Power converter, control method and charging pile

Abstract

A power converter, a control method and a charging pile relate to the technical field of power electronics, and the power converter comprises a power conversion circuit, a first power switch, a first resistor and a controller. The first end of the power conversion circuit is connected with a power supply, and the second end is connected with a load and comprises a first port and a second port. The first resistor and the first power switch are connected in series and then are connected between the first port and the second port; the controller is configured to control the first power switch to be switched on under the condition that the working state of the power conversion circuit meets a preset condition, and the preset condition comprises that the difference value between the port voltage of the power conversion circuit and the first preset voltage is larger than a first preset value. Wherein the port voltage is the voltage between the first port and the second port of the second end of the power conversion circuit. By utilizing the scheme, the overshoot voltage can be reduced to protect the power conversion circuit when the load at the output end is reduced or unloaded on the premise of not changing the dynamic adjustment rate of the power converter.

Description

Technical Field

[0001] This application relates to the field of power electronics technology, specifically to a power converter, a control method, and a charging pile. Background Technology

[0002] LLC resonant circuits are typically used in cascade with inverter circuits. By dynamically adjusting the switching frequency of the power switching devices in the inverter circuit, the LLC resonant circuit can achieve a constant output voltage and reduce the switching losses of the power switching devices, thereby improving efficiency.

[0003] Charging piles are generally equipped with LLC resonant circuits. When the load is a power battery pack, the voltage of the power battery pack is relatively stable. Therefore, in order to ensure the reliable operation of the entire system, the dynamic adjustment rate of the switching frequency of the power switching devices in the inverter circuit is generally slow.

[0004] However, when the load connected to the output of the charging pile is unloaded, the output voltage may overshoot due to the slow dynamic adjustment rate of the switching frequency of the power switching devices in the inverter circuit, which can easily damage the charging pile. Summary of the Invention

[0005] In view of this, this application provides a power converter, a control method, and a charging pile, which can reduce overshoot voltage to protect the power conversion circuit when the load at the output terminal decreases or is unloaded.

[0006] In a first aspect, this application provides a power converter, which includes a power conversion circuit, a first power switch, a first resistor, and a controller. A first terminal of the power conversion circuit is connected to a power source, and a second terminal of the power conversion circuit is connected to a load. The second terminal of the power conversion circuit includes a first port and a second port. The first resistor and the first power switch are connected in series between the first port and the second port. The controller is configured to control the first power switch to conduct when the operating state of the power conversion circuit meets preset conditions. The preset conditions include: the difference between the port voltage of the power conversion circuit and a first preset voltage is greater than a first preset value. The port voltage is the voltage between the first port and the second port of the second terminal of the power conversion circuit.

[0007] The power converter provided in this application has a first power switch and a first resistor connected in series between the first and second ports of the power conversion circuit. When the output load of the power conversion circuit switches to a smaller load or when load unloading occurs, the port voltage of the power conversion circuit will rise. If the difference between the port voltage and a first preset voltage is greater than a first preset value, it indicates that a voltage overshoot has occurred. At this time, the controller controls the first power switch to turn on, connecting the first resistor to the circuit, so that the first resistor can quickly dissipate electrical energy to reduce the overshoot voltage. Using this scheme, the overshoot voltage can be reduced to protect the power conversion circuit when the output load decreases or is unloaded, without changing the dynamic adjustment rate of the power converter.

[0008] In one possible implementation, the controller is further configured to turn on the first power switch when the power conversion circuit stops operating. At this time, the first resistor acts as a bleeder resistor, discharging the energy stored in the output capacitor when the power conversion circuit stops operating, thereby reducing the residual voltage of the output capacitor. In this case, the first power switch and the first resistor can be referred to as a bleeder circuit. This application reuses the existing bleeder circuit on the power converter to suppress overshoot voltage during load switching or unloading, eliminating the need for additional hardware circuitry and improving practicality.

[0009] In one possible implementation, the preset condition further includes: the rate of decrease of the port current of the power conversion circuit is greater than a second preset value. Here, the port current is the current between the first port and the second port.

[0010] In this implementation, by detecting the rate of decrease of the port current and combining it with the changes in the port voltage, it is possible to accurately identify whether there is load unloading or switching to a smaller load, thereby improving the accuracy of control and reducing the probability of misjudgment.

[0011] In one possible implementation, the controller is further configured to, after turning on the first power switch, turn off the first power switch if the port voltage of the power conversion circuit is less than a second preset voltage.

