Voltage conversion system, conversion method and charging pile

Abstract

The invention provides a voltage conversion system, a conversion method and a charging pile. An input module of the voltage conversion system comprises at least two input units; the output module comprises at least two output units; the voltage conversion module comprises at least two voltage conversion units, one voltage conversion unit is arranged between each input unit and the corresponding output unit, and a switch piece used for adjusting the output voltage of the voltage conversion unit is arranged in each voltage conversion unit; the first voltage-sharing control unit is arranged to detect the input voltage of the at least two input units and / or the output voltage of the at least two output units, and outputs the first control signal according to the input voltage and / or the output voltage; according to the invention, the duty ratio of the control signal received by the switching element in the at least one voltage conversion unit is adjusted through the first control signal, so that the output voltage output by the at least one voltage conversion unit to the corresponding output unit is adjusted, and the balance of the output voltages among different voltage conversion units is improved.

Description

Technical Field

[0001] The present application belongs to the technical field of voltage conversion systems, and in particular, relates to a voltage conversion system, a conversion method and a charging pile. Background Art

[0002] The voltage conversion system can be used for direct current to direct current conversion. In the related art, the voltage conversion system includes multiple input units and multiple output units. If there is a voltage imbalance between the multiple input units or between the multiple output units, it is easy to cause the output voltage of the voltage conversion system to be unstable.

[0003] Therefore, how to improve the voltage balancing performance of the voltage conversion system is a problem that those skilled in the art currently need to solve. Summary of the invention

[0004] The purpose of the present application is to provide a voltage conversion system, a conversion method and a charging pile, aiming to solve the problem of low voltage equalization performance of the voltage conversion system in traditional technology.

[0005] A first aspect of an embodiment of the present application provides a voltage conversion system, the voltage conversion system comprising:

[0006] An input module, comprising at least two input units;

[0007] An output module, comprising at least two output units, and arranged in one-to-one correspondence with the two input units;

[0008] A voltage conversion module, comprising at least two voltage conversion units, wherein the voltage conversion unit is disposed between each input unit and the corresponding output unit, and a switch element for adjusting the output voltage of the voltage conversion unit is disposed in the voltage conversion unit;

[0009] A first voltage balancing control unit is used to detect the input voltage of at least two of the input units and / or the output voltage of at least two of the output units, and output a first control signal according to the input voltage and / or the output voltage, wherein the first control signal is used to adjust the duty cycle of the switch element in at least one of the voltage conversion units receiving the control signal, so as to adjust the output voltage output by at least one of the voltage conversion units to the corresponding output unit.

[0010] In some embodiments of the present application, the first voltage balancing control unit includes a first sub-control unit, the first sub-control unit is used to obtain the input voltages of the two input units, and output a first sub-control signal for adjusting the duty cycle of the switch element receiving the control signal;

[0011] And / or, the first voltage balancing control unit includes a second sub-control unit, and the second sub-control unit is used to obtain the output voltages of the two output units and output a second sub-control signal for adjusting the duty cycle of the control signal received by the switch element.

[0012] In some embodiments of the present application, the first sub-control unit includes:

[0013] A first difference operator, used for performing a difference operation on the input voltages of the two input units;

[0014] The input voltage equalizing controller is used to output the first sub-control signal according to the difference result of the input voltage.

[0015] And / or, the second sub-control unit includes:

[0016] A second difference operator, used for performing a difference operation on the output voltages of the two output units;

[0017] The output voltage equalizing controller is used to output the second sub-control signal according to the difference result of the output voltage.

[0018] In some embodiments of the present application, the input voltage equalizing controller and the output voltage equalizing controller are selected from at least one of a proportional controller, a proportional-integral controller, a proportional-differential controller, a proportional-integral-differential control, and a proportional resonant controller.

[0019] In some embodiments of the present application, the first voltage balancing control unit includes a weighted controller, the weighted controller is used to receive the first sub-control signal and the second sub-control signal, and is used to form a third sub-control signal according to the first sub-control signal and the second sub-control signal;

[0020] The weighted controller is used to adjust the weights of the first sub-control signal and the second sub-control signal according to the current flow directions of the voltage conversion module, the input module and the output module, and then output the third sub-control signal.

[0021] In some embodiments of the present application, the weighted controller is configured to adjust the weight of the first sub-control signal to 1 when the current flows from the input module to the voltage conversion module and from the voltage conversion module to the output module;

[0022] The weighting controller is configured to adjust the weight of the second sub-control signal to 1 when current flows from the output module to the voltage conversion module and from the voltage conversion module to the input module.

