage mode, constant voltage output;

[0078] When the load current exceeds the set value CC of the constant current mode, it enters the constant current mode, constant current output, and voltage drops;

[0079] When the load current is less than the set value CC of the constant current mode, the constant current mode is exited and the constant voltage mode is entered. The output voltage recovers and the constant voltage output is maintained.

[0080] In one embodiment of the present application, the DC-DC parallel system 1 includes: two parallel transformer modules, two bidirectional switch modules, a non-real-time control module 131 and a real-time control module 132, see Figure 3 , Figure 3 The module diagram of the DC-DC parallel system 1 provided in this application is when n=2.

[0081] As an example, the first bidirectional switch module 121 and the first bidirectional switch module 122 both include structures that can be controlled to be turned on and off, and the on and off states of the first bidirectional switch module 121 and the first bidirectional switch module 122 depend on the difference between the output voltages V1 and V2 of the first transformer module 111 and the second transformer module 112.

[0082] See also Figure 4 , Figure 4 The diagram of the bidirectional switch hysteresis on and off is shown. The on and off of the first bidirectional switch module 121 and the first bidirectional switch module 122 have hysteresis characteristics, that is, when the output voltage V1 drops below the output voltage V2 and the difference reaches the hysteresis threshold ΔV a When the output voltage V1 rises, the output voltage V1 rises to a value greater than the output voltage V2, and the difference reaches the hysteresis threshold ΔV b When the output voltage V1 and the output voltage V2 are close to 0, the bidirectional switch switches from the on state to the off state. The hysteresis characteristic can be designed to prevent the bidirectional switch from switching between on and off repeatedly when the difference between the output voltage V1 and the output voltage V2 is close to 0. Specifically, the hysteresis threshold ΔV a and hysteresis threshold ΔV b In the off state, the first bidirectional switch module 121 and the first bidirectional switch module 122 have a bidirectional voltage blocking capability.

[0083] See also Figure 5 , Figure 5This is a circuit diagram of the first specific embodiment of the DC-DC parallel system proposed in this application. In this specific embodiment, the first bidirectional switch module 521 includes: a diode D1, a diode D2, a diode D3, a diode D4, and a switch tube Q1. The anode of diode D1 is connected to the cathode of diode D2, and the midpoint of the connection is the first end of the first bidirectional switch module 521; the cathode of diode D1 is connected to the cathode of diode D3, and the anode of diode D2 is connected to the anode of diode D4; the anode of diode D3 is connected to the cathode of diode D4, and the midpoint of the connection is the third end of the first bidirectional switch module 521. The first end of the switch tube Q1 is connected to the midpoint of the connection between diodes D1 and D3, and the second end of the switch tube Q1 is connected to the midpoint of the connection between diodes D2 and D4. The second bidirectional switch module 522 includes: a diode D5, a diode D6, a diode D7, a diode D8, and a switch tube Q2. The connection method of the diode D1 is the same as that of the first bidirectional switch module 521, and will not be repeated here.

[0084] See also Figure 6 , Figure 6 This is a circuit diagram of the second specific embodiment of the DC-DC parallel system proposed in this application. In this specific embodiment, the first bidirectional switch module 621 includes: a switch tube Q3 and a switch tube Q4. The first end of the switch tube Q3 is the first end of the first bidirectional switch module 621, the second end of the switch tube Q3 is connected to the second end of the switch tube Q4, and the first end of the switch tube Q4 is the third end of the first bidirectional switch module 621; the second bidirectional switch module 622 includes: a switch tube Q5 and a switch tube Q6. The second end of the switch tube Q5 is the first end of the second bidirectional switch module 64, the first end of the switch tube Q5 is connected to the first end of the switch tube Q6, and the second end of the switch tube Q6 is the third end of the second bidirectional switch module 64.

