DCDC bidirectional charging and discharging device and system

Abstract

The invention discloses a DCDC bidirectional charging and discharging device and system, the DCDC bidirectional charging and discharging device comprises a first bidirectional inversion module, a first transformer, a second bidirectional inversion module, a first auxiliary power supply module, a second auxiliary power supply module and a first control module, and a first battery module outputs a first DC voltage to the second auxiliary power supply module; the first auxiliary power supply module converts the second DC voltage according to the first control signal and then outputs a third DC voltage to the second auxiliary power supply module; the second auxiliary power supply module converts the first direct current voltage or the third direct current voltage according to the second control signal and then outputs a starting voltage to the first control module. According to the technical scheme, the two stages of auxiliary power supply modules are arranged, so that the system can be automatically started under the condition that the voltage exists in the battery on any side; the problem that an existing isolation type bidirectional DCDC converter cannot be started in a low-voltage battery feed state or a dormant state is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of energy storage inverters, and particularly to a DCDC bidirectional charging and discharging device and system. Background Art

[0002] With the rapid development of new energy vehicle and smart grid technologies, the bidirectional DCDC converter has become an important interface for energy interaction between electric vehicles and the external power grid, and is widely used in scenarios such as on-vehicle charging systems, V2H (Vehicle to Home), and V2G (Vehicle to Grid). To meet the energy conversion requirements between high-voltage and low-voltage batteries, the bidirectional DCDC system not only needs to support forward and reverse energy flows, but also requires the ability to start autonomously when either end battery is feeding. In the prior art, there are mainly the following three types of solutions: 1. Non-isolated bidirectional DCDC converter: This type of solution has a simple structure, low cost, and convenient development. However, since there is no electrical isolation between the input and output, once a short circuit or overload occurs on one side, the fault current can quickly conduct to the other side, easily causing system-level damage, having serious safety hazards, and being difficult to pass the safety certifications of vehicle regulations or the power grid.

[0003] 2. Isolated bidirectional DCDC converter: Electrical isolation between the input and output is achieved through a first transformer, which has higher safety. However, most of these solutions can only start the system through the low-voltage side auxiliary power supply unit. When the low-voltage battery is severely feeding or in a dormant state, the power supply circuit cannot be started, resulting in the inability to activate the system although there is sufficient electrical energy on the high-voltage side, thus affecting vehicle startup and function recovery.

[0004] 3. Multi-output auxiliary power supply solution: Some systems attempt to introduce multiple sets of output power supplies to supply power to each subsystem to meet the auxiliary power supply requirements. However, due to rough structural design, when the voltage of the low-voltage side battery is too low or completely powered off, autonomous activation still cannot be achieved, and power supply startup must rely on external devices or manual operations, increasing the user's difficulty of use and maintenance costs, and reducing the overall reliability and practicality of the system. Summary of the Invention

[0005] Embodiments of the present invention provide a DCDC bidirectional charging and discharging device and system to solve the above technical problems.

[0006] A first aspect of an embodiment of the present invention provides a DCDC bidirectional charging and discharging device, including: A first bidirectional inverter module, one end of which is connected to a first power module, and performs bidirectional conversion on a first DC voltage and a first AC voltage output or received by the first power module; A first transformer, which includes a primary coil and a secondary coil, and the primary coil is connected to the other end of the first bidirectional inverter module; A second bidirectional inverter module, one end of which is connected to the secondary coil, and the other end is connected to a second power module, for bidirectionally converting the second DC voltage and the second AC voltage output or received by the second power module, wherein the first DC voltage is less than the second DC voltage; A first auxiliary power supply module, one end of which is connected to the second power module, and the other end is connected to the first power module; A second auxiliary power supply module, one end of which is respectively connected to the first power module and the first auxiliary power supply module; A first control module, which is respectively connected to the control end of the first bidirectional inverter module, the control end of the second bidirectional inverter module, and the other end of the second auxiliary power supply module; The first battery module outputs a first DC voltage to the second auxiliary power supply module; The first auxiliary power supply module converts the second DC voltage according to a first control signal and outputs a third DC voltage to the second auxiliary power supply module; The second auxiliary power supply module converts the first DC voltage or the third DC voltage according to a second control signal and outputs a startup voltage to the first control module.

[0007] Optionally, the second auxiliary power supply module converts the larger one of the first DC voltage and the third DC voltage according to a second external control signal and outputs a startup voltage to the first control module.

[0008] Optionally, the first auxiliary power supply module includes a second transformer, a first rectifying and filtering module, and a second control module. The first end of the primary coil of the second transformer is connected to the positive pole of the second power module, the second end of the primary coil of the second transformer is connected to one end of the second control module, the other end of the second control module is connected to the negative pole of the second power module, the first end of the secondary coil of the second transformer is connected to the first input end of the first rectifying and filtering module, the second end of the secondary coil of the second transformer is connected to the second input end of the first rectifying and filtering module, the first output end of the first rectifying and filtering module is connected to the positive pole of the first power module, and the second output end of the first rectifying and filtering module is connected to the negative pole of the first power module; The second control module controls the second transformer to convert the second DC voltage into a second AC voltage according to the first control signal; The first rectifying and filtering module rectifies and filters the second AC voltage and then outputs a third DC voltage.

[0009] Optionally, the second control module includes: A first enabling unit, configured to receive a first control signal and output a first enabling signal; A first control unit, whose input end is connected to the output end of the first enabling unit, and outputs a first PWM control signal according to the first enabling signal; A first power unit, whose control end is connected to the output end of the first control unit, whose first output end is one end of the second control module, and whose second output end is the other end of the second control module, and is configured to convert the second DC voltage into a third AC voltage according to the first PWM control signal.

