WO2021203735A1

WO2021203735A1 - Power converter, charger, and charging system and method

Info

Publication number: WO2021203735A1
Application number: PCT/CN2020/138250
Authority: WO
Inventors: 张维; 程洋; 崔兆雪
Original assignee: 华为技术有限公司
Priority date: 2020-04-07
Filing date: 2020-12-22
Publication date: 2021-10-14
Also published as: CN111555638A

Abstract

A power converter, charger (1000), and charging system and method. The power converter comprises: a power factor correction (PFC) circuit (200), a direct current bus capacitor (C), a power conversion circuit (600), and a controller (700). A first terminal of the PFC circuit (200) is used for connecting to an alternating current, a second terminal of the PFC circuit (200) is used for connecting to a first terminal of the power conversion circuit (600), and the direct current bus capacitor (C) forms a parallel connection with the second terminal of the PFC circuit (200); the power conversion circuit (600) is used for charging the direct current bus capacitor (C) under the control of the controller (700) after converting electrical energy supplied from a device (800); and the controller (700) is used for controlling, before the first terminal of the PFC circuit (200) is connected to the alternating current power, the power conversion circuit (600) to charge the direct current bus capacitor (C) after converting the electrical energy supplied from the device (800). The power converter does not need to additionally add a hardware device such as a pre-charging circuit, thus reducing the volume of the power converter and reducing the production costs of the power converter.

Description

Power converter, charger, charging system and method

This application claims the priority of a Chinese patent application filed with the State Intellectual Property Office of the People’s Republic of China, the application number is 202010267080.2, and the invention title is "a power converter, charger, charging system and method" on April 7, 2020. The entire content is incorporated into this application by reference.

Technical field

This application relates to the field of power electronics technology, and in particular to a power converter, charger, charging system and method.

Background technique

As shown in Figure 1, if the input of the power converter is alternating current and the output is direct current, it generally includes the previous-stage electromagnetic interference filter (EMC, Electro Magnetic Compatibility) circuit 100, power factor correction (PFC, Power Factor Correction) circuit 200, A DC bus capacitor C, a DC-DC (DC-DC) circuit 300. As shown in FIG. 2, if the input of the power converter is AC power and the output is AC power, the difference from FIG. 1 is that the final stage circuit is a DC-AC (DC-AC) circuit 400 instead of a DC-DC circuit 300.

For Figures 1 and 2, when the input end of the power converter is connected to AC power, the AC power is directly connected to the DC bus capacitor C. At this time, a large inrush current is generated and damages the components in each circuit. Therefore, in order to prevent The inrush current is too large, and the voltage of the DC bus capacitor needs to be controlled to increase slowly. When the voltage of the bus capacitor is increased, the normal power conversion is performed to ensure the safety of the devices in each circuit.

In order to solve the above problems, in the prior art, a pre-charging circuit 500 is added before the PFC circuit 200. See FIG. 3. When the input terminal of the power converter is connected to AC power, the control relay K is disconnected. At this time, the soft starting resistor R is The DC bus capacitor C is charged. When the voltage on C is charged to a certain value, the relay K is closed to start the power conversion.

However, the disadvantage of this technical solution is that a pre-charging circuit 500 needs to be added before the PFC circuit 200, which additionally increases the volume and cost of the power converter.

Summary of the invention

In order to solve the above technical existence, this application provides a power converter, charger, charging system and method, which can charge the DC bus capacitor before the AC power is turned on without increasing the volume and cost of the power converter.

In the first aspect, this application provides a power converter, including: a power factor correction PFC circuit, a DC bus capacitor, a power conversion circuit, and a controller; the first end of the PFC circuit is used to connect to alternating current, and the second end of the PFC circuit Used to connect the first end of the power conversion circuit, the DC bus capacitor is connected in parallel to the second end of the PFC circuit; the power conversion circuit is used to convert the DC power output by the PFC circuit and output it to the device under the control of the controller. Under the control of the controller, the power provided by the device is converted to charge the DC bus capacitor; the controller is used to control the power conversion circuit to convert the power provided by the device to the DC bus before the AC power is connected to the first end of the PFC circuit Capacitor charging; also used to control the first end of the PFC circuit to be connected to AC power when the voltage of the DC bus capacitor reaches the preset voltage, so that the power conversion circuit converts the DC power output by the PFC circuit and outputs it to the device.

The power converter does not add new hardware. The power converter includes a PFC circuit, a DC bus capacitor, a power conversion circuit and a controller. Before the AC power is connected to the PFC circuit, the controller controls the power conversion circuit to convert the electrical energy provided by the device to charge the DC bus capacitor. When the voltage of the DC bus capacitor reaches the preset voltage, it controls the first end of the PFC circuit to connect to the AC power. Pass. In this way, it is avoided that the AC power is directly connected to the DC bus capacitor C to generate a large inrush current and cause damage to the components in the PFC circuit. The power converter utilizes the existing hardware and is controlled by the controller to realize the pre-charging of the DC bus capacitor, without additional hardware equipment such as a pre-charging circuit, which reduces the volume of the power converter and reduces the production cost of the power converter .

Preferably, the power conversion circuit includes: a direct current-direct current DC-DC circuit; the first end of the DC-DC circuit is used to connect to the second end of the PFC circuit, and the second end of the DC-DC circuit is used to connect to the device.

Preferably, the DC-DC circuit includes a primary switch circuit, a transformer, and a secondary switch circuit; the device includes a battery; the first terminal of the primary switch circuit is used to connect to the second terminal of the PFC circuit; the second terminal of the primary switch circuit Used to connect the primary winding of the transformer; the secondary winding of the transformer is connected to the first end of the secondary switch circuit, and the second end of the secondary switch circuit is used to connect the battery; the controller is specifically used to control the power conversion circuit to provide the battery After the electric energy is converted, the DC bus capacitor is charged.

In this embodiment, the power conversion circuit of the power converter includes a primary side switch circuit, a transformer, and a secondary side switch circuit. When the DC bus capacitor is precharged, the device that provides DC power to the DC bus capacitor may be a battery. The controller controls the secondary-side switching circuit and the primary-side switching circuit, transforms the DC power provided by the battery through a transformer, and then charges the DC bus capacitor. After the voltage of the DC bus capacitor reaches the preset voltage, connect the power converter to the AC power, so as to avoid direct input of AC power to the DC bus capacitor, resulting in a large inrush current and damaging the internal components of the power converter . Further, after the power converter is connected to the AC power, the controller controls the primary side switch circuit and the secondary side switch circuit to convert the DC power output from the PFC circuit, and then charge the battery.

