Bidirectional DCDC circuit and control method thereof

Abstract

The invention provides a bidirectional DCDC circuit and a control method thereof, in the bidirectional DCDC circuit, a first power supply module, a second power supply module, a main circuit, a first sampling circuit, a second sampling circuit, a first driving circuit, a second driving circuit and a controller are correspondingly connected, so that a topological structure and a circuit loop can be simplified, and the device cost is reduced; moreover, when the power supply is transmitted between the first power supply module and the second power supply module, the controller determines a target transformation ratio combination of the main circuit according to the first conditioning signal and the second conditioning signal, and then controls the main circuit to be switched to the target transformation ratio combination based on the switching control signal through the first driving circuit and the second driving circuit. Therefore, according to the target transformation ratio combination, the input and output voltage and the input and output current of the main circuit are controlled, a unified driving signal is adopted for driving, and the stability of the output voltage and the output current is ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of battery energy management and energy storage, and in particular to a bidirectional DCDC circuit and a control method thereof. Background Art

[0002] At present, in the field of battery energy management and energy storage, the charging and discharging of the battery is realized by designing an isolated bidirectional DCDC converter, that is, the DCDC converter can both charge and discharge the battery, and at the same time, the isolation of the battery and the external power supply must be ensured to ensure safety. However, the number of battery strings varies in different scenarios, and the fluctuation range of the external power supply is also large. Therefore, the bidirectional DCDC converter needs to adapt to a wide input and output range.

[0003] In the related art, bidirectional DCDC converters are usually implemented by cascading multiple converters or by using wide range PWM pulse width modulation to adapt to a wide input and output range, such as Figure 1 As shown, a two-stage converter architecture is adopted, the first-stage converter 1 adopts a non-isolated topology to achieve a wide range of voltage regulation effect, and the second-stage converter 2 adopts an isolated topology to complete the electrical isolation between the battery side and the outside.

[0004] but, Figure 1 The topological structure is complex, requiring more switching devices and filtering devices, and the device is large in size and high in cost. In addition, Figure 1 The topological structure requires many drive signals, complex control algorithms and loops, and high requirements for the system control part; moreover, the electromagnetic compatibility design is complex and rectification is difficult; in addition, the duty cycle of PWM varies widely, the current and voltage stress of the switching device is large, the selection is difficult, and the cost is high; and the duty cycle of PWM needs to be more than 50%, and slope compensation needs to be added in the current peak control mode, which increases the complexity of the circuit and deteriorates the single-cycle current limiting effect.

[0005] Therefore, how to simplify the topology and circuit loop, reduce device costs, use a unified drive signal for driving, and ensure the stability of output voltage and current has become a problem that technical personnel in this field need to solve urgently. Summary of the invention

[0006] In view of this, an embodiment of the present invention provides a bidirectional DCDC circuit and a control method thereof to simplify the topology structure and circuit loop, reduce device cost, adopt a unified driving signal for driving, and ensure the stability of output voltage and current.

[0007] To achieve the above objectives, the embodiments of the present invention provide the following technical solutions:

[0008] A first aspect of an embodiment of the present invention discloses a bidirectional DCDC circuit, comprising: a first power module, a second power module, a main circuit, a first sampling circuit, a second sampling circuit, a first driving circuit, a second driving circuit and a controller;

[0009] The two power supply terminals of the main circuit are respectively connected to the positive electrode and the negative electrode of the first power module and the positive electrode and the negative electrode of the second power module, and the two driving control terminals of the main circuit are respectively connected to the controller through the first driving circuit and the second driving circuit;

[0010] The sampling end of the first sampling circuit is connected to the first power supply module, and the output end of the first sampling circuit is connected to the controller;

[0011] A sampling end of the second sampling circuit is connected to the second power supply module, and an output end of the second sampling circuit is connected to the controller;

[0012] The controller is used to obtain a first conditioning signal output by the first sampling circuit and a second conditioning signal output by the second sampling circuit when power is transmitted between the first power module and the second power module, determine a target transformation ratio combination of the main circuit according to the first conditioning signal and the second conditioning signal, control the main circuit to switch to the target transformation ratio combination through the first drive circuit and the second drive circuit based on an output switching control signal, and control the input and output voltage and input and output current of the main circuit according to the target transformation ratio combination through the first drive circuit and the second drive circuit based on an output drive control signal; the first conditioning signal is obtained by the first sampling circuit sampling the input and output voltage and current of the first power module and conditioning it, and the second conditioning signal is obtained by the second sampling circuit sampling the input and output voltage and current of the second power module and conditioning it.

[0013] Optionally, the main circuit includes: a transformer, a first single-pole double-throw relay, a first switch tube, a first absorption circuit and a first filter capacitor;

[0014] Two ends of the primary first winding of the transformer are connected to the positive electrode of the first power module through two contacts of the first single-pole double-throw relay;

[0015] A first end of the first absorption circuit is connected to the first single-pole double-throw relay, and a second end of the first absorption circuit is connected to the second end of the primary second winding;

[0016] The first end of the first switch tube is connected to the second end of the primary second winding, the second end is connected to the negative electrode of the first power module, and the third end is connected to the first drive circuit;

[0017] The first filter capacitor is connected in parallel to the positive electrode and the negative electrode of the first power module.

[0018] Optionally, the main circuit further includes: a second single-pole double-throw relay, a second switch tube, a second absorption circuit and a second filter capacitor;

[0019] Two ends of the first winding of the secondary side of the transformer are connected to the positive electrode of the second power module through two contacts of the second single-pole double-throw relay;

[0020] A first end of the second absorption circuit is connected to the second single-pole double-throw relay, and a second end of the second absorption circuit is connected to the second end of the second winding of the secondary side;

[0021] The first end of the second switch tube is connected to the second end of the secondary second winding, the second end is connected to the negative electrode of the second power module, and the third end is connected to the second drive circuit;

[0022] The second filter capacitor is connected in parallel to the positive electrode and the negative electrode of the second power module.

[0023] Optionally, the controller is further used for:

[0024] When power is transmitted from the first power module to the second power module, a first conditioned signal output by the first sampling circuit and a second conditioned signal output by the second sampling circuit are obtained;

[0025] Determining a target forward transformation ratio combination of the main circuit according to the first conditioning signal and the second conditioning signal;

[0026] By means of the first drive circuit and the second drive circuit, based on the output switching control signal, the first single-pole double-throw relay and the second single-pole double-throw relay in the main circuit are controlled to switch from the current transformation ratio combination to the target forward transformation ratio combination;

[0027] According to the target forward transformation ratio combination, the first drive circuit and the second drive circuit are used to control the input and output voltages and the input and output currents of the first switch tube in the main circuit based on the output drive control signal.

[0028] Optionally, the controller is further used for:

[0029] When power is transmitted from the second power module to the first power module, a first conditioned signal output by the first sampling circuit and a second conditioned signal output by the second sampling circuit are obtained;

[0030] Determining a target reverse transformation ratio combination of the main circuit according to the first conditioning signal and the second conditioning signal;

[0031] By means of the first drive circuit and the second drive circuit, based on the output switching control signal, the first single-pole double-throw relay and the second single-pole double-throw relay in the main circuit are controlled to switch from the current transformation ratio combination to the target reverse transformation ratio combination;

[0032] According to the target reverse transformation ratio combination, the input and output voltage and the input and output current of the second switch tube in the main circuit are controlled based on the output drive control signal through the first drive circuit and the second drive circuit.

[0033] Optionally, the sampling end of the first sampling circuit is also connected to a line between the power end of the main circuit and the negative electrode of the first power module;

[0034] The sampling end of the second sampling circuit is also connected to the connection line between the power supply end of the main circuit and the negative electrode of the second power supply module.

[0035] Optionally, the controller is further used for:

[0036] Obtaining an output voltage feedback value and an output current feedback value outputted by the main circuit to the first power module, wherein the output voltage feedback value and the output current feedback value are obtained by conditioning the voltage and current outputted by the main circuit after sampling by the first sampling circuit;

[0037] According to the output voltage feedback value and the output current feedback value of the main circuit, the duty cycle of the drive control signal is modulated in real time to obtain a stable output voltage or output current.