[0010] Optionally, the first rectifying and filtering module includes a first diode, a second diode, and a first capacitor. The anode of the first diode is the first input end of the first rectifying and filtering module. The cathode of the first diode is respectively connected to the anode of the second diode and one end of the first capacitor. The cathode of the second diode is the first output end of the first rectifying and filtering module. The other end of the first capacitor is respectively the second input end and the second output end of the first rectifying and filtering module.

[0011] Optionally, the second auxiliary power supply module includes a third transformer, a second rectifying and filtering module, and a third control module. The first end of the primary coil of the third transformer is connected to the positive pole of the first power supply module. The second end of the primary coil of the third transformer is connected to one end of the third control module. The other end of the third control module is connected to the negative pole of the first power supply module. The first end of the secondary coil of the third transformer is connected to the first input end of the second rectifying and filtering module. The second end of the secondary coil of the third transformer is connected to the second input end of the second rectifying and filtering module. The first output end of the second rectifying and filtering module is connected to the first power supply input end of the first control module. The second output end of the second rectifying and filtering module is connected to the second power supply input end of the first control module; The third control module controls the third transformer to convert the third DC voltage into a fourth AC voltage according to the second control signal; The second rectifying and filtering module rectifies and filters the fourth AC voltage and then outputs a startup voltage.

[0012] Optionally, the third control module includes: A second enabling unit, configured to receive a second control signal and output a second enabling signal; A second control unit, whose input end is connected to the output end of the second enabling unit, and outputs a second PWM control signal according to the second enabling signal; A second power unit, whose control terminal is connected to the output terminal of the second control unit, whose first output terminal is one end of the third control module, and whose second output terminal is the other end of the third control module, is configured to convert the third DC voltage into a fifth AC voltage according to the second PWM control signal.

[0013] Optionally, the second rectification and filtering module includes a third diode and a second capacitor. The anode of the third diode is the first input terminal of the second rectification and filtering module. The cathode of the third diode and one end of the second capacitor are commonly connected as the first output terminal of the second rectification and filtering module. The other end of the second capacitor is respectively the second input terminal and the second output terminal of the second rectification and filtering module.

[0014] Optionally, the DCDC bidirectional charge and discharge device further includes a sixth diode. The anode of the sixth diode is connected to the positive electrode of the first power module, and the cathode of the sixth diode is connected to the first end of the primary coil of the third transformer.

[0015] In a second aspect of the embodiments of the present invention, a DCDC bidirectional charge and discharge system is provided, including the DCDC bidirectional charge and discharge device, the first power module, and the second power module described in the first aspect.

[0016] The technical effects of the embodiments of the present invention are as follows: By setting two - stage auxiliary power supply modules, the system can be autonomously started when there is voltage on any side of the battery, solving the problem that the existing isolated bidirectional DCDC converter cannot be started under the condition of low - voltage battery power feeding or dormancy state. The first auxiliary power supply module uses the high - voltage - side electrical energy to supply power to the second auxiliary power supply module, and combines with the second auxiliary power supply module to convert the voltage from any side and output the starting voltage, so as to ensure that the first control module has a stable power - on ability, realize the bidirectional self - activation start of the system, improve the reliability and practicability of the system, and effectively meet the application requirements of multiple scenarios such as in - vehicle charging. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the description of the embodiments of the present invention will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0018] Figure 1 FIG. 1 is a schematic structural diagram of a DCDC bidirectional charge and discharge device provided in Embodiment 1 of the present invention; Figure 2 FIG. 2 is a schematic structural diagram of the first auxiliary power supply module in a DCDC bidirectional charge and discharge device provided in Embodiment 1 of the present invention; Figure 3 It is a schematic structural diagram of a second control module in a first auxiliary power supply module of a DCDC bidirectional charging and discharging device provided in the first embodiment of the present invention; Figure 4 It is a schematic structural diagram of a second auxiliary power supply module of a DCDC bidirectional charging and discharging device provided in the first embodiment of the present invention; Figure 5 It is a schematic structural diagram of a third control module in a second auxiliary power supply module of a DCDC bidirectional charging and discharging device provided in the first embodiment of the present invention; Figure 6 It is a circuit diagram of a DCDC bidirectional charging and discharging device provided in the first embodiment of the present invention; In the figure: 101, a first bidirectional inverter module; 102, a first transformer; 103, a second bidirectional inverter module; 104, a first power supply module; 105, a second power supply module; 106, a first auxiliary power supply module; 107, a second auxiliary power supply module; 108, a first control module; 111, a first rectifying and filtering module; 112, a second transformer; 113, a second control module; 121, a first enabling unit; 122, a first control unit; 123, a first power unit; 131, a second rectifying and filtering module; 132, a third transformer; 133, a third control module; 141, a second enabling unit; 142, a second control unit; 143, a second power unit. Detailed implementation manners

[0019] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0020] It should be understood that the present invention can be implemented in different forms and should not be construed as limited to the embodiments set forth herein. On the contrary, providing these embodiments will make the disclosure thorough and complete, and will fully convey the scope of the present invention to those skilled in the art. In the drawings, for clarity, the dimensions and relative dimensions of layers and regions may be exaggerated. The same reference numerals denote the same elements throughout the same drawings.