Preferably, the storage battery includes a high-voltage battery and a low-voltage battery; the controller is specifically used to control the power conversion circuit to convert the electric energy provided by the low-voltage battery or the high-voltage battery to charge the DC bus capacitor.

Preferably, the secondary side switch circuit includes: a secondary side high voltage switch circuit and a secondary side low voltage switch circuit; the secondary side winding of the transformer includes a first secondary side winding and a second secondary side winding; the first secondary side winding is connected to the secondary side high voltage switch circuit The first end of the secondary side high voltage switch circuit is used to connect the second end of the high voltage battery; the second secondary winding is connected to the first end of the secondary side low voltage switch circuit, and the second end of the secondary side low voltage switch circuit is used to connect the low voltage battery The controller is specifically used to control the secondary low-voltage switch circuit to provide the energy of the low-voltage battery to the second secondary winding of the transformer, so that the power conversion circuit converts the electric energy provided by the low-voltage battery to charge the DC bus capacitor.

The power converter can be applied to the charger of an electric vehicle. The DC-DC circuit of the power converter includes a primary side switch circuit, a transformer, a secondary side high voltage switch circuit, and a secondary side low voltage switch circuit. When pre-charging the DC bus capacitor, the DC bus capacitor is charged by the DC power provided by the low-voltage battery of the electric vehicle, so as to avoid direct input of AC power to the DC bus capacitor, resulting in a large inrush current and causing damage to the internal components of the power converter. damage. Since the voltage of the low-voltage battery is low, there is no danger of high-voltage electric shock. Therefore, the low-voltage battery can remain connected to the charger when it is not charging. When it is necessary to pre-charge the DC bus capacitor, it is convenient and quick to directly use the low-voltage battery to pre-charge the DC bus capacitor.

Preferably, the preset voltage is the peak voltage of alternating current.

When the DC bus capacitor is precharged, the voltage of the DC bus capacitor reaches the preset voltage, and then the power converter is connected to the AC power, for example, the preset voltage is the peak voltage of the AC power. Since the voltage of the DC bus capacitor has reached the peak voltage of the AC power, when the AC power is switched on, the power converter will not generate a large inrush current, thereby avoiding damage to the internal components of the power converter.

In the second aspect, this application provides a charger applied to electric vehicles, including: a power factor correction PFC circuit, a DC bus capacitor, a DC-DC circuit, and a charger controller; the first end of the PFC circuit is used to connect to AC Charging interface, the second end of the PFC circuit is used to connect to the first end of the DC-DC circuit, and the DC bus capacitor is connected in parallel to the second end of the PFC circuit; the DC-DC circuit is used to connect the PFC under the control of the charger controller The DC power output by the circuit is converted to charge the battery on the electric vehicle. It is also used to charge the DC bus capacitor after converting the electrical energy provided by the battery under the control of the charger controller; the charger controller is used in the PFC circuit Before the first terminal is connected to the AC power, the DC-DC circuit is controlled to convert the electric energy provided by the battery to charge the DC bus capacitor; it is also used to control the first terminal of the PFC circuit to connect to the AC power when the voltage of the DC bus capacitor reaches the preset voltage. The DC-DC circuit converts the direct current output from the PFC circuit to charge the battery.

The charger does not add new hardware. The charger includes a power factor correction PFC circuit, a DC bus capacitor, a DC-DC circuit and a charger controller. Before connecting the charger to the power supply interface, using the existing hardware, the charger controller controls the DC-DC circuit to charge the DC bus capacitor with the DC power provided by the battery. There is no need to add additional hardware devices such as pre-charging circuits. The volume of the charger is reduced and the production cost of the charger is reduced.

Preferably, the storage battery includes a low-voltage battery; and the charger controller is specifically used to control the DC-DC circuit to convert the electric energy provided by the low-voltage battery to charge the DC bus capacitor.

Preferably, the battery further includes: a high voltage battery; the DC-DC circuit includes a primary side switch circuit, a transformer, a secondary side high voltage switch circuit, and a secondary side low voltage switch circuit; the first end of the primary side switch circuit is connected to the second end of the PFC circuit; The second end of the primary switching circuit is connected to the primary winding of the transformer; the first secondary winding of the transformer is connected to the first end of the secondary high-voltage switching circuit, and the second end of the secondary high-voltage switching circuit is used to connect the high-voltage battery; The second secondary winding is connected to the first end of the secondary low-voltage switch circuit, and the second end of the secondary low-voltage switch circuit is used to connect the low-voltage battery; the controller is specifically used to control the secondary low-voltage switch circuit to provide the energy of the low-voltage battery to The second secondary winding of the transformer enables the DC-DC circuit to convert the electric energy provided by the low-voltage battery and charge the DC bus capacitor.

When the voltage of the DC bus capacitor reaches the preset voltage, the charger controller controls the primary switch circuit to input the DC power provided by the PFC circuit to the primary winding of the transformer, and then inputs it to the secondary low-voltage switch through the second secondary winding of the transformer T The first end of the circuit controls the secondary side low-voltage switch circuit to charge the low-voltage battery with the direct current output from the PFC circuit. The charger controller can also control the primary side switch circuit and the secondary side high voltage switch circuit to charge the high voltage battery.

In the third aspect, this application provides a charging system, including a charger and a power supply device; the power supply device is used to send charging start request information to the charger before providing electric energy to the charger; the charger includes energy storage and Filtered DC bus capacitor, the charger is used to send feedback information to the power supply device on the charging start request information when the voltage of the DC bus capacitor reaches the preset voltage; the power supply device is also used to charge the battery after receiving the feedback information The machine provides electricity.

Preferably, the charger is the charger of any one of the second aspect of the application.

