阅读说明：本技术 功率调节方法、装置和充电设备 (Power regulation method and device and charging equipment ) 是由 范杨平 陈敬庚 王立 孙利辉 于 2019-10-24 设计创作，主要内容包括：本发明的实施例提供了一种功率调节方法、装置和充电设备,涉及开关电源技术领域。该功率调节装置包括功率变换器和阻尼补偿电路,阻尼补偿电路并联于功率变换器的输入端,阻尼补偿电路通过输入线缆与电源电连接；功率变换器用于获取其输入端的当前电压信号,并根据当前电压信号与预设功率限制曲线调节功率变换器的当前输入功率；其中,预设功率限制曲线根据阻尼补偿电路的阻尼参数、预设限制功率和零功率电压确定,阻尼参数根据输入线缆的线路参数确定。通过在功率变换器的输入端并联阻尼补偿电路,当功率变换器工作在长距离输入线缆低压大功率的情况下时,能够抑制功率变换器的输入震荡,以及增强充电设备的带载能力。(The embodiment of the invention provides a power adjusting method, a power adjusting device and charging equipment, and relates to the technical field of switching power supplies. The power regulating device comprises a power converter and a damping compensation circuit, wherein the damping compensation circuit is connected in parallel with the input end of the power converter, and is electrically connected with a power supply through an input cable; the power converter is used for acquiring a current voltage signal of an input end of the power converter and adjusting the current input power of the power converter according to the current voltage signal and a preset power limit curve; the preset power limiting curve is determined according to damping parameters of the damping compensation circuit, preset limiting power and zero-power voltage, and the damping parameters are determined according to line parameters of the input cable. By connecting the damping compensation circuit in parallel at the input end of the power converter, when the power converter works under the condition of low-voltage and high-power of a long-distance input cable, the input oscillation of the power converter can be restrained, and the loading capacity of the charging equipment can be enhanced.)

1. A power regulating device is characterized by comprising a power converter and a damping compensation circuit, wherein the damping compensation circuit is connected in parallel with the input end of the power converter, and is electrically connected with a power supply through an input cable;

the power converter is used for acquiring a current voltage signal of the input end and regulating the current input power of the power converter according to the current voltage signal and a preset power limit curve; the preset power limit curve is determined according to a damping parameter of the damping compensation circuit, preset limit power and zero power voltage, and the damping parameter is determined according to a line parameter of the input cable.

2. The power regulating device according to claim 1, wherein the damping compensation circuit includes a damping resistor and a damping capacitor, one end of the damping resistor is electrically connected to both the input terminal of the power converter and the input cable, the other end of the damping resistor is electrically connected to one end of the damping capacitor, and the other end of the damping capacitor is electrically connected to both the input terminal of the power converter and the input cable.

3. The power regulating device of claim 1, wherein the damping parameter is obtained by an ac model scan.

4. The power regulating device of claim 1, wherein the preset limit power comprises active power, preset demand power, load power, and input cable power.

5. The power conditioning device according to claim 4, wherein the maximum power value of the preset power limit curve is determined according to the safe output power, the effective power, the preset required power, the load power and the input cable power, and the minimum power value of the preset power limit curve is calculated according to the zero-power voltage; wherein the safe output power is determined according to a damping parameter of the damping compensation circuit.

6. The power regulating device of claim 1, wherein the line parameters comprise a value of an equivalent resistance and a value of an equivalent inductance of the input cable.

7. The power conditioning apparatus according to claim 1, wherein the power converter is configured to obtain a current power corresponding to the current voltage signal according to the current voltage signal and the preset power limit curve, and adjust the current input power of the power converter according to the current power.

8. A power regulation method applied to a power converter, wherein an input end of the power converter is connected in parallel with a damping compensation circuit, and the damping compensation circuit is electrically connected with a power supply through an input cable, the method comprising:

acquiring a current voltage signal of an input end of the power converter;

adjusting the current input power of the power converter according to the current voltage signal and a preset power limit curve; the preset power limit curve is determined according to a damping parameter of the damping compensation circuit, preset limit power and zero power voltage, and the damping parameter is determined according to a line parameter of the input cable.