[0021] It should be understood that when an element or layer is referred to as "on", "adjacent to", "connected to" or "coupled to" another element or layer, it can be directly on, adjacent to, connected or coupled to the other element or layer, or there may be intervening elements or layers. In contrast, when an element is referred to as "directly on", "directly adjacent to", "directly connected to" or "directly coupled to" another element or layer, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc. may be used to describe various elements, components, regions, layers and / or parts, these elements, components, regions, layers and / or parts should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or part from another element, component, region, layer or part. Thus, without departing from the teachings of the present invention, the first element, component, region, layer or part discussed below may be denoted as the second element, component, region, layer or part.

[0022] The purpose of the terms used herein is only to describe specific embodiments and is not a limitation of the present invention. As used herein, the singular forms "a", "an" and "the" are also intended to include the plural forms unless the context clearly dictates otherwise. It should also be understood that the terms "comprising" and / or "including", when used in this specification, specify the presence of the stated features, integers, steps, operations, elements and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups. As used herein, the term "and / or" includes any and all combinations of the associated listed items.

[0023] To fully understand the present invention, detailed structures and steps will be presented in the following description to illustrate the technical solutions proposed by the present invention. The preferred embodiments of the present invention are described in detail below. However, in addition to these detailed descriptions, the present invention may have other embodiments.

[0024] Embodiment 1 The first embodiment provides a DCDC bidirectional charge and discharge device, as Figure 1 shown, comprising: A first bidirectional inverter module 101, one end of which is connected to a first power module 104, for bidirectionally converting the first DC voltage and the first AC voltage output or received by the first power module 104; A first transformer 102, which includes a primary coil and a secondary coil, and the primary coil is connected to the other end of the first bidirectional inverter module 101; A second bidirectional inverter module 103, one end of which is connected to the secondary coil and the other end of which is connected to a second power module 105, for bidirectionally converting the second DC voltage and the second AC voltage output or received by the second power module 105, wherein the first DC voltage is less than the second DC voltage; The first auxiliary power supply module 106, one end of which is connected to the second power supply module 105 and the other end is connected to the first power supply module 104; The second auxiliary power supply module 107, one end of which is respectively connected to the first power supply module 104 and the first auxiliary power supply module 106; The first control module 108, which is respectively connected to the control end of the first bidirectional inverter module 101, the control end of the second bidirectional inverter module 103, and the other end of the second auxiliary power supply module 107; The first battery module outputs a first DC voltage to the second auxiliary power supply module 107; The first auxiliary power supply module 106 converts the second DC voltage according to the first control signal and outputs a third DC voltage to the second auxiliary power supply module 107; The second auxiliary power supply module 107 converts the first DC voltage or the third DC voltage according to the second control signal and outputs a startup voltage to the first control module 108.

[0025] Among them, the first bidirectional inverter module 101 realizes the bidirectional AC-DC voltage conversion between the first power module 104 and the first transformer 102, supporting bidirectional energy flow. The first bidirectional inverter module 101 can adopt a full-bridge or half-bridge inverter topology. For example, a bridge inverter circuit composed of four MOSFETs / IGBTs can work in the forward or reverse direction through PWM control. The first transformer 102 provides electrical isolation and realizes the conversion of energy between the first side and the second side. The first transformer 102 can be a high-frequency isolation transformer, having a primary winding and a secondary winding, and the iron core is of E-type or toroidal type. The second bidirectional inverter module 103 realizes the bidirectional AC-DC conversion between the second power module 105 and the secondary of the first transformer 102 to support charging or discharging operations. The second bidirectional inverter module 103 can also adopt a full-bridge or half-bridge topology, supporting the conversion from high-voltage DC to AC or from AC to DC. The first auxiliary power supply module 106 takes power from the second power module 105 (high-voltage side), and after step-down / isolation processing, outputs it to the first power module 104 (low-voltage side) for auxiliary power supply. The first auxiliary power supply module 106 can be a small-power isolated DCDC converter, such as a flyback or forward topology, with a rectified output and a voltage stabilization module. The second auxiliary power supply module 107 receives the first DC voltage output by the first power module 104, or receives the third DC voltage output by the first auxiliary power supply module 106, and after processing, outputs a stable start-up voltage to the first control module 108. The second auxiliary power supply module 107 can be an auxiliary DCDC module with multiple input terminals, including a switching power supply chip, an inductor, a capacitor, a rectifier tube, and input selection logic inside. The first control module 108 is used to centrally control the whole machine, control the conduction and conversion of the first bidirectional inverter module 101 and the second bidirectional inverter module 103, and receive the start-up voltage of the second auxiliary power supply module 107. The first control module 108 can be centered around an MCU or DSP, and is composed of a driving chip, an AD sampling circuit, a communication interface, etc.

[0026] The working process of this technical solution is as follows: 1. Startup situation of the first power module 104 (low-voltage side): The first power module 104 outputs the first DC voltage to supply the second auxiliary power supply module 107; the second auxiliary power supply module 107 converts the first DC voltage and outputs a start-up voltage to the first control module 108; after detecting the effective voltage, the first control module 108 starts the first bidirectional inverter module 101; the first bidirectional inverter module 101 outputs an AC signal to the primary of the first transformer 102; it is transmitted to the secondary through the first transformer 102, and is converted into a second DC voltage by the second bidirectional inverter module 103 to charge the second power module 105 (realize boost charging).