When the charger is charging, the power supply device sends charging start request information to the charger controller; after the charger controller receives the charging start request information, the charger controller controls the DC-DC circuit to convert the electrical energy provided by the low-voltage battery to the The DC bus capacitor is charged; when the charger controller confirms that the voltage of the DC bus capacitor reaches the preset voltage, it sends feedback information to the power supply device; after the power supply device receives the feedback information, it controls the internal switch K1 and switch K2 to close, through the power supply interface Provide power to the charger. With this charging system, when the electric vehicle uses the charger to charge the electric vehicle, there is no need to add new hardware inside the electric vehicle charger. The existing hardware of the charger is used to realize the pre-charging of the DC bus capacitor through the control of the charger controller, without additional hardware equipment such as a pre-charging circuit, which reduces the size of the charger and reduces the production cost of the charger.

In a fourth aspect, the present application provides a pre-charging method, which is applied to a first device, the first device includes a power converter and a battery, the power converter includes a DC bus capacitor for energy storage and filtering, and the method includes: receiving The charging start request information sent by the power supply device; in response to the charging start request information, the electric energy provided by the battery is used to charge the DC bus capacitor; when the voltage of the DC bus capacitor reaches the preset voltage, the feedback of the charging start request information is sent to the power supply device Information, so that the power supply device provides power to the charger through the power supply interface.

The first device including the power converter and the storage battery is controlled by the above method, and there is no need to add new hardware inside the power converter. Before the power converter is connected to AC power, the existing hardware equipment inside the power converter can be used to complete the alignment. Pre-charging of DC bus capacitors. Therefore, there is no need to add additional hardware devices such as a pre-charging circuit, which reduces the volume of the power converter and reduces the production cost of the power converter. When the voltage of the DC bus capacitor reaches the preset voltage, the feedback information of the charging start request information is sent to the power supply device, and the power supply device provides power to the power converter through the power supply interface, thereby avoiding and avoiding the direct connection of AC power to the DC bus A large rush current is generated on the capacitor, causing damage to the components in the PFC circuit.

This application has at least the following advantages:

The power converter does not add new hardware. The power converter includes a PFC circuit, a DC bus capacitor, a power conversion circuit and a controller. Before the AC power is connected to the PFC circuit, the controller controls the power conversion circuit to convert the electrical energy provided by the device to charge the DC bus capacitor. When the voltage of the DC bus capacitor reaches the preset voltage, it controls the first end of the PFC circuit to connect to the AC power. Pass. Therefore, it is avoided that the AC power is directly connected to the DC bus capacitor C to generate a relatively large inrush current and cause damage to the components in the PFC circuit. In the technical solution of the present application, the existing hardware is used to realize the pre-charging of the DC bus capacitor through the control of the controller, without additional hardware equipment such as a pre-charging circuit, which reduces the volume of the power converter and reduces the power conversion. The production cost of the device.

Description of the drawings

Figure 1 is a schematic diagram of a power converter;

Figure 2 is a schematic diagram of another power converter;

Figure 3 is a schematic diagram of yet another power converter;

4 is a schematic diagram of a power converter provided by an embodiment of the application;

FIG. 5 is a schematic diagram of another power converter provided by an embodiment of the application;

FIG. 6 is a schematic diagram of still another power converter provided by an embodiment of the application;

FIG. 7 is a schematic diagram of yet another power converter provided by an embodiment of the application;

FIG. 8 is a schematic diagram of a charger provided by an embodiment of the application;

FIG. 9 is a schematic diagram of another charger provided by an embodiment of the application;

FIG. 10 is a schematic diagram of a DC-DC circuit provided by an embodiment of the application;

FIG. 11 is a schematic diagram of another DC-DC circuit provided by an embodiment of the application;

FIG. 12 is a schematic diagram of a charging system provided by an embodiment of the application;

FIG. 13 is a schematic diagram of another charging system provided by an embodiment of the application;

FIG. 14 is a flowchart of a precharging method provided by an embodiment of the application.

Detailed ways

The function of the power converter is to transform the power supply at the input end and provide the converted electric energy to the back-end equipment. However, the moment when the input end of the power converter is switched on, a large rush current will be generated, which will damage the internal components. The technical solution provided by the embodiments of the present application is to use subsequent equipment to charge the DC bus capacitor inside the power converter before the power converter is turned on, increase the voltage of the DC bus capacitor, and then turn on the power, thereby avoiding direct power-on The power supply generates inrush current and damages the internal components.

The embodiments of the application do not limit the application scenarios of the power converter. For example, it can provide power for servers in various scenarios, or power supply for base stations in network equipment, or provide power for backup power supplies in the above various scenarios, such as uninterruptible power supplies. (UPS, Uninterrupted Power Supply).

In addition, the power converter can also be applied to the on-board charger of an electric vehicle to charge the battery on the electric vehicle.

In order to enable those skilled in the art to better understand the technical solutions provided by the embodiments of the present application, the technical solutions in the embodiments of the present application will be clearly described below in conjunction with the drawings in the embodiments of the present application.

Power converter embodiment one:

Refer to FIG. 4, which is a schematic diagram of a power converter according to an embodiment of the application.

The power converter includes: a power factor correction PFC circuit 200, a DC bus capacitor C, a power conversion circuit 600, and a controller 700.

Wherein, the first end of the PFC circuit 200 is used to connect to alternating current, the second end of the PFC circuit 200 is used to connect to the first end of the power conversion circuit 600, and the DC bus capacitor C is connected in parallel to the second end of the PFC circuit 200.

The function implemented by the PFC circuit 200 is to rectify the alternating current into direct current, and at the same time, it can also convert the direct current, for example, boost the direct current.

The power conversion circuit 600 is used to convert the DC power output by the PFC circuit 200 and output to the device 800 under the control of the controller, and is also used to charge the DC bus capacitor after converting the electrical energy provided by the device under the control of the controller.

The controller 700 is used for controlling the power conversion circuit 600 to convert the electrical energy provided by the device 800 to charge the DC bus capacitor C before the AC power is connected to the first end of the PFC circuit; also for charging the DC bus capacitor C when the voltage of the DC bus capacitor C reaches a preset value When the voltage is applied, the first end of the PFC circuit 200 is controlled to be connected to the alternating current, so that the power conversion circuit converts the direct current output from the PFC circuit and outputs it to the device.

In order to reduce the large current impact generated when the AC power source is connected, the preset voltage can be set according to the voltage of the AC power connected to the first end of the PFC circuit 200, and is generally set to the peak voltage of the AC power source, or higher than the peak voltage.

