Power module and charging system
By using a single-pole double-throw switch and resistor voltage divider technology in the LLC resonant converter, the problem of excessive voltage change rate of the anti-reverse diode during series-parallel switching is solved, improving the system reliability and preventing damage to electrolytic capacitors.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- XIAN LINCHR NEW ENERGY TECH CO LTD
- Filing Date
- 2025-06-23
- Publication Date
- 2026-06-02
Smart Images
Figure CN224319251U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of charging technology, and in particular to a power module and charging system. Background Technology
[0002] In power electronic systems, there are many types of series and parallel topologies for LLC resonant converters, and different operating modes can be achieved by switching between series and parallel connections.
[0003] Currently, the most common topology uses three relays for series-parallel switching, with two relays in parallel and one in series. Furthermore, to improve system reliability, some designs employ a dual-path reverse-voltage protection diode configuration at the output to prevent damage to the circuit from reverse voltage.
[0004] However, this design of combining a three-relay topology with a reverse protection diode has the following problems in practical applications: when the relay performs a switching action, if the voltage of the external load is high, the reverse protection diode will be subjected to an extremely high voltage change rate (dv / dt). For ordinary reverse protection diodes, this can easily cause dynamic avalanche breakdown, thereby reducing the reliability of the LLC resonant converter. Utility Model Content
[0005] The main objective of this application is to provide a power module and charging system that reduces the probability of reverse diode failure during series-parallel switching and ensures that the electrolytic capacitor is not damaged due to reverse diode failure, thereby improving the reliability of the power module.
[0006] To achieve the above objectives, this application provides a power module, including an AC conversion unit and a DC / DC output unit, wherein the AC conversion unit is connected to the DC / DC output unit, and the DC / DC output unit includes an output unit and an anti-reverse unit;
[0007] The output unit includes at least a first DC output branch, a second DC output branch, a first switch, and a second switch. The first DC output branch includes a first output terminal and a second output terminal. The second DC output branch includes a third output terminal and a fourth output terminal. The common terminal, the first contact, and the second contact of the first switch are respectively connected to the third output terminal, the second output terminal, and the first output terminal in sequence. The second switch is connected between the second output terminal and the fourth output terminal.
[0008] The anti-reverse unit includes a first diode and a first resistor. The anode of the first diode is connected to the second contact of the first switch, and the cathode of the first diode is connected to the first output terminal and the positive terminal of the load. One end of the first resistor is connected to the anode of the first diode, and the other end of the first resistor is connected to the fourth output terminal and the negative terminal of the load.
[0009] Optionally, the anti-reverse unit also includes a first capacitor, which is connected in parallel across the first resistor.
[0010] Optionally, the anti-reverse unit also includes a second diode, a second capacitor, and a second resistor; the anode of the second diode is connected to the first output terminal, and the cathode of the second diode is connected to the positive terminal of the load; the second capacitor and the second resistor are connected in series and then in parallel across the two ends of the second diode.
[0011] Optionally, when the power module is in a shutdown state, the common terminal of the first switch and the first contact are connected to form a circuit.
[0012] Optionally, the output unit further includes a third capacitor and a fourth capacitor; one end of the third capacitor serves as the first output terminal of the output unit, and the other end of the third capacitor serves as the second output terminal of the output unit; one end of the fourth capacitor serves as the third output terminal of the output unit, and the other end of the third capacitor serves as the fourth output terminal of the output unit.
[0013] Optionally, the DC / DC output unit also includes an inverter unit, a resonant unit, and a rectifier unit; one end of the inverter unit is connected to the AC conversion unit, the other end of the inverter unit is connected to one end of the resonant unit, the other end of the resonant unit is connected to the rectifier unit, and the other end of the rectifier unit is connected to the output unit.
[0014] Optionally, the AC conversion unit includes a fifth capacitor and a sixth capacitor, and the inverter unit includes a third switch, a fourth switch, a fifth switch, a sixth switch, a seventh switch, an eighth switch, a ninth switch, and a tenth switch; the third switch and the fourth switch are connected in series and then in parallel across the fifth capacitor, the fifth switch and the sixth switch are connected in series and then in parallel across the fifth capacitor, the seventh switch and the eighth switch are connected in series and then in parallel across the sixth capacitor, the ninth switch and the tenth switch are connected in series and then in parallel across the sixth capacitor, and the fifth capacitor and the sixth capacitor are connected in parallel.
[0015] Optionally, the resonant unit includes a seventh capacitor, an eighth capacitor, a first inductor, a second inductor, a first transformer, and a second transformer; one end of the seventh capacitor is connected between the third and fourth switches, and the other end of the seventh capacitor is connected to one end of the first inductor; one end of the primary winding of the first transformer is connected to the other end of the first inductor, and the other end of the primary winding of the first transformer is connected between the fifth and sixth switches; one end of the eighth capacitor is connected between the seventh and eighth switches, and the other end of the eighth capacitor is connected to one end of the second inductor; one end of the primary winding of the second transformer is connected to the other end of the second inductor, and the other end of the primary winding of the second transformer is connected between the ninth and tenth switches.