[0027] 2. Startup condition of the second power supply module 105 (high voltage side): The first auxiliary power supply module 106 is connected to the second power supply module 105 to obtain the second DC voltage; after transformation, the third DC voltage is output to the second auxiliary power supply module 107; the second auxiliary power supply module 107 transforms the third DC voltage and outputs the startup voltage to the first control module 108; the first control module 108 starts the system and drives the second bidirectional inverter module 103 to invert the second DC voltage into an AC signal; the AC signal is transmitted to the primary coil through the first transformer 102 and rectified into the first DC voltage by the first bidirectional inverter module 101, and then output to the first power supply module 104 (to achieve step-down discharge).

[0028] The technical effect of the technical solution provided in the first embodiment is as follows: By setting two - stage auxiliary power supply modules, the system can be autonomously started when there is voltage on either side of the battery, solving the problem that the existing isolated bidirectional DCDC converter cannot be started under the condition of low - voltage battery power supply or dormancy state; the first auxiliary power supply module 106 uses the high - voltage - side electric energy to supply power to the second auxiliary power supply module 107, and combines the second auxiliary power supply module 107 to transform the voltage from either side and output the startup voltage, so as to ensure that the first control module 108 has a stable power - on ability, realize the bidirectional self - activation startup of the system, improve the reliability and practicability of the system, and effectively meet the application requirements of multiple scenarios such as in - vehicle charging.

[0029] As an implementation manner, the second auxiliary power supply module 107 transforms the larger one of the first DC voltage and the third DC voltage according to the second external control signal and outputs the startup voltage to the first control module 108.

[0030] Among them, the second auxiliary power supply module 107 includes a multi - input power supply selection circuit, which has two input terminals, respectively receiving the first DC voltage from the first power supply module 104 and the third DC voltage from the first auxiliary power supply module 106. Inside the second auxiliary power supply module 107, there is a voltage comparison and switching unit, which is used to detect the level values of the two input voltages in real time after receiving the second external control signal and select the one with the larger voltage value as the main power supply. The selected power supply is subjected to power conversion processing through a boost, rectification or voltage - regulation module, and then a stable startup voltage is output to the first control module 108. The second external control signal can be issued by the system control unit according to the current working mode, input power supply state or user configuration strategy, and is used to trigger the input voltage comparison and selection process.

[0031] The technical effect of this embodiment is as follows: By introducing a dual-input comparison and selection mechanism into the second auxiliary power supply module 107, it can automatically select the higher-voltage one of the first DC voltage and the third DC voltage for conversion and output after receiving the second control signal, thereby providing a more stable and reliable startup voltage for the first control module 108. This solution not only improves the adaptive ability of the system under different power supply states but also avoids the control failure problem caused by insufficient low-voltage power supply, significantly enhancing the startup reliability and operation safety of the whole machine.

[0032] As an embodiment, as Figure 2 shown, the first auxiliary power supply module 106 includes a second transformer 112, a first rectification and filtering module 111, and a second control module 113. The first end of the primary coil of the second transformer 112 is connected to the positive pole of the second power supply module 105, the second end of the primary coil of the second transformer 112 is connected to one end of the second control module 113, the other end of the second control module 113 is connected to the negative pole of the second power supply module 105, the first end of the secondary coil of the second transformer 112 is connected to the first input terminal of the first rectification and filtering module 111, the second end of the secondary coil of the second transformer 112 is connected to the second input terminal of the first rectification and filtering module 111, the first output terminal of the first rectification and filtering module 111 is connected to the positive pole of the first power supply module 104, and the second output terminal of the first rectification and filtering module 111 is connected to the negative pole of the first power supply module 104. The second control module 113 controls the second transformer 112 to convert the second DC voltage into a second AC voltage according to the first control signal. The first rectification and filtering module 111 rectifies and filters the second AC voltage and then outputs a third DC voltage.

[0033] Among them, the second transformer 112 is used to achieve electrical isolation and voltage conversion between the second power supply module 105 (high-voltage side) and the second auxiliary power supply module 107. The second transformer 112 can be an isolation-type high-frequency transformer, with the primary coil connected to the second power supply module 105 and the secondary coil outputting an AC voltage for the first rectification and filtering module 111 to rectify and filter. The second control module 113 receives the first control signal, performs switching control on the DC voltage provided by the second power supply module 105, and converts it into a high-frequency AC voltage for input to the second transformer 112. The structure of the second control module 113 can include a DCDC controller composed of a PWM control driver and power switching devices (such as MOSFET, IGBT). For example, a forward or flyback topology is adopted. The first rectification and filtering module 111 is used to rectify and filter the alternating current output by the second transformer 112 and finally output a stable third DC voltage to supply the second auxiliary power supply module 107. The structure of the first rectification and filtering module 111 can be composed of a rectifier bridge (diode or synchronous rectifier tube) and filter capacitors.

[0034] The technical effect of this embodiment is as follows: By arranging a second transformer 112, a second control module 113, and a first rectification and filtering module 111 in the first auxiliary power supply module 106, when the second power supply module 105 has power output, the high-voltage direct current is converted into isolated and stable low-voltage direct current and output to the first power supply module 104 or the second auxiliary power supply module 107, so as to ensure that the system can still be actively provided with a starting voltage by the high-voltage side when the battery on the low-voltage side is powered off. This solution significantly improves the self-recovery ability and overall power supply redundancy of the system under abnormal conditions, and effectively enhances the safety and reliability of the bidirectional DCDC system.