The AC power is connected to the input end of the power converter, and during normal operation, the electrical energy is transmitted to the device 800 through the PFC circuit 200 and the power conversion circuit 600. However, in this embodiment, it is introduced that when the input terminal of the power converter is not connected to AC power, the controller 700 controls the electrical energy from the device 800 to charge the DC bus capacitor C through the power conversion circuit 600.

The power converter provided in this embodiment does not add new hardware. When it is necessary to provide power to the device 800, the PFC circuit 200 is not directly connected to AC power. Instead, the controller 700 pre-controls the power conversion circuit 600 to convert the power provided by the device 800 to charge the DC bus capacitor C. The voltage of the DC bus capacitor C will increase. When the voltage of the DC bus capacitor C increases to a preset voltage, the controller 700 controls the first terminal of the PFC circuit 200 to be connected to AC power. Since the controller 700 controls the power conversion circuit 600 in advance to increase the voltage of the DC bus capacitor C to a preset voltage, it is avoided that the AC power is directly connected to the DC bus capacitor C to generate a large inrush current, which will affect the components in the PFC circuit 200 Cause damage. In the technical solution of this embodiment, using the existing hardware, the controller 700 precharges the DC bus capacitor C by controlling the power transmission direction of the power conversion circuit 600, without adding additional hardware devices such as a precharging circuit, which reduces The volume of the power converter reduces the production cost of the power converter.

In a possible implementation manner, when the voltage of the DC bus capacitor C rises to a preset voltage, the controller 700 controls the first terminal of the PFC circuit 200 to be connected to AC power, the PFC circuit 200 outputs DC power, and the controller 700 controls the power The conversion circuit 600 converts the direct current output from the PFC circuit 200 and outputs it to the device 800 to supply power to the device 800.

The power conversion circuit 600 has the characteristics of bidirectional power transfer. Under the control of the controller 700, the power conversion circuit 600 can transfer power from the device 800 side to the DC bus capacitor C side, and can also transfer power from the DC bus capacitor C side. Pass it to the device 800 side.

The process of the power conversion circuit 600 transferring electrical energy from the device 800 side to the DC bus capacitor C side may be: the controller 700 controls the power conversion circuit 600 to convert the electrical energy provided by the device 800 to charge the DC bus capacitor C.

Under the control of the controller 700, the power conversion circuit 600 transmits electrical energy from the device 800 side to the DC bus capacitor C side. The electrical energy provided by the device 800 may be direct current or alternating current.

The process of the power conversion circuit 600 transferring electric energy from the DC bus capacitor C side to the device 800 side may be: the controller 700 controls the power conversion circuit 600 to convert the electric energy output by the PFC circuit 200, and then outputs DC power to charge the device 800.

Under the control of the controller 700, the power conversion circuit 600 transmits electric energy from the DC bus capacitor C side to the device 800 side. The electric energy output by the power conversion circuit 600 may be direct current or alternating current. When the output of the power conversion circuit 600 is alternating current, the power conversion circuit 600 includes an inverter circuit in addition to a DC-DC DC-DC circuit.

In the power converter provided in the embodiment of the present application, before the input end of the power converter is connected to AC power, the controller 700 controls the power conversion circuit 600 to convert the DC power provided by the device 800 to charge the DC bus capacitor C. The AC power provided by the device 800 can also be converted to charge the DC bus capacitor C. After the voltage of the DC bus capacitor C reaches the preset voltage, the controller 700 controls the power conversion circuit 600 to convert the DC power input by the PFC circuit 200 and output DC power to charge the device 800, and can also convert the DC power input by the PFC circuit 200 Then output AC power to charge the device 800. The adaptable range of the power converter is further improved.

Power converter embodiment two:

For ease of understanding, the following briefly describes the application scenario of the power converter in this embodiment. The power converter can output direct current and supply power to devices that require direct current.

Refer to FIG. 5, which is a schematic diagram of another power converter provided by an embodiment of the application.

The power conversion circuit 600 of the power converter includes a DC-DC DC-DC circuit 610.

The controller 700 can control the DC-DC circuit 610 to convert the DC power provided by the device 800 to charge the DC bus capacitor C.

When the voltage of the DC bus capacitor C reaches the preset voltage, the controller 700 controls the first terminal of the PFC circuit 200 to be connected to AC power. Therefore, it is avoided that the AC power is directly connected to the DC bus capacitor C, which generates a relatively large inrush current and damages the components in the PFC circuit 200.

Refer to FIG. 6, which is a schematic diagram of still another power converter provided by an embodiment of the application.

The DC-DC circuit 610 of the power converter includes: a primary side switch circuit 611, a transformer T, and a secondary side switch circuit 612.

Among them, the device 800 includes: a battery 810.

The first end of the primary switch circuit 611 is connected to the second end of the PFC circuit 200.

The second end of the primary switch circuit 611 is connected to the primary winding of the transformer T.

The secondary winding of the transformer T is connected to the first terminal of the secondary switch circuit 612, and the second terminal of the secondary switch circuit 612 is used to charge the battery 810.

The controller 700 is used for controlling the power conversion circuit 600 to convert the electric energy provided by the storage battery 810 to charge the DC bus capacitor C.

The controller 700 of the power converter can control the primary side switch circuit 611 and the secondary side switch circuit 612 to convert the DC power provided by the battery 810 through the transformer T, and then charge the DC bus capacitor C.

In a possible implementation manner, when the DC bus capacitor C is precharged, the controller 700 controls the secondary switch circuit 612 to input the DC power provided by the battery 810 to the secondary winding, the secondary winding and the primary winding of the transformer T Through magnetic field coupling, electric energy is provided as the primary winding of T, and the primary winding of T is provided to the first end of the primary switching circuit 611, and the DC bus capacitor C is charged through the primary switching circuit 611.

After the voltage of the DC bus capacitor C reaches the preset voltage, the controller 700 controls the first terminal of the PFC circuit 200 to be connected to AC power. The controller 700 controls the primary side switch circuit 611 and the secondary side switch circuit 612 to charge the battery 810.