[0016] Optionally, the rectifier unit includes a third diode, a fourth diode, a fifth diode, a sixth diode, a seventh diode, an eighth diode, a ninth diode, and a tenth diode; the anode of the third diode is connected to the cathode of the fourth diode to form a first node, the anode of the fifth diode is connected to the cathode of the sixth diode to form a second node, the cathode of the third diode is connected to the cathode of the fifth diode and then connected to one end of a third capacitor, the anode of the fourth diode is connected to the anode of the sixth diode and then connected to the other end of the third capacitor; the anode of the seventh diode is connected to the cathode of the eighth diode to form a third node, the anode of the ninth diode is connected to the cathode of the tenth diode to form a fourth node, the cathode of the seventh diode is connected to the cathode of the ninth diode and then connected to one end of the fourth capacitor, the anode of the eighth diode is connected to the anode of the tenth diode and then connected to the other end of the fourth capacitor; the first secondary winding of the first transformer is connected in series with the first secondary winding of the second transformer and then connected to the first node and the second node, the second secondary winding of the first transformer is connected in series with the second secondary winding of the second transformer and then connected to the third node and the fourth node.
[0017] In addition, to achieve the above objectives, this application also provides a charging system, including at least two power modules as described above, a controller, a power distribution device, and at least one charging interface; the power distribution device is connected to the controller, each power module, and each charging interface respectively, and the controller is connected to each power module respectively.
[0018] The power module of this application adopts a single-pole double-throw first switch and uses the first switch in conjunction with a first resistor. When the power module needs to be output in series, the common terminal of the first switch and the first contact are connected and conducting. At this time, the first resistor can divide the voltage with the first diode. When the power module needs to be output in parallel, the common terminal of the first switch and the second contact are connected and conducting. Since there is a certain voltage across the first diode before the series-parallel switching, the voltage change rate across the first diode will not be too large when switching to parallel output. Therefore, the probability of the first diode failure is effectively reduced, thereby improving the reliability of the power module. Attached Figure Description
[0019] Figure 1 This is a partial structural diagram of a power module in the prior art;
[0020] Figure 2 This is one of the structural schematic diagrams of the power module according to an embodiment of this application;
[0021] Figure 3 This is a second schematic diagram of the power module structure according to an embodiment of this application;
[0022] Figure 4 This is the third schematic diagram of the power module in the embodiment of this application;
[0023] Figure 5 This is the fourth schematic diagram of the power module in the embodiment of this application;
[0024] Figure 6 This is the fifth schematic diagram of the power module in the embodiments of this application;
[0025] Figure 7 This is a schematic diagram of a charging system according to an embodiment of this application;
[0026] In the diagram, 100 is the AC conversion unit; 200 is the DC / DC output unit; 210 is the output unit; 220 is the anti-reverse unit; 230 is the inverter unit; 240 is the resonant unit; 250 is the rectifier unit; 710 is the power module; 720 is the charging interface; 730 is the controller; and 740 is the power distribution device.
[0027] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation
[0028] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0029] In the field of charging piles, DC / DC output series-parallel topology is a commonly used topology. This topology can flexibly adapt to different voltage and power requirements by switching between series and parallel.
[0030] Currently, there are many types of DC / DC output series-parallel topologies in existing charging piles. Common DC / DC output series-parallel topologies include... Figure 1 As shown, it uses three relays to achieve series-parallel switching, with two relays for parallel connection and one relay for series connection. However, this DC / DC output series-parallel topology has certain problems during series-parallel switching, resulting in insufficient reliability.
[0031] Specifically, such as Figure 1As shown, when the power module is not activated and a high-voltage external load battery is connected to its output, if it is necessary to switch the DC / DC output from series mode to parallel mode, since the reverse protection diode D1-2 is floating in series mode (0V), a high voltage will be instantaneously applied across it when the DC / DC output switches from series to parallel mode. For example, if the external load battery voltage is 1000V, a 1000V voltage will be instantaneously applied across D1-2 when switching to parallel mode, causing the voltage across D1-2 to change from 0V to 1000V. Therefore, the reverse protection diode D1-2 has a very high voltage change rate (dv / dt) when the DC / DC output switches between series and parallel modes.
[0032] For ordinary reverse protection diodes, a high voltage change rate can easily cause dynamic avalanche breakdown, leading to diode failure. If the reverse protection diode D1-2 fails, the voltage of the external load will be applied across the electrolytic capacitor C1-2, which will damage the electrolytic capacitor C1-2, reducing the reliability of the power module and increasing the maintenance and replacement costs.
[0033] Therefore, this application provides a power module and charging system. By adding a single-pole double-throw double-contact switch and a first resistor to the DC / DC output series-parallel topology, the voltage difference of the anti-reverse diode in the DC / DC output series-parallel topology before and after series-parallel switching is kept within a reasonable range. This effectively reduces the voltage change rate of the anti-reverse diode during series-parallel switching, thereby reducing the probability of failure and damage to the anti-reverse diode and electrolytic capacitor, and effectively improving the reliability of the DC / DC output series-parallel topology in the power module.
[0034] The power module of this application embodiment will be described in detail below.
[0035] Figure 2 This is one of the structural schematic diagrams of the power module according to an embodiment of this application. For example... Figure 2 As shown, the power module may include an AC conversion unit 100 and a DC / DC output unit 200. The AC conversion unit 100 is connected to the DC / DC output unit 200, and the DC / DC output unit 200 includes an output unit 210 and an anti-reverse unit 220.
[0036] The output unit 210 includes at least a first DC output branch, a second DC output branch, a first switch K1, and a second switch K2. The first DC output branch may include a first output terminal S1 and a second output terminal S2. The second DC output branch may include a third output terminal S3 and a fourth output terminal S4. The common terminal a0, the first contact a1, and the second contact a2 of the first switch K1 are sequentially connected to the third output terminal S3, the second output terminal S2, and the first output terminal S1, respectively. The second switch K2 is connected between the second output terminal S2 and the fourth output terminal S4. The anti-reverse unit 220 includes a first diode D1 and a first resistor R1. The anode of the first diode D1 is connected to the second contact a2 of the first switch K1, and the cathode of the first diode D1 is connected to the first output terminal S1 and the positive terminal of the load. One end of the first resistor R1 is connected to the anode of the first diode D1, and the other end of the first resistor R1 is connected to the fourth output terminal S4 and the negative terminal of the load.