[0035] As an embodiment, as Figure 3 shown, the second control module 113 includes: A first enabling unit 121 for receiving a first control signal and outputting a first enabling signal; A first control unit 122, whose input end is connected to the output end of the first enabling unit 121, and outputs a first PWM control signal according to the first enabling signal; A first power unit 123, whose control end is connected to the output end of the first control unit 122, whose first output end is one end of the second control module 113, and whose second output end is the other end of the second control module 113, for converting the second DC voltage into a third AC voltage according to the first PWM control signal.

[0036] Among them, the first enabling unit 121 is used to receive the first control signal output by the first control module 108 and output a first enabling signal when the enabling condition is met. The first enabling unit 121 can be a level recognition circuit, an optocoupler isolator, or a simple MOS switch circuit, which is used to ensure that the subsequent circuit starts to work only under permitted conditions. The first control unit 122, whose input end is connected to the output end of the first enabling unit 121; when receiving the first enabling signal, the first control unit 122 starts to work and outputs a first PWM control signal. The first control unit 122 can be an independent PWM control chip or a PWM logic module integrated in the MCU, which is used to control the frequency and duty cycle of the PWM. The first power unit 123, whose control end is connected to the output end of the first control unit 122, is used to receive the first PWM control signal. One end of the first power unit 123 is connected to the positive pole of the second power supply module 105, and the other end is connected to the negative pole of the second power supply module 105 to form a chopping path. Driven by the first PWM control signal, the first power unit 123 converts the high-voltage DC voltage of the second power supply module 105 into a high-frequency third AC voltage for the input of the primary coil of the subsequent transformer.

[0037] The technical effect of this embodiment lies in that: by introducing a hierarchical control structure of the first enabling unit 121, the first control unit 122, and the first power unit 123 into the second control module 113, precise management and conversion of the output voltage of the second power supply module 105 are achieved; this embodiment can, after receiving the first control signal, intelligently drive the power unit to convert high-voltage direct current into high-frequency alternating current, providing input for subsequent isolation transformation, effectively improving the response speed and control accuracy of the system, while enhancing the startup flexibility of the module and the safety and reliability of the overall system.

[0038] As an embodiment, the first rectifying and filtering module 111 includes a first diode, a second diode, and a first capacitor. The anode of the first diode is the first input terminal of the first rectifying and filtering module 111. The cathode of the first diode is respectively connected to the anode of the second diode and one end of the first capacitor. The cathode of the second diode is the first output terminal of the first rectifying and filtering module 111. The other end of the first capacitor is respectively the second input terminal and the second output terminal of the first rectifying and filtering module 111.

[0039] Among them, the first diode, as a rectifying device, is used to conduct and transmit the positive half-cycle of the alternating current input from the secondary coil of the second transformer 112, providing a rectifying channel for the subsequent stage; the second diode and the first diode together form a half-bridge rectifying structure, conducting in the negative half-cycle of the secondary output of the second transformer 112 to achieve full-wave rectification of the alternating current; the first capacitor is used to filter the rectified pulsating direct current voltage, eliminate the alternating current component in the voltage, and output a stable direct current voltage; The technical effect of this embodiment lies in that: by arranging the first diode, the second diode, and the first capacitor in the first rectifying and filtering module 111, effective rectification and filtering of the high-frequency alternating current output from the secondary of the transformer are achieved, and a stable third direct current voltage is output; this structure is simple and has a fast response, can significantly reduce the ripple of the output voltage, improve the stability and reliability of the auxiliary power supply, and thus provide a safer and continuous power supply guarantee for the subsequent control module.

[0040] As an embodiment, as Figure 4As shown, the second auxiliary power supply module 107 includes a third transformer 132, a second rectification and filtering module 131, and a third control module 133. The first end of the primary coil of the third transformer 132 is connected to the positive pole of the first power supply module 104, the second end of the primary coil of the third transformer 132 is connected to one end of the third control module 133, the other end of the third control module 133 is connected to the negative pole of the first power supply module 104, the first end of the secondary coil of the third transformer 132 is connected to the first input terminal of the second rectification and filtering module 131, the second end of the secondary coil of the third transformer 132 is connected to the second input terminal of the second rectification and filtering module 131, the first output terminal of the second rectification and filtering module 131 is connected to the first power supply input terminal of the first control module 108, and the second output terminal of the second rectification and filtering module 131 is connected to the second power supply input terminal of the first control module 108; The third control module 133 controls the third transformer 132 to convert the third DC voltage into a fourth AC voltage according to the second control signal; The second rectification and filtering module 131 rectifies and filters the fourth AC voltage and then outputs a startup voltage.

[0041] Among them, the third transformer 132 realizes electrical isolation and is used to transmit the direct current provided by the first power supply module 104 to the second rectification and filtering module 131 after conversion; the third transformer 132 can be a high-frequency isolation transformer. The primary coil receives the high-frequency alternating current after switch control, and after the secondary output voltage is rectified and filtered, it is output. The iron core can be selected from E-shaped or toroidal structures to reduce leakage inductance. After receiving the second control signal, the third control module 133 drives the third DC voltage provided by the first power supply module 104 and converts it into a high-frequency pulse (fourth AC voltage) for input to the third transformer 132; the third control module 133 can include a PWM control unit and a power switch unit. The PWM control unit generates a PWM signal with a specific frequency and duty cycle; the power switch unit includes MOSFET or IGBT and is used to chop the direct current into alternating current. The second rectification and filtering module 131 rectifies and filters the fourth AC voltage output by the secondary of the third transformer 132 to form a stable startup voltage; the structure of the second rectification and filtering module 131 can include a rectifier bridge (diode or synchronous rectifier tube) and a filter capacitor.