[0012] In this implementation, the first power switch can be disconnected in a timely manner to avoid undershooting of the port voltage.

[0013] In one possible implementation, the controller is further configured to, after controlling the first power switch to turn on, control the first power switch to turn off if it is determined that the electrical energy consumed by the first resistor is greater than a preset electrical energy value. The electrical energy consumed by the first resistor is determined based on the port voltage of the power conversion circuit, the resistance value of the first resistor, and the on-time of the first power switch.

[0014] In this implementation, the first power switch can be disconnected in time to avoid damage to the first resistor.

[0015] In one possible implementation, the controller is further configured to, after turning on the first power switch, turn off the first power switch if it is determined that the power of the first resistor is greater than a preset power value. The power of the first resistor is determined based on the port voltage of the power conversion circuit, the resistance value of the first resistor, and the on-time of the first power switch.

[0016] In one possible implementation, the controller is further configured to turn on the first power switch when the power conversion circuit stops operating. In this implementation, the first resistor reuses an existing bleeder resistor, and the first power switch reuses the power switching device in the bleeder circuit, avoiding the need for additional hardware circuitry.

[0017] In this implementation, the first power switch can be disconnected in time to avoid damage to the first resistor.

[0018] Secondly, this application also provides a control method for a power converter, which can be applied to control the power converter provided by the first aspect and any implementation thereof. The method includes: controlling the first power switch of the power converter to be turned on when the operating state of the power conversion circuit of the power converter meets preset conditions; wherein the preset conditions include: the difference between the port voltage of the power conversion circuit and a first preset voltage is greater than a first preset value, and the port voltage is the voltage between the first port and the second port of the second end of the power conversion circuit.

[0019] Using this method, the overshoot voltage can be reduced to protect the power conversion circuit when the output load decreases or is unloaded, without changing the dynamic adjustment rate of the power converter.

[0020] In one possible implementation, the preset condition further includes: the rate of decrease of the port current of the power conversion circuit is greater than a second preset value. Here, the port current is the current between the first port and the second port.

[0021] In one possible implementation, the method further includes: after controlling the first power switch to be turned on, if the port voltage of the power conversion circuit is less than the second preset voltage, controlling the first power switch to be turned off.

[0022] In one possible implementation, the method further includes: after controlling the first power switch to turn on, if it is determined that the electrical energy consumed by the first resistor is greater than a preset electrical energy value, controlling the first power switch to turn off, wherein the electrical energy consumed by the first resistor is determined based on the port voltage of the power conversion circuit, the resistance value of the first resistor, and the on-time of the first power switch.

[0023] In one possible implementation, the method further includes: after controlling the first power switch to turn on, if it is determined that the power of the first resistor is greater than a preset power value, controlling the first power switch to turn off, wherein the power of the first resistor is determined based on the port voltage of the power conversion circuit, the resistance value of the first resistor, and the on-time of the first power switch.

[0024] Thirdly, this application also provides a charging pile, which includes the power converter provided by the first aspect and any implementation thereof.

[0025] Fourthly, this application also provides a computer storage medium for storing a computer program, which, when executed, implements the method described in the second aspect and any implementation thereof.

[0026] Fifthly, this application also provides a controller for executing the control method of the power converter provided in the second aspect and any implementation thereof. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of a charging station;

[0028] Figure 2 A schematic diagram of the power converter provided in the embodiments of this application. Figure 1 ;

[0029] Figure 3 A schematic diagram of the power converter provided in the embodiments of this application. Figure 2 ;

[0030] Figure 4 A graph showing the relationship between the withstand power and operating time of the first resistor provided in an embodiment of this application;

[0031] Figure 5 A flowchart of a control method for a power converter provided in an embodiment of this application;

[0032] Figure 6 A schematic diagram of a charging pile provided in an embodiment of this application;

[0033] Figure 7 This is a schematic diagram of a controller provided in an embodiment of this application. Detailed Implementation

[0034] To enable those skilled in the art to better understand the technical solution of this application, the application scenario of the technical solution of this application will be described first below.

[0035] See Figure 1 The image shows a schematic diagram of a charging station.

[0036] The vehicle 30 may include a power battery pack, and the input terminal of the charging pile 20 may be connected to the AC power grid 10 to convert the alternating current (AC) provided by the AC power grid 10 into direct current (DC) to charge the power battery pack.