[0037] First, it should be noted that the power module in this embodiment can be used in charging piles or energy storage systems, such as integrated DC charging piles and split DC charging piles. Therefore, the load described in this embodiment can be the battery of an electric vehicle to be charged, or the battery of other devices, etc., and the load is not specifically limited here.
[0038] In this embodiment, the power module may include an AC conversion unit 100 and a DC / DC output unit 200. The AC conversion unit 100 rectifies the AC power input from the power grid into DC power, and then uses a large-capacity electrolytic capacitor for voltage regulation and filtering before outputting the DC / DC power. The DC / DC output unit 200 converts the output through two or more LLC resonant cavities, and achieves a wide output range from 50V to 1000V by using a series-parallel combination of switches on the output side.
[0039] Specifically, the AC conversion unit 100 may include an input EMC module, a soft-start circuit, a PFC module, a fifth capacitor C5, and a sixth capacitor C6. The input EMC module is primarily used to suppress electromagnetic interference input from the mains side and improve the electromagnetic compatibility of the power module. The soft-start circuit is used during the soft-start process of the power module to limit the inrush current during power-on and prevent instantaneous large currents from impacting circuit components (such as the rectifier bridge and capacitors).
[0040] A PFC module (Power Factor Correction module) is used to optimize the power factor of a power supply and improve energy efficiency. A PFC module can consist of several switching transistors and diodes. During AC-DC conversion, traditional rectifier circuits can cause input current waveform distortion, generating a large number of harmonics and reducing the power factor (PF). The PFC module adjusts the phase of the input current through active (e.g., Boost PFC) or passive (e.g., valley-filling circuits) methods to synchronize it with the voltage, thereby raising the power factor to near 1. The fifth capacitor C5 and the sixth capacitor C6 are both electrolytic capacitors on the DC bus in the AC conversion unit 100.
[0041] It should be noted that the specific structure of the AC conversion unit 100 can refer to the specific structure of the AC conversion unit 100 of the existing power module. The AC conversion unit 100 is not the main content of the embodiments of this application, so the embodiments of this application will not be described in detail or specifically limited.
[0042] Furthermore, the DC / DC output unit 200 may include an output unit 210 and an anti-reverse unit 220, both located on the output side of the DC / DC output unit 200. In this embodiment, the DC / DC output unit 200 may include two branches (i.e., a first DC output branch and a second DC output branch), both branches having identical structures, and both branches are connected in parallel across the terminals of the fifth capacitor C5 and the sixth capacitor C6, respectively. Both branches can further convert and rectify the DC power output from the AC conversion unit 100 to enable the power module to meet different charging requirements.
[0043] As an example, if the first DC output branch can output 100V, then connecting the first and second DC output branches in series will yield an output voltage of 200V; connecting the first and second DC output branches in parallel will yield an output voltage of 100V. This increases the output voltage range of the power module.
[0044] In this embodiment, since the DC / DC output unit 200 has two branches, the output unit 210 may include four output terminals: a first output terminal S1, a second output terminal S2, a third output terminal S3, and a fourth output terminal S4. The first output terminal S1 and the second output terminal S2 are also the two output terminals of the first DC output branch, and the third output terminal S3 and the fourth output terminal S4 are the two output terminals of the first DC output branch.
[0045] In addition, the output unit 210 also includes a first switch K1 and a second switch K2. The first switch K1 can be a single-pole double-throw switch, the second switch K2 can be a single-pole single-throw switch, and both the first switch K1 and the second switch K2 can be relays. In this embodiment, the common terminal a0 of the first switch K1 is connected to the third output terminal S3 of the output unit 210, the first contact a1 of the first switch K1 is connected to the second output terminal S2 of the output unit 210, and the second contact a2 of the first switch K1 is connected to the first output terminal S1 of the output unit 210. The second switch K2 is connected between the second output terminal S2 and the fourth output terminal S4 of the output unit 210.
[0046] By controlling the switching of the first switch K1 and the second switch K2, the power module can be controlled to output in either series or parallel mode. Specifically, when the common terminal a0 of the first switch K1 is connected to the first contact a1 and the second switch K2 is open, the two branches are connected in series, and the power module enters the series output mode; when the common terminal a0 of the first switch K1 is connected to the second contact a2 and the second switch K2 is closed, the two branches are connected in parallel, and the power module enters the parallel output mode.
[0047] In this embodiment, the anti-reverse unit 220 can be disposed between the first output terminal S1 and the third output terminal S3 of the output unit 210. The anti-reverse unit 220 is used to prevent the high voltage of the downstream load from being directly connected, causing damage to the electrolytic capacitor in the power module. The anti-reverse unit 220 may include a first diode D1 and a first resistor R1, wherein the cathode of the first diode D1 can be connected to the first output terminal S1 of the output unit 210 and the positive terminal of the load, the anode of the first diode D1 is connected to the second contact a2 of the first switch K1 and one end of the first resistor R1, and the other end of the first resistor R1 is connected to the fourth output terminal S4 of the output unit 210 and the negative terminal of the load.