[0042] The working process of this embodiment is as follows: when the second control signal is received, the third control module 133 is activated, and a PWM signal is output to control the on / off of the power device, so that the third DC voltage is converted into a high-frequency pulsating voltage (i.e., the fourth AC voltage) and supplied to the primary coil of the third transformer 132. The third transformer 132 transforms this voltage to the secondary coil and outputs it to the second rectification and filtering module 131. The second rectification and filtering module 131 performs rectification and filtering on it, and finally outputs a stable startup voltage, which is respectively sent to the first power input terminal and the second power input terminal of the first control module 108 to ensure that the system control core has a stable working voltage.

[0043] The technical effect of this embodiment is that by setting the third transformer 132, the third control module 133 and the second rectification and filtering module 131 in the second auxiliary power supply module 107, when the first power supply module 104 has the output ability, it can independently convert its DC voltage into an isolated high-frequency alternating current, and further rectify and filter to output a stable startup voltage for the control module to use. This design not only improves the independence and reliability of the system during startup on the low-voltage side, but also enhances the safety and anti-interference ability of the system through the isolation structure, providing a flexible and efficient auxiliary startup solution for the bidirectional power supply system.

[0044] As an embodiment, as Figure 5 shown, the third control module 133 includes: A second enabling unit 141, configured to receive the second control signal and output a second enabling signal; A second control unit 142, whose input terminal is connected to the output terminal of the second enabling unit 141, and outputs a second PWM control signal according to the second enabling signal; A second power unit 143, whose control terminal is connected to the output terminal of the second control unit 142, whose first output terminal is one end of the third control module 133, and whose second output terminal is the other end of the third control module 133, and is configured to convert the third DC voltage into a fifth AC voltage according to the second PWM control signal.

[0045] Among them, the second enabling unit 141 is used to receive a second control signal from the system controller, determine whether to enter the working state, and output a second enabling signal when the conditions are met, for starting the subsequent control and power unit; the second enabling unit 141 can adopt an optocoupler (for isolation and anti-interference), a level detection circuit, a MOS switch or a level converter, which plays the role of logical judgment and drive signal isolation. After receiving the second enabling signal output by the second enabling unit 141, the second control unit 142 starts and generates a group of second PWM control signals with a specific frequency and duty cycle, for driving the second power unit 143; the second control unit 142 is implemented by a dedicated PWM controller or by the internal PWM timer module of a microcontroller (MCU); the output frequency is generally from dozens of kHz to hundreds of kHz, suitable for driving power devices such as MOSFETs. The second power unit 143 conducts and turns off according to the second PWM second signal output by the second control unit 142, realizes the chopping of the third DC voltage, and outputs a high-frequency pulsed AC signal (i.e., the fifth AC voltage), for exciting the third transformer 132; the second power unit 143 can be selected in a single-tube switching mode, or adopt structures such as push-pull, half-bridge, full-bridge, etc., and is composed of power devices such as N-type MOSFETs or IGBTs.

[0046] The technical effect of this embodiment lies in that: by setting the second enabling unit 141, the second control unit 142 and the second power unit 143 in the third control module 133, the controlled high-frequency conversion of the third DC voltage is realized, and a stable fifth AC voltage is output for the transformer to use; this embodiment not only improves the flexibility and reliability of the low-voltage side power supply startup, but also realizes the precise triggering and energy management of the system startup through hierarchical control, effectively improving the adaptive ability and safety performance of the overall system under various working conditions.

[0047] As an embodiment, the second rectifying and filtering module 131 includes a third diode and a second capacitor. The anode of the third diode is the first input end of the second rectifying and filtering module 131, and the cathode of the third diode and one end of the second capacitor are commonly connected as the first output end of the second rectifying and filtering module 131. The other end of the second capacitor is respectively the second input end and the second output end of the second rectifying and filtering module 131.

[0048] Among them, the third diode is used to rectify the fifth AC voltage output by the third control module 133 through the transformer, and unidirectionally conduct it into a pulsating direct current; the second capacitor is used to filter and smooth the pulsating direct current voltage rectified by the third diode, so as to eliminate the voltage ripple and output a stable DC startup voltage.

[0049] The technical effect of this embodiment is as follows: By setting the third diode and the second capacitor in the second rectification and filtering module 131, the efficient rectification and filtering of the high-frequency fifth AC voltage are achieved, and a stable DC startup voltage with low ripple is output, providing a reliable working power supply for the control module. This structure has a fast response and a compact volume, ensuring both the voltage conversion efficiency and improving the stability of the system during the startup process on the low-voltage side and the overall power supply quality.

[0050] The following is an illustration of this embodiment through a specific circuit structure: As Figure 6 shown, the first bidirectional inverter module 101 includes a first MOS transistor Q1, a second MOS transistor Q2, a third MOS transistor Q3, and a fourth MOS transistor Q4; the drain of the first MOS transistor Q1 and the drain of the second MOS transistor Q2 are commonly connected as the first end of the first bidirectional inverter module 101 and are connected to the positive pole of the first power supply module 104, the source of the third MOS transistor Q3 and the source of the fourth MOS transistor Q4 are commonly connected as the second end of the first bidirectional inverter module 101 and are connected to the negative pole of the first power supply module 104, the source of the first MOS transistor Q1 and the drain of the third MOS transistor Q3 are commonly connected as the third end of the first bidirectional inverter module 101 and are connected to the first end of the primary coil of the transformer TX1, and the source of the second MOS transistor Q2 and the drain of the fourth MOS transistor Q4 are commonly connected as the fourth end of the first bidirectional inverter module 101 and are connected to the second end of the primary coil of the transformer TX1.