[0023] In some embodiments of the present application, the voltage conversion system also includes a common-mode output unit for outputting a second control signal, wherein the second control signal is a common-mode control signal, and the switch element is used to adjust the output voltage of the voltage conversion unit to the corresponding output module according to the first control signal and the second control signal.

[0024] In some embodiments of the present application, the at least two voltage conversion units include a first voltage conversion unit and a second voltage conversion unit, the first voltage conversion unit is provided with a first switch element, and the second voltage conversion unit is provided with a second switch element;

[0025] The voltage conversion system further includes an adder and a third difference operator, wherein the adder is used to perform an addition operation on the first control signal and the second control signal, and to output a third control signal according to the operation result, wherein the third control signal is used to adjust the duty cycle of the control signal received by the first switch;

[0026] The third difference operator is used to perform a subtraction operation on the first control signal and the second control signal, and to output a fourth control signal according to the operation result, wherein the fourth control signal is used to adjust the duty cycle of the control signal received by the second switch element.

[0027] In some embodiments of the present application, the voltage conversion system further includes a second voltage balancing control unit, which is connected to the at least two input units and is used to balance the voltage between the at least two input units.

[0028] In some embodiments of the present application, the at least two input units include a first input unit and a second input unit, and the second voltage equalizing control unit includes an energy storage element, which is used to obtain electrical energy from one of the first input unit and the second input unit, and the energy storage element is used to supply energy to the other of the first input unit and the second input unit.

[0029] In some embodiments of the present application, the at least two input units are arranged in series; and / or the at least two output units are arranged in series.

[0030] In a second aspect, the present application further provides a voltage conversion method, which is applied to the above-mentioned voltage conversion system and is used to balance the output voltages of at least two of the output units.

[0031] In some embodiments of the present application, the voltage conversion method includes:

[0032] Obtaining an output current value of the output module, and determining whether the output current value is less than a preset current threshold;

[0033] If yes, the first pressure balancing control unit is turned off and the second pressure balancing control unit is turned on; if no, the first pressure balancing control unit is turned on.

[0034] In some embodiments of the present application, the voltage conversion method includes:

[0035] Obtaining a voltage difference between output voltages of at least two output units, and determining whether the voltage difference is less than a preset difference threshold;

[0036] If yes, the second pressure balancing control unit is turned off; if no, the second pressure balancing control unit is turned on.

[0037] In a third aspect, the present application also provides a charging pile, which includes the above-mentioned voltage conversion system.

[0038] The beneficial effect of the present application lies in that in the voltage conversion system, conversion method and charging pile of the present application, the voltage conversion system includes an input module, an output module, a voltage conversion module and a first voltage equalizing control unit; the input module includes at least two input units; the output module includes at least two output units; the voltage conversion module includes at least two voltage conversion units, and a voltage conversion unit is arranged between each input unit and its corresponding output unit, and a switch element for adjusting the output voltage of the voltage conversion unit is arranged in the voltage conversion unit; the present application detects the input voltage of at least two input units and / or the output voltage of at least two output units by setting a first voltage equalizing control unit, and outputs a first control signal according to the input voltage and / or the output voltage; the present application adjusts the duty cycle of the switch element in at least one voltage conversion unit receiving the control signal through the first control signal, so as to adjust the output voltage output by at least one voltage conversion unit to the corresponding output unit, which is beneficial to improve the balance of the output voltage between different voltage conversion units. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 A schematic diagram of the framework structure of a voltage conversion system provided in one embodiment of the present application;

[0040] Figure 2 A schematic diagram of the framework structure of a voltage conversion system provided in another embodiment of the present application;

[0041] Figure 3 A schematic diagram of the framework structure of a voltage conversion system provided in yet another embodiment of the present application;

[0042] Figure 4 A control block diagram of a voltage conversion system provided in one embodiment of the present application;

[0043] Figure 5 A schematic diagram of the framework structure of a voltage conversion system provided in yet another embodiment of the present application;

[0044] Figure 6 A schematic diagram of the circuit structure of a voltage conversion system provided in one embodiment of the present application;

[0045] Figure 7 A schematic diagram of control steps of a voltage conversion system provided in one embodiment of the present application;

[0046] Figure 8 A control block diagram of a voltage conversion system provided by another embodiment of the present application;

[0047] Fig. 9 Another control block diagram of a voltage conversion system provided by another embodiment of the present application;

[0048] Fig.10 A schematic diagram of the circuit structure of a voltage conversion system provided by another embodiment of the present application;

[0049] Fig.11 A schematic diagram of the steps of a voltage conversion method provided in one embodiment of the present application;

[0050] Fig.12 A schematic diagram of the steps of a voltage conversion method provided in one embodiment of the present application.