[0085] See also Figure 7 , Figure 7 This is a circuit diagram of the third specific embodiment of the DC-DC parallel system proposed in this application. In this specific embodiment, the first bidirectional switch module 721 includes: a switch tube Q7 and a switch tube Q8. The second end of the switch tube Q7 is connected to the first end of the switch tube Q8, and the midpoint of the connection is the first end of the first bidirectional switch module 721. The first end of the switch tube Q7 is connected to the second end of the switch tube Q8, and the midpoint of the connection is the third end of the first bidirectional switch module 721. The second bidirectional switch module 722 includes: a switch tube Q9, a switch tube Q10, and a switch tube Q11. 10 Its connection method is consistent with that of the first bidirectional switch module 721 and will not be repeated here.

[0086] Please continue reading Figure 2The non-real-time control module 131 is a control module that has no strict requirements on response time. The control process delay is too large to meet the real-time requirements of the DC-DC parallel system 1. The response speed is in the millisecond level or even the second level. It allows for delayed or batch processing of signals. It is used to send and receive control signals through the communication protocol, participate in the PD protocol handshake communication process after the charger is connected to the power-consuming device, and the parameter configuration process before the first transformation module 111 and the second transformation module 112 are started.

[0087] As an example, the non-real-time control module 131 includes: an embedded microcontroller of model ABOV A94P830.

[0088] As examples, the communication protocols include: I2C communication protocol and SPI communication protocol.

[0089] As an example, see Figure 8 , Figure 8 FIG. 1 is a schematic diagram of the control logic of the non-real-time control module 131. The control logic of the non-real-time control module 131 includes:

[0090] Obtain source and load capability information through PD protocol handshake;

[0091] Sending the configuration data to the transformer module and the non-real-time control module 132 via the communication protocol;

[0092] The setting values ​​of the constant current mode and the constant voltage mode of the parallel transformer modules are dynamically adjusted as needed to distribute the output power of the parallel transformer modules.

[0093] The non-real-time control module 132 is a control module with strict requirements on response time. Since the communication protocol used by the non-real-time control module 131 has a large delay, the real-time control of the DC-DC parallel system 1 is completed through the non-real-time control module 132. The response speed is at the microsecond level or even the nanosecond level. It is used to control the output voltage and current parameters of the first transformer module 111 and the second transformer module 112 in real time to ensure output stability and not cause damage to the load electrical equipment.

[0094] As an example, the non-real-time control module 132 includes: a hardware analog circuit, a digital controller, wherein the digital controller includes a micro control unit (MCU) and a digital signal processor (DSP).

[0095] For example, loads include: electrical devices such as mobile phones, laptops, power banks, etc.

[0096] The present application provides a DC-DC parallel system with two transformer modules connected in parallel for output. When lightly loaded, the first transformer module outputs current, while the second transformer module does not output current and is disconnected from the output to prevent backflow and circulating current. When heavily loaded, the second transformer module is connected in real time to provide additional output. Furthermore, by rewriting the set value CC of the constant current mode and the set value CV of the constant voltage mode, dynamic distribution of the output current between the two transformer modules is achieved.

[0097] This application also provides a control method for a DC-DC parallel system, which is applied to the above-mentioned DC-DC parallel system. Figure 9 , Figure 9 This is a flow chart of a control method for a DC-DC parallel system provided in this application. The control method for a DC-DC parallel system includes:

[0098] Step S1: Obtain the capability information of the source and load through the PD protocol handshake, designate one of the transformer modules as the master module and the remaining transformer modules as slave modules;

[0099] Step S2: respectively setting the set value CC of the constant current mode and the set value CV of the constant voltage mode of the parallel transformer modules, all modules start running, and the main module enters the constant voltage mode to control the output voltage;

[0100] Step S3: Determine whether the load current is greater than the set value of the constant current mode of the main module. If so, proceed to step S5; if not, proceed to step S4;

[0101] Step S4: the master module outputs voltage, the bidirectional switch of the slave module is disconnected, and the slave module does not output; return to step S3;

[0102] Step S5: The main module enters the constant current mode, and the output voltage of the main module begins to drop;

[0103] Step S6: When the output voltage of the master module drops below the set value of the constant voltage mode of the slave module, the bidirectional switch of the slave module is turned on, the slave module starts to output current, and the slave module enters the constant voltage mode, and the output voltage is controlled by the slave module;

[0104] Step S7: If the load current continues to increase and becomes greater than the sum of the constant current mode settings of the master module and the slave module, the slave module enters the constant current mode and the output voltage continues to drop.