[0051] The second bidirectional inverter module 103 includes a fifth MOS transistor Q5, a sixth MOS transistor Q6, a seventh MOS transistor Q7, and an eighth MOS transistor Q8; the source of the fifth MOS transistor Q5 and the drain of the seventh MOS transistor Q7 are commonly connected as the first end of the second bidirectional inverter module 103 and are connected to the first end of the secondary coil of the transformer TX1; the source of the sixth MOS transistor Q6 and the drain of the eighth MOS transistor Q8 are commonly connected as the second end of the second bidirectional inverter module 103 and are connected to one end of the inductor L1, the other end of the inductor L1 is connected to one end of the capacitor C5, and the other end of the capacitor C5 is connected to the second end of the secondary coil of the transformer TX1; the drain of the fifth MOS transistor Q5 and the drain of the sixth MOS transistor Q6 are commonly connected as the third end of the second bidirectional inverter module 103 and are connected to the positive pole of the second power supply module 105; the source of the seventh MOS transistor Q7 and the source of the eighth MOS transistor Q8 are commonly connected as the fourth end of the second bidirectional inverter module 103 and are connected to the negative pole of the second power supply module 105.

[0052] The first auxiliary power supply module 106 includes a transformer T1, a diode D1, a diode D2, a capacitor C1, and a second control module 113. The first end of the primary coil of the transformer T1 is connected to the positive pole of the second power supply module 105, the first end of the primary coil of the transformer T1 is connected to the first end of the second control module 113, the second end of the second control module 113 is connected to the negative pole of the second power supply module 105, the first end of the secondary coil of the transformer T1 is connected to the anode of the diode D1, the cathode of the diode D1 is respectively connected to the anode of the diode D2 and the first end of the capacitor C1, the cathode of the diode D2 is connected to the cathode of the diode D6, the anode of the diode D6 is connected to the positive pole of the first power supply module 104, and the second end of the secondary coil of the transformer T1 is respectively connected to the second end of the capacitor C1 and the negative pole of the first power supply module 104.

[0053] The second auxiliary power supply module 107 includes a transformer T2, a diode D3, a diode D4, a diode D5, a capacitor C2, a capacitor C3, a capacitor C4, and a third control module 133. The first end of the primary coil of the transformer T2 is connected to the cathode of the diode D6, the second end of the primary coil of the transformer T2 is connected to the first end of the third control module 133, the second end of the third control module 133 is connected to the negative pole of the first power supply module 104, the first end of the secondary coil of the transformer T2 is connected to the anode of the diode D3, the cathode of the diode D3 and the first end of the capacitor C2 are commonly connected as a first output terminal, the second end of the secondary coil of the transformer T2 is connected to the anode of the diode D4, the cathode of the diode D4 and the first end of the capacitor C3 are commonly connected as a second output terminal, the third end of the secondary coil of the transformer T2, the second end of the capacitor C3, and the first end of the capacitor C4 are commonly connected as a negative output terminal, the fourth end of the secondary coil of the transformer T2 is connected to the cathode of the diode D5, and the anode of the diode D5 and the second end of the capacitor C4 are commonly connected as a third output terminal.

[0054] The working process of this circuit structure is as follows: The first power supply module 104 provides energy input for the first power conversion unit and also supplies power to the second auxiliary power supply module 107. After being transformed, the second auxiliary power supply module 107 outputs through the secondary side second rectification and filtering unit (diode D3 and capacitor C2) and the third rectification and filtering unit (diode D4 and capacitor C3) to provide auxiliary power supply for the first control module 108. The fourth rectification and filtering unit (diode D5 and capacitor C4) is used for the input power supply. The fourth rectification and filtering unit is connected to an external power supply. When the power levels of both the first power supply module 104 and the second power supply module 105 are relatively low, it is used to supply power to either the first power supply module 104 or the second power supply module 105. The energy isolated and converted by the main transformer TX1 is provided with energy output through the second power supply module 105 (i.e., the high voltage side) and also supplies power to the first auxiliary power supply module 106. The energy input to the first auxiliary power supply module 106 is output through the secondary side first rectification and filtering module after being transformed to supply power to the second auxiliary power supply module 107. Then, after being transformed by the second auxiliary power supply module 107, it outputs through the secondary side second rectification and filtering unit, the third rectification and filtering unit, and the fourth rectification and filtering unit to provide auxiliary power supply for the first control module 108. On the one hand, the energy of the second auxiliary power supply module 107 comes from the low voltage side input terminal, and on the other hand, it comes from the output terminal of the first auxiliary power supply module 106. The energy of the first auxiliary power supply module 106 comes from the high voltage side. That is to say, the energy input from the low voltage side or the high voltage side can provide stable and reliable power supply for the whole machine through the auxiliary power supply system, and can also complete the two-way start control of the entire bidirectional power converter by receiving external communication and remotely controlling the start of the auxiliary power supply.

[0055] Embodiment 2 This Embodiment 2 provides a DCDC bidirectional charging and discharging system, including the DCDC bidirectional charging and discharging device provided in Embodiment 1, the first power supply module, and the second power supply module.

[0056] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included in the protection scope of the present invention.