[0051] Explanation of specific element symbols: 100-input module, 110-input unit, 200-voltage conversion module, 210-voltage conversion unit, 211-switch element, 300-output module, 310-output unit, 400-first voltage equalizing control unit, 410-first sub-control unit, 420-second sub-control unit, 500-common mode output unit, OP1-first difference operator, OP2-second difference operator, OP3-third difference operator, OP4-addition operator, L-first inductor, Q1-first switch tube, Q2-second switch tube, D1-first diode, D2-second diode. DETAILED DESCRIPTION

[0052] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0053] It should be noted that when an element is referred to as being "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0054] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0055] It is important to know that the voltage conversion system is a key component widely used in various electronic devices. Its core function is to achieve effective conversion between different voltage levels, especially in the application scenario of DC-DC. Such systems are usually designed with multiple input units and multiple output units to meet the flexible adaptation of complex electronic devices to diverse voltage requirements.

[0056] In the related art, voltage imbalance is prone to occur between multiple input units or multiple output units during actual operation. Voltage imbalance may lead to uneven current distribution, which in turn causes an increase in power loss within the system. In severe cases, it may even cause some components to overheat, accelerate their aging process, and ultimately affect the service life of the entire voltage conversion system. This voltage imbalance may even directly lead to unstable output voltage, which cannot meet the stringent requirements of the back-end load for stable and accurate voltage supply, thereby affecting the performance and stability of the entire electronic device.

[0057] For example, in the current electric vehicle field, the output voltage of the charging pile needs to cover multiple ranges. Therefore, two power supplies and two DC converters are required to achieve the output of different platform voltages through series-parallel switching of input and output. For the case of input / output series connection, it is easy to have an unbalanced output voltage, especially for the case where both input and output are connected in series.

[0058] Based on this, the present application improves the voltage conversion system, conversion method and charging pile in the related technology.

[0059] See also Figure 1 , Figure 1The schematic diagram of the framework structure of the voltage conversion system provided by the present embodiment is shown; the voltage conversion system of the present embodiment includes an input module 100, an output module 300, a voltage conversion module 200 and a first voltage balancing control unit 400; the input module 100 includes at least two input units 110; the output module 300 includes at least two output units 310, and is arranged one-to-one with the two input units 110; the voltage conversion module 200 includes at least two voltage conversion units 210, a voltage conversion unit 210 is arranged between each input unit 110 and its corresponding output unit 310, and a switch 211 for adjusting the output voltage of the voltage conversion unit 210 is arranged in the voltage conversion unit 210; the first voltage balancing control unit 400 is used to detect the input voltage of at least two input units 110 and / or the output voltage of at least two output units 310, and output a first control signal according to the input voltage and / or the output voltage, the first control signal is used to adjust the duty cycle of the switch 211 in at least one voltage conversion unit 210 receiving the control signal, so as to adjust the output voltage output by at least one voltage conversion unit 210 to the corresponding output unit 310.

[0060] It should be explained that the input module 100, as the input starting point in the voltage conversion system, can be used to connect an external power supply; the output module 300, as the output end point in the voltage conversion system, can be used to connect a load. The voltage conversion module 200 can be used to realize the conversion between DC and AC, and can also be used to realize the step-up / step-down of DC / AC voltage. Exemplarily, the voltage conversion module 200 is a DC-to-DC converter. The first voltage balancing control unit 400 can be implemented by a controller, a control chip, etc. The first voltage balancing control unit 400 can monitor and control the duty cycle of the switch element 211 according to the input voltage and / or the output voltage, so as to adjust the output voltage.

[0061] It is understandable that the first voltage balancing control unit 400 can detect the output voltages of the two output units 310, and output the first control signal according to the two output voltages, and adjust the output voltage of the voltage conversion unit 210 to the output unit 310 through the first control signal. The first voltage balancing control unit 400 can also detect the input voltages of the two input units 110, and output the first control signal according to the two input voltages. If there is a deviation in the input voltage of the input unit 110, it will cause the output voltage to be easily deviated. In this way, the output voltage of the voltage conversion unit 210 to the output unit 310 can also be adjusted through the first control signal.