[0037] The charging station 20 shown in the figure includes a power factor correction (PFC) circuit 21, an inverter circuit 22, an LLC resonant circuit 23, a transformer 24, a rectifier circuit 25, and a charging gun 26.

[0038] The input of the power factor correction circuit 21 is connected to the AC power grid 10. It is used to rectify the AC power into DC power and perform power factor correction. The output of the power factor correction circuit 21 is connected to the input of the inverter circuit 22. The inverter circuit 22 inverts the DC power into AC power, which is then transmitted to the primary winding of the transformer 24 via the LLC resonant circuit 23, so that the secondary winding of the transformer 24 generates AC power. The inverter circuit 22 can also be called a DC / AC converter circuit. The rectifier circuit 25 converts the AC power generated by the secondary winding of the transformer 24 into DC power, which is then used to charge the power battery pack of the vehicle 30 via the charging gun 26.

[0039] The LLC resonant circuit 23 specifically includes a resonant inductor Lr, a resonant capacitor Cr, and a magnetizing inductor Lm. The inverter circuit 22 includes power switching devices, such as insulated gate bipolar transistors (IGBTs), metal-oxide-semiconductor field-effect transistors (MOSFETs), silicon carbide metal-oxide-semiconductor (SiC MOSFETs), etc., which are not specifically limited in the embodiments of this application.

[0040] By using the LLC resonant circuit 23, soft switching of the power switching devices in the inverter circuit 22 can be achieved by dynamically adjusting the switching frequency of the power switching devices, thereby reducing the switching losses of the power switching devices and improving the efficiency of the power converter.

[0041] For charging pile 20, because the voltage of the connected power battery pack is relatively stable, the dynamic adjustment rate of the switching frequency of the power switching devices is generally slow to ensure the reliable operation of the entire system. However, when the load is unloaded at the output end of charging pile 20, the untimely adjustment of the switching frequency may cause overshoot in the output voltage, resulting in increased voltage stress on the components in the charging pile and making it easy to damage the charging pile.

[0042] To address the aforementioned technical problems, this application provides a power converter, a control method, and a charging pile. The power converter's power conversion circuit includes a first port and a second port at its second terminal. A first resistor and a first power switch are connected in series between the first and second ports. When the conversion circuit's operating state meets preset conditions, the first power switch is turned on, dissipating electrical energy through the first resistor to reduce overshoot voltage and protect the power converter. The preset conditions include: the difference between the port voltage of the power conversion circuit and a first preset voltage is greater than a first preset value; the port voltage is the voltage between the first and second ports of the power conversion circuit's second terminal. These preset conditions allow for the determination of reduced load or unloading at the output terminal, improving reliability.

[0043] The terms "first" and "second" used in this application description are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated.

[0044] In this application, unless otherwise expressly specified and limited, the term "connection" shall be interpreted broadly. For example, "connection" may be a fixed connection, a detachable connection, or an integral part; it may be a direct connection or an indirect connection through an intermediate medium.

[0045] See Figure 2 This figure is a schematic diagram of the power converter provided in an embodiment of this application. Figure 1 .

[0046] The power converter 40 may include: a power conversion circuit 41, a first power switch S1, a first resistor R1, and a controller 42.

[0047] The first terminal of the power conversion circuit 41 is connected to the power supply 50, and the second terminal of the power conversion circuit 41 is connected to the load.

[0048] In one possible implementation, the power conversion circuit 41 includes an LLC resonant circuit. Specifically, taking the power converter 40 applied in a charging station as an example, see below. Figure 1 The power conversion circuit 41 may include Figure 1The circuit includes a power factor correction circuit 21, an inverter circuit 22, an LLC resonant circuit 23, a transformer 24, and a rectifier circuit 25. At this time, the power conversion circuit 41 is an AC / DC conversion circuit. The first terminal of the power conversion circuit 41 is the AC terminal, and the connected power supply 50 can be an AC power source; the second terminal of the power conversion circuit 41 is the DC terminal, and the connected load can be a power battery pack.

[0049] The second terminal of the power conversion circuit 41 may include a first port P1 and a second port P2.

[0050] The power converter 40 can also be applied to other scenarios, which will not be described again in this embodiment.

[0051] Figure 2 The first resistor R1 and the first power switch S1 are connected in series between the first port P1 and the second port P2. The first switch S1 can be of the type IGBT, IGCT, MOSFET, SiC MOSFET, etc., and this embodiment does not specifically limit it.