In this embodiment, the power conversion circuit 600 of the power converter includes a primary side switch circuit 611, a transformer T, and a secondary side switch circuit 612. When the DC bus capacitor C is precharged, the device 800 that provides DC power to the DC bus capacitor C may be the battery 810. The controller 700 controls the secondary side switch circuit 611 and the primary side switch circuit 612, converts the DC power provided by the battery 810 through the transformer T, and then charges the DC bus capacitor C. After the voltage of the DC bus capacitor C reaches the preset voltage, the power converter is connected to the AC power, so as to avoid direct input of AC power to the DC bus capacitor C, which will cause a large inrush current to the internal components of the power converter. Cause damage. Further, after the power converter is connected to AC power, the controller 700 controls the primary side switch circuit 611 and the secondary side switch circuit 612 to convert the DC power output from the PFC circuit 200 to charge the battery.

Power converter embodiment three:

For ease of understanding, the following briefly describes a scenario in which the power converter in this embodiment is applied to a charger of an electric vehicle as an example. The power converter can be located inside the charger.

Refer to FIG. 7, which is a schematic diagram of yet another power converter provided by an embodiment of the application.

In this embodiment, when applied to an electric vehicle, the battery 810 of the electric vehicle may include a high-voltage battery 810a and a low-voltage battery 810b.

The high-voltage battery 810a is used to provide electrical energy for the motor of the electric vehicle; the low-voltage battery 810b is used to provide electrical energy for the control system and auxiliary equipment of the electric vehicle.

The controller 700 of the power converter controls the power conversion circuit 600 to convert the electric energy provided by the high-voltage battery 810a or the low-voltage battery 810b to charge the DC bus capacitor C.

The DC-DC circuit 610 of the power converter includes a primary side switch circuit 611, a transformer T, a secondary side high voltage switch circuit 612a, and a secondary side low voltage switch circuit 612b.

The secondary winding of the transformer T includes a first secondary winding and a second secondary winding.

The first secondary winding is connected to the first terminal of the secondary high-voltage switch circuit 612a, and the second terminal of the secondary high-voltage switch circuit 612a is used to charge the high-voltage battery 810a.

The second secondary winding is connected to the first terminal of the secondary low-voltage switch circuit 612b, and the second terminal of the secondary low-voltage switch circuit 612b is used to charge the low-voltage battery 810b.

The controller 700 of the power converter controls the primary side switch circuit 611 and the secondary side high voltage switch circuit 612a, and converts the electric energy provided by the high voltage battery 810a to the DC bus capacitor C; or, the controller 700 of the power converter controls the primary side The switch circuit 611 and the secondary side low voltage switch circuit 612b convert the electric energy provided by the low voltage battery 810b to the DC bus capacitor C.

The battery 810 of an electric vehicle includes a high-voltage battery 810a and a low-voltage battery 810b; among them, the high-voltage battery 810a provides a higher voltage, which can provide driving power for the vehicle; the low-voltage battery 810b provides a lower voltage, which can provide the control system of the vehicle And auxiliary equipment to provide electricity. Compared with the high-voltage battery 810a, the low-voltage battery 810b provides lower voltage and higher safety. The low-voltage battery 810b may always be connected to the secondary-side low-voltage switch circuit 612b. If the high-voltage battery 810a is always connected to the secondary-side high-voltage switch circuit 612a, there is a risk of causing a safety accident. Therefore, when the high-voltage battery 810a is not charged, the connection between the high-voltage battery 810a and the secondary side high-voltage switch circuit 612a can be disconnected.

The following takes the use of the low-voltage battery 810b of the electric vehicle as the DC bus capacitor C for precharging as an example to introduce the technical solutions of the embodiments of the present application.

In a possible implementation manner, the power converter may be applied to a charger of an electric vehicle, and the DC bus capacitor C of the power converter inside the charger is precharged before the charger is connected to AC power. The controller 700 controls the secondary-side low-voltage switch circuit 612b to input the DC power provided by the low-voltage battery 810b to the second secondary winding of the transformer T, and supplies it to the first end of the primary switch circuit 611 through the primary winding of the transformer T. The controller 700 The control primary switch circuit 611 will charge the DC bus capacitor C.

After the voltage of the DC bus capacitor C reaches the preset voltage, the controller 700 controls the first terminal of the PFC circuit 200 to be connected to AC power.

After the PFC circuit 200 is connected to AC power, the controller 700 controls the primary switching circuit 611 to input the DC power provided by the PFC circuit 200 to the primary winding of the transformer T, and provides it to the secondary high voltage switching circuit 612a through the first secondary winding of the transformer T The first end of the secondary side high voltage switch circuit 612a is controlled to charge the DC power output by the PFC circuit 200 to the high voltage battery 810a.

After the PFC circuit 200 is connected to AC power, the controller 700 controls the primary switching circuit 611 to input the DC power provided by the PFC circuit 200 to the primary winding of the transformer T, and then to the secondary low-voltage switching circuit 612b through the second secondary winding of the transformer T The first end of the secondary side low-voltage switch circuit 612b is controlled to charge the low-voltage battery 810b with the direct current output from the PFC circuit 200.

In this embodiment, the charging of the high-voltage battery 810a and/or the low-voltage battery 810b of the electric vehicle is not limited, and can be determined according to the actual conditions of the high-voltage battery 810a and the low-voltage battery 810b.

In addition, when the DC bus capacitor C is precharged, the voltage of the DC bus capacitor C reaches the preset voltage, and then the power converter is connected to the AC power, for example, the preset voltage is the peak voltage of the AC power. Since the voltage of the DC bus capacitor C has reached the peak voltage of the AC power, no large inrush current will be generated when the power converter is switched on the AC power, thereby avoiding damage to the internal components of the power converter.

In this embodiment, the power converter can be applied to a charger of an electric vehicle. The DC-DC circuit 200 of the power converter includes a primary side switch circuit 611, a transformer T, a secondary side high voltage switch circuit 612a, and a secondary side low voltage switch circuit 612b. . When the DC bus capacitor C is pre-charged, the DC bus capacitor C is charged by the DC power provided by the low-voltage battery 810b of the electric vehicle, so as to avoid direct input of AC power to the DC bus capacitor C, resulting in a large inrush current, which is harmful to the power converter. The internal components are damaged. Since the voltage of the low-voltage battery 810b is low, there is no danger of high-voltage electric shock. Therefore, the low-voltage battery 810b can remain connected to the charger when it is not charging. When the DC bus capacitor C needs to be precharged, the low-voltage battery 810b is directly used to precharge the DC bus capacitor C, which is convenient and quick.