[0038] Optionally, the controller is further used for:

[0039] Obtaining an output voltage feedback value and an output current feedback value outputted from the main circuit to the second power supply module, wherein the output voltage feedback value and the output current feedback value are obtained by conditioning the voltage and current outputted from the main circuit by the second sampling circuit after sampling;

[0040] According to the output voltage feedback value and the output current feedback value of the main circuit, the duty cycle of the drive control signal is modulated in real time to obtain a stable output voltage or output current.

[0041] A second aspect of an embodiment of the present invention discloses a control method for a bidirectional DCDC circuit, which is applied to a controller in the bidirectional DCDC circuit described in any one of the first aspects of the embodiments of the present invention, comprising:

[0042] When power is transmitted between the first power module and the second power module, a first conditioned signal output by the first sampling circuit and a second conditioned signal output by the second sampling circuit are obtained, wherein the first conditioned signal is conditioned after the first sampling circuit samples the voltage and current input and output of the first power module, and the second conditioned signal is conditioned after the second sampling circuit samples the voltage and current input and output of the second power module;

[0043] Determining a target transformation ratio combination of a main circuit according to the first conditioning signal and the second conditioning signal;

[0044] Controlling the main circuit to switch to the target transformation ratio combination based on the output switching control signal through the first driving circuit and the second driving circuit;

[0045] According to the target transformation ratio combination, the input / output voltage and the input / output current of the main circuit are controlled based on the output drive control signal through the first drive circuit and the second drive circuit.

[0046] Optionally, also include:

[0047] Obtaining input and output voltage feedback values ​​and input and output current feedback values ​​of the main circuit;

[0048] According to the input and output voltage feedback values ​​and the input and output current feedback values ​​of the main circuit, the duty cycle of the drive control signal is modulated in real time to obtain a stable output current or output voltage.

[0049] Optionally, when power is transmitted between the first power module and the second power module, obtaining a first conditioned signal output by the first sampling circuit and a second conditioned signal output by the second sampling circuit includes:

[0050] When power is transmitted from the first power module to the second power module, a first conditioned signal output by the first sampling circuit and a second conditioned signal output by the second sampling circuit are obtained.

[0051] Optionally, determining a target transformation ratio combination of a main circuit according to the first conditioning signal and the second conditioning signal includes:

[0052] Calculating a first lower limit value of a transformer ratio according to the first conditioned signal and the second conditioned signal;

[0053] determining all forward ratio combinations of the transformer;

[0054] A target forward transformation ratio combination matching the first lower limit value is selected from all the forward transformation ratio combinations.

[0055] Optionally, controlling the main circuit to switch to the target transformation ratio combination based on the output switching control signal through the first drive circuit and the second drive circuit includes:

[0056] Sending the output switching control signal to the main circuit through the first driving circuit and the second driving circuit;

[0057] Based on the switching control signal, the first single-pole double-throw relay and the second single-pole double-throw relay in the main circuit are controlled to switch from the current transformation ratio combination to the target forward transformation ratio combination.

[0058] Optionally, the controlling the output voltage and the output current of the main circuit based on the output drive control signal through the first drive circuit and the second drive circuit according to the target transformation ratio combination includes:

[0059] According to the target forward transformation ratio combination, the output drive control signal is sent to the main circuit through the first drive circuit and the second drive circuit;

[0060] Based on the driving control signal, the input and output voltage and the input and output current of the first switch tube in the main circuit are controlled.

[0061] Optionally, also include:

[0062] Obtaining input and output voltage feedback values ​​and input and output current feedback values ​​of the first switch tube;

[0063] According to the input-output voltage feedback value and the input-output current feedback value of the first switch tube, the duty cycle of the drive control signal is modulated in real time to obtain a stable output current or output voltage.

[0064] Optionally, when power is transmitted between the first power module and the second power module, obtaining a first conditioned signal output by the first sampling circuit and a second conditioned signal output by the second sampling circuit includes:

[0065] When power is transmitted from the second power module to the first power module, a first conditioned signal output by the first sampling circuit and a second conditioned signal output by the second sampling circuit are obtained.

[0066] Optionally, determining a target transformation ratio combination of a main circuit according to the first conditioning signal and the second conditioning signal includes:

[0067] Calculating a second lower limit value of the transformer ratio according to the first conditioned signal and the second conditioned signal;

[0068] Determining all reverse ratio combinations of the transformer;

[0069] A target reverse transformation ratio combination matching the second lower limit value is selected from all the reverse transformation ratio combinations.

[0070] Optionally, controlling the main circuit to switch to the target transformation ratio combination based on the output switching control signal through the first drive circuit and the second drive circuit includes:

[0071] Sending the output switching control signal to the main circuit through the first driving circuit and the second driving circuit;

[0072] Based on the switching control signal, the first single-pole double-throw relay and the second single-pole double-throw relay in the main circuit are controlled to switch from the current transformation ratio combination to the target reverse transformation ratio combination.

[0073] Optionally, the controlling the output voltage and the output current of the main circuit based on the output drive control signal through the first drive circuit and the second drive circuit according to the target transformation ratio combination includes:

[0074] According to the target reverse transformation ratio combination, the output drive control signal is sent to the main circuit through the first drive circuit and the second drive circuit;

[0075] Based on the drive control signal, the input and output voltage and the input and output current of the second switch tube in the main circuit are controlled.

[0076] Optionally, also include:

[0077] Obtaining input and output voltage feedback values ​​and input and output current feedback values ​​of the second switch tube;

[0078] According to the input-output voltage feedback value and the input-output current feedback value of the second switch tube, the duty cycle of the drive control signal is modulated in real time to obtain a stable output current or output voltage.

[0079] Based on the above-mentioned embodiment of the present invention, a bidirectional DCDC circuit and a control method thereof are provided. The bidirectional DCDC circuit includes: a first power supply module, a second power supply module, a main circuit, a first sampling circuit, a second sampling circuit, a first drive circuit, a second drive circuit and a controller; the two power supply ends of the main circuit are respectively connected to the positive pole and the negative pole of the first power supply module and the positive pole and the negative pole of the second power supply module, and the two drive control ends of the main circuit are respectively connected to the controller through the first drive circuit and the second drive circuit; the sampling end of the first sampling circuit is connected to the first power supply module, and the output end of the first sampling circuit is connected to the controller; the sampling end of the second sampling circuit is connected to the second power supply module, and the output end of the second sampling circuit is connected to the controller; the controller is used to when the power supply is between the first power supply module and When transmitting between the first and second power supply modules, a first conditioning signal output by the first sampling circuit and a second conditioning signal output by the second sampling circuit are obtained, and a target transformation ratio combination of the main circuit is determined according to the first conditioning signal and the second conditioning signal, and the main circuit is controlled to switch to the target transformation ratio combination based on the output switching control signal through the first drive circuit and the second drive circuit, and the input and output voltage and input and output current of the main circuit are controlled based on the output drive control signal according to the target transformation ratio combination through the first drive circuit and the second drive circuit; the first conditioning signal is obtained by the first sampling circuit sampling the input and output voltage and current of the first power supply module and conditioning, and the second conditioning signal is obtained by the second sampling circuit sampling the input and output voltage and current of the second power supply module and conditioning. In this solution, the first power module, the second power module, the main circuit, the first sampling circuit, the second sampling circuit, the first drive circuit, the second drive circuit and the controller are connected accordingly, thereby simplifying the topology structure and the circuit loop and reducing the device cost; moreover, when the power is transmitted between the first power module and the second power module, the controller determines the target transformation ratio combination of the main circuit according to the first conditioning signal and the second conditioning signal, and then controls the main circuit to switch to the target transformation ratio combination based on the switching control signal through the first drive circuit and the second drive circuit, so that the input and output voltages and input and output currents of the main circuit are controlled according to the target transformation ratio combination, so as to achieve driving with a unified drive signal and ensure the stability of the output voltage and current. BRIEF DESCRIPTION OF THE DRAWINGS

[0080] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0081] Figure 1 A schematic diagram of the structure of an existing wide-range bidirectional DCDC provided in an embodiment of the present invention;

[0082] Figure 2 A schematic diagram of the structure of a bidirectional DCDC circuit provided by an embodiment of the present invention;

[0083] Figure 3 A schematic diagram of the structure of another bidirectional DCDC circuit provided by an embodiment of the present invention;

[0084] Figure 4 A schematic diagram of the structure of a bidirectional DCDC circuit in a practical application scenario provided by an embodiment of the present invention;

[0085] Figure 5 A schematic flow chart of a control method for a bidirectional DCDC circuit provided by an embodiment of the present invention;

[0086] Figure 6 A flow chart of another method for controlling a bidirectional DCDC circuit provided by an embodiment of the present invention;

[0087] Figure 7 A schematic flow chart of another method for controlling a bidirectional DCDC circuit provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0088] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0089] In this application, the terms "comprises", "comprising" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprising a ..." does not exclude the presence of other identical elements in the process, method, article or device comprising the element.