[0052] The controller 42 is configured to turn on the first power switch when the operating state of the power conversion circuit 41 meets preset conditions. The preset conditions include: the difference between the port voltage Uosns of the power conversion circuit 41 and the first preset voltage Uoref1 is greater than a first preset value Uth.

[0053] Wherein, the port voltage Uosns is the voltage between the first port P1 and the second port P2 of the second terminal of the power conversion circuit 41.

[0054] The controller 42 in this embodiment can be an application-specific integrated circuit (ASIC), a programmable logic device (PLD), a digital signal processor (DSP), or a combination thereof. The PLD can be a complex programmable logic device (CPLD), a field-programmable gate array (FPGA), a generic array logic (GAL), or any combination thereof; this embodiment does not impose specific limitations.

[0055] The working principle of the power converter provided in this application is explained in detail below.

[0056] The first power switch S1 and the first resistor R1 form an energy consumption circuit.

[0057] The preset conditions include: the difference between the port voltage Uosns of the power conversion circuit 41 and the first preset voltage Uoref1 is greater than the first preset value Uth.

[0058] If the preset conditions are not met, the load on the surface remains stable. The load needs to be connected to a stable input voltage to maintain a stable working state. Therefore, the power converter 40 needs to keep the port voltage Uosns stable. At this time, the controller controls the first power switch S1 to open to avoid the first resistor R1 being connected to the circuit and generating additional losses.

[0059] Under preset conditions, this indicates a significant increase in port voltage Uosns, indicating voltage overshoot. Voltage overshoot occurs because when the load is unloaded or suddenly decreases, the dynamic adjustment rate of the switching frequency of the switching devices in the power conversion circuit 41 is slow, resulting in untimely port voltage adjustment. At this time, the controller 42 controls the first power switch S1 to turn on, connecting the first resistor R1 to the circuit. The first resistor R1 can withstand short-term voltage spikes, consuming electrical energy to dissipate the energy of the voltage spikes, thereby suppressing the voltage spike.

[0060] In summary, the solution provided by the embodiments of this application can reduce overshoot voltage to protect the power conversion circuit when the output load decreases or is unloaded, without changing the dynamic adjustment rate of the power converter.

[0061] The first power switch S1 and the first resistor R1 in this embodiment can reuse existing circuit components, which will be described in detail below with reference to the accompanying drawings.

[0062] See Figure 2 This figure is a schematic diagram of the power converter provided in an embodiment of this application. Figure 2 .

[0063] A DC-side capacitor Co is typically installed between the first port P1 and the second port P2 of the second terminal of the power conversion circuit 41. The DC-side capacitor Co smooths the port voltage, stabilizes the system, absorbs instantaneous current, prevents instantaneous voltage spikes, and stores electrical energy, which is released when needed to meet high power demands. To discharge the energy stored in the DC-side capacitor Co and reduce its voltage when the power converter 40 is turned off, a discharge circuit is typically connected in parallel with the DC-side capacitor Co.

[0064] The bleeder circuit may include a power switching device and a bleeder resistor connected in series. In the embodiments of this application, considering that the existing bleeder resistor can withstand short-term voltage spikes, and that the output voltage overshoot caused by load switching or unloading is also short-term, the first power switch S1 and the first resistor R1 in this embodiment can directly reuse the bleeder circuit. That is, the first resistor R1 reuses the existing bleeder resistor, and the first power switch S1 reuses the power switching device in the bleeder circuit, avoiding the need for additional hardware circuitry.

[0065] The first power switch S1 and the first resistor R1 can discharge the electrical energy of the DC-side capacitor Co. Specifically, the controller 42 is configured to turn on the first power switch S1 when the power conversion circuit 41 stops working, for example, when the charging pile stops charging the power battery pack. At this time, the first resistor R1 is used to consume the electrical energy stored on the DC-side capacitor Co of the power conversion circuit 41 to quickly reduce the voltage on the DC-side capacitor Co.

[0066] The controller 42 is also configured to control the first power switch to turn on when the operating state of the power conversion circuit 41 meets preset conditions.

[0067] In one possible implementation, the preset condition includes: the difference between the port voltage Uosns of the power conversion circuit 41 and the first preset voltage Uoref1 is greater than the first preset value Uth.