[0062] In the related art, when the voltage conversion system outputs two output voltages, there is a problem that the difference between the two output voltages is large. However, the present application sets a first voltage balancing control unit 400 to detect the input voltage of at least two input units 110 and / or the output voltage of at least two output units 310, and outputs a first control signal according to the input voltage and / or the output voltage; the present application adjusts the duty cycle of the switch element 211 in at least one voltage conversion unit 210 receiving the control signal through the first control signal to adjust the output voltage outputted by at least one voltage conversion unit 210 to the corresponding output unit 310, which is conducive to improving the balance of the output voltages between different voltage conversion units 210.

[0063] In some embodiments, the first voltage balancing control unit 400 adjusts any one of the switch elements 211 in at least two voltage conversion units 210, and can achieve voltage balance by adjusting one output voltage to make it close to another output voltage. In other embodiments, the first voltage balancing control unit 400 adjusts two switch elements 211 in at least two voltage conversion units 210, and can achieve voltage balance by adjusting the two output voltages to be close to each other.

[0064] In some embodiments of this application, please refer to Figure 2 , Figure 2 A schematic diagram of the framework structure of the voltage conversion system provided in this embodiment is shown; the first voltage equalization control unit 400 of this embodiment includes a first sub-control unit 410, which is used to obtain the input voltages of the two input units 110 and output a first sub-control signal for adjusting the duty cycle of the switch element 211 receiving the control signal.

[0065] Specifically, when the current flows in the forward direction (ie, the same direction as the current flowing from the input unit 110 to the output unit 310 ), the first sub-control unit 410 may be activated first, and the switch element 211 may be adjusted according to the input voltages of the two input units 110 .

[0066] In some embodiments of this application, please refer to Figure 3 , Figure 3 A schematic diagram of the framework structure of the voltage conversion system provided in this embodiment is shown; the first voltage equalization control unit 400 of this embodiment includes a second sub-control unit 420, and the second sub-control unit 420 is used to obtain the output voltage of the two output units 310 and output a second sub-control signal for adjusting the duty cycle of the switch element 211 receiving the control signal.

[0067] Specifically, when the current flows in the negative direction (ie, opposite to the direction of the current flowing from the input unit 110 to the output unit 310 ), the second sub-control unit 420 may be activated first and the switch element 211 may be adjusted according to the input voltages of the two output units 310 .

[0068] In some embodiments of this application, please refer to Figure 4 , Figure 4 The control block diagram of the voltage conversion system provided by the present embodiment is shown. The first sub-control unit 410 of the present embodiment includes a first difference operator OP1 and an input voltage equalization controller; the first difference operator OP1 is used to perform a difference operation on the input voltages of the two input units 110; the input voltage equalization controller is used to output a first sub-control signal according to the difference result of the input voltages.

[0069] It can be understood that the first difference operator OP1 calculates the voltage difference between the input voltages of the two input units 110, and the input voltage equalization controller outputs the first sub-control signal according to the voltage difference.

[0070] In some embodiments, the input voltage equalization controller includes but is not limited to one or more of a proportional (P) controller, a proportional integral (PI) controller, a proportional derivative (PD) controller, a proportional integral derivative (PID) controller, and a proportional resonant (PR) controller.

[0071] In some embodiments of this application, please continue to refer to Figure 4 The second sub-control unit 420 of this embodiment includes a second difference operator OP2 and an output voltage equalizing controller; the second difference operator OP2 is used to perform a difference operation on the output voltages of the two output units 310; the output voltage equalizing controller is used to output a second sub-control signal according to the difference result of the output voltage.

[0072] It can be understood that the second difference operator OP2 calculates the voltage difference between the output voltages of the two output units 310, and the output voltage equalization controller outputs the second sub-control signal according to the voltage difference.

[0073] In some embodiments, the output voltage equalizing controller includes but is not limited to one or more of a proportional (P) controller, a proportional integral (PI) controller, a proportional differential (PD) controller, a proportional integral differential (PID) controller, and a proportional resonant (PR) controller.

[0074] In some embodiments of this application, please continue to refer to Figure 4 The first voltage balancing control unit 400 of this embodiment includes a weighted controller, which is used to receive the first sub-control signal and the second sub-control signal, and to generate a voltage balancing control signal according to the first sub-control signal ( Figure 4 dmDutyVin) and the second sub-control signal ( Figure 4 dmDutyVout) shown in FIG. Figure 4dmDuty shown in the figure); the weighted controller is used to adjust the weights of the first sub-control signal and the second sub-control signal and then output the third sub-control signal according to the current flow direction of the voltage conversion module 200, the input module 100 and the output module 300.