Charger embodiment one:

For ease of understanding, the following describes the scenario where the charger in this embodiment is applied to an electric vehicle as an example, and the charger may be a vehicle-mounted charger.

Refer to FIG. 8, which is a schematic diagram of a charger provided by an embodiment of the application.

The charger 1000 can be applied to an electric vehicle, and the electric vehicle includes a storage battery.

The charger 1000 includes a power factor correction PFC circuit 200, a DC bus capacitor C, a DC-DC circuit 610, and a charger controller 900.

The first end of the PFC circuit 200 is used to connect to an AC charging interface, the second end of the PFC circuit 200 is used to connect to the first end of the DC-DC circuit 610, and the DC bus capacitor C is connected in parallel to the second end of the PFC circuit 200.

The DC-DC circuit 610 is used to convert the DC power output by the PFC circuit 200 under the control of the charger controller 900 to charge the battery 810, and is also used to charge the battery 810 under the control of the charger controller 900 After the electric energy is converted, the DC bus capacitor C is charged.

The charger controller 900 is used to control the DC-DC circuit 610 to convert the electric energy provided by the battery 810 to charge the DC bus capacitor C before the AC power is connected to the first end of the PFC circuit 200. When the voltage of the DC bus capacitor C reaches the preset value When the voltage is set, the first end of the PFC circuit 200 is controlled to be connected to AC power, so that the DC-DC circuit converts the DC power output by the PFC circuit 200 and then charges the battery 810. The power supply equipment is located on the ground, and the charger is located on the electric vehicle, and the power supply equipment on the ground is used to charge the storage battery through the charger.

After the charger is connected to the power supply interface, the power supply device will send charging start request information to the charger controller 900. After the charger controller 900 receives the charging start request information, it needs to precharge the DC bus capacitor C inside the charger. In this embodiment, the process of precharging the DC bus capacitor C inside the charger is introduced. The charger controller 900 controls the DC-DC circuit to convert the electric energy provided by the battery 810 of the electric vehicle to charge the DC bus capacitor C.

When the voltage of the DC bus capacitor C reaches the preset voltage, the charger controller 900 sends feedback information on the charging start request information to the power supply device.

After the power supply device receives the feedback information on the charging start request information sent by the charger controller 900, it closes the switch between the power supply device and the power supply interface, so that the power supply device provides AC power to the charger through the power supply interface. Therefore, it is avoided that the AC power is directly connected to the DC bus capacitor C to generate a large inrush current and cause damage to the internal components of the charger.

In this embodiment, no new hardware is added to the charger. The charger includes a power factor correction PFC circuit 200, a DC bus capacitor C, a DC-DC circuit 610, and a charger controller 900. Before connecting the charger to the power supply interface, using the existing hardware, the charger controller 900 controls the DC-DC circuit 610 to charge the DC bus capacitor C provided by the storage battery 810 without additional pre-charging circuits, etc. The hardware equipment reduces the size of the charger and reduces the production cost of the charger.

After the power supply device connects the AC power to the charger through the power supply interface, the charger uses the electric energy provided by the power supply device to charge the battery 810 of the electric vehicle.

Charger embodiment two:

Refer to FIG. 9, which is a schematic diagram of another charger provided by an embodiment of the application.

The charger provided in this embodiment corresponds to the case where the storage battery 810 includes a high-voltage battery 810a and a low-voltage battery 810b.

The charger controller 700 is specifically configured to control the DC-DC circuit 610 to convert the electric energy provided by the high-voltage battery 810a or the low-voltage battery 810b to charge the DC bus capacitor C.

The DC-DC circuit of the charger includes a primary side switch circuit 611, a transformer T, a secondary side high voltage switch circuit 612a, and a secondary side low voltage switch circuit 612b.

Refer to FIG. 10, which is a schematic diagram of a DC-DC circuit provided by an application embodiment.

This figure provides an implementation of a secondary-side low-voltage switch circuit in a DC-DC circuit. The secondary-side low-voltage switch circuit 612b may include capacitors Cr2 and C2 and switch tubes S5, S6, S7, and S8.

Refer to FIG. 11, which is a schematic diagram of another DC-DC circuit provided in an application embodiment.

This figure provides another implementation of the secondary-side low-voltage switch circuit in the DC-DC circuit. The secondary-side low-voltage switch circuit 612b may include an inductor L1, capacitors C4 and C5, and switch tubes S9, S10, S11, S12, and S13. And S14.

The first secondary winding of the transformer T is connected to the first terminal of the secondary high-voltage switch circuit 612a, and the second terminal of the secondary high-voltage switch circuit 612a is used to charge the high-voltage battery 810a.

The second secondary winding of the transformer T is connected to the first terminal of the secondary low-voltage switch circuit 612b, and the second terminal of the secondary low-voltage switch circuit 612b is used to charge the low-voltage battery 810b.

The controller T is specifically used to control the secondary low-voltage switch circuit 612 to provide the energy of the low-voltage battery 810a to the second secondary winding of the transformer T, so that the DC-DC circuit 610 converts the electric energy provided by the low-voltage battery 810a to the DC bus The capacitor C is charged.

Since the voltage of the high-voltage battery 810a of the electric vehicle is relatively high, if the high-voltage battery 810a is always connected to the secondary side high-voltage switch circuit 612a, there will be a safety accident of high-voltage electric shock. Therefore, when the high-voltage battery 810a is not charged, try to disconnect the high-voltage battery 810a from the secondary side high-voltage switch circuit 612a.

In the embodiment of the present application, the low-voltage battery 810b of an electric vehicle is used as an example for precharging the DC bus capacitor C.

In a possible implementation manner, after the charger receives the charging start request information sent by the power supply device, the charger controller 900 controls the secondary low-voltage switch circuit 612b to input the DC power provided by the low-voltage battery 810b to the second secondary winding of the transformer T , The primary winding of the transformer T is provided to the first end of the primary switching circuit 611, and the charger controller 900 controls the primary switching circuit 611 to charge the DC bus capacitor C.