[0048] It is understandable that if the anti-reverse unit 220 does not have a first resistor R1 (i.e., if...) Figure 1 As shown in the DC / DC output series-parallel topology, when a load is connected to the output side of the power module, the power module is not started, and the power module is currently outputting in series mode, the first diode D1 is in a floating state, and the voltage of the first diode D1 is 0V. If it is necessary to switch from series mode to parallel mode, at the instant of switching to parallel mode, the voltage at the output port of the power module (i.e., the voltage of the load) will be instantaneously applied across the first diode D1. If the load voltage is high voltage, the voltage across the first diode D1 will instantly increase from 0V to high voltage (e.g., 1000V). This will cause the first diode D1 to have a large voltage change rate when switching between series and parallel modes, making the first diode D1 susceptible to transient avalanche breakdown.
[0049] In addition, the contacts of the first switch K1 may experience some jitter when switching between series and parallel modes. Such jitter may cause the voltage across the first diode D1 to oscillate between 0V and high voltage, thereby further increasing the probability of transient avalanche breakdown of the first diode D1.
[0050] The present application embodiment effectively solves the above-mentioned problem by adding a first resistor R1 between the first diode D1 and the fourth output terminal S4 of the output unit 210. Specifically, in practical applications, the first diode D1 may have leakage current, which can be equivalent to a large resistor connected in parallel with the first diode D1. This resistor is denoted as the equivalent resistance Rt. The branch containing the equivalent resistance Rt forms a leakage current path. At this time, the equivalent resistance Rt and the first resistor R1 can divide the voltage. It should be noted that the first resistor R1 can be selected as a resistor with a small resistance value, and the resistance value of the first resistor R1 is much smaller than the resistance value of the equivalent resistance. However, the resistance value of the first resistor R1 cannot be too small. It only needs to meet the withstand voltage requirement and power derating requirement, and the voltage division should not exceed a certain range. The resistance value of the equivalent resistance is determined by the voltage of the external load and the leakage current.
[0051] Under normal circumstances, the leakage current of the first diode D1 is small. With a constant voltage, the equivalent resistance Rt of the first diode D1 is large, and much larger than the resistance of the first resistor R1. Therefore, the voltage drop across the equivalent resistance Rt is also much greater than the voltage drop across the first resistor R1. The voltage drop across the first resistor R1 can be approximated as 0V, and regardless of the output mode of the DC / DC output unit 200, the voltage drop across the first resistor R1 can remain approximately 0V. This prevents sudden voltage oscillations across the first diode D1, thus achieving safe and reliable series-parallel switching.
[0052] As an example, if the external load voltage is 1000V and the leakage current of the first diode D1 is 1mA, then the equivalent resistance Rt is equivalent to a 1MΩ resistor, and the resistance of the equivalent resistance Rt is much larger than that of the first resistor R1. When a load is connected to the output side of the power module, the power module is not started, and the power module is currently outputting in series mode, the equivalent resistance Rt is connected in series with the first resistor R1, and the voltage across them is 1000V. The equivalent resistance Rt and the first resistor R1 divide the voltage by 1000V. Because the resistance of the equivalent resistance Rt is much larger than that of the first resistor R1, the voltage drop across the first diode D1 is closer to 1000V. When the power module switches from series mode to parallel mode, since the electrolytic capacitor can be considered to be in a short-circuit state at the moment of switching, the voltage across the first diode D1 instantly becomes 1000V. However, because the voltage of the first diode D1 was close to 1000V before the switch, the rate of change of the voltage across the first diode D1 before and after the switch is small, thus achieving a safe and reliable mode switching. The principle for switching from parallel mode to series mode is the same, so it will not be repeated here.
[0053] Therefore, by using a single-pole double-throw first switch K1 and adding a first resistor R1, the first switch K1 and the first resistor R1 work together to effectively reduce the voltage change rate of the first diode D1 during series-parallel switching, prevent transient changes and oscillations in the voltage of the first diode D1 when the first switch K1 is activated, thereby reducing the risk of failure of the first diode D1 and improving the reliability of the power module.
[0054] Figure 3 This is the second schematic diagram of the power module in an embodiment of this application.
[0055] like Figure 3 As shown, in some embodiments, the anti-reverse unit 220 further includes a first capacitor C1, which is connected in parallel across the two ends of the first resistor R1.
[0056] Understandably, in practical applications, the first diode D1 usually has not only leakage current but also parasitic capacitance Ct. When the leakage current is very small, voltage division can be achieved through parasitic capacitance.
[0057] Therefore, in this embodiment, a first capacitor C1 can be connected in parallel across the two ends of the first resistor R1. When the leakage current of the first diode D1 is small, the first capacitor C1 and the parasitic capacitance of the first diode D1 are used to divide the voltage to prevent transient changes and oscillations in the voltage of the first diode D1 when the first switch K1 is activated.
[0058] Specifically, the parasitic capacitance of the first diode D1 is typically very small (usually in the picofarad range). Therefore, a capacitor with a capacitance larger than the parasitic capacitance can be selected as the first capacitor C1. For example, a nanofarad capacitor can be chosen as the first capacitor C1. Since a larger capacitance results in a smaller voltage drop, the voltage drop across the parasitic capacitance of the first diode D1 will be much greater than the voltage drop across the first capacitor C1.