[0075] It should be explained that the weighted controller is used to adjust the weight ratio of the first sub-control signal and the second sub-control signal. For example, if the weight of the first sub-control signal is 1 and the weight of the second sub-control signal is 0, the third sub-control signal can be formed entirely by the first sub-control signal; if the weight of the first sub-control signal is 0.5 and the weight of the second sub-control signal is 0.5, the third sub-control signal is formed by the first sub-control signal * 50% + the second sub-control signal * 50%; if the weight of the first sub-control signal is 0 and the weight of the second sub-control signal is 1, the third sub-control signal can be formed entirely by the second sub-control signal.

[0076] It can be understood that when the average current in the system is a positive current, the weight of the first sub-control signal is selected as 1, and the weight of the second sub-control signal is selected as 0. At this time, the switch element 211 is completely controlled by the first sub-control signal. In other words, since the current is a positive current, after adjusting the switch element 211 according to the input voltage, if the input voltage is balanced, the output voltage is automatically balanced. When the average current in the system is a negative current, the weight of the first sub-control signal is selected as 0, and the weight of the second sub-control signal is selected as 1. At this time, the switch element 211 is completely controlled by the second sub-control signal. In other words, since the current is a negative current, after adjusting the switch element 211 according to the output voltage, if the output voltage is balanced, the input voltage is automatically balanced.

[0077] In some embodiments, the weight adjustment method of the weighting controller is linear, nonlinear, or based on a lookup table / algorithm.

[0078] In some embodiments of the present application, the weighted controller is configured to adjust the weight of the first sub-control signal to 1 when the current flows from the input module 100 to the voltage conversion module 200 and from the voltage conversion module 200 to the output module 300; the weighted controller is configured to adjust the weight of the second sub-control signal to 1 when the current flows from the output module 300 to the voltage conversion module 200 and from the voltage conversion module 200 to the input module 100.

[0079] In some embodiments of this application, please continue to refer to Figure 4 Also see Figure 5 , Figure 5 Schematic diagram of the framework structure of the voltage conversion system provided in this embodiment; the voltage conversion system in this embodiment also includes a common mode output unit 500 for outputting a second control signal ( Figure 4cmDuty shown in the figure), the second control signal is a common mode control signal, and the switch element 211 is used to adjust the output voltage of the voltage conversion unit 210 output to the corresponding output module 300 according to the first control signal and the second control signal.

[0080] It should be explained that the common mode output unit 500 can output the second control signal based on the signal of the energy transmission loop. Exemplarily, the signal of the energy transmission loop includes the signal of the voltage loop ( Figure 4 cmVerr shown in the figure), the current loop signal ( Figure 4 cmIerr) and the power ring signal ( Figure 4 The second control signal is output after the signal of the voltage loop, the signal of the current loop and the signal of the power loop are cascaded or competed.

[0081] It is understandable that the switch element 211 can be controlled by the common mode control in this embodiment and the differential mode control in any of the above embodiments to improve the control accuracy.

[0082] In some embodiments of this application, please continue to refer to Figure 4 The at least two voltage conversion units 210 of this embodiment include a first voltage conversion unit 210 and a second voltage conversion unit 210. The first voltage conversion unit 210 is provided with a first switch 211, and the second voltage conversion unit 210 is provided with a second switch 211. The voltage conversion system also includes an adder OP4 and a third difference operator OP3. The adder OP4 is used to perform an addition operation on the first control signal and the second control signal, and is used to output a third control signal ( Figure 4 The third control signal is used to adjust the duty cycle of the control signal received by the first switch 211; the third difference operator OP3 is used to perform a subtraction operation on the first control signal and the second control signal, and to output a fourth control signal ( Figure 4 The fourth control signal is used to adjust the duty cycle of the control signal received by the second switch element 211.

[0083] It should be explained that the first voltage-balanced control unit 400 needs to output two first control signals respectively when controlling the first switch 211 and the second switch 211, and the common-mode output unit 500 needs to output two second control signals respectively when controlling the first switch 211 and the second switch 211; the adder OP4 in this embodiment adds the first control signal and the second control signal to obtain a third control signal for controlling the first switch 211. The third difference operator OP3 in this embodiment subtracts the first control signal and the second control signal to obtain a third control signal for controlling the second switch 211.

[0084] See also Figure 6 and Figure 7 , Figure 6 A schematic diagram of the circuit structure of the voltage conversion system of this embodiment is shown; Figure 7 A schematic diagram of control steps of the voltage conversion system of this embodiment is shown. Figure 6 The bidirectional source is a power source for supplying power to the first input unit 110 ( Figure 4 Vin1 shown in FIG. 1 ) and the second input unit 110 ( Figure 4 The Vin2 shown in FIG. Figure 6 DCDC1 in the figure is the first voltage conversion unit 210, and DCDC2 is the second voltage conversion unit 210. The first conversion unit outputs voltage to the first output unit 310 ( Figure 4 The second conversion unit outputs a voltage to the second output unit 310 ( Figure 4 Vout2) shown in FIG. Figure 6 The arrow in the middle points to the direction of current flow.