[0068] In this implementation, the power converter 40 also includes a voltage sampling circuit 43, which is used to sample the port voltage of the power converter 41 and send the result to the controller 42. The voltage sampling circuit 43 can be a voltage divider resistor network.

[0069] In another possible implementation, to improve control accuracy and avoid misjudgments of load switching or unloading, the preset condition further includes: the rate of decrease of the port current Iosns of the power conversion circuit 41 is greater than a second preset value. Here, the port current Iosns is the current between the first port P1 and the second port P2 of the second terminal of the power conversion circuit 41.

[0070] In this implementation, the controller controls the first power switch S1 to turn on when the difference between the port voltage Uosns of the power conversion circuit 41 and the first preset voltage Uoref1 is greater than the first preset value Uth, and the rate of decrease of the port current Iosns is greater than the second preset value.

[0071] Specifically, when the load is unloaded or switched to a smaller load, the output current of the power conversion circuit 41 drops rapidly, and the port voltage rises. Therefore, by detecting the rate of decrease of the port current Iosns (-dIosns / dt) and combining it with the change in the port voltage Uosns, it is possible to accurately identify whether the load has been unloaded or switched to a smaller load, thereby improving the accuracy of control and reducing the probability of misjudgment.

[0072] In this implementation, the power converter 40 includes a voltage sampling circuit 43 and a current sampling circuit 44. The current sampling circuit is used to send the sampling result of the port current of the power converter 41 to the controller 42.

[0073] The voltage sampling circuit 43 and the current sampling circuit 44 can also directly reuse existing detection circuits used for feedback control, fault identification and other functions.

[0074] After the controller 42 controls the first power switch S1 to turn on, it can also control the first power switch S1 to turn off in time to avoid damage to the first resistor R1 and to prevent the first resistor R1 from consuming too much energy.

[0075] The following describes in detail how the controller 42 determines when the first power switch S1 is disconnected.

[0076] In one possible implementation, the controller 42 can determine when the first power switch S1 is turned off based on the cumulative energy consumed by the first resistor R1.

[0077] See Figure 4 The figure shows the relationship between the withstand power and operating time of the first resistor provided in the embodiment of this application.

[0078] The first resistor R1 is a reused bleeder resistor. For high-power resistors like bleeder resistors, there is a corresponding... Figure 4 The graph shows the relationship between the withstand power and the operating time. This graph illustrates the change in the withstand power of the first resistor R1 with the operating time. The integral of the withstand power Pr with respect to the operating time t represents the maximum energy Wn that the first resistor R1 can withstand within the operating time t, as shown in the following equation (1):

[0079] .

[0080] Figure 4 The system shown represents the inherent properties of the first resistor, namely, the correspondence between the withstand power and time can be predetermined. Therefore, the maximum energy Wn that the first resistor R1 can withstand during the working time t can also be predetermined and saved, for example, in the form of data pairs (Wn1,t1), (Wn2,t2), ..., (Wnx,tx), which can be called when needed.

[0081] The controller 42 is further configured to, after controlling the first power switch to turn on, control the first power switch to turn off if it is determined that the electrical energy Wr consumed by the first resistor R1 is greater than a preset electrical energy Wth. The electrical energy Wr consumed by the first resistor R1 is determined based on the port voltage Uosns of the power conversion circuit, the resistance value of the first resistor R1, and the on-time t of the first power switch.

[0082] In this application embodiment, the preset electrical energy Wth is not specifically limited. In actual application, in order to ensure that the first resistor R1 is not damaged, the preset electrical energy Wth corresponding to the working time t is less than or equal to the maximum energy Wn that the first resistor R1 can withstand within the working time t.

[0083] In this embodiment, Wth equals Wn / 2 as an example. By derating the first resistor R1 by half to withstand energy usage, the reliable operation of the first resistor R1 is ensured.

[0084] At this time, the relationship between the electrical energy Wr consumed by the first resistor R1 during operation and the working time is shown in the following formula (2):

[0085] .

[0086] After determining Wr, the controller 42 compares Wr with the preset electrical energy Wth. If Wr is less than or equal to Wth, the first power switch S1 is kept on; if Wr is greater than Wth, the first power switch S1 is turned off to avoid damage to the first resistor.

[0087] The following are specific examples to illustrate this.