When the voltage of the DC bus capacitor C reaches the preset voltage, the charger controller 900 controls the primary side switch circuit 611 to input the DC power provided by the PFC circuit 200 to the primary winding of the transformer T, and input it through the second secondary winding of the transformer T To the first terminal of the secondary side low-voltage switch circuit 612b, the secondary side low-voltage switch circuit 612b is controlled to charge the low-voltage battery 810b with the direct current output from the PFC circuit 200.

The charger controller 900 can also control the primary side switch circuit 611 and the secondary side high voltage switch circuit 612a to charge the high voltage battery 810a.

When charging the high-voltage battery 810a and the low-voltage battery 810b of an electric vehicle, the charging process can be to charge the high-

voltage batteries

810a and 810b at the same time; it can also be the high-voltage battery 810a first, and then the low-voltage battery 810b; Charge the low-voltage battery 810b, and then charge the high-voltage battery 810a.

In addition, in the process of using the charger to charge the high-voltage battery 810a and/or the low-voltage battery 810b of the electric vehicle, a certain amount of electromagnetic interference may be generated, which reduces the charging quality. Therefore, in all the above embodiments, the EMC circuit 100 may also be included, that is, the first end of the PFC circuit 200 is connected to the EMC circuit 100 to reduce electromagnetic interference and improve the charging quality.

Examples of charging systems:

Based on the charger provided in the above embodiment, an embodiment of the present application also provides a charging system, which will be described in detail below with reference to the accompanying drawings.

Refer to FIG. 12, which is a schematic diagram of a charging system provided by an embodiment of the application.

The charging system includes: a charger 1000 and a power supply device 2000.

The power supply device 2000 is configured to send charging start request information to the charger controller 900 before providing electric energy to the charger 1000.

The charger controller 900 includes a DC bus capacitor C for energy storage and filtering, and the charger 1000 is used to send feedback information on the charging start request information to the power supply device 2000 when the voltage of the DC bus capacitor C reaches a preset voltage .

The power supply device 2000 is also used to provide electrical energy to the charger 1000 after receiving the feedback information.

The charger of the charging system may be any charger 1000 in the first embodiment of the charger or the second embodiment of the charger.

Refer to FIG. 13, which is a schematic diagram of another charging system provided by an embodiment of the application.

The following describes the working process in conjunction with the hardware diagram of FIG. 12 and the flowchart of FIG. 13.

The electric vehicle 4000 uses a charger to charge the high-voltage battery and/or the low-voltage battery, including the following steps:

Step 1: The power supply device sends charging start request information to the charger.

When the charger 1000 is plugged into the charging socket of the power supply interface 3000 through the charging plug, the power supply device 2000 detects that the charger 1000 is connected to the power supply interface 3000, and the power supply device 2000 will generate a connection confirmation signal (CC, Connection Confirm), and send the CC signal As the charging start request information, the power supply equipment 2000 sends the charging start request information to the charger 1000 through the communication between the power supply control device and the vehicle control device.

Step 2: The charger controller controls the DC-DC circuit to convert the electric energy provided by the low-voltage battery of the electric vehicle to charge the DC bus capacitor.

Through the communication between the power supply control device and the vehicle control device, after the charger 1000 receives the charging start request information sent by the power supply device 2000, the charger controller controls the DC-DC circuit to convert the electric energy provided by the low-voltage battery of the electric vehicle 4000 Charge the DC bus capacitor C after conversion. There is no need to add a new hardware circuit inside the charger 1000, and the DC bus capacitor C can be precharged through the charger controller, which reduces the size of the charger 1000 and reduces the production cost of the charger 1000.

Step 3: The charger controller judges whether the voltage of the DC bus capacitor reaches the preset voltage; if yes, execute step 4; if not, execute step 2.

The charger controller judges the voltage of the DC bus capacitor C. If the voltage of the DC bus capacitor C reaches the preset voltage, the charger 1000 generates a control pilot signal (CP, Control Pilot), and uses the CP signal as the start of charging The feedback information of the request information is sent to the power supply device 2000.

If the voltage of the DC bus capacitor C does not reach the preset voltage, the charger controller continues to control the DC-DC circuit to charge the DC bus capacitor C with energy provided by the low-voltage battery.

Step 4: The charger controller sends feedback information on the charging start request information to the power supply device.

Through the communication between the vehicle control device and the power supply control device, the charger controller sends feedback information on the charging start request information to the power supply equipment 2000.

Step 5: The power supply device receives the feedback information of the charging start request information, and controls the switch K1 and the switch K2 to close.

After the power supply device 2000 receives the feedback information, it indicates that the voltage of the DC bus capacitor C of the charger 1000 has reached the preset voltage, and then the switch K1 and the switch K2 are closed to start charging the charger. Therefore, it is avoided that the AC power is directly connected to the DC bus capacitor C to generate a large inrush current and cause damage to the internal components of the charger.

In this embodiment, when the charger 1000 needs to be charged, the power supply device 2000 sends charging start request information to the charger controller; after the charger controller receives the charging start request information, the charger controller controls the DC-DC circuit The electric energy provided by the low-voltage battery is converted to charge the DC bus capacitor C; when the charger controller confirms that the voltage of the DC bus capacitor C reaches the preset voltage, it sends feedback information to the power supply device 2000; after the power supply device 2000 receives the feedback information, it controls The internal switch K1 and the switch K2 are closed, and the charger 1000 is provided with electric energy through the power supply interface 3000. With this charging system, when the electric vehicle 4000 uses the charger 1000 to charge the electric vehicle 4000, there is no need to add new hardware inside the charger 1000 of the electric vehicle 4000. The existing hardware of the charger 1000 is used to pre-charge the DC bus capacitor C through the control of the charger controller, without additional hardware equipment such as a pre-charging circuit, which reduces the size of the charger 1000 and reduces the size of the charger 1000. Cost of production.

Method embodiment:

Refer to FIG. 14, which is a flowchart of a precharging method provided by an embodiment of the application.

The pre-charging method is applied to a first device. The first device includes a power converter and a storage battery. The power converter includes a DC bus capacitor for energy storage and filtering. The method includes:

Step 1401: Receive charging start request information sent by the power supply device.

Step 1402: In response to the charge start request message, use the electric energy provided by the battery to charge the DC bus capacitor.

Step 1403: When the voltage of the DC bus capacitor reaches the preset voltage, send feedback information on the charging start request information to the power supply device, so that the power supply device provides power to the charger through the power supply interface.