[0059] When a load is connected to the output side of the power module, the power module is not started, and the power module is currently outputting in series mode, the parasitic capacitance is connected in series with the first capacitor C1, and the voltage across the parasitic capacitance and the first capacitor C1 is the output port voltage (i.e., the load voltage). Because the capacitance of the parasitic capacitance is much smaller than that of the first capacitor C1, the voltage drop across the first diode D1 is larger and closer to the output port voltage. When the power module switches from series mode to parallel mode, since the electrolytic capacitor can be considered to be in a short-circuit state at the moment of switching, the voltage across the first diode D1 instantly becomes the output port voltage. However, because the voltage of the first diode D1 before switching is close to the output port voltage, the rate of change of the voltage across the first diode D1 before and after switching is small, thus preventing the voltage across the first diode D1 from abruptly oscillating, achieving safe and reliable series-parallel switching. In addition, the first capacitor C1 also has a certain filtering effect.
[0060] Figure 4 This is the third schematic diagram of the power module in the embodiment of this application.
[0061] like Figure 4 As shown, in some embodiments, the anti-reverse unit 220 further includes a second diode D2, a second capacitor C2, and a second resistor R2. The anode of the second diode D2 is connected to the first output terminal S1, and the cathode of the second diode D2 is connected to the positive terminal of the load; the second capacitor C2 and the second resistor R2 are connected in series and then in parallel across the two ends of the second diode D2.
[0062] In this embodiment, the anti-reverse unit 220 may further include a second diode D2, which, like the first diode D1, serves the same anti-reverse function. Furthermore, the second capacitor C2 and the second resistor R2 can form an RC absorption circuit to absorb the high-voltage spikes applied to the second diode D2, thereby protecting the second diode D2 and preventing it from breaking down.
[0063] Understandably, since the capacitance of the electrolytic capacitor in the power module is much larger than the capacitance of the parasitic capacitance of the second diode D2, the capacitive reactance of the parasitic capacitance is greater than that of the electrolytic capacitor. Furthermore, since the second diode D2 and the electrolytic capacitor are connected in series, the voltage drop across the second diode D2 will be significantly greater when the contactor between the load and the power module closes. This results in a very high reverse voltage spike across the second diode D2, which can cause it to fail and subsequently damage the electrolytic capacitor. Therefore, in this embodiment, an RC snubber circuit is connected in parallel with the second diode D2 to reduce the probability of its failure.
[0064] Figure 5 This is the fourth schematic diagram of the power module in the embodiment of this application.
[0065] like Figure 5 As shown, in some embodiments, the output unit 210 further includes a third capacitor C3 and a fourth capacitor C4. One end of the third capacitor C3 serves as the first output terminal S1 of the output unit 210, and the other end of the third capacitor C3 serves as the second output terminal S2 of the output unit 210; one end of the fourth capacitor C4 serves as the third output terminal S3 of the output unit 210, and the other end of the third capacitor C3 serves as the fourth output terminal S4 of the output unit 210.
[0066] It should be noted that both the third capacitor C3 and the fourth capacitor C4 can be electrolytic capacitors.
[0067] In this embodiment, the third capacitor C3 and the fourth capacitor C4 are two electrolytic capacitors on the output bus of the DC / DC output unit 200. As mentioned in the previous embodiment, the DC / DC output unit 200 may include two branches, both of which are used to implement DC-DC conversion. The third capacitor C3 and the fourth capacitor C4 can not only store the DC output from these two branches respectively, but also perform smoothing and filtering processing on the DC output.
[0068] Specifically, when alternating current passes through the rectifier bridge of the DC / DC output unit 200, although it has been converted into direct current, this direct current is not completely smooth but exhibits certain fluctuations. This is because the rectification process only flips the negative half-cycle of the alternating current to the positive half-cycle, rather than completely converting it into a constant direct current. The third capacitor C3 and the fourth capacitor C4 serve to store charge here, charging during voltage peaks and discharging during voltage drops, thereby filling in the dips in the voltage waveform and making the output voltage smoother and more stable.
[0069] In this embodiment, the two ends of the third capacitor C3 can be used as the first output terminal S1 and the second output terminal S2 of the output unit 210, respectively, and the two ends of the fourth capacitor C4 can be used as the third output terminal S3 and the fourth output terminal S4 of the output unit 210, respectively.
[0070] Figure 6 This is the fifth schematic diagram of the power module in the embodiment of this application.
[0071] like Figure 6 As shown, in some embodiments, the DC / DC output unit 200 further includes an inverter unit 230, a resonant unit 240, and a rectifier unit 250. One end of the inverter unit 230 is connected to the AC conversion unit 100, the other end of the inverter unit 230 is connected to one end of the resonant unit 240, the other end of the resonant unit 240 is connected to the rectifier unit 250, and the other end of the rectifier unit 250 is connected to the output unit 210.
[0072] It should be noted that, for ease of demonstration, Figure 5 Only a portion of the power module's structure is shown.
[0073] In this embodiment, after the AC conversion unit 100 converts the AC power input from the power grid into DC power, the DC power is input to the DC / DC output unit 200. The inverter module in the DC / DC output unit 200 receives the converted DC power and then converts it back into high-frequency AC power. The inverter module can be composed of multiple switching transistors, and by controlling the alternating on and off of each transistor, the DC power is converted into high-frequency AC power. This achieves efficient power transmission and conversion, improves transformer efficiency, enables flexible power regulation, and reduces switching losses.
[0074] Furthermore, the resonant unit 240 can be composed of an inductor, a capacitor, and a transformer. The resonant unit 240 can utilize the resonant characteristics to achieve efficient energy transfer and provide electrical isolation and voltage regulation. Finally, the rectifier unit 250 can be composed of multiple rectifier diodes. The rectifier unit 250 is used to convert the high-frequency AC power transmitted through the resonant unit 240 and stepped down by the transformer into DC power to charge the load.