[0085] After the voltage balancing starts, the voltage conversion system in this embodiment needs to first update the input differential mode controller, that is, the input voltage balancing controller outputs the first sub-control signal, and then update the output differential mode controller, that is, the output voltage balancing controller outputs the second sub-control signal. Then the differential mode control quantity is weighted, that is, the first sub-control signal and the second sub-control signal are weighted by the weighted controller to output the third sub-control signal. Finally, the common and differential mode Duty are transformed into Duty1 and Duty2, that is, the third control signal and the fourth control signal for controlling the first switch 211 and the second switch 211 are output through the adder OP4 and the third subtractor.

[0086] In some embodiments of this application, please refer to Figure 8 and Fig. 9 , Figure 8 shows a control block diagram provided by this embodiment, Fig. 9 Another control block diagram provided by this embodiment is shown. The voltage conversion system of this embodiment also includes a second voltage balancing control unit ( Figure 8 The second voltage balancing control unit is connected to at least two input units 110 and is used to balance the voltage between the at least two input units 110.

[0087] It is understandable that in this embodiment, the voltage balancing of the input voltage is controlled by a hardware balancing bridge. And before or after starting the second voltage balancing control unit, the first voltage balancing control unit 400 needs to be turned off, that is, the output signal is sent to the weighted controller ( Figure 8 The control amount selection shown in ).

[0088] In some embodiments, Figure 8 As shown, the second voltage balancing control unit can be controlled by acquiring the difference in input voltage between at least two input units 110 .

[0089] In other embodiments, Fig. 9 As shown, the second voltage balancing control unit can be controlled by obtaining the difference in output voltage between at least two output units 310 .

[0090] In some embodiments of this application, please refer to Fig.10 , Fig.10 The control block diagram provided by this embodiment is shown. In this embodiment, at least two input units 110 include a first input unit and a second input unit, and the second voltage-balanced control unit includes an energy storage element, which is used to obtain electrical energy from one of the first input unit and the second input unit, and the energy storage element is used to supply energy to the other of the first input unit and the second input unit.

[0091] It should be explained that, when the input voltage of the first input unit is higher than the input voltage of the second input unit, the balance of the input voltages of the two can be achieved by absorbing the electric energy of the first input unit and / or supplying energy to the second input unit. When the input voltage of the second input unit is higher than the input voltage of the first input unit, the balance of the input voltages of the two can be achieved by absorbing the electric energy of the second input unit and / or supplying energy to the first input unit.

[0092] In some embodiments, the energy storage element includes a first inductor L, a first link, and a second link. A first loop is formed between the first link, the first inductor L, and the first input unit 110, and a second loop is formed between the second link, the first inductor L, and the second input unit 110. When the first loop is turned on, the first inductor L obtains and stores the electric energy in the first input unit 110, and when the second loop is turned on, the first inductor L releases the electric energy to the second input unit 110 to achieve voltage balance.

[0093] In some embodiments, a first switch tube Q1 and a first diode D1 are provided on the first link, the first diode D1 is connected in parallel with the first switch tube Q1, and the anode of the first diode D1 is connected to the first inductor L, and the cathode is connected to the first input unit 110. A second switch tube Q2 and a second diode D2 are provided on the second link, the second diode D2 is connected in parallel with the second switch tube Q2, and the anode of the second diode D2 is connected to the second input unit 110, and the cathode is connected to the first inductor L.

[0094] In some embodiments, the first switch tube Q1 and the second switch tube Q2 are selected from MOS tubes and / or triodes.

[0095] In some embodiments of the present application, at least two input units 110 are arranged in series; and / or, at least two output units 310 are arranged in series.

[0096] Furthermore, in order to better implement the voltage conversion system in any of the above embodiments, based on the above voltage conversion system, the present application also provides a voltage conversion method for balancing the output voltages of at least two output units 310 .

[0097] In some embodiments of this application, please refer to Fig.11 , Fig.11 The schematic diagram of the steps of the voltage conversion method provided by this embodiment is shown. The voltage conversion method of this embodiment includes:

[0098] The output current value of the output module 300 is obtained, and it is determined whether the output current value is less than a preset current threshold value; specifically, the absolute value of the output current value may be taken and then compared with the preset current threshold value.