In this embodiment, the first device including the power converter and the storage battery is controlled by the above method, and there is no need to add new hardware inside the power converter. Before the power converter is connected to AC power, the existing internal power converter is used. The hardware device can complete the pre-charging of the DC bus capacitor. Therefore, there is no need to add additional hardware devices such as a pre-charging circuit, which reduces the volume of the power converter and reduces the production cost of the power converter. When the voltage of the DC bus capacitor reaches the preset voltage, the feedback information of the charging start request information is sent to the power supply device, and the power supply device provides power to the power converter through the power supply interface, thereby avoiding and avoiding the direct connection of AC power to the DC bus A large rush current is generated on the capacitor, causing damage to the components in the PFC circuit.

It should be understood that in this application, "at least one (item)" refers to one or more, and "multiple" refers to two or more. "And/or" is used to describe the association relationship of associated objects, indicating that there can be three types of relationships, for example, "A and/or B" can mean: only A, only B, and both A and B , Where A and B can be singular or plural. The character "/" generally indicates that the associated objects before and after are in an "or" relationship. "The following at least one item (a)" or similar expressions refers to any combination of these items, including any combination of a single item (a) or a plurality of items (a). For example, at least one of a, b, or c can mean: a, b, c, "a and b", "a and c", "b and c", or "a and b and c" ", where a, b, and c can be single or multiple.

The above are only preferred embodiments of the application, and do not limit the application in any form. Although this application has been disclosed as above in preferred embodiments, it is not intended to limit the application. Anyone familiar with the art, without departing from the scope of the technical solution of the present application, can use the methods and technical content disclosed above to make many possible changes and modifications to the technical solution of the present application, or be modified into equivalent changes. Examples. Therefore, any simple amendments, equivalent changes, and modifications made to the above embodiments based on the technical essence of the application without departing from the content of the technical solution of the application still fall within the protection scope of the technical solution of the application.

Claims

A power converter, characterized by comprising: a power factor correction PFC circuit, a DC bus capacitor, a power conversion circuit and a controller;

The first end of the PFC circuit is used to connect to alternating current, the second end of the PFC circuit is used to connect to the first end of the power conversion circuit, and the DC bus capacitor is connected in parallel to the second end of the PFC circuit;

The power conversion circuit is used to convert the direct current output from the PFC circuit and output it to a device under the control of the controller, and is also used to convert the electrical energy provided by the device under the control of the controller Then charge the DC bus capacitor;

The controller is configured to control the power conversion circuit to convert the electrical energy provided by the device to charge the DC bus capacitor before the AC power is connected to the first end of the PFC circuit; When the voltage of the bus capacitor reaches the preset voltage, the first terminal of the PFC circuit is controlled to be connected to the AC power, so that the power conversion circuit converts the DC power output by the PFC circuit and outputs it to the device.
The power converter according to claim 1, wherein the power conversion circuit comprises: a DC-DC DC-DC circuit;

The first end of the DC-DC circuit is used to connect to the second end of the PFC circuit, and the second end of the DC-DC circuit is used to connect to the device.
The power converter according to claim 2, wherein the DC-DC circuit includes a primary-side switching circuit, a transformer, and a secondary-side switching circuit;

The device includes a battery;

The first end of the primary switch circuit is used to connect to the second end of the PFC circuit;

The second end of the primary switch circuit is used to connect the primary winding of the transformer;

The secondary winding of the transformer is connected to the first end of the secondary switch circuit, and the second end of the secondary switch circuit is used to connect to the battery;

The controller is specifically configured to control the power conversion circuit to charge the DC bus capacitor after converting the electric energy provided by the battery.
The power converter according to claim 3, wherein the storage battery includes a high-voltage battery and a low-voltage battery;

The controller is specifically configured to control the power conversion circuit to convert the electric energy provided by the low-voltage battery or the high-voltage battery to charge the DC bus capacitor.
The power converter according to claim 4, wherein the secondary side switch circuit comprises: a secondary side high voltage switch circuit and a secondary side low voltage switch circuit; the secondary winding of the transformer comprises a first secondary winding and a first secondary winding. Two secondary windings;

The first secondary winding is connected to the first end of the secondary high-voltage switch circuit, and the second end of the secondary high-voltage switch circuit is used to connect the high-voltage battery;

The second secondary winding is connected to the first end of the secondary low-voltage switch circuit, and the second end of the secondary low-voltage switch circuit is used to connect the low-voltage battery;

The controller is specifically configured to control the secondary-side low-voltage switch circuit to provide the energy of the low-voltage battery to the second secondary winding of the transformer, so that the power conversion circuit can use the electric energy provided by the low-voltage battery After the conversion, the DC bus capacitor is charged.
The power converter according to any one of claims 1 to 5, wherein the preset voltage is a peak voltage of the alternating current.
A charger, characterized in that it is applied to electric vehicles, and includes: a power factor correction PFC circuit, a DC bus capacitor, a DC-DC circuit, and a charger controller;

The first end of the PFC circuit is used to connect to an AC charging interface, the second end of the PFC circuit is used to connect to the first end of the DC-DC circuit, and the DC bus capacitor is connected in parallel to the first end of the PFC circuit. Two ends

The DC-DC circuit is used to convert the direct current output from the PFC circuit to charge the battery on the electric vehicle under the control of the charger controller, and is also used to charge the battery on the electric vehicle under the control of the charger controller. Convert the electric energy provided by the battery under the control of, and then charge the DC bus capacitor;

The charger controller is used to control the DC-DC circuit to convert the electric energy provided by the battery to charge the DC bus capacitor before the AC power is connected to the first end of the PFC circuit; When the voltage of the DC bus capacitor reaches a preset voltage, the first terminal of the PFC circuit is controlled to be connected to the AC power, so that the DC-DC circuit converts the DC power output by the PFC circuit to the The battery is charged.
The charger according to claim 7, wherein the storage battery comprises a low-voltage battery;

The charger controller is specifically configured to control the DC-DC circuit to convert the electric energy provided by the low-voltage battery to charge the DC bus capacitor.
The charger according to claim 8, wherein the battery further comprises: a high voltage battery; the DC-DC circuit comprises a primary side switch circuit, a transformer, a secondary side high voltage switch circuit, and a secondary side low voltage switch circuit;

The first end of the primary switch circuit is connected to the