[0090] As can be seen from the background technology, the existing method of realizing a bidirectional DCDC converter to adapt to a wide input and output range has a complex topology structure and circuit loop, which increases the device cost, does not use a unified driving signal for driving, and cannot ensure the stability of the output voltage and current.

[0091] Therefore, an embodiment of the present invention provides a bidirectional DCDC circuit and a control method thereof. In this solution, a first power module, a second power module, a main circuit, a first sampling circuit, a second sampling circuit, a first drive circuit, a second drive circuit and a controller are connected correspondingly, thereby simplifying the topology structure and the circuit loop and reducing the device cost; moreover, when the power is transmitted between the first power module and the second power module, the controller determines the target transformation ratio combination of the main circuit according to the first conditioning signal and the second conditioning signal, and then controls the main circuit to switch to the target transformation ratio combination based on the switching control signal through the first drive circuit and the second drive circuit, so that the input and output voltages and the input and output currents of the main circuit are controlled according to the target transformation ratio combination, so as to achieve driving with a unified drive signal and ensure the stability of the output voltage and current.

[0092] like Figure 2 As shown, it is a structural schematic diagram of a bidirectional DCDC circuit provided by an embodiment of the present invention. The bidirectional DCDC circuit 1 includes: a first power module 10, a second power module 11, a main circuit 12, a first sampling circuit 13, a first drive circuit 14, a second sampling circuit 15, a second drive circuit 16 and a controller 17.

[0093] In the embodiment of the present invention, the first power module 10 , the second power module 11 , the main circuit 12 , the first sampling circuit 13 , the first driving circuit 14 , the second sampling circuit 15 , the second driving circuit 16 and the controller 17 are electrically connected.

[0094] In the embodiment of the present invention, the controller 17 can be understood as a control circuit.

[0095] Specifically, the two power supply ends of the main circuit 12 are respectively connected to the positive and negative poles of the first power supply module 10 and the positive and negative poles of the second power supply module 11, and the two drive control ends of the main circuit 12 are respectively connected to the controller 17 through the first drive circuit 14 and the second drive circuit 16.

[0096] In the embodiment of the present invention, the first power module 10 may be represented as U1 , and the second power module 11 may be represented as U2 .

[0097] In a specific implementation, the first power supply end of the main circuit 12 is connected to the positive and negative poles of the first power supply module 10 through two DC bus bars, and the second power supply end is connected to the positive and negative poles of the second power supply module 11 through two DC bus bars.

[0098] In a specific embodiment, the first power supply end of the main circuit 12 is connected to the positive and negative poles of the second power supply module 11 through two DC bus bars, and the second power supply end is connected to the positive and negative poles of the first power supply module 10 through two DC bus bars.

[0099] The first driving control end of the main circuit 12 is connected to the controller 17 through the first driving circuit 14 , and the second driving control end is connected to the controller 17 through the second driving circuit 16 .

[0100] In a specific embodiment, the first driving control terminal of the main circuit 12 is connected to the controller 17 through the second driving circuit 16 , and the second driving control terminal is connected to the controller 17 through the first driving circuit 14 .

[0101] Specifically, a sampling end of the first sampling circuit 13 is connected to the first power supply module 10 , and an output end of the first sampling circuit 13 is connected to the controller 17 .

[0102] In a specific embodiment, a sampling end of the first sampling circuit 13 is connected to the second power supply module 11 , and an output end of the first sampling circuit 13 is connected to the controller 17 .

[0103] Specifically, a sampling end of the second sampling circuit 15 is connected to the second power supply module 11 , and an output end of the second sampling circuit 15 is connected to the controller 17 .

[0104] In a specific embodiment, a sampling end of the second sampling circuit 15 is connected to the first power module 10 , and an output end of the second sampling circuit 15 is connected to the controller 17 .

[0105] However, the above specific connection method is not limited thereto, as long as the first power module 10, the second power module 11, the main circuit 12, the first sampling circuit 13, the first drive circuit 14, the second sampling circuit 15, the second drive circuit 16 and the controller 17 are electrically connected.

[0106] The first power module 10 and the second power module 11 provide power for the main circuit.

[0107] In some embodiments, the first power module 10 may be a battery or a DC voltage source.

[0108] In some embodiments, the second power module 11 may be a battery or a DC voltage source.

[0109] The main circuit 12 is used to perform corresponding control operations based on the control signal of the controller 17.

[0110] The first sampling circuit 13 and the second sampling circuit 15 are used to sample the input and output voltage and current, and to condition the sampled voltage and current, and to send the conditioned signals to the controller 17 .

[0111] In some embodiments, the first sampling circuit 13 and the second sampling circuit 15 are provided with a conditioning module, and the sampled voltage and current are conditioned by the conditioning module to obtain a voltage signal or a current signal that meets the output requirements.

[0112] In some embodiments, the controller 17 is preferably a PWM (Pulse Width Modulation) driver chip.

[0113] In some embodiments, the controller 17 is preferably a MCU (Microcontroller Unit) chip.

[0114] When the controller 17 uses a PWM drive chip to drive the main circuit, the stability of the output voltage and current is closed-loop controlled by a hardware analog circuit. See the following for details.

[0115] When the controller 17 uses an MCU chip to drive the main circuit, the stability of the output voltage and current is achieved by digital control of the MCU. See the following for details.

[0116] Specifically, when power is transmitted between the first power module 10 and the second power module 11, the first sampling circuit 13 samples the voltage and current input and output of the first power module 10, conditions the sampled voltage and current, obtains a first conditioning signal, and outputs the first conditioning signal to the controller 17.

[0117] The second sampling circuit 15 samples the voltage and current input and output by the second power module 11 , conditions the sampled voltage and current to obtain a second conditioned signal, and outputs the second conditioned signal to the controller 17 .

[0118] The controller 17 obtains the first conditioned signal output by the first sampling circuit 13 and the second conditioned signal output by the second sampling circuit 15 , and determines the target transformation ratio combination of the main circuit 12 according to the first conditioned signal and the second conditioned signal.

[0119] The controller 17 controls the main circuit 12 to switch to the target transformation ratio combination based on the output switching control signal through the first drive circuit 14 and the second drive circuit 16 .

[0120] The controller 17 controls the input / output voltage and the input / output current of the main circuit 12 based on the drive control signal outputted through the first drive circuit 14 and the second drive circuit 16 according to the target transformation ratio combination.

[0121] It should be noted that the power may be transmitted from the first power module 10 to the second power module 11 , or may be transmitted from the second power module 101 to the first power module 10 .

[0122] Among them, power supply can be understood as energy.

[0123] That is to say, energy can be transferred from U1 to U2, or from U2 to U1.

[0124] It should be noted that determining the target transformation ratio combination of the main circuit 12 can be determining the target forward transformation ratio combination of the main circuit 12, or it can be determining the target reverse transformation ratio combination of the main circuit 12, which depends on the power transmission direction. For details, please refer to the following description.