[0088] Taking the on-time of the first power switch as t1 as an example, the controller 42 can determine the maximum energy Wn1 corresponding to the current on-time t1 from multiple data pairs of maximum energy Wn and working time t based on the on-time t1 of the first power switch. Taking the preset energy Wth equal to Wn / 2 as an example, the preset energy Wth at this time is Wn1 / 2. Based on the above equation (2), the cumulative energy Wr1 consumed by the first resistor R1 within the on-time t1 can be determined, and the controller 42 compares Wr1 with Wth. If Wr1 is less than or equal to Wth, the first power switch S1 is kept on, and the above calculation method is used to determine the relationship between Wr1 and Wth again at the on-time t2. If Wr1 is greater than Wth, the first power switch S1 is controlled to be turned off. The embodiments of this application do not specifically limit the time interval between the two determinations of the relationship between Wr1 and Wth.

[0089] In another possible implementation, the controller 42 can determine when the first power switch S1 is turned off based on the power of the first resistor R1.

[0090] The controller 42 is also configured to, after controlling the first power switch S1 to turn on, control the first power switch S1 to turn off if it is determined that the power Pr of the first resistor R1 is greater than a preset power value Pth. The power Pr of the first resistor R1 is determined based on the port voltage Uosns of the power conversion circuit 41, the resistance value of the first resistor R1, and the on-time t of the first power switch S1.

[0091] The controller 42 can determine the power Pr of the first resistor R1 based on the following equation (3):

[0092] .

[0093] See also Figure 4 , Figure 4 The system shown represents the inherent properties of the first resistor, namely the correspondence between the withstand power Pn and the operating time t. This relationship can be predetermined and stored, for example, in the form of data pairs (Pn1,t1), (Pn2,t2), ..., (Pnx,tx), which can be retrieved when needed.

[0094] In this application embodiment, the preset power value Pth is not specifically limited. In actual application, in order to ensure that the first resistor R1 is not damaged, the preset power value Pth corresponding to the working time t is less than or equal to the withstand power Pn.

[0095] The following examples illustrate this point.

[0096] Taking the on-time of the first power switch S1 as t1 as an example, the controller 42 can determine the withstand power Pn1 corresponding to the on-time t1 from multiple data pairs of the correspondence between the withstand power Pn and the working time t. Taking the preset power value Pth as equal to half of the withstand power as an example, the first resistor R1 is derated by half of its withstand power to ensure that the first resistor R1 can operate reliably. Then the preset power value Pth = Pn1 / 2. Based on the above equation (3), the power Pr1 of the first resistor R1 when the on-time is t1 can be determined. The controller 42 compares Pr1 with Pth. If Pr1 is less than or equal to Pth, the first power switch S1 is kept on, and the above calculation method is used to determine the relationship between Pr1 and Pth when the on-time is t2. If Pr1 is greater than Pth, the first power switch S1 is controlled to be turned off. The embodiments of this application do not specifically limit the time interval between the two determinations of the relationship between Pr1 and Pth.

[0097] In another possible implementation, the controller 42 can determine the timing of the first power switch S1 being turned off based on the port voltage Uosns of the power conversion circuit 41.

[0098] The controller 42 is configured to, after controlling the first power switch S1 to turn on, control the first power switch S1 to turn off when the port voltage Uosns of the power conversion circuit 41 is less than the second preset voltage Uoref2.

[0099] In your application, the second preset voltage Uoref2 is not specifically limited.

[0100] In one possible implementation, the second preset voltage Uoref2 is greater than or equal to the first preset voltage Uoref1, for example, Uoref2 = Uoref1 + 3V.

[0101] When the port voltage Uosns of the power conversion circuit 41 is less than the second preset voltage Uoref2, it can be considered that the voltage overshoot of the port voltage Uosns is small and can be ignored. Continuing to keep the first power switch S1 on may cause the port voltage to undershoot. Therefore, the first power switch S1 can be turned off.

[0102] It is understandable that the above-mentioned multiple technical solutions for determining the timing of the disconnection of the first power switch S1 can be applied simultaneously. That is, when the controller 42 determines that the conditions of any of the above implementation methods are met, it can control the first power switch S1 to disconnect.

[0103] In summary, by utilizing the technical solution provided in this application embodiment, the overshoot voltage can be reduced to protect the power conversion circuit when the output load decreases or is unloaded, without changing the dynamic adjustment rate of the power converter. Furthermore, the first power switch S1 can be disconnected in a timely manner to avoid damage to the first resistor or to prevent undershoot at the port voltage.

[0104] Based on the power converter provided in the above embodiments, this application also provides a control method for the power converter, which will be described in detail below with reference to the accompanying drawings.