[0075] Continue to refer to Figure 6 In some embodiments, the inverter unit 230 includes a third switch Q1, a fourth switch Q2, a fifth switch Q3, a sixth switch Q4, a seventh switch Q5, an eighth switch Q6, a ninth switch Q7, and a tenth switch Q8.
[0076] Specifically, the third switch Q1 and the fourth switch Q2 are connected in series and then in parallel across the fifth capacitor C5; the fifth switch Q3 and the sixth switch Q4 are connected in series and then in parallel across the fifth capacitor C5; the seventh switch Q5 and the eighth switch Q6 are connected in series and then in parallel across the sixth capacitor C6; the ninth switch Q7 and the tenth switch Q8 are connected in series and then in parallel across the sixth capacitor C6; and the fifth capacitor C5 and the sixth capacitor C6 are connected in parallel.
[0077] It should be noted that the third switch Q1, the fourth switch Q2, the fifth switch Q3, the sixth switch Q4, the seventh switch Q5, the eighth switch Q6, the ninth switch Q7, and the tenth switch Q8 can be power electronic switches, such as MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors), IGBTs (Insulated-Gate Bipolar Transistors), etc. In this embodiment, the third switch Q1, the fourth switch Q2, the fifth switch Q3, the sixth switch Q4, the seventh switch Q5, the eighth switch Q6, the ninth switch Q7, and the tenth switch Q8 are N-MOS switches.
[0078] Specifically, taking N-MOS switches as an example, the third terminals of switches Q1, Q2, Q3, Q4, Q5, Q6, Q7, and Q8 are all connected to the controller of the charging system. The first terminal of switch Q1 is connected to one end of capacitor C5, the second terminal of switch Q1 is connected to the first terminal of switch Q2, and the second terminal of switch Q2 is connected to the other end of capacitor C5. The first terminal of switch Q3 is connected to one end of capacitor C5, the second terminal of switch Q3 is connected to the first terminal of switch Q4, and the second terminal of switch Q4 is connected to the other end of capacitor C5.
[0079] The first terminal of the seventh switch Q5 is connected to one end of the sixth capacitor C6, the second terminal of the seventh switch Q5 is connected to the first terminal of the eighth switch Q6, and the second terminal of the eighth switch Q6 is connected to the other end of the sixth capacitor C6. The first terminal of the ninth switch Q7 is connected to one end of the sixth capacitor C6, the second terminal of the ninth switch Q7 is connected to the first terminal of the tenth switch Q8, and the second terminal of the tenth switch Q8 is connected to the other end of the sixth capacitor C6.
[0080] It should be noted that the third electrode of the third switch Q1, the fourth switch Q2, the fifth switch Q3, the sixth switch Q4, the seventh switch Q5, the eighth switch Q6, the ninth switch Q7, and the tenth switch Q8 is the gate electrode, and the first electrode can be either the source or the drain electrode, and the second electrode can also be either the source or the drain electrode.
[0081] Continue to refer to Figure 6 In some embodiments, the resonant unit 240 includes a seventh capacitor C7, an eighth capacitor C8, a first inductor L1, a second inductor L2, a first transformer T1, and a second transformer T2.
[0082] Among them, one end of the seventh capacitor C7 is connected between the third switch Q1 and the fourth switch Q2, and the other end of the seventh capacitor C7 is connected to one end of the first inductor L1. One end of the primary coil of the first transformer T1 is connected to the other end of the first inductor L1, and the other end of the primary coil of the first transformer T1 is connected between the fifth switch Q3 and the sixth switch Q4. One end of the eighth capacitor C8 is connected between the seventh switch Q5 and the eighth switch Q6, and the other end of the eighth capacitor C8 is connected to one end of the second inductor L2. One end of the primary coil of the second transformer T2 is connected to the other end of the second inductor L2, and the other end of the primary coil of the second transformer T2 is connected between the ninth switch Q7 and the tenth switch Q8.
[0083] In this embodiment, the seventh capacitor C7 and the first inductor L1, and the eighth capacitor C8 and the second inductor L2, respectively form two resonant circuits, determining the operating frequency of the resonant unit 240. By selecting appropriate capacitor values, the resonant frequency can be adjusted to match the required switching frequency range. Furthermore, the seventh capacitor C7 and the eighth capacitor C8 help stabilize the output voltage, reduce voltage fluctuations, and have a certain filtering effect. The first inductor L1 and the second inductor L2 can store energy and release it when needed, and also help control current peaks, protecting other components in the circuit from overcurrent damage.
[0084] The main function of the first transformer T1 and the second transformer T2 is to raise or lower the voltage to the required voltage. In addition, the first transformer T1 and the second transformer T2 can also provide necessary electrical isolation to ensure the safety of the high-voltage side and the low-voltage side.
[0085] Continue to refer to Figure 6 In some embodiments, the rectifier unit 250 includes a third diode D3, a fourth diode D4, a fifth diode D5, a sixth diode D6, a seventh diode D7, an eighth diode D8, a ninth diode D9, and a tenth diode D10.
[0086] In this configuration, the anode of the third diode D3 is connected to the cathode of the fourth diode D4 to form the first node N1, the anode of the fifth diode D5 is connected to the cathode of the sixth diode D6 to form the second node N2, the cathode of the third diode D3 is connected to the cathode of the fifth diode D5 and then connected to one end of the third capacitor C3, and the anode of the fourth diode D4 is connected to the anode of the sixth diode D6 and then connected to the other end of the third capacitor C3.