[0125] Continue to see Figure 2 , the sampling end of the first sampling circuit 13 is also connected to the connection line between the power end of the main circuit 12 and the negative electrode of the first power module 10;

[0126] At this time, the controller 17 is also used to: obtain the output voltage feedback value and the output current feedback value output by the main circuit 12 to the first power supply module 10, and according to the output voltage feedback value and the output current feedback value of the main circuit 12, modulate the duty cycle of the drive control signal in real time to obtain a stable output voltage or output current.

[0127] The output voltage feedback value and the output current feedback value are obtained by the first sampling circuit 13 sampling the voltage and current output by the main circuit 12 and then conditioning them.

[0128] The sampling end of the second sampling circuit 15 is also connected to the connection line between the power end of the main circuit 12 and the negative electrode of the second power module 11 .

[0129] At this time, the controller 17 is also used to: obtain the output voltage feedback value and the output current feedback value output by the main circuit 12 to the second power supply module 11, and according to the output voltage feedback value and the output current feedback value of the main circuit 12, modulate the duty cycle of the drive control signal in real time to obtain a stable output voltage or output current.

[0130] The output voltage feedback value and the output current feedback value are obtained by the second sampling circuit 15 sampling the voltage and current output by the main circuit 12 and then conditioning them.

[0131] In the embodiment of the present invention, the main circuit includes: a transformer, a first single-pole double-throw relay, a first switch tube, a first absorption circuit and a first filter capacitor.

[0132] like Figure 3 As shown, it is a structural schematic diagram of another bidirectional DCDC circuit provided by an embodiment of the present invention, wherein the main circuit 12 includes: a transformer T, a first single-pole double-throw relay RL1, a first switch tube S1, a first absorption circuit and a first filter capacitor C1.

[0133] Specifically, two ends of the primary first winding of the transformer T are connected to the positive electrode of the first power module 10 through two contacts of the first single-pole double-throw relay RL1;

[0134] A first end of the first absorption circuit is connected to the first single-pole double-throw relay RL1, and a second end of the first absorption circuit is connected to the second end of the primary second winding;

[0135] The first end of the first switch tube S1 is connected to the second end of the primary second winding, the second end is connected to the negative electrode of the first power module 10, and the third end is connected to the first drive circuit 14;

[0136] The first filter capacitor C1 is connected in parallel to the positive electrode and the negative electrode of the first power module 10 .

[0137] Among them, the transformer T is a device that uses the principle of electromagnetic induction to change the AC voltage.

[0138] The primary side of the transformer T uses two windings with the numbers of turns np1 and np2 respectively, that is, the first winding of the primary side is np1 and the second winding of the primary side is np2.

[0139] The first single-pole double-throw relay RL1 can avoid the transformer turn-to-turn short circuit problem caused by contact adhesion.

[0140] The first switch tube S1 utilizes an electronic switch device (such as the first single-pole double-throw relay RL1) to continuously "turn on" and "turn off" the electronic switch device through a control circuit (i.e., the controller 12), so that the electronic device performs pulse modulation on the input voltage, thereby realizing DC / AC, DC / DC voltage conversion, as well as adjustable output voltage and automatic voltage stabilization.

[0141] The first absorption circuit is used to absorb the energy stored in the leakage inductance of the transformer T to avoid excessively high voltage spikes when the first switch tube S1 is turned off.

[0142] The first filter capacitor C1 is used to remove clutter and noise in the circuit, provide a stable power supply voltage, and protect the normal operation of other electronic components.

[0143] Continue to see Figure 3 The main circuit 12 also includes: a second single-pole double-throw relay RL2, a second switch tube S2, a second absorption circuit and a second filter capacitor C2.

[0144] Specifically, two ends of the first winding of the secondary side of the transformer T are connected to the positive electrode of the second power module 11 through two contacts of the second single-pole double-throw relay RL2;

[0145] A first end of the second absorption circuit is connected to the second single-pole double-throw relay RL2, and a second end is connected to the second end of the second winding of the secondary side;

[0146] A first end of the second switch tube S2 is connected to the second end of the secondary second winding, a second end is connected to the negative electrode of the second power module 11, and a third end is connected to the second drive circuit 16;

[0147] The second filter capacitor C2 is connected in parallel to the positive electrode and the negative electrode of the second power module 11 .

[0148] Among them, the functions of the second single-pole double-throw relay RL1, the second switch tube S2, the second absorption circuit and the second filter capacitor C2 are similar to those of the first single-pole double-throw relay RL1, the first switch tube S1, the first absorption circuit and the first filter capacitor C1 described above, which can be referred to and will not be repeated here.

[0149] The secondary side of the transformer T uses two windings, and the numbers of turns are ns1 and ns2 respectively, that is, the first winding of the secondary side is ns1, and the second winding of the secondary side is ns2.

[0150] Furthermore, the first switch tube S1 and the second switch tube S2 include but are not limited to a PMOS switch tube, an NMOS switch tube and a triode.

[0151] in accordance with Figure 3 , in a specific implementation, when power is transmitted from the first power module 10 to the second power module 11, the controller 17 obtains the first conditioning signal output by the first sampling circuit 13 and the second conditioning signal output by the second sampling circuit 15;

[0152] It should be noted that the power is transmitted from the first power module 10 to the second power module 11 , which means that the bidirectional DCDC circuit is working in the forward direction, and the energy is transmitted from U1 to U2 .

[0153] The controller 17 determines the target forward transformation ratio combination of the main circuit 12 according to the first conditioning signal and the second conditioning signal;

[0154] It should be noted that when the circuit works in the forward direction, the transformer can form four transformation ratio relationships, namely (ns1+ns2) / np2, (ns1+ns2) / (np1+np2), ns2 / np2 and ns2 / (np1+np2).

[0155] When working in the forward direction, the relationship between U2 and U1 is: U2 = U1*Nsp*D / (1-D),

[0156] Wherein, Nsp is the transformer ratio, D is the duty cycle of switch S1, D<0.5.

[0157] In practical applications, after the controller 17 obtains the values ​​of U1 and U2, that is, after the controller 17 obtains the first conditioning signal and the second conditioning signal, the lower limit of Nsp is obtained by calculating the relationship between U2 and U1, and the target forward ratio combination of the main circuit can be determined by selecting the combination closest to the lower limit of Nsp from the four possible ratio combinations.

[0158] The controller 17 controls the first single-pole double-throw relay RL1 and the second single-pole double-throw relay RL2 in the main circuit 12 to switch from the current transformation ratio combination to the target forward transformation ratio combination based on the output switching control signal through the first drive circuit 14 and the second drive circuit 16;

[0159] The controller 17 controls the input and output voltage and the input and output current of the first switch tube S1 in the main circuit 12 based on the output drive control signal through the first drive circuit 14 and the second drive circuit 16 according to the target forward transformation ratio combination.

[0160] in accordance with Figure 3 , in a specific implementation, when power is transmitted from the second power module 11 to the first power module 10, the controller 17 obtains the first conditioning signal output by the first sampling circuit 13 and the second conditioning signal output by the second sampling circuit 15;

[0161] It should be noted that the power is transmitted from the second power module 11 to the first power module 10 , which means that the bidirectional DCDC circuit is working in the reverse direction, and the energy is transmitted from U2 to U1 .

[0162] The controller 17 determines the target reverse ratio combination of the main circuit 12 according to the first conditioning signal and the second conditioning signal;

[0163] It should be noted that when the circuit works in reverse, the transformer can form four transformation ratio relationships, namely (np1+np2) / ns2, (np1+np2) / (ns1+ns2), np2 / ns2 and np2 / (ns1+ns2).

[0164] When working in reverse, the relationship between U1 and U2 is: U1=U2*Nps*D / (1-D),

[0165] Wherein, Nps is the transformer ratio, D is the duty cycle of switch S2, and D<0.5.

[0166] In actual applications, after the controller 17 obtains the values ​​of U1 and U2, that is, after the controller 17 obtains the first conditioning signal and the second conditioning signal, the lower limit of the value of Nps is obtained by calculating the relationship between U1 and U2, and the combination closest to the lower limit of the value of Nps is selected from the four possible transformation ratio combinations to determine the target reverse transformation ratio combination of the main circuit.