[0099] If yes, the first pressure balancing control unit 400 is turned off, and the second pressure balancing control unit is turned on; if no, the first pressure balancing control unit 400 is turned on.

[0100] That is to say, when the output current value does not reach the preset current threshold, the current in the circuit is small, and the balancing bridge through the second voltage balancing control unit is sufficient to meet the voltage balancing requirement; when the output current value reaches the preset current threshold, the current in the circuit is large, and the balancing bridge through the second voltage balancing control unit is insufficient to meet the voltage balancing requirement, and it is necessary to turn on the first voltage balancing control unit 400 to balance the voltage through software.

[0101] For details, please continue to see Fig.11After the software voltage balancing is interrupted, it is determined whether the absolute value of the output current is less than the current threshold (preset current threshold). If so, the control ratio of the first control signal is set to 0, that is, the control of the switch 211 by the first voltage balancing control unit 400 is turned off, and the control of the switch 211 by the common mode output unit 500 is still retained. Otherwise, the switch 211 is controlled according to the control method of the combination of the first voltage balancing control unit 400 and the common mode output unit 500 in the above embodiment.

[0102] In some embodiments of this application, please refer to Fig.12 , Fig.12 The schematic diagram of the steps of the voltage conversion method provided by this embodiment is shown. The voltage conversion method of this embodiment includes:

[0103] The voltage difference between the output voltages of at least two output units 310 is obtained, and it is determined whether the voltage difference is less than a preset difference threshold; specifically, the absolute value of the voltage difference may be taken and compared with the preset difference threshold.

[0104] If yes, the second pressure balancing control unit is turned off; if no, the second pressure balancing control unit is turned on.

[0105] That is to say, when the voltage equalization error (voltage difference) does not reach the voltage equalization threshold (preset difference threshold), the balancing bridge of the second voltage equalization control unit is not sufficient to meet the voltage equalization requirement, and it is necessary to turn on the first voltage equalization control unit 400 to perform voltage equalization through software; when the voltage equalization error (voltage difference) reaches the voltage equalization threshold (preset difference threshold), the balancing bridge of the second voltage equalization control unit is sufficient to meet the voltage equalization requirement.

[0106] In some embodiments, in the process of switching between the first voltage balancing control unit 400 and the second voltage balancing control unit, a linear weighted transition method may be used for switching.

[0107] Furthermore, in order to better implement the voltage conversion system in any of the above embodiments, based on the above voltage conversion system, the present application also provides a charging pile, which includes the above voltage conversion system.

[0108] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0109] The basic concepts have been described above. Obviously, for those skilled in the art, the above detailed disclosure is only for example and does not constitute a limitation of the present application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements and amendments to the present application. Such modifications, improvements and amendments are suggested in the present application, so such modifications, improvements and amendments still belong to the spirit and scope of the exemplary embodiments of the present application.

[0110] At the same time, the present application uses specific words to describe the embodiments of the present application. For example, "one embodiment", "an embodiment", and / or "some embodiments" refer to a certain feature, structure or characteristic related to at least one embodiment of the present application. Therefore, it should be emphasized and noted that "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or more in different positions in this specification does not necessarily refer to the same embodiment. In addition, some features, structures or characteristics in one or more embodiments of the present application can be appropriately combined.

[0111] Similarly, it should be noted that in order to simplify the description of the disclosure of this application and thus help understand one or more embodiments of the invention, in the above description of the embodiments of this application, multiple features are sometimes combined into one embodiment, figure or description thereof. However, this disclosure method does not mean that the features required by the object of this application are more than the features mentioned in the claims. In fact, the features of the embodiments are less than all the features of the single embodiment disclosed above.

[0112] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A voltage conversion system, characterized in that: The voltage conversion system comprises: An input module, comprising at least two input units; An output module, comprising at least two output units, and arranged in one-to-one correspondence with the two input units; A voltage conversion module, comprising at least two voltage conversion units, wherein the voltage conversion unit is disposed between each input unit and the corresponding output unit, and a switch element for adjusting the output voltage of the voltage conversion unit is disposed in the voltage conversion unit; A first voltage balancing control unit is used to detect the input voltage of at least two of the input units and / or the output voltage of at least two of the output units, and output a first control signal according to the input voltage and / or the output voltage, wherein the first control signal is used to adjust the duty cycle of the switch element in at least one of the voltage conversion units receiving the control signal, so as to adjust the output voltage output by at least one of the voltage conversion units to the corresponding output unit.