9. The power regulation method of claim 8 wherein the step of regulating the input power to the power converter based on the present voltage signal and a preset power limit curve comprises:

obtaining the current power corresponding to the current voltage signal according to the current voltage signal and the preset power limit curve;

and adjusting the current input power of the power converter according to the current power.

10. A charging apparatus comprising a power conditioning device according to any one of claims 1 to 7.

Technical Field

The invention relates to the technical field of switching power supplies, in particular to a power adjusting method, a power adjusting device and charging equipment.

Background

An input filter of a current DC-DC (Direct current-Direct current) converter generates resonance due to excessive use of a ceramic capacitor, and thus, an unstable phenomenon occurs under the condition of low voltage and high power. Meanwhile, the input cable of the DC-DC converter has large impedance drop, which causes the voltage fluctuation of the input port of the DC-DC converter to be large, so that the on-load regulation rate of the DC-DC converter is poor and the output power cannot be regulated in a self-adaptive manner.

Disclosure of Invention

The invention aims to provide a power regulating method, a power regulating device and a charging device, which can solve the problems of poor on-load regulation rate and unstable voltage of the charging device.

Embodiments of the invention may be implemented as follows:

in a first aspect, an embodiment of the present invention provides a power conditioning apparatus, including a power converter and a damping compensation circuit, where the damping compensation circuit is connected in parallel to an input end of the power converter, and the damping compensation circuit is electrically connected to a power supply through an input cable;

the power converter is used for acquiring a current voltage signal of an input end and regulating the current input power of the power converter according to the current voltage signal and a preset power limit curve; the preset power limit curve is determined according to a damping parameter of the damping compensation circuit, preset limit power and zero power voltage, and the damping parameter is determined according to a line parameter of the input cable.

In a second aspect, an embodiment of the present invention provides a power regulating method applied to a power converter, where an input end of the power converter is connected in parallel with a damping compensation circuit, and the damping compensation circuit is electrically connected to a power supply through an input cable, where the method includes:

acquiring a current voltage signal of an input end of the power converter;

adjusting the current input power of the power converter according to the current voltage signal and a preset power limit curve; the preset power limit curve is determined according to a damping parameter of the damping compensation circuit, preset limit power and zero power voltage, and the damping parameter is determined according to a line parameter of the input cable.

In a third aspect, an embodiment of the present invention provides a charging apparatus, including the power conditioning device according to the foregoing embodiment.

The embodiment of the invention has the beneficial effects that the damping compensation circuit is connected in parallel at the input end of the power converter, so that when the power converter works under the condition of low voltage and high power of a long-distance input cable, the input oscillation of the power converter can be inhibited, and the loading capacity of the charging equipment is enhanced. Meanwhile, the power converter can self-adaptively adjust the current input power according to the stable safety condition by setting the preset power limit curve, so that the self-adaptive adjustment of the output power is realized. And the preset power limiting curve is determined according to the damping parameters of the damping compensation circuit, so that the input power of the power converter can be limited in a safe stable area, and the unstable factors are eliminated.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.

Fig. 1 is a block diagram of a charging device according to an embodiment of the present invention;

fig. 2 is a block diagram of a power conditioning device according to an embodiment of the present invention;

fig. 3 is a schematic diagram of an equivalent model of a power conditioning apparatus according to an embodiment of the present invention;

FIG. 4 is an equivalent diagram of an AC model according to an embodiment of the present invention;

fig. 5 is a flowchart illustrating a power adjustment method according to an embodiment of the present invention.

Icon: 100-a charging device; 110-a power regulating device; 111-a power converter; 112-a damping compensation circuit; 120-an input cable; 200-a power supply; 300-load.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.

In the description of the present invention, it should be noted that if the terms "upper", "lower", "inside", "outside", etc. indicate an orientation or a positional relationship based on that shown in the drawings or that the product of the present invention is used as it is, this is only for convenience of description and simplification of the description, and it does not indicate or imply that the device or the element referred to must have a specific orientation, be constructed in a specific orientation, and be operated, and thus should not be construed as limiting the present invention. Furthermore, the appearances of the terms "first," "second," and the like, if any, are used solely to distinguish one from another and are not to be construed as indicating or implying relative importance. It should be noted that the features of the embodiments of the present invention may be combined with each other without conflict.