[0167] The controller 17 controls the first single-pole double-throw relay RL1 and the second single-pole double-throw relay RL2 in the main circuit 12 to switch from the current transformation ratio combination to the target reverse transformation ratio combination based on the output switching control signal through the first drive circuit 14 and the second drive circuit 16;

[0168] The controller 17 controls the input and output voltage and the input and output current of the second switch tube S2 in the main circuit 12 based on the output drive control signal through the first drive circuit 14 and the second drive circuit 16 according to the target reverse transformation ratio combination.

[0169] In order to better understand the above bidirectional DCDC circuit, Figure 4 , which is a schematic diagram of the structure of a bidirectional DCDC circuit in a practical application scenario provided by an embodiment of the present invention.

[0170] exist Figure 4 In the embodiment, both ends of the primary winding np1 of the transformer T are connected to U1 through two contacts of the single-pole double-throw relay RL1. Both ends of the secondary winding ns1 of the transformer T are connected to U2 through two contacts of the single-pole double-throw relay RL2.

[0171] The first end of the absorption circuit 1 is connected to the single-pole double-throw relay RL1, and the second end is connected to the second end of the primary winding np2.

[0172] The first end of the switch tube S1 is connected to the second end of the primary winding np2 , the second end is connected to the negative electrode of U1 , and the third end is connected to the drive circuit 1 .

[0173] The filter capacitor C1 is connected in parallel to the positive and negative electrodes of U1.

[0174] A first end of the absorption circuit 2 is connected to the single-pole double-throw relay RL2, and a second end of the absorption circuit 2 is connected to the second end of the secondary winding ns2.

[0175] The first end of the switch tube S2 is connected to the second end of the secondary winding ns2 , the second end is connected to the negative electrode of U2 , and the third end is connected to the drive circuit 2 .

[0176] The filter capacitor C2 is connected in parallel to the positive electrode and the negative electrode of U2.

[0177] In actual applications, when the circuit works in the forward direction (U1 transmits to U2), the transformer can form four transformation ratio relationships, namely (ns1+ns2) / np2, (ns1+ns2) / (np1+np2), ns2 / np2, and ns2 / (np1+np2).

[0178] When working in the forward direction, the relationship between U2 and U1 is: U2 = U1*Nsp*D / (1-D),

[0179] Wherein, Nsp is the transformer ratio, D is the duty cycle of switch S1, D<0.5.

[0180] After the controller obtains the values ​​of U1 and U2, that is, after the controller 17 obtains the first conditioning signal and the second conditioning signal, it obtains the lower limit of Nsp by calculating the relationship between U2 and U1, and selects the combination closest to the lower limit of Nsp from the four possible transformation ratio combinations.

[0181] The controller 17 then sends a signal to switch the states of RL1 and RL2 to the determined combination.

[0182] After the relay state switching is completed, the controller 17 generates a driving signal to control S1, and adjusts the duty cycle of the driving signal in real time according to the input and output side voltage and current feedback values ​​to obtain a stable current or voltage.

[0183] In actual applications, when the circuit works in reverse (U2 is transmitted to U1), the transformer can form four ratio relationships, namely (np1+np2) / ns2, (np1+np2) / (ns1+ns2), np2 / ns2, and np2 / (ns1+ns2).

[0184] When working in reverse, the relationship between U1 and U2 is: U1=U2*Nps*D / (1-D),

[0185] Wherein, Nps is the transformer ratio, D is the duty cycle of switch S2, and D<0.5.

[0186] After the controller obtains the values ​​of U1 and U2, that is, after the controller 17 obtains the first conditioning signal and the second conditioning signal, it obtains the lower limit of the value of Nps by calculating the relationship between U1 and U2, and selects the combination closest to the lower limit of the value of Nps from the four possible transformation ratio combinations.

[0187] The controller 17 then sends a signal to switch the states of RL1 and RL2 to the determined combination.

[0188] After the relay state switching is completed, the controller 17 generates a drive signal to control S2, and adjusts the duty cycle of the drive signal in real time according to the input and output side voltage and current feedback values ​​to obtain a stable current or voltage.

[0189] It can be seen from the above description that the bidirectional DCDC circuit described above adopts a single-stage bidirectional flyback topology, has a simple architecture, requires only two switching tubes and a main transformer, has a small device size, and is low in cost;

[0190] Moreover, the transformer uses two windings on the primary and secondary sides respectively, and the windings of the primary and secondary sides are switched by a single-pole double-throw relay respectively. The single-pole double-throw relay can avoid the problem of short circuit between transformer turns caused by contact adhesion.

[0191] In addition, the primary and secondary ratios can form four different ratio combinations by using different single-pole double-throw relay switching states. The system samples the input and output voltages and calculates the relationship between the input and output voltages to determine which primary and secondary ratio combination to use. The flexible configuration of the primary and secondary ratios allows the circuit's drive duty cycle to be maintained below 0.5, reducing the current and voltage stress during circuit operation, making the circuit loop control design simpler and more reliable, the protection more timely, and having better electromagnetic compatibility performance.

[0192] In addition, the controller can use an integrated PWM driver chip or an MCU / DSP to generate a drive signal. When an integrated PWM chip is used to drive the primary and secondary switches, the stability of the output voltage and current is controlled by a hardware analog circuit in a closed loop; when an MCU is used to generate a wave to drive the primary and secondary switches, the stability of the output voltage and current is achieved by digital control of the MCU.

[0193] Based on the above-mentioned embodiment of the present invention, a bidirectional DCDC circuit is provided. In the bidirectional DCDC circuit, a first power module, a second power module, a main circuit, a first sampling circuit, a second sampling circuit, a first drive circuit, a second drive circuit and a controller are connected correspondingly, thereby simplifying the topology structure and the circuit loop and reducing the device cost; moreover, when the power is transmitted between the first power module and the second power module, the controller determines the target transformation ratio combination of the main circuit according to the first conditioning signal and the second conditioning signal, and then controls the main circuit to switch to the target transformation ratio combination based on the switching control signal through the first drive circuit and the second drive circuit, so that the input and output voltages and the input and output currents of the main circuit are controlled according to the target transformation ratio combination, so as to achieve driving with a unified drive signal and ensure the stability of the output voltage and current.

[0194] Corresponding to the bidirectional DCDC circuit shown in the above-mentioned embodiment of the present invention, the embodiment of the present invention also provides a control method of a bidirectional DCDC circuit, which is applied to the controller in the bidirectional DCDC circuit described in any of the above-mentioned embodiments. The specific structure and working principle of the bidirectional DCDC circuit can be referred to the above-mentioned embodiments, and will not be described one by one here.

[0195] like Figure 5 As shown, the control method of the bidirectional DCDC circuit mainly includes the following steps:

[0196] Step S501: When power is transmitted between the first power module and the second power module, execute step S502; otherwise, end the operation.

[0197] In the process of implementing step S501, if power is transmitted between the first power module and the second power module, it means that the bidirectional DCDC circuit is in a working state, and step S502 is executed; if no power is transmitted between the first power module and the second power module, it means that the bidirectional DCDC circuit is in a shutdown state, and the operation is terminated directly.

[0198] Step S502: obtaining a first conditioned signal output by the first sampling circuit and a second conditioned signal output by the second sampling circuit.

[0199] In step S502, a first conditioned signal is obtained by sampling and conditioning the voltage and current input and output of the first power module by a first sampling circuit.

[0200] The second conditioned signal is obtained by conditioning the second sampling circuit after sampling the voltage and current input and output of the second power module.

[0201] In the specific implementation of step S502 , when it is determined that power is transmitted between the first power module and the second power module, a first conditioned signal output by the first sampling circuit and a second conditioned signal output by the second sampling circuit are obtained.

[0202] Step S503: Determine a target transformation ratio combination of the main circuit according to the first conditioning signal and the second conditioning signal.

[0203] It should be noted that the target transformation ratio combination may be a target forward transformation ratio combination or a target reverse transformation ratio combination.

[0204] In the specific implementation of step S503, the lower limit value of the transformer ratio is calculated according to the first conditioning signal and the second conditioning signal, all transformer ratio combinations are determined, and a target ratio combination matching the lower limit value is selected from all ratio combinations.