[0087] The anode of the seventh diode D7 is connected to the cathode of the eighth diode D8 to form the third node N3. The anode of the ninth diode D9 is connected to the cathode of the tenth diode D10 to form the fourth node N4. The cathode of the seventh diode D7 is connected to the cathode of the ninth diode D9 and then connected to one end of the fourth capacitor C4. The anode of the eighth diode D8 is connected to the anode of the tenth diode D10 and then connected to the other end of the fourth capacitor C4.
[0088] The first secondary coil of the first transformer T1 is connected in series with the first secondary coil of the second transformer T2 and then connected to the first node N1 and the second node N2. The second secondary coil of the first transformer T1 is connected in series with the second secondary coil of the second transformer T2 and then connected to the third node N3 and the fourth node N4.
[0089] In this embodiment, the rectifier unit 250 includes two sets of rectifier bridges, each consisting of four rectifier diodes. A third capacitor C3 is connected in parallel to the two output terminals of the first set of rectifier bridges, and a fourth capacitor C4 is connected in parallel to the two output terminals of the second set of rectifier bridges. Specifically, the first set of rectifier bridges consists of a third diode D3, a fourth diode D4, a fifth diode D5, and a sixth diode D6. The anode of the third diode D3 is connected to the cathode of the fourth diode D4 to form a first node N1, and the anode of the fifth diode D5 is connected to the cathode of the sixth diode D6 to form a second node N2. In this embodiment, the first secondary winding of the first transformer T1 and the first secondary winding of the second transformer T2 are connected in series to the first node N1 and the second node N2. The cathode of the third diode D3 is connected to the cathode of the fifth diode D5 and then connected to one end of the third capacitor C3, and the anode of the fourth diode D4 is connected to the anode of the sixth diode D6 and then connected to the other end of the third capacitor C3.
[0090] Similarly, the second rectifier bridge consists of a seventh diode D7, an eighth diode D8, a ninth diode D9, and a tenth diode D10. The anode of the seventh diode D7 is connected to the cathode of the eighth diode D8 to form a third node N3, and the anode of the ninth diode D9 is connected to the cathode of the tenth diode D10 to form a fourth node N4. In this embodiment, the second secondary winding of the first transformer T1 and the second secondary winding of the second transformer T2 are connected in series to the third node N3 and the fourth node N4. The cathode of the seventh diode D7 is connected to the cathode of the ninth diode D9 and then connected to one end of the fourth capacitor C4, and the anode of the eighth diode D8 is connected to the anode of the tenth diode D10 and then connected to the other end of the fourth capacitor C4.
[0091] In some implementations, when the power module is in a shutdown state, the common terminal a0 of the first switch K1 and the first contact a1 are connected to form a circuit.
[0092] Understandably, in existing DC / DC output series-parallel topologies, because three single-pole single-throw switches are used, the first diode D1 is always connected. If the power module outputs in series mode, and the first diode D1 fails and short-circuits, high voltage from the external load will flow into the DC / DC output unit 200, causing damage to the fourth capacitor C4. Similarly, if the power module outputs in parallel mode, and the first diode D1 and the second diode D2 fail and short-circuit, high voltage from the external load will flow into the DC / DC output unit 200, causing damage to the third capacitor C3 and the fourth capacitor C4.
[0093] To further prevent the failure of the first diode D1 and the second diode D2, this embodiment of the application also proposes setting the power module to series mode when it is in a shutdown state, that is, the power module defaults to outputting in series mode when it is powered on. Specifically, before each shutdown of the power module, the common terminal a0 of the first switch K1 is connected to the first contact a1, and the second switch K2 is in the open state. With this setting, even if the first diode D1 fails, the fourth capacitor C4 will not be damaged.
[0094] When powering up the power module, if it is determined based on actual needs that the power module requires high-voltage output, and the power module operates in series mode during high-voltage operation, then the power module can be directly started to output. If it is determined based on actual needs that the power module requires low-voltage output, and the power module operates in parallel mode during low-voltage operation, then it is necessary to switch the states of the first switch K1 and the second switch K2 to switch the power module from series to parallel operation before starting the power module and outputting.
[0095] When shutting down the power module, if the power module is in series mode, it can be directly stopped. If the power module is in parallel mode, the states of the first switch K1 and the second switch K2 need to be switched to change the power module from parallel to series before stopping the power module.
[0096] Therefore, the power module in this embodiment not only employs a single-pole double-throw first switch K1, enabling it to disconnect parallel branches, but also utilizes the first switch K1 in conjunction with the first resistor R1 to ensure a low voltage change rate for the first diode D1 during series-parallel switching, thereby reducing the risk of diode D1 failure and effectively improving the reliability of the power module. Furthermore, by setting the power module to be in series mode when in shutdown state, the safety of the electrolytic capacitors in the power module is further guaranteed, further enhancing the reliability of the power module.
[0097] Based on the above embodiments, this application also provides a charging system. Figure 7 This is a schematic diagram of a charging system according to an embodiment of this application. Figure 7 As shown, the charging system may include at least two power modules 710 as described above, at least two charging interfaces 720, a controller 730, and a power distribution device 740.
[0098] The power module 710 is used to convert the AC power from the power grid into DC power and supply it to each charging interface 720; the controller 730 is used to obtain the power demand of each charging interface 720 and generate a scheduling command according to the topology in the power distribution device 740 and the power demand; the power distribution device 740 is used to control the opening or closing of the switch according to the scheduling command so as to distribute the output power of each power module 710 to each charging interface 720.
[0099] In one optional implementation, the charging system provided in this application is an integrated DC charging pile, with the charging interface 720 used to connect the charging gun, which is then connected to the main unit of the charging system via a gun mount on the main body of the charging system.