Referring to fig. 1, which is a block diagram of an implementable structure of a charging apparatus 100 provided in the present embodiment, the charging apparatus 100 includes a power conditioning device 110, the power conditioning device 110 is electrically connected to a power source 200 through an input cable, and the power conditioning device 110 is electrically connected to a load 300. The power conditioning device 110 is configured to convert a source voltage provided by the power source 200 into an operating voltage, and provide the operating voltage to the load 300, so that the load 300 is charged.

Wherein, the power source 200 may be a charging pile; the load 300 may be an electric automobile, an electric bus, or the like; the source voltage may be a three-phase naturally rectified voltage.

Fig. 2 is a block diagram of an implementation of the power conditioning device 110 shown in fig. 1. The power conditioning device 110 includes a power converter 111 and a damping compensation circuit 112, the damping compensation circuit 112 is connected in parallel to an input end of the power converter 111, and the damping compensation circuit 112 is electrically connected to the power supply 200 through an input cable 120.

In this embodiment, the power converter 111 is configured to obtain a current voltage signal at an input end thereof, and adjust a current input power of the power converter 111 according to the current voltage signal and a preset power limit curve; the preset power limit curve is determined according to the damping parameter of the damping compensation circuit 112, the preset limit power and the zero power voltage, and the damping parameter is determined according to the line parameter of the input cable 120.

It can be understood that the power converter 111 is configured to obtain a current power corresponding to the current voltage signal according to the current voltage signal and a preset power limit curve, and adjust the input power of the power converter 111 according to the current power. In other words, the preset power limit curve includes a plurality of voltage values and a power value corresponding to each voltage value, that is, the plurality of voltage values and the power value corresponding to each voltage value constitute the preset power limit curve which is a continuity function curve. The plurality of voltage values are voltage values corresponding to different voltage signals at the input end of the power converter 111, and the power value corresponds to the input power corresponding to different voltage signals at the input end of the power converter 111.

Further, as shown in fig. 3, the damping compensation circuit 112 includes a damping resistor R_-dampAnd a damping capacitor C_-dampDamping resistance R_-dampOne end of and power changeThe input terminal of the converter 111 is electrically connected to the input cable 120, and the damping resistor R_-dampAnother terminal of (1) and a damping capacitor C_-dampIs electrically connected to the damping capacitor C_-dampAnd the other end of the same is electrically connected to both the input of the power converter 111 and the input cable 120. It can be understood that the damping resistor R_-dampIs electrically connected to the positive pole of the input terminal of the power converter 111, and the damping resistor R_-dampIs also electrically connected to the positive pole of the power supply 200 via the input cable 120, and a damping capacitor C_-dampIs electrically connected to the negative pole of the input terminal of the power converter 111, and a damping capacitor C_-dampAnd the other end of the same is also electrically connected to the negative pole of the power supply 200 via the input cable 120. Where r shown in fig. 3 is an equivalent resistance of the input cable 120, L is an equivalent inductance of the input cable 120, rc is an equivalent series resistance of an input capacitance of the power converter 111, C is an input capacitance of the power converter 111, and Rin is an equivalent ac small signal of the input resistance of the power converter 111.

In this embodiment, the damping parameter includes a damping resistance R_-dampResistance value and damping capacitance C_-dampThe line parameters of input cable 120 include the value of the equivalent resistance and the value of the equivalent inductance of input cable 120.

In this embodiment, the value of the equivalent resistance and the value of the equivalent inductance of the input cable 120 can be calculated according to the material, length, thickness, and area of the input cable 120. In another embodiment, the value of the equivalent inductance of the input cable 120 can also be estimated from empirical formulas, i.e. in terms of two wires 2 mH/km.

In the present embodiment, the damping resistor R_-dampResistance value and damping capacitance C_-dampThe capacitance value of (a) can be obtained by scanning an alternating current model. Referring to fig. 4, an equivalent schematic diagram of an ac model includes a first inductor L1, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a first capacitor C1, a second capacitor C2, and an ac source I1, one end of the first inductor L1 is grounded, the other end of the first inductor L1 is electrically connected to one end of the first resistor R1, the other end of the first resistor R1 is electrically connected to one end of the fourth resistor R4 and the first resistor R4One end of a capacitor C1 is electrically connected with the anode of the alternating current source I1, the other end of a fourth resistor R4 is electrically connected with one end of a second resistor R2 and one end of a second capacitor C2, the other end of a first capacitor C1 is electrically connected with one end of a third resistor R3, and the other end of the second resistor R2, the other end of the second capacitor C2, the other end of the third resistor R3 and the cathode of the alternating current source I1 are all grounded.