[0205] Step S504: Controlling the main circuit to switch to the target transformation ratio combination based on the output switching control signal through the first driving circuit and the second driving circuit.

[0206] In the process of specifically implementing step S504, based on the target transformation ratio combination, a switching control signal is output, and the output switching control signal is sent to the main circuit through the first drive circuit and the second drive circuit to determine the current transformation ratio combination of the first single-pole double-throw relay and the second single-pole double-throw relay in the main circuit. Based on the switching control signal, the first single-pole double-throw relay and the second single-pole double-throw relay in the main circuit are controlled to switch from the current transformation ratio combination to the target transformation ratio combination.

[0207] In actual applications, when the target transformation ratio combination is a target forward transformation ratio combination, a switching control signal is output based on the target forward transformation ratio combination, and the output switching control signal is sent to the main circuit through the first drive circuit and the second drive circuit to determine the current transformation ratio combination of the first single-pole double-throw relay and the second single-pole double-throw relay in the main circuit. Based on the switching control signal, the first single-pole double-throw relay and the second single-pole double-throw relay in the main circuit are controlled to switch from the current transformation ratio combination to the target forward transformation ratio combination.

[0208] When the target transformation ratio combination is a target reverse transformation ratio combination, a switching control signal is output based on the target reverse transformation ratio combination, and the output switching control signal is sent to the main circuit through the first drive circuit and the second drive circuit to determine the current transformation ratio combination of the first single-pole double-throw relay and the second single-pole double-throw relay in the main circuit, and based on the switching control signal, the first single-pole double-throw relay and the second single-pole double-throw relay in the main circuit are controlled to switch from the current transformation ratio combination to the target reverse transformation ratio combination.

[0209] Step S505: According to the target transformation ratio combination, the input and output voltages and the input and output currents of the main circuit are controlled based on the output drive control signals through the first drive circuit and the second drive circuit.

[0210] In the specific implementation process of step S505, after completing the relay state switching, a drive control signal is output according to the target ratio combination, and the input and output voltage and input and output current of the main circuit are controlled based on the output drive control signal through the first drive circuit and the second drive circuit.

[0211] In actual applications, when the target transformation ratio combination is a target forward transformation ratio combination, after completing the relay state switching, a drive control signal is output according to the target forward transformation ratio combination, and the input and output voltage and input and output current of the first switch tube in the main circuit are controlled based on the output drive control signal through the first drive circuit and the second drive circuit.

[0212] When the target transformation ratio combination is a target reverse transformation ratio combination, after completing the relay state switching, a drive control signal is output according to the target reverse transformation ratio combination, and the input and output voltage and input and output current of the second switch tube in the main circuit are controlled based on the output drive control signal through the first drive circuit and the second drive circuit.

[0213] Preferably, after executing step S505 to control the input and output voltages and the input and output currents of the main circuit based on the output drive control signal, the method further includes:

[0214] The input and output voltage feedback values ​​and the input and output current feedback values ​​of the main circuit are obtained, and the duty cycle of the drive control signal is modulated in real time according to the input and output voltage feedback values ​​and the input and output current feedback values ​​of the main circuit to obtain a stable output current or output voltage.

[0215] It should be noted that the flexible configuration of the primary-secondary ratio enables the driving duty cycle of the circuit to be maintained below 0.5.

[0216] Based on a control method for a bidirectional DCDC circuit provided by the above-mentioned embodiment of the present invention, when power is transmitted between a first power module and a second power module, the controller determines a target transformation ratio combination of a main circuit according to a first conditioning signal and a second conditioning signal, and then controls the main circuit to switch to the target transformation ratio combination based on a switching control signal through a first drive circuit and a second drive circuit, thereby controlling the input and output voltages and the input and output currents of the main circuit according to the target transformation ratio combination, and realizing driving with a unified drive signal to ensure the stability of the output voltage and current.

[0217] Based on the above-mentioned embodiment of the present invention, a control method for a bidirectional DCDC circuit is provided. Figure 6 FIG. 1 is a flow chart of another method for controlling a bidirectional DCDC circuit provided by an embodiment of the present invention, wherein the method for controlling a bidirectional DCDC circuit mainly includes the following steps:

[0218] Step S601: When power is transmitted from the first power module to the second power module, execute step S602; otherwise, end the operation.

[0219] In the process of implementing step S601, if power is transmitted from the first power module to the second power module, it means that the bidirectional DCDC circuit is in a working state, and step S602 is executed; if no power is transmitted from the first power module to the second power module, it means that the bidirectional DCDC circuit is in a shutdown state, and the operation is terminated directly.

[0220] Step S602: obtaining a first conditioned signal output by the first sampling circuit and a second conditioned signal output by the second sampling circuit.

[0221] In the specific implementation of step S602 , when it is determined that power is transmitted from the first power module to the second power module, a first conditioned signal output by the first sampling circuit and a second conditioned signal output by the second sampling circuit are obtained.

[0222] Step S603: Calculate a first lower limit value of the transformer ratio according to the first conditioned signal and the second conditioned signal.

[0223] In the specific implementation of step S603, when the circuit is working in the forward direction, after the controller obtains the values ​​of U1 and U2, that is, after obtaining the first conditioning signal and the second conditioning signal, it calculates the first lower limit value of the transformer ratio according to the relationship between U2 and U1: U2 = U1*Nsp*D / (1-D).

[0224] Wherein, Nsp is the transformer ratio, D is the duty cycle of switch S1, D<0.5.

[0225] Step S604: determine all forward transformation ratio combinations of the transformer.

[0226] In the process of implementing step S604, when the circuit works in the forward direction (U1 is transmitted to U2), it is determined that the transformer can form four transformation ratio relationships, that is, all forward transformation ratio combinations of the transformer are determined to be: (ns1+ns2) / np2, (ns1+ns2) / (np1+np2), ns2 / np2 and ns2 / (np1+np2).

[0227] Step S605: Select a target forward transformation ratio combination that matches the first lower limit value from all forward transformation ratio combinations.

[0228] In the process of implementing step S605, the target forward ratio combination of the main circuit can be determined by selecting the combination closest to the lower limit of Nsp from the four possible forward ratio combinations. For example, the target forward ratio combination that matches the first lower limit value is selected from all forward ratio combinations as (ns1+ns2) / np2.

[0229] Step S606: Send the output switching control signal to the main circuit through the first driving circuit and the second driving circuit.

[0230] In the specific implementation of step S606, a switching control signal is output based on the target forward transformation ratio combination, and the output switching control signal is sent to the main circuit through the first drive circuit and the second drive circuit.

[0231] Step S607: Based on the switching control signal, the first single-pole double-throw relay and the second single-pole double-throw relay in the main circuit are controlled to switch from the current transformation ratio combination to the target forward transformation ratio combination.

[0232] In the process of specifically implementing step S607, the current transformation ratio combination of the first single-pole double-throw relay and the second single-pole double-throw relay in the main circuit is determined, and based on the switching control signal, the first single-pole double-throw relay and the second single-pole double-throw relay in the main circuit are controlled to switch from the current transformation ratio combination to the target forward transformation ratio combination.

[0233] Step S608: According to the target forward transformation ratio combination, the output drive control signal is sent to the main circuit through the first drive circuit and the second drive circuit.

[0234] In the specific implementation of step S608, after the relay state switching is completed, a drive control signal is output according to the target forward transformation ratio combination, and the output drive control signal is sent to the main circuit through the first drive circuit and the second drive circuit.

[0235] Step S609: Based on the driving control signal, the input and output voltages and the input and output currents of the first switch tube in the main circuit are controlled.

[0236] Preferably, after executing step S609 to control the input and output voltages and the input and output currents of the first switch tube in the main circuit based on the drive control signal, the method further includes:

[0237] The input and output voltage feedback values ​​and the input and output current feedback values ​​of the first switch tube are obtained, and the duty cycle of the drive control signal is modulated in real time according to the input and output voltage feedback values ​​and the input and output current feedback values ​​of the first switch tube to obtain a stable output current or output voltage.