[0105] Step S8: When the load current decreases to a value greater than the set value of the constant current mode of the master module but less than the sum of the set values ​​of the constant current modes of the master module and the slave module, the slave module exits the constant current mode and enters the constant voltage mode, and the output voltage is controlled by the slave module;

[0106] Step S9: The load current continues to decrease until it is less than the set value of the constant current mode of the master module. The master module exits the constant current mode and enters the constant voltage mode. The master module pulls up the output voltage. When the output voltage is higher than the set value of the constant voltage mode of the slave module, the bidirectional switch of the slave module is disconnected and the slave module stops outputting.

[0107] Specifically, in step S1 , the main module may include: a transformer module with a large source or load capacity, a transformer module with a small source or load capacity, or a module that successfully shakes hands first.

[0108] Specifically, in step S2, the setting value of the constant voltage mode of the master module is slightly higher than the setting value of the constant voltage mode of the slave module; the setting value of the constant current mode and the setting value of the constant voltage mode of the master module and each slave module are respectively selected according to the needs, and the setting value CC of the constant current mode and the setting value CV of the constant voltage mode of each slave module are respectively selected according to the needs.

[0109] In a specific embodiment of the present application, the first port 2 is the first source, the second port 3 is the second source, and the third port 4 is the load. The DC-DC parallel system 1 includes: 2 parallel transformer modules, 2 bidirectional switch modules, a non-real-time control module 131 and a real-time control module 132. Figure 3 and Figure 9 The working process of the control method of DC-DC parallel system is introduced.

[0110] See also Figure 10 , Figure 10 After the first source, the second source and the load are connected and the PD protocol handshake is completed, the first transformer module 111 is designated as the master module and the second transformer module 112 is designated as the slave module.

[0111] During the period t0-t1, the load current increases from zero but does not exceed the set value CC1 of the constant current mode of the first transformer module 111. The first transformer module 111 operates in constant voltage mode, controlling the output voltage V1 to be slightly higher than that of the second transformer module 112. At this time, the output current of the second transformer module 112 is zero, and the first bidirectional switch module 122 remains off to prevent current from flowing back from the first transformer module 111 into the second transformer module 112.

[0112] At t1-t2, the load current exceeds the set value CC1 of the constant current mode of the first transformer module 111, but is lower than the sum of the set values ​​of the constant current modes of the two transformer modules. At this time, the first transformer module 111 enters the constant current mode, the output current is constant, and the output voltage V1 begins to drop. Figure 4 As shown, when the output voltage V1 drops below the output voltage V2 and the difference reaches the hysteresis threshold ΔV aWhen , the first bidirectional switch module 122 is turned on, the second transformer module 112 starts to output current and works in a constant voltage mode, and the output voltage is controlled by the second transformer module 112.

[0113] At t2-t3, the load current continues to increase and reaches the set value CC2 of the constant current mode of the second transformer module 112. The second transformer module 112 also enters the constant current mode to prevent the current from increasing further. The load current stabilizes at the sum of the set values ​​of the constant current modes of the first transformer module 111 and the second transformer module 112. If the load attempts to increase the current further, the output voltage will become uncontrollable and begin to drop.

[0114] At t3-t4, the load current decreases to a value lower than the sum of the set values ​​of the constant current mode of the first transformer module 111 and the second transformer module 112, but greater than the set value CC1 of the constant current mode of the first transformer module 111. At this time, the second transformer module 112 recovers from the constant current mode to the constant voltage mode, controlling the output voltage to be stable. The first transformer module 111 is still operating in the constant current mode.