It is understood that the first inductor L1 is an equivalent inductor of the input cable 120, the first resistor R1 is an equivalent resistor of the input cable 120, and the fourth resistor R4 is a damping resistor R_-dampThe second capacitor C2 is a damping capacitor C_-dampThe first capacitor C1 is an input capacitor of the power converter 111, and the third resistor R3 is an equivalent series resistance of the input capacitor of the power converter 111.

In the present embodiment, the value of the ac model first inductance L1, the value of the first resistor R1, the value of the first capacitor C1, and the value of the third resistor R3 are set according to the known values of the equivalent inductance and the equivalent resistance of the input cable 120, the input capacitance of the power converter 111, and the equivalent series resistance of the input capacitance of the power converter 111. Due to damping capacitance C_-dampThe function of (C) is a dc blocking function, and in principle, the larger the capacitor is, the better the capacitor is, so that the second capacitor C2 can be 10Cin in general and can be adjusted according to practical limitations. Then, damping resistor R_-dampSetting the value range of the fourth resistor R4 as a variable, generating a group of scanning curves with frequency as abscissa and voltage as ordinate, and determining the value of the fourth resistor R4 corresponding to the curve with the minimum peak value in the plurality of scanning curves as the damping resistor R_-dampThe optimum value of (2). Of course, the damping resistor R can be further adjusted according to actual conditions_-dampThe value of (b) is, for example, the actual resistance, the inrush current, or the like.

The values of the input capacitance of the power converter 111 and the equivalent series resistance of the input capacitance of the power converter 111 are determined when the power converter 111 is manufactured, the value of the input capacitance of a single power converter 111 is generally 220uF, the value of the equivalent series resistance of a single power converter 111 is 0.5ohm, and in actual use, a form in which a plurality of power converters 111 are directly connected in parallel may be adopted. The alternating current source I1 may provide a current of 1A.

In this embodiment, the damping parameter of a single damping compensation circuit 112 may be determined first, and in actual use, a form in which a plurality of damping compensation circuits 112 are directly connected in parallel may be adopted to enhance performance, that is, in actual use, only the number of damping compensation circuits 112 needs to be determined.

In this embodiment, the safe output power of the damping compensation circuit 112 can be determined by checking the output impedance change of the damping compensation circuit 112 under the condition of different numbers of damping compensation circuits 112, and the preset power limit curve can be determined according to the safe output power, the preset limit power and the zero power voltage of the damping compensation circuit 112. Wherein, the output impedance of the damping compensation circuit 112 is a plurality of damping resistors R calculated after the parallel connection of different numbers of damping compensation circuits 112_-dampValue after parallel connection.

It can be understood that, determining the safe output power of the damping compensation circuit 112 may first obtain the critical input power by calculating according to the critical resistance value of the damping compensation circuit 112, and then derating the critical input power to obtain the safe output power. The critical input power can be multiplied by a coefficient of 0.7 to perform derating processing to obtain safe output power, the derating processing is performed on the critical input power to enable the power converter 111 to have enough reaction time to perform power regulation, the current input power of the power converter 111 is prevented from exceeding the maximum power of a safe stable area, the power converter 111 can always operate in the safe stable area, and the voltage oscillation condition cannot occur.

The critical resistance value of the damping compensation circuit 112 may be obtained according to the output impedance of the damping compensation circuit 112, the output impedance of the damping compensation circuit 112 is divided into dc, resonance and intermediate frequency damping, and the maximum value of the dc, resonance and intermediate frequency damping is determined as the critical resistance value of the damping compensation circuit 112. The dc, resonant and mid-frequency damping of the damping compensation circuit 112 can be calculated according to the following formulas:

wherein Z is_outlrcRepresenting the value of the output impedance, C, of an LRC filter consisting of damping compensation circuit 112, input cable 120 and the input capacitance of power converter 111_dampDamping capacitance C representing damping compensation circuit 112_-dampValue of (A), R_dampDamping resistor R representing damping compensation circuit 112_-dampL represents the value of the equivalent inductance of the input cable 120, r represents the value of the equivalent resistance of the input cable 120, and ω represents the frequency of the LRC filter. And because the input capacitance of the power converter 111 is small, it can be ignored when calculating the output impedance of the LRC filter.