[0105] See Figure 5 The figure is a flowchart of the control method for the power converter provided in an embodiment of this application.

[0106] This method is applied to the power converter provided in any of the above embodiments, and will not be described in detail here. It includes the following steps:

[0107] S11: Determine whether the operating state of the power conversion circuit of the power converter meets the preset conditions.

[0108] If yes, execute S12; otherwise, execute S13.

[0109] In this embodiment, the first power switch and the first resistor of the power converter are connected in series between the first port and the second port of the second end of the power conversion circuit. The first end of the power conversion circuit is connected to the power supply, and the second end of the power conversion circuit is connected to the load. The second end of the power conversion circuit includes the first port and the second port.

[0110] The preset conditions include: the difference between the port voltage of the power conversion circuit and the first preset voltage is greater than the first preset value, and the port voltage is the voltage between the first port and the second port.

[0111] S12: Turns off the first power switch of the control power converter.

[0112] At this time, the load remains stable. The load needs to be connected to a stable input voltage to maintain a stable working state. Therefore, the first power switch S1 is turned off to avoid the first resistor being connected to the circuit and causing additional losses.

[0113] S13: Controls the first power switch of the power converter to turn on.

[0114] At this time, load unloading or a sudden decrease in load occurs, controlling the first power switch to turn on, connecting the first resistor to the circuit. The first resistor can withstand short-term voltage spikes. The first resistor consumes electrical energy to dissipate the energy of the voltage spike, thereby suppressing the voltage process.

[0115] In summary, the control method provided in this application embodiment can reduce overshoot voltage to protect the power conversion circuit when the output load decreases or is unloaded, without changing the dynamic adjustment rate of the power converter.

[0116] In one possible implementation, the preset condition in S11 further includes: the rate of decrease of the port current of the power conversion circuit is greater than a second preset value. Here, the port current is the current between the first port and the second port.

[0117] By adding a determination of the rate of decrease of port current, the accuracy of control can be improved, and misjudgments of load switching or unloading can be avoided.

[0118] In one possible implementation, after S13, the following S14 is also included:

[0119] If it is determined that the electrical energy consumed by the first resistor is greater than the preset electrical energy value, the first power switch is controlled to open.

[0120] The electrical energy consumed by the first resistor is determined based on the port voltage of the power conversion circuit, the resistance value of the first resistor, and the conduction time of the first power switch.

[0121] In this implementation, the first power switch can be disconnected in time to prevent the first resistor from being damaged due to excessive energy in a short period of time.

[0122] In another possible implementation, after S13, the following step S15 is also included: after controlling the first power switch to be turned on, if it is determined that the power of the first resistor is greater than the preset power value, the first power switch is controlled to be turned off.

[0123] The power of the first resistor is determined based on the port voltage of the power conversion circuit, the resistance value of the first resistor, and the conduction time of the first power switch.

[0124] In this implementation, the first power switch can be disconnected in time to prevent the first resistor from being damaged due to excessive power.

[0125] In another possible implementation, after S13, the following step S16 is also included: after controlling the first power switch to be turned on, if the port voltage of the power conversion circuit is less than the second preset voltage, the first power switch is controlled to be turned off.

[0126] In this implementation, the first power switch can be disconnected in time to avoid the port voltage downshoot of the power conversion circuit.

[0127] It is understood that the above steps S14-S16 for determining the timing of disconnection of the first power switch can be applied simultaneously. When any one of the above steps S14-S16 is satisfied, the first power switch can be controlled to disconnect.

[0128] Based on the power converter provided in the above embodiments, this application also provides a charging pile, which includes a power converter, as described in detail below with reference to the accompanying drawings.

[0129] See Figure 6 The figure is a schematic diagram of a charging pile provided in an embodiment of this application.

[0130] The charging pile 20 includes a power converter 40. For a detailed description of the power converter 40, please refer to the above embodiments and we will not repeat it here again.

[0131] See also Figure 1 The power converter 40 may include Figure 1 The power converter 40 includes an inverter circuit 22, an LLC resonant circuit 23, a transformer 24, and a rectifier circuit 25. The power converter 40 may further include a power factor correction circuit 21.

[0132] The charging station 20 may also include a charging gun 26 for connecting to the vehicle 30.

[0133] In one possible implementation, see Figure 7 The figure is a schematic diagram of a controller provided in an embodiment of this application.