[0238] Based on a control method for a bidirectional DCDC circuit provided by the above-mentioned embodiment of the present invention, when power is transmitted from a first power module to a second power module, the controller determines the target forward transformation ratio combination of the main circuit according to the first conditioning signal and the second conditioning signal, and then controls the main circuit to switch to the target forward transformation ratio combination based on the switching control signal through the first drive circuit and the second drive circuit, thereby controlling the input and output voltages and input and output currents of the main circuit according to the target forward transformation ratio combination, and realizing driving with a unified drive signal to ensure the stability of the output voltage and current.

[0239] Based on the above-mentioned embodiment of the present invention, a control method for a bidirectional DCDC circuit is provided. Figure 7 FIG. 1 is a flow chart of another method for controlling a bidirectional DCDC circuit provided by an embodiment of the present invention, wherein the method for controlling a bidirectional DCDC circuit mainly includes the following steps:

[0240] Step S701: When power is transmitted from the second power module to the first power module, execute step S702; otherwise, end the operation.

[0241] In the specific implementation of step S701, if power is transmitted from the second power module to the first power module, it means that the bidirectional DCDC circuit is in a working state, and step S702 is executed; if no power is transmitted from the second power module to the first power module, it means that the bidirectional DCDC circuit is in a shutdown state, and the operation is terminated directly.

[0242] Step S702: obtaining a first conditioned signal output by the first sampling circuit and a second conditioned signal output by the second sampling circuit.

[0243] In the specific implementation of step S702 , when it is determined that power is transmitted from the second power module to the first power module, a first conditioned signal output by the first sampling circuit and a second conditioned signal output by the second sampling circuit are obtained.

[0244] Step S703: Calculate a second lower limit value of the transformer ratio according to the first conditioned signal and the second conditioned signal.

[0245] In the specific implementation of step S703, when the circuit works in reverse, after the controller obtains the values ​​of U1 and U2, that is, after obtaining the first conditioning signal and the second conditioning signal, it calculates the second lower limit value of the transformer ratio according to the relationship between U1 and U2: U1=U2*Nps*D / (1-D).

[0246] Wherein, Nsp is the transformer ratio, D is the duty cycle of switch S1, D<0.5.

[0247] Step S704: determine all reverse transformation ratio combinations of the transformer.

[0248] In the process of implementing step S704, when the circuit works in reverse (U2 is transmitted to U1), it is determined that the transformer can form four ratio relationships, that is, all reverse ratio combinations of the transformer are determined to be: (np1+np2) / ns2, (np1+np2) / (ns1+ns2), np2 / ns2 and np2 / (ns1+ns2).

[0249] Step S705: Select a target reverse transformation ratio combination that matches the second lower limit value from all reverse transformation ratio combinations.

[0250] In the process of implementing step S705, the target reverse ratio combination of the main circuit can be determined by selecting the combination closest to the lower limit of Nsp from the four possible reverse ratio combinations. For example, the target reverse ratio combination that matches the second lower limit value is selected from all reverse ratio combinations as (np1+np2) / ns2.

[0251] Step S706: sending the output switching control signal to the main circuit through the first driving circuit and the second driving circuit.

[0252] In the specific implementation of step S706, a switching control signal is output based on the target reverse transformation ratio combination, and the output switching control signal is sent to the main circuit through the first drive circuit and the second drive circuit.

[0253] Step S707: Based on the switching control signal, the first single-pole double-throw relay and the second single-pole double-throw relay in the main circuit are controlled to switch from the current transformation ratio combination to the target reverse transformation ratio combination.

[0254] In the process of specifically implementing step S707, the current transformation ratio combination of the first single-pole double-throw relay and the second single-pole double-throw relay in the main circuit is determined, and based on the switching control signal, the first single-pole double-throw relay and the second single-pole double-throw relay in the main circuit are controlled to switch from the current transformation ratio combination to the target reverse transformation ratio combination.

[0255] Step S708: according to the target reverse transformation ratio combination, the output drive control signal is sent to the main circuit through the first drive circuit and the second drive circuit.

[0256] In the specific implementation of step S708, after the relay state switching is completed, a drive control signal is output according to the target reverse ratio combination, and the output drive control signal is sent to the main circuit through the first drive circuit and the second drive circuit.

[0257] Step S709: Based on the driving control signal, the input and output voltages and the input and output currents of the second switch tube in the main circuit are controlled.

[0258] Preferably, after executing step S709 to control the input and output voltage and the input and output current of the second switch tube in the main circuit based on the driving control signal, the method further includes:

[0259] The input and output voltage feedback values ​​and the input and output current feedback values ​​of the second switch tube are obtained, and the duty cycle of the drive control signal is modulated in real time according to the input and output voltage feedback values ​​and the input and output current feedback values ​​of the second switch tube to obtain a stable output current or output voltage.

[0260] Based on a control method for a bidirectional DCDC circuit provided by the above-mentioned embodiment of the present invention, when power is transmitted from the second power module to the first power module, the controller determines the target reverse ratio combination of the main circuit according to the first conditioning signal and the second conditioning signal, and then controls the main circuit to switch to the target reverse ratio combination based on the switching control signal through the first drive circuit and the second drive circuit, thereby controlling the input and output voltages and input and output currents of the main circuit according to the target reverse ratio combination, and realizing driving with a unified drive signal to ensure the stability of the output voltage and current.

[0261] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can refer to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the system or system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can refer to the partial description of the method embodiment. The system and system embodiments described above are merely schematic, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without creative work.

[0262] Professionals may further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in the above description according to function. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0263] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A bidirectional DCDC circuit, characterized in that: include: A first power supply module, a second power supply module, a main circuit, a first sampling circuit, a second sampling circuit, a first drive circuit, a second drive circuit and a controller; The two power supply terminals of the main circuit are respectively connected to the positive electrode and the negative electrode of the first power module and the positive electrode and the negative electrode of the second power module, and the two driving control terminals of the main circuit are respectively connected to the controller through the first driving circuit and the second driving circuit; The sampling end of the first sampling circuit is connected to the first power supply module, and the output end of the first sampling circuit is connected to the controller; A sampling end of the second sampling circuit is connected to the second power supply module, and an output end of the second sampling circuit is connected to the controller; The controller is used to obtain a first conditioning signal output by the first sampling circuit and a second conditioning signal output by the second sampling circuit when power is transmitted between the first power module and the second power module, determine a target transformation ratio combination of the main circuit according to the first conditioning signal and the second conditioning signal, control the main circuit to switch to the target transformation ratio combination through the first drive circuit and the second drive circuit based on an output switching control signal, and control the input and output voltage and input and output current of the main circuit according to the target transformation ratio combination through the first drive circuit and the second drive circuit based on an output drive control signal; the first conditioning signal is obtained by the first sampling circuit sampling the input and output voltage and current of the first power module and conditioning it, and the second conditioning signal is obtained by the second sampling circuit sampling the input and output voltage and current of the second power module and conditioning it.

2. The bidirectional DCDC circuit according to claim 1, characterized in that: The main circuit comprises: a transformer, a first single-pole double-throw relay, a first switch tube, a first absorption circuit and a first filter capacitor; Two ends of the primary first winding of the transformer are connected to the positive electrode of the first power module through two contacts of the first single-pole double-throw relay; A first end of the first absorption circuit is connected to the first single-pole double-throw relay, and a second end of the first absorption circuit is connected to the second end of the primary second winding; The first end of the first switch tube is connected to the second end of the primary second winding, the second end is connected to the negative electrode of the first power module, and the third end is connected to the first drive circuit; The first filter capacitor is connected in parallel to the positive electrode and the negative electrode of the first power module.

3. The bidirectional DCDC circuit according to claim 2, characterized in that: The main circuit also includes: a second single-pole double-throw relay, a second switch tube, a second absorption circuit and a second filter capacitor; Two ends of the first winding of the secondary side of the transformer are connected to the positive electrode of the second power module through two contacts of the second single-pole double-throw relay; A first end of the second absorption circuit is connected to the second single-pole double-throw relay, and a second end of the second absorption circuit is connected to the second end of the second winding of the secondary side; The first end of the second switch tube is connected to the second end of the secondary second winding, the second end is connected to the negative electrode of the second power module, and the third end is connected to the second drive circuit; The second filter capacitor is connected in parallel to the positive electrode and the negative electrode of the second power module.