[0115] At t4-t5, the load current continues to drop to below the set value CC1 of the constant current mode of the first transformer module 111. The first transformer module 111 returns from the constant current mode to the constant voltage mode. The output voltage is controlled by the first transformer module 111. The output current of the second transformer module 112 drops to zero. When the output voltage V1 increases to be higher than the output voltage V2 and the difference reaches the hysteresis threshold ΔV b When , the first bidirectional switch module 122 is disconnected to prevent the current from flowing back from the first transformer module 111 to the second transformer module 112, and the second transformer module 112 stops outputting.

[0116] As an example, see Figure 11 , Figure 11 This is a waveform diagram of the voltage and current changing with the load current when two parallel transformer modules dynamically distribute the output current in this application.

[0117] During the interval t2-t3, the load current continues to increase, but has not yet reached the constant current mode setting CC2 of the second transformer module 112. To dynamically distribute the output power between the two transformer modules, the non-real-time control module 131 rewrites the constant current mode setting CC1 of the first transformer module 111. For example, if the setting CC1 decreases by 10% at time t2, the output current of the second transformer module 112 increases by a corresponding amount, while the total output current and output voltage remain unchanged. If the setting CC1 of the constant current mode of the first transformer module 111 increases by 10% at time t3, the output current of the second transformer module 112 decreases accordingly, while the total output current and output voltage remain unchanged.

[0118] The present application also provides a charging cable, which includes n+1 ports and the above-mentioned DC-DC parallel system 1; the first ends of the n ports are respectively connected to the first end of the DC-DC parallel system 1, and the first end of the n+1th port is connected to the second end of the DC-DC parallel system 1.

[0119] Specifically, the first end of the nth port is connected to the third end of the nth transformer module, and the second ends of the n ports are respectively connected to the second ends of the non-real-time control modules 131 .

[0120] The first end of the (n+1)th port is connected to the third end of the n bidirectional switch modules respectively, and the second end of the (n+1)th port is connected to the third end of the non-real-time control module 131 .

[0121] Specifically, the n+1 ports include: a first port 2 to an n+1th port n+2.

[0122] As an example, the n+1 ports of the charging cable are USB ports.

[0123] As an example, the third terminals of the n ports are respectively connected to a source, and the third terminal of the (n+1)th port (n+2) is connected to a load.

[0124] As another example, the third ends of the n ports are respectively connected to the load, and the third end of the (n+1)th port (n+2) is connected to the source.

[0125] In one embodiment of the present application, the charging cable includes three ports. Figure 12 The charging cable includes a first port 2, a second port 3, a third port 4 and the above-mentioned DC-DC parallel system 1; the first end of the first port 2 is connected to the first terminal of the first end of the DC-DC parallel system 1, the first end of the second port 3 is connected to the second terminal of the first end of the DC-DC parallel system 1, and the first end of the third port 4 is connected to the first terminal of the second end of the DC-DC parallel system 1.

[0126] Specifically, the DC-DC parallel system 1 includes: two parallel transformer modules, two bidirectional switch modules, a non-real-time control module 131 and a real-time control module 132 .

[0127] Specifically, the first end of the first port 2 is connected to the third end of the first voltage transformation module 111, and the second end of the first port 2 is connected to the second end of the non-real-time control module 131;

[0128] A first end of the second port 3 is connected to a third end of the second voltage transformation module 112 , and a second end of the second port 3 is connected to a second end of the non-real-time control module 131 ;

[0129] A first end of the third port 4 is connected to the third end of the first bidirectional switch module 121 and the third end of the first bidirectional switch module 122 , respectively. A second end of the third port 4 is connected to the third end of the non-real-time control module 131 .

[0130] As an example, the charging line can combine the outputs of two sources (different voltages, different powers) and combine them into one output to provide to the load, or it can communicate with two sources and one load to ensure their normal operation and distribute the output power of the two sources within the capacity.

[0131] Furthermore, the charging cable can also transmit in the reverse direction. According to the bidirectional switch module, it can realize the one-to-two function, distribute the energy of one source to two USB ports, charge two load devices at the same time, and distribute power between the two devices according to demand, realizing a bidirectional two-to-one or one-to-two charging cable.