[0134] The controller 42 may include a memory 1011 and a processor 1012. The processor 1012 may drive the first power switch S1 in the power converter 40.

[0135] The memory 1011 can be random access memory (RAM), flash memory, read-only memory (ROM), EPROM, non-volatile read-only memory (Electronic Programmable ROM), register, hard disk, removable disk, etc.

[0136] The memory 1011 can store computer instructions. When the computer instructions stored in the memory 1011 are executed by the processor 1012, the processor 1012 can be used to execute the control method of the power converter. The memory 1011 can also store data, such as information related to the first preset voltage, first preset value, second preset value, preset energy value, preset power value, and second preset voltage involved in the above embodiments.

[0137] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented in software, it can be implemented, in whole or in part, as a computer program product. A computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the flow or function according to the embodiments of this application is generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape) or a semiconductor medium (e.g., solid-state disk (SSD)).

[0138] This application also provides a readable storage medium for storing the methods provided in the above embodiments. Examples include random access memory (RAM), flash memory, read-only memory (ROM), EPROM, non-volatile read-only memory (EPROM), registers, hard disks, removable disks, or any other form of storage medium in the art.

[0139] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. Regarding the methods disclosed in the embodiments, since they correspond to the product embodiments disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to in the description of the product embodiments.

[0140] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A power converter, characterized in that, include: Power conversion circuit, first power switch, first resistor, controller; The first terminal of the power conversion circuit is connected to the power supply, and the second terminal of the power conversion circuit is connected to the load. The second terminal of the power conversion circuit includes a first port and a second port. The first resistor and the first power switch are connected in series between the first port and the second port; The controller is configured to control the first power switch to turn on when the operating state of the power conversion circuit meets preset conditions. The preset conditions include: the difference between the port voltage of the power conversion circuit and a first preset voltage is greater than a first preset value. The port voltage is the voltage between the first port and the second port of the second terminal of the power conversion circuit.

2. The power converter according to claim 1, characterized in that, The preset condition also includes: the rate of decrease of the port current of the power conversion circuit is greater than the second preset value; Wherein, the port current is the current between the first port and the second port.

3. The power converter according to claim 1 or 2, characterized in that, The controller is further configured to, after controlling the first power switch to be turned on, control the first power switch to be turned off when the port voltage of the power conversion circuit is less than a second preset voltage.

4. The power converter according to claim 3, characterized in that, The controller is further configured to, after controlling the first power switch to turn on, control the first power switch to turn off if it is determined that the electrical energy consumed by the first resistor is greater than a preset electrical energy value, wherein the electrical energy consumed by the first resistor is determined based on the port voltage of the power conversion circuit, the resistance value of the first resistor, and the on-time of the first power switch.

5. The power converter according to claim 3, characterized in that, The controller is further configured to, after controlling the first power switch to be turned on, control the first power switch to be turned off if it is determined that the power of the first resistor is greater than a preset power value, wherein the power of the first resistor is determined based on the port voltage of the power conversion circuit, the resistance value of the first resistor, and the on-time of the first power switch.

6. The power converter according to claim 1, characterized in that, The controller is also configured to control the first power switch to turn on when the power conversion circuit stops working.

7. The circuit according to claim 2, characterized in that, The power converter also includes a voltage sampling circuit and a current sampling circuit; The voltage sampling circuit is used to send the sampling results of the port voltage of the power conversion circuit to the controller; The current sampling circuit is used to send the sampling results of the port current of the power conversion circuit to the controller.

8. A control method for a power converter, characterized in that, include: When the operating state of the power conversion circuit of the power converter meets the preset conditions, the first power switch of the power converter is controlled to be turned on. The second end of the power conversion circuit includes a first port and a second port. The first power switch and the first resistor of the power converter are connected in series between the first port and the second port. The first end of the power conversion circuit is connected to the power supply, and the second end of the power conversion circuit is connected to the load. The preset conditions include: the difference between the port voltage of the power conversion circuit and the first preset voltage is greater than the first preset value, and the port voltage is the voltage between the first port and the second port of the second end of the power conversion circuit.

9. The control method according to claim 8, characterized in that, The preset condition also includes: the rate of decrease of the port current of the power conversion circuit is greater than the second preset value; Wherein, the port current is the current between the first port and the second port.

10. A charging pile, characterized in that, The charging pile includes the power converter according to any one of claims 1-7.

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