4. The bidirectional DCDC circuit according to any one of claims 1 to 3, characterized in that: The controller is also used for: When power is transmitted from the first power module to the second power module, a first conditioned signal output by the first sampling circuit and a second conditioned signal output by the second sampling circuit are obtained; Determining a target forward transformation ratio combination of the main circuit according to the first conditioning signal and the second conditioning signal; By means of the first drive circuit and the second drive circuit, based on the output switching control signal, the first single-pole double-throw relay and the second single-pole double-throw relay in the main circuit are controlled to switch from the current transformation ratio combination to the target forward transformation ratio combination; According to the target forward transformation ratio combination, the first drive circuit and the second drive circuit are used to control the input and output voltages and the input and output currents of the first switch tube in the main circuit based on the output drive control signal.

5. The bidirectional DCDC circuit according to any one of claims 1 to 3, characterized in that: The controller is also used for: When power is transmitted from the second power module to the first power module, a first conditioned signal output by the first sampling circuit and a second conditioned signal output by the second sampling circuit are obtained; Determining a target reverse transformation ratio combination of the main circuit according to the first conditioning signal and the second conditioning signal; By means of the first drive circuit and the second drive circuit, based on the output switching control signal, the first single-pole double-throw relay and the second single-pole double-throw relay in the main circuit are controlled to switch from the current transformation ratio combination to the target reverse transformation ratio combination; According to the target reverse transformation ratio combination, the input and output voltage and the input and output current of the second switch tube in the main circuit are controlled based on the output drive control signal through the first drive circuit and the second drive circuit.

6. The bidirectional DCDC circuit according to claim 1, characterized in that: The sampling end of the first sampling circuit is also connected to the connection line between the power supply end of the main circuit and the negative electrode of the first power supply module; The sampling end of the second sampling circuit is also connected to the connection line between the power supply end of the main circuit and the negative electrode of the second power supply module.

7. The bidirectional DCDC circuit according to claim 6, characterized in that: The controller is also used for: Obtaining an output voltage feedback value and an output current feedback value outputted by the main circuit to the first power module, wherein the output voltage feedback value and the output current feedback value are obtained by conditioning the voltage and current outputted by the main circuit after sampling by the first sampling circuit; According to the output voltage feedback value and the output current feedback value of the main circuit, the duty cycle of the drive control signal is modulated in real time to obtain a stable output voltage or output current.

8. The bidirectional DCDC circuit according to claim 6, characterized in that: The controller is also used for: Obtaining an output voltage feedback value and an output current feedback value outputted from the main circuit to the second power supply module, wherein the output voltage feedback value and the output current feedback value are obtained by conditioning the voltage and current outputted from the main circuit by the second sampling circuit after sampling; According to the output voltage feedback value and the output current feedback value of the main circuit, the duty cycle of the drive control signal is modulated in real time to obtain a stable output voltage or output current.

9. A control method for a bidirectional DCDC circuit, characterized in that: A controller used in a bidirectional DCDC circuit according to any one of claims 1 to 8, comprising: When power is transmitted between the first power module and the second power module, a first conditioned signal output by the first sampling circuit and a second conditioned signal output by the second sampling circuit are obtained, wherein the first conditioned signal is conditioned after the first sampling circuit samples the voltage and current input and output of the first power module, and the second conditioned signal is conditioned after the second sampling circuit samples the voltage and current input and output of the second power module; Determining a target transformation ratio combination of a main circuit according to the first conditioning signal and the second conditioning signal; Controlling the main circuit to switch to the target transformation ratio combination based on the output switching control signal through the first driving circuit and the second driving circuit; According to the target transformation ratio combination, the input / output voltage and the input / output current of the main circuit are controlled based on the output drive control signal through the first drive circuit and the second drive circuit.

10. The method according to claim 9, characterized in that Also includes: Obtaining input and output voltage feedback values ​​and input and output current feedback values ​​of the main circuit; According to the input and output voltage feedback values ​​and the input and output current feedback values ​​of the main circuit, the duty cycle of the drive control signal is modulated in real time to obtain a stable output current or output voltage.

11. The method according to claim 9, characterized in that When the power is transmitted between the first power module and the second power module, obtaining a first conditioned signal output by the first sampling circuit and a second conditioned signal output by the second sampling circuit comprises: When power is transmitted from the first power module to the second power module, a first conditioned signal output by the first sampling circuit and a second conditioned signal output by the second sampling circuit are obtained.

12. The method according to claim 11, characterized in that Determining a target transformation ratio combination of a main circuit according to the first conditioning signal and the second conditioning signal includes: Calculating a first lower limit value of a transformer ratio according to the first conditioned signal and the second conditioned signal; determining all forward ratio combinations of the transformer; A target forward transformation ratio combination matching the first lower limit value is selected from all the forward transformation ratio combinations.

13. The method according to claim 12, characterized in that The controlling the main circuit to switch to the target transformation ratio combination based on the output switching control signal by the first driving circuit and the second driving circuit comprises: Sending the output switching control signal to the main circuit through the first driving circuit and the second driving circuit; Based on the switching control signal, the first single-pole double-throw relay and the second single-pole double-throw relay in the main circuit are controlled to switch from the current transformation ratio combination to the target forward transformation ratio combination.

14. The method according to claim 13, characterized in that The controlling of the output voltage and the output current of the main circuit based on the output drive control signal by the first drive circuit and the second drive circuit according to the target transformation ratio combination includes: According to the target forward transformation ratio combination, the output drive control signal is sent to the main circuit through the first drive circuit and the second drive circuit; Based on the driving control signal, the input and output voltage and the input and output current of the first switch tube in the main circuit are controlled.

15. The method according to any one of claims 11 to 14, characterized in that Also includes: Obtaining input and output voltage feedback values ​​and input and output current feedback values ​​of the first switch tube; According to the input-output voltage feedback value and the input-output current feedback value of the first switch tube, the duty cycle of the drive control signal is modulated in real time to obtain a stable output current or output voltage.

16. The method according to claim 9, characterized in that When the power is transmitted between the first power module and the second power module, obtaining a first conditioned signal output by the first sampling circuit and a second conditioned signal output by the second sampling circuit comprises: When power is transmitted from the second power module to the first power module, a first conditioned signal output by the first sampling circuit and a second conditioned signal output by the second sampling circuit are obtained.

17. The method according to claim 16, characterized in that Determining a target transformation ratio combination of a main circuit according to the first conditioning signal and the second conditioning signal includes: Calculating a second lower limit value of the transformer ratio according to the first conditioned signal and the second conditioned signal; Determining all reverse ratio combinations of the transformer; A target reverse transformation ratio combination matching the second lower limit value is selected from all the reverse transformation ratio combinations.

18. The method according to claim 17, characterized in that The controlling the main circuit to switch to the target transformation ratio combination based on the output switching control signal by the first driving circuit and the second driving circuit comprises: Sending the output switching control signal to the main circuit through the first driving circuit and the second driving circuit; Based on the switching control signal, the first single-pole double-throw relay and the second single-pole double-throw relay in the main circuit are controlled to switch from the current transformation ratio combination to the target reverse transformation ratio combination.

19. The method according to claim 18, characterized in that The controlling of the output voltage and the output current of the main circuit based on the output drive control signal by the first drive circuit and the second drive circuit according to the target transformation ratio combination includes: According to the target reverse transformation ratio combination, the output drive control signal is sent to the main circuit through the first drive circuit and the second drive circuit; Based on the drive control signal, the input and output voltage and the input and output current of the second switch tube in the main circuit are controlled.

20. The method according to any one of claims 16 to 19, characterized in that Also includes: Obtaining input and output voltage feedback values ​​and input and output current feedback values ​​of the second switch tube; According to the input-output voltage feedback value and the input-output current feedback value of the second switch tube, the duty cycle of the drive control signal is modulated in real time to obtain a stable output current or output voltage.

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