[0132] The present application also provides a charger, which includes: a plug, an AC-DC conversion system, a battery, n+1 ports and the above-mentioned DC-DC parallel system 1; the first ends of the n ports are respectively connected to the first end of the DC-DC parallel system 1, and the first end of the n+1th port is connected to the second end of the DC-DC parallel system 1; the third ends of one or more of the n ports are connected to the first end of the AC-DC conversion system, the third ends of one or more of the n ports are connected to the first end of the battery, and the first end of the plug is connected to the second end of the AC-DC conversion system.

[0133] Specifically, the first end of the nth port is connected to the third end of the nth transformer module, and the second ends of the n ports are respectively connected to the second ends of the non-real-time control modules 131 .

[0134] The first end of the (n+1)th port is connected to the third end of the n bidirectional switch modules respectively, and the second end of the (n+1)th port is connected to the third end of the non-real-time control module 131 .

[0135] Specifically, the n+1 ports include: a first port 2 to an n+1th port n+2.

[0136] As an example, the (n+1)th port of the charger is a USB port.

[0137] In one embodiment of the present application, the charger includes three ports. Figure 13 The charger is a charger product containing a battery inside, including: a plug 8, an AC-DC conversion system 9, a battery 10, a first port 2, a second port 3, a third port 4 and the above-mentioned DC-DC parallel system 1;

[0138] A first end of the first port 2 is connected to a first terminal of the first end of the DC-DC parallel system 1, a first end of the second port 3 is connected to a second terminal of the first end of the DC-DC parallel system 1, and a first end of the third port 4 is connected to a first terminal of the second end of the DC-DC parallel system 1;

[0139] A first end of the AC-DC conversion system 9 is connected to the third end of the first port 2 , a first end of the battery 10 is connected to the third end of the second port 3 , and a first end of the plug 8 is connected to the second end of the AC-DC conversion system 9 .

[0140] As an example, the third port 4 is a USB port.

[0141] Specifically, the DC-DC parallel system 1 includes: two parallel transformer modules, two bidirectional switch modules, a non-real-time control module 131 and a real-time control module 132 .

[0142] Specifically, the first end of the first port 2 is connected to the third end of the first voltage transformation module 111, and the second end of the first port 2 is connected to the second end of the non-real-time control module 131;

[0143] A first end of the second port 3 is connected to a third end of the second voltage transformation module 112 , and a second end of the second port 3 is connected to a second end of the non-real-time control module 131 ;

[0144] A first end of the third port 4 is connected to the third end of the first bidirectional switch module 121 and the third end of the first bidirectional switch module 122 , respectively. A second end of the third port 4 is connected to the third end of the non-real-time control module 131 .

[0145] As an example, a third end of the third port 4 is connected to a load.

[0146] For example, the charger can convert 110V or 220V AC power into a low-voltage DC power source to supply a separate load. Alternatively, it can charge the internal battery separately via a bidirectional switch module. This allows the battery's stored energy to be discharged when the user unplugs the charger, acting as a mobile power bank. The hybrid charger can also operate in hybrid mode, where the charger and battery are connected in parallel to supply power to a high-power load. Alternatively, when the load requires less power, the charger can switch to simultaneously supply power to the load and charge the internal battery, creating a hybrid charger.

[0147] The DC-DC parallel system and its control method, charging cable, and charger of the present application have n transformer modules connected in parallel for output, and can intelligently distribute the output current according to the input capability difference of the corresponding input source of each DC-DC transformer module. When lightly loaded, the first transformer module outputs, while the remaining transformer modules do not output and are disconnected from the output to prevent backflow of circulating current. When heavily loaded, the remaining transformer modules are connected in real time to provide additional output, thereby achieving optimized parallel operation under the condition of asymmetric input source capability. By adopting a bidirectional switch, the problem of limited energy flow caused by the use of unidirectional conducting devices in traditional parallel circuits is effectively solved. When the bidirectional switch is turned off, it has a bidirectional voltage blocking capability, forming a circulating current suppression mechanism that can effectively prevent energy backflow between DC-DC transformer modules with different input source capabilities. At the same time, the bidirectional switch is designed to have a hysteresis characteristic, which can prevent the bidirectional switch from repeatedly switching between on and off when the difference in output voltage is close to 0.