When ω is equal to 0, the output impedance of the LRC filter is the dc damping of the damping compensation circuit 112, and the value of the output impedance of the LRC filter is the value of the equivalent resistance of the input cable 120. When ω is 0, it can be understood that the equivalent inductance of the input cable 120 is short-circuited, and the damping capacitance C of the damping compensation circuit 112 is short-circuited_-dampAnd (4) opening the circuit. When in useIn the meantime, the output impedance of the LRC filter is the resonance point damping of the damping compensation circuit 112, and the value of the output impedance of the LRC filter is calculated by the following expression:

when ω ═ infinity, the output impedance of the LRC filter is the intermediate frequency damping of the damping compensation circuit 112, and the value of the output impedance of the LRC filter is the damping resistance R of the damping compensation circuit 112_-dampThe value of (c). When ω ═ infinity, it can be understood as the damping capacitance C of the damping compensation circuit 112_-dampShort circuit and open circuit of the equivalent inductance of the input cable 120.

In the present embodiment, in the case of direct current, since both the voltage and the current at the input terminal of the power converter 111 are positive, the input resistance at the input terminal of the power converter 111 is a positive number. However, the equivalent ac impedance of the input resistance of the power converter 111 is negative. The negative equivalent ac impedance of the input resistor of the power converter 111 represents the opposite trend of the voltage and current at the input terminal of the power converter 111. When the output is performed in the constant power mode, the voltage at the input end of the power converter 111 increases, and the current at the input end of the power converter 111 decreases correspondingly; the voltage at the input of the power converter 111 decreases and the current at the input of the power converter 111 increases accordingly, which further increases the oscillation of the power converter 111 and makes the power converter 111 unstable. Since the output impedance of the LRC filter and the input resistance of the input terminal of the power converter 111 form a voltage dividing circuit, the source voltage provided by the power supply 200 and the voltage of the input terminal of the power converter 111 can be expressed by the following formula:

wherein, V_INRepresents the source voltage, V, provided by the power supply 200_INCRepresenting the voltage at the input of the power converter 111, Z_INPUTRepresenting the input resistance, Z, of the input of the power converter 111_outlrcRepresenting the output impedance of the LRC filter.

Since the equivalent AC impedance of the input resistance of the power converter 111 is negative, i.e. Z_INPUTThe alternating current of (2) is negative. If Z is_INPUT+Z_outlrcIf the value of (d) is greater than zero, the voltage at the input divided by the power converter 111 is negative, which represents no solution, i.e., divergence and convergence. Therefore Z_INPUT+Z_outlrcIs less than zero, which is understood to follow the negative impedance crossover stability criterion, and is also understood to mean that the absolute value of the ac current at the input resistance of the power converter 111 must not be less than the maximum value of the output impedance of the LRC filter. Therefore, the damping compensation circuit 112 is required to be added to reduce the peak value of the output impedance of the LRC filter, so that the power converter 111 operates in a stable, non-oscillating, safe stable region.

In this embodiment, the equivalent ac impedance of the input resistor of the power converter 111 may be calculated by performing laplace transform on the voltage of the output terminal of the power converter 111 and the voltage of the input terminal of the power converter 111, and may specifically be obtained according to the following formula:

wherein Q represents a quality factor, ξ represents a damping factor, V_ORepresenting the voltage at the output of the power converter 111.

In this embodiment, when the damping factor is 0, the calculated value is a critical stable calculated value of the equivalent ac impedance of the input resistor of the power converter 111, and may be specifically represented by the following formula:

in the present embodiment, the preset limit power includes an effective power, a preset required power, a load power, and an input cable power. It is understood that the effective power refers to the input power of the power converter with an input efficiency greater than 75%, i.e. the power transformer can provide more than 75% of the power supplied by the power source 200 to the load 300; the preset required power may be a required value of the power that the customer can supply to the power converter 111 when the charging apparatus 100 is produced; the load power may be the maximum acceptable power of the load 300; the cable power may be the power obtained by the power transformer at the maximum current input to cable 120.