[0100] In one optional implementation, the charging system provided in this application embodiment is a split-type DC charging pile. The charging system also includes multiple charging terminals. The charging interface 720 is used to connect the charging terminals. The charging terminals are set separately from the main body of the charging system. The charging terminals are equipped with a single charging gun or dual charging guns for outputting power to electric vehicles.
[0101] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.
[0102] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.
[0103] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions 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.
Claims
1. A power module, characterized in that, It includes an AC conversion unit and a DC / DC output unit, wherein the AC conversion unit is connected to the DC / DC output unit, and the DC / DC output unit includes an output unit and an anti-reverse unit; The output unit includes at least a first DC output branch, a second DC output branch, a first switch, and a second switch. The first DC output branch includes a first output terminal and a second output terminal. The second DC output branch includes a third output terminal and a fourth output terminal. The common terminal, the first contact, and the second contact of the first switch are respectively connected to the third output terminal, the second output terminal, and the first output terminal in sequence. The second switch is connected between the second output terminal and the fourth output terminal. The anti-reverse unit includes a first diode and a first resistor. The anode of the first diode is connected to the second contact of the first switch, and the cathode of the first diode is connected to the first output terminal and the positive terminal of the load. One end of the first resistor is connected to the anode of the first diode, and the other end of the first resistor is connected to the fourth output terminal and the negative terminal of the load.
2. The power module according to claim 1, characterized in that, The anti-reverse unit also includes a first capacitor, which is connected in parallel across the two ends of the first resistor.
3. The power module according to claim 1, characterized in that, The anti-reverse unit also includes a second diode, a second capacitor, and a second resistor; The anode of the second diode is connected to the first output terminal, and the cathode of the second diode is connected to the positive terminal of the load. The second capacitor and the second resistor are connected in series and then in parallel across the two ends of the second diode.
4. The power module according to claim 1, characterized in that, When the power module is in the off state, the common terminal of the first switch and the first contact are connected to form a circuit.
5. The power module according to any one of claims 1 to 4, characterized in that, The output unit also includes a third capacitor and a fourth capacitor; One end of the third capacitor serves as the first output terminal of the output unit, and the other end of the third capacitor serves as the second output terminal of the output unit. One end of the fourth capacitor serves as the third output terminal of the output unit, and the other end of the third capacitor serves as the fourth output terminal of the output unit.
6. The power module according to claim 5, characterized in that, The DC / DC output unit also includes an inverter unit, a resonant unit, and a rectifier unit; One end of the inverter unit is connected to the AC conversion unit, the other end of the inverter unit is connected to one end of the resonant unit, the other end of the resonant unit is connected to the rectifier unit, and the other end of the rectifier unit is connected to the output unit.
7. The power module according to claim 6, characterized in that, The AC conversion unit includes a fifth capacitor and a sixth capacitor, and the inverter unit includes a third switch, a fourth switch, a fifth switch, a sixth switch, a seventh switch, an eighth switch, a ninth switch, and a tenth switch. The third switch and the fourth switch are connected in series and then in parallel across the two ends of the fifth capacitor; the fifth switch and the sixth switch are connected in series and then in parallel across the two ends of the fifth capacitor. The seventh switch and the eighth switch are connected in series and then in parallel across the six capacitors; the ninth switch and the tenth switch are connected in series and then in parallel across the six capacitors. The fifth capacitor is connected in parallel with the sixth capacitor.
8. The power module according to claim 7, characterized in that, The resonant unit includes a seventh capacitor, an eighth capacitor, a first inductor, a second inductor, a first transformer, and a second transformer; One end of the seventh capacitor is connected between the third switch and the fourth switch, and the other end of the seventh capacitor is connected to one end of the first inductor. One end of the primary winding of the first transformer is connected to the other end of the first inductor, and the other end of the primary winding of the first transformer is connected between the fifth switch and the sixth switch. One end of the eighth capacitor is connected between the seventh switch and the eighth switch, and the other end of the eighth capacitor is connected to one end of the second inductor. One end of the primary winding of the second transformer is connected to the other end of the second inductor, and the other end of the primary winding of the second transformer is connected between the ninth switch and the tenth switch.
9. The power module according to claim 8, characterized in that, The rectifier unit includes a third diode, a fourth diode, a fifth diode, a sixth diode, a seventh diode, an eighth diode, a ninth diode, and a tenth diode; The anode of the third diode is connected to the cathode of the fourth diode to form a first node, the anode of the fifth diode is connected to the cathode of the sixth diode to form a second node, the cathode of the third diode is connected to the cathode of the fifth diode and then connected to one end of the third capacitor, and the anode of the fourth diode is connected to the anode of the sixth diode and then connected to the other end of the third capacitor. The anode of the seventh diode is connected to the cathode of the eighth diode to form a third node, the anode of the ninth diode is connected to the cathode of the tenth diode to form a fourth node, the cathode of the seventh diode is connected to the cathode of the ninth diode and then connected to one end of the fourth capacitor, and the anode of the eighth diode is connected to the anode of the tenth diode and then connected to the other end of the fourth capacitor. The first secondary coil of the first transformer is connected in series with the first secondary coil of the second transformer and then connected to the first node and the second node. The second secondary coil of the first transformer is connected in series with the second secondary coil of the second transformer and then connected to the third node and the fourth node.
10. A charging system, characterized in that, It includes at least two power modules, a controller, a power distribution device, and at least one charging interface as described in any one of claims 1 to 9; The power distribution device is connected to the controller, each of the power modules and each of the charging interfaces, and the controller is connected to each of the power modules.