[0148] Furthermore, the set value CC of the constant current mode and the set value CV of the constant voltage mode are rewritten by the real-time control module and the non-real-time control module, and they work together to realize dynamic power distribution. Regardless of whether it is a one-to-n or n-to-one charging situation, non-uniform dynamic power distribution can be realized to ensure rapid power rebalancing and complete system-level non-real-time power optimization and allocation, thereby significantly improving the compatibility, safety and operating efficiency of the parallel system of multiple mobile power supplies or chargers, and is especially suitable for parallel scenarios of heterogeneous devices with different output voltages, currents and powers.

[0149] Although the present application has been disclosed above with reference to the embodiments, they are not intended to limit the present application. Anyone with ordinary knowledge in the technical field may make slight changes and modifications without departing from the spirit and scope of the present application. Therefore, the scope of protection of the present application shall be determined by the scope of the appended patent application.

Claims

1. A DC-DC parallel system, characterized in that: Including any number of parallel-connected transformer modules, the same number of bidirectional switch modules, non-real-time control modules and real-time control modules; The first end of each transformer module is connected to the first end of the non-real-time control module, and the second end of each transformer module is connected to the first end of the corresponding bidirectional switch module and the first end of the real-time control module respectively; The second end of each bidirectional switch module is connected to the second end of the real-time control module, and the third end of each bidirectional switch module is connected.

2. The DC-DC parallel system according to claim 1, wherein: Each voltage conversion module includes: a step-down DC-DC converter, a step-up DC-DC converter, or a step-up / step-down DC-DC converter.

3. The DC-DC parallel system according to claim 2, wherein: Each transformer module is used to: Obtaining updated constant voltage mode setting values ​​and constant current mode setting values ​​through a non-real-time control module; Start output voltage; Enter constant voltage mode, constant voltage output; When the load current exceeds the set value of the constant current mode, it enters the constant current mode, constant current output, and voltage drops; When the load current is less than the set value of the constant current mode, the constant current mode is exited and the constant voltage mode is entered. The output voltage recovers and the constant voltage output is maintained.

4. The DC-DC parallel system according to claim 3, wherein: The non-real-time control module is used to: Obtain source and load capability information through PD protocol handshake; Send configuration data to the transformer module and real-time control module through the communication protocol; The setting values ​​of the constant current mode and the constant voltage mode of the parallel transformer modules are dynamically adjusted as needed to distribute the output power of the parallel transformer modules.

5. The DC-DC parallel system according to claim 1, wherein: The real-time control module includes: hardware simulation circuit, micro control unit and digital signal processor.

6. The DC-DC parallel system according to claim 1, wherein: Each bidirectional switch module includes: a first diode, a second diode, a third diode, a fourth diode and a first switching tube; the anode of the first diode is connected to the cathode of the second diode, and the connection midpoint is the first end of the bidirectional switch module; the cathode of the first diode is connected to the cathode of the third diode, and the anode of the second diode is connected to the anode of the fourth diode; the anode of the third diode is connected to the cathode of the fourth diode, and the connection midpoint is the third end of the bidirectional switch module, the first end of the first switching tube is connected to the connection midpoint of the first and third diodes, and the second end of the first switching tube is connected to the connection midpoint of the second and fourth diodes.