In this embodiment, the preset power limit curve may be obtained according to the following specific working principle, first, a maximum power value that can be calibrated in the preset power limit curve is determined according to the safe output power, the effective power, the preset required power, the load power and the input cable power of the damping compensation circuit 112, that is, a power value corresponding to a minimum one of the safe output power, the effective power, the preset required power, the load power and the input cable power of the damping compensation circuit 112 is selected as the maximum power value that can be calibrated in the preset power limit curve, and since the safe input impedance of the power converter 111 is a fixed value, the corresponding maximum voltage value may be calculated according to the maximum power value that can be calibrated in the preset power limit curve. And then, taking the zero-power voltage as a minimum voltage value which can be calibrated in a preset power limit curve, and calculating according to the zero-power voltage to obtain a corresponding minimum power value. And finally, carrying out linear connection according to the minimum voltage value and the minimum power value which can be calibrated and the maximum voltage value and the maximum power value which can be calibrated to obtain a preset power limit curve. The zero power voltage may be set to 200V, and when the voltage value corresponding to the voltage signal at the input terminal of the power converter 111 is lower than the lowest voltage value (e.g. 200V) of the input voltage of the power converter 111, the power converter 111 stops operating.

Fig. 5 is a schematic flow chart of the power adjustment method according to the present embodiment. It should be noted that the power adjustment method in the embodiment of the present application is not limited by fig. 5 and the following specific sequence, and it should be understood that, in other embodiments, the sequence of some steps in the power adjustment method in the embodiment of the present application may be interchanged according to actual needs, or some steps in the power adjustment method may be omitted or deleted. It should be noted that the basic principle and the generated technical effect of the power adjusting method provided by the present embodiment are the same as those of the above embodiments, and for the sake of brief description, no part of the present embodiment is mentioned, and reference may be made to the corresponding contents in the above embodiments. The power regulation method can be applied to the power converter 111 described above, and the specific process shown in fig. 5 will be described in detail below.

Step S101, obtaining a current voltage signal of an input end of the power converter.

Step S102, adjusting the current input power of the power converter according to the current voltage signal and a preset power limit curve; the preset power limiting curve is determined according to damping parameters of the damping compensation circuit, preset limiting power and zero-power voltage, and the damping parameters are determined according to line parameters of the input cable.

In the present embodiment, the preset limit power includes an effective power, a preset required power, a load power, and an input cable power. The line parameters include the value of the equivalent resistance and the value of the equivalent inductance of the input cable 120.

In this embodiment, the power converter 111 is configured to obtain a current power corresponding to the current voltage signal according to the current voltage signal and a preset power limit curve, and adjust the input power of the power converter 111 according to the current power. It is understood that the preset power limit curve includes a plurality of voltage values and a power value corresponding to each voltage value, that is, the plurality of voltage values and the power value corresponding to each voltage value constitute the preset power limit curve. The plurality of voltage values are voltage values corresponding to different voltage signals at the input end of the power converter 111, and the power value corresponds to the input power corresponding to different voltage signals at the input end of the power converter 111.

In summary, the power adjusting method, the power adjusting device, and the charging device provided in the embodiments of the present invention include a power converter and a damping compensation circuit, where the damping compensation circuit is connected in parallel to an input end of the power converter, and the damping compensation circuit is electrically connected to a power supply through an input cable; the power converter is used for acquiring a current voltage signal of an input end of the power converter and adjusting the current input power of the power converter according to the current voltage signal and a preset power limit curve; the preset power limiting curve is determined according to damping parameters of the damping compensation circuit, preset limiting power and zero-power voltage, and the damping parameters are determined according to line parameters of the input cable. By connecting the damping compensation circuit in parallel at the input end of the power converter, when the power converter works under the condition of low-voltage and high-power of a long-distance input cable, the input oscillation of the power converter can be restrained, and the loading capacity of the charging equipment can be enhanced. Meanwhile, the power converter can self-adaptively adjust the current input power according to the stable safety condition by setting the preset power limit curve, so that the self-adaptive adjustment of the output power is realized. And the preset power limiting curve is determined according to the damping parameters of the damping compensation circuit, so that the input power of the power converter can be limited in a safe area, and the unstable factors are eliminated.

The above description is only for the specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.