Claims

1. A DCDC bidirectional charging and discharging device, characterized in that, Comprising: A first bidirectional inverter module, one end of which is connected to a first power module, for bidirectionally converting a first DC voltage and a first AC voltage output or received by the first power module; A first transformer, which includes a primary coil and a secondary coil, and the primary coil is connected to the other end of the first bidirectional inverter module; A second bidirectional inverter module, one end of which is connected to the secondary coil and the other end of which is connected to a second power module, for bidirectionally converting a second DC voltage and a second AC voltage output or received by the second power module, wherein the first DC voltage is less than the second DC voltage; A first auxiliary power supply module, one end of which is connected to the second power module and the other end of which is connected to the first power module; A second auxiliary power supply module, one end of which is respectively connected to the first power module and the first auxiliary power supply module; A first control module, which is respectively connected to the control ends of the first bidirectional inverter module, the second bidirectional inverter module and the other end of the second auxiliary power supply module; The first battery module outputs a first DC voltage to the second auxiliary power supply module; The first auxiliary power supply module converts the second DC voltage according to a first control signal and outputs a third DC voltage to the second auxiliary power supply module; The second auxiliary power supply module converts the first DC voltage or the third DC voltage according to a second control signal and outputs a startup voltage to the first control module.

2. The DCDC bidirectional charging and discharging device according to claim 1, characterized in that, The second auxiliary power supply module converts the larger one of the first DC voltage and the third DC voltage according to a second external control signal and outputs a startup voltage to the first control module.

3. The DCDC bidirectional charge and discharge device according to claim 1, characterized in that, The first auxiliary power supply module includes a second transformer, a first rectification and filtering module and a second control module. The first end of the primary coil of the second transformer is connected to the positive electrode of the second power module, the second end of the primary coil of the second transformer is connected to one end of the second control module, the other end of the second control module is connected to the negative electrode of the second power module, the first end of the secondary coil of the second transformer is connected to the first input end of the first rectification and filtering module, the second end of the secondary coil of the second transformer is connected to the second input end of the first rectification and filtering module, the first output end of the first rectification and filtering module is connected to the positive electrode of the first power module, and the second output end of the first rectification and filtering module is connected to the negative electrode of the first power module; The second control module controls the second transformer to convert the second DC voltage into a second AC voltage according to the first control signal; The first rectification and filtering module rectifies and filters the second AC voltage and then outputs a third DC voltage.

4. The DCDC bidirectional charging and discharging device according to claim 3, wherein The second control module includes: A first enabling unit, for receiving a first control signal and outputting a first enabling signal; A first control unit, the input end of which is connected to the output end of the first enabling unit, and outputting a first PWM control signal according to the first enabling signal; The first power unit, whose control terminal is connected to the output terminal of the first control unit, whose first output terminal is one end of the second control module, and whose second output terminal is the other end of the second control module, is configured to convert the second DC voltage into a third AC voltage according to the first PWM control signal.

5. The DCDC bidirectional charging and discharging device according to claim 3, characterized in that, The first rectification and filtering module includes a first diode, a second diode, and a first capacitor. The anode of the first diode is the first input terminal of the first rectification and filtering module. The cathode of the first diode is respectively connected to the anode of the second diode and one end of the first capacitor. The cathode of the second diode is the first output terminal of the first rectification and filtering module. The other end of the first capacitor is respectively the second input terminal and the second output terminal of the first rectification and filtering module.

6. The DCDC bidirectional charging and discharging device according to claim 1, wherein The second auxiliary power supply module includes a third transformer, a second rectification and filtering module, and a third control module. The first end of the primary coil of the third transformer is connected to the positive pole of the first power supply module. The second end of the primary coil of the third transformer is connected to one end of the third control module. The other end of the third control module is connected to the negative pole of the first power supply module. The first end of the secondary coil of the third transformer is connected to the first input terminal of the second rectification and filtering module. The second end of the secondary coil of the third transformer is connected to the second input terminal of the second rectification and filtering module. The first output terminal of the second rectification and filtering module is connected to the first power supply input terminal of the first control module. The second output terminal of the second rectification and filtering module is connected to the second power supply input terminal of the first control module. The third control module controls the third transformer to convert the third DC voltage into a fourth AC voltage according to the second control signal. The second rectification and filtering module rectifies and filters the fourth AC voltage and then outputs a startup voltage.

7. The DCDC bidirectional charging and discharging device according to claim 6, wherein The third control module includes: A second enabling unit, configured to receive the second control signal and output a second enabling signal. A second control unit, whose input terminal is connected to the output terminal of the second enabling unit, and outputs a second PWM control signal according to the second enabling signal. A second power unit, whose control terminal is connected to the output terminal of the second control unit, whose first output terminal is one end of the third control module, and whose second output terminal is the other end of the third control module, is configured to convert the third DC voltage into a fifth AC voltage according to the second PWM control signal.

8. The DCDC bidirectional charging and discharging device according to claim 6, characterized in that, The second rectification and filtering module includes a third diode and a second capacitor. The anode of the third diode is the first input terminal of the second rectification and filtering module. The cathode of the third diode and one end of the second capacitor are commonly connected as the first output terminal of the second rectification and filtering module. The other end of the second capacitor is respectively the second input terminal and the second output terminal of the second rectification and filtering module.

9. The DCDC bidirectional charging and discharging device according to claim 6, wherein, The DCDC bidirectional charge and discharge device further includes a sixth diode. The anode of the sixth diode is connected to the positive pole of the first power supply module. The cathode of the sixth diode is connected to the first end of the primary coil of the third transformer.

10. A DCDC bidirectional charging and discharging system, characterized in that, Including the DCDC bidirectional charging and discharging device according to any one of claims 1 to 9, a first power supply module, and a second power supply module.

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