7. A control method for a DC-DC parallel system, applied to the DC-DC parallel system according to any one of claims 1 to 6, characterized in that: include: Step S1: Obtain the capability information of the source and load through the PD protocol handshake, designate one of the transformer modules as the master module and the remaining transformer modules as slave modules; Step S2: respectively setting the set value CC of the constant current mode and the set value CV of the constant voltage mode of the parallel transformer modules, all modules start running, and the main module enters the constant voltage mode to control the output voltage; Step S3: Determine whether the load current is greater than the set value of the constant current mode of the main module. If so, proceed to step S5; if not, proceed to step S4; Step S4: the master module outputs voltage, the bidirectional switch of the slave module is disconnected, and the slave module does not output; return to step S3; Step S5: The main module enters the constant current mode, and the output voltage of the main module begins to drop; Step S6: When the output voltage of the master module drops below the set value of the constant voltage mode of the slave module, the bidirectional switch of the slave module is turned on, the slave module starts to output current, and the slave module enters the constant voltage mode, and the output voltage is controlled by the slave module; Step S7: If the load current continues to increase and becomes greater than the sum of the constant current mode settings of the master module and the slave module, the slave module enters the constant current mode and the output voltage continues to drop. Step S8: When the load current decreases to a value greater than the set value of the constant current mode of the master module but less than the sum of the set values ​​of the constant current modes of the master module and the slave module, the slave module exits the constant current mode and enters the constant voltage mode, and the output voltage is controlled by the slave module; Step S9: The load current continues to decrease until it is less than the set value of the constant current mode of the master module. The master module exits the constant current mode and enters the constant voltage mode. The master module pulls up the output voltage. When the output voltage is higher than the set value of the constant voltage mode of the slave module, the bidirectional switch of the slave module is disconnected and the slave module stops outputting.

8. The control method of the DC-DC parallel system according to claim 7, wherein: The main modules include: The transformer module with large source or load capacity, the transformer module with small source or load capacity, and the module that successfully shakes hands first.

9. The control method of the DC-DC parallel system according to claim 8, characterized in that: The set value of the constant voltage mode of the master module is higher than the set value of the constant voltage mode of the slave module.

10. The control method of the DC-DC parallel system according to claim 9, characterized in that: The setting values ​​of the constant current mode and the constant voltage mode of the master module and each slave module are selected according to the needs.

11. A charging cable, characterized in that: include: n+1 ports and the DC-DC parallel system according to any one of claims 1 to 6; the first end of the (n+1)th port is connected to the second end of the DC-DC parallel system, and the first ends of the 1st to nth ports are respectively connected to the first end of the DC-DC parallel system.

12. The charging cable according to claim 11, wherein: The first end of the n+1th port is connected to the third end of each bidirectional switch module, and the second end of the n+1th port is connected to the third end of the non-real-time control module; The first ends of the 1st to nth ports are respectively connected to the third ends of the corresponding voltage transformation modules, and the second ends of the 1st to nth ports are connected to the second end of the non-real-time control module.

13. The charging cable according to claim 12, wherein: The third end of the (n+1)th port is connected to the load, and the third ends of the first to nth ports are connected to the source.

14. The charging cable according to claim 12, wherein: The third end of the (n+1)th port is connected to the source, and the third ends of the first to nth ports are connected to the load.

15. The charging cable according to claim 12, wherein: The n+1 ports are USB ports.

16. A charger, characterized in that: include: A plug, an AC-DC conversion system, a battery, n+1 ports, and a DC-DC parallel system according to any one of claims 1 to 6; The first ends of the 1st to nth ports are connected to the first end of the DC-DC parallel system, and the first end of the (n+1th) port is connected to the second end of the DC-DC parallel system; the third ends of one or more of the 1st to nth ports are connected to the first end of the AC-DC conversion system, the third ends of one or more of the 1st to nth ports are connected to the first end of the battery, and the first end of the plug is connected to the second end of the AC-DC conversion system.

17. The charger according to claim 16, wherein: The first end of the n+1th port is connected to the third end of each bidirectional switch module, and the second end of the n+1th port is connected to the third end of the non-real-time control module; The first ends of the 1st to nth ports are respectively connected to the third ends of the corresponding voltage transformation modules, and the second ends of the 1st to nth ports are connected to the second end of the non-real-time control module.

18. The charger according to claim 16, wherein: The (n+1)th port is a USB port.

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