2. The voltage conversion system according to claim 1, characterized in that: The first voltage balancing control unit includes a first sub-control unit, the first sub-control unit is used to obtain the input voltages of the two input units, and output a first sub-control signal for adjusting the duty cycle of the control signal received by the switch element; And / or, the first voltage balancing control unit includes a second sub-control unit, and the second sub-control unit is used to obtain the output voltages of the two output units and output a second sub-control signal for adjusting the duty cycle of the control signal received by the switch element.

3. The voltage conversion system according to claim 2, characterized in that: The first sub-control unit comprises: A first difference operator, used for performing a difference operation on the input voltages of the two input units; An input voltage equalizing controller, configured to output the first sub-control signal according to a difference result of the input voltage; And / or, the second sub-control unit includes: A second difference operator, used for performing a difference operation on the output voltages of the two output units; The output voltage equalizing controller is used to output the second sub-control signal according to the difference result of the output voltage.

4. The voltage conversion system according to claim 3, characterized in that: The input voltage balancing controller and the output voltage balancing controller are selected from at least one of a proportional controller, a proportional-integral controller, a proportional-differential controller, a proportional-integral-differential control, and a proportional resonant controller.

5. The voltage conversion system according to claim 2, characterized in that: The first voltage balancing control unit includes a weighted controller, the weighted controller is used to receive the first sub-control signal and the second sub-control signal, and is used to form a third sub-control signal according to the first sub-control signal and the second sub-control signal; The weighted controller is used to adjust the weights of the first sub-control signal and the second sub-control signal according to the current flow directions of the voltage conversion module, the input module and the output module, and then output the third sub-control signal.

6. The voltage conversion system according to claim 5, characterized in that: The weighted controller is configured to adjust the weight of the first sub-control signal to 1 when the current flows from the input module to the voltage conversion module and from the voltage conversion module to the output module; The weighting controller is configured to adjust the weight of the second sub-control signal to 1 when current flows from the output module to the voltage conversion module and from the voltage conversion module to the input module.

7. The voltage conversion system according to any one of claims 1 to 6, characterized in that: The voltage conversion system also includes a common-mode output unit for outputting a second control signal, where the second control signal is a common-mode control signal, and the switch element is used to adjust the output voltage output by the voltage conversion unit to the corresponding output module according to the first control signal and the second control signal.

8. The voltage conversion system according to claim 7, characterized in that: The at least two voltage conversion units include a first voltage conversion unit and a second voltage conversion unit, wherein the first voltage conversion unit is provided with a first switch element, and the second voltage conversion unit is provided with a second switch element; The voltage conversion system further includes an adder and a third difference operator, wherein the adder is used to perform an addition operation on the first control signal and the second control signal, and to output a third control signal according to the operation result, wherein the third control signal is used to adjust the duty cycle of the control signal received by the first switch; The third difference operator is used to perform a subtraction operation on the first control signal and the second control signal, and to output a fourth control signal according to the operation result, wherein the fourth control signal is used to adjust the duty cycle of the control signal received by the second switch element.

9. The voltage conversion system according to claim 1, characterized in that: The voltage conversion system further includes a second voltage balancing control unit, which is connected to the at least two input units and is used to balance the voltage between the at least two input units.

10. The voltage conversion system according to claim 9, characterized in that: The at least two input units include a first input unit and a second input unit, and the second voltage equalizing control unit includes an energy storage element, which is used to obtain electrical energy from one of the first input unit and the second input unit, and the energy storage element is used to supply energy to the other of the first input unit and the second input unit.

11. The voltage conversion system according to any one of claims 1 to 10, characterized in that: The at least two input units are arranged in series; and / or the at least two output units are arranged in series.

12. A voltage conversion method, characterized in that: The voltage conversion method is applied to the voltage conversion system according to any one of claims 1 to 11, and is used to balance the output voltages of at least two of the output units.

13. The voltage conversion method according to claim 12, characterized in that: The voltage conversion method comprises: Obtaining an output current value of the output module, and determining whether the output current value is less than a preset current threshold; If yes, the first pressure balancing control unit is turned off and the second pressure balancing control unit is turned on; if no, the first pressure balancing control unit is turned on.

14. The voltage conversion method according to claim 12, characterized in that: The voltage conversion method comprises: Obtaining a voltage difference between output voltages of at least two output units, and determining whether the voltage difference is less than a preset difference threshold; If yes, the second pressure balancing control unit is turned off; if no, the second pressure balancing control unit is turned on.

15. A charging pile, characterized in that: The charging pile comprises the voltage conversion system according to any one of claims 1 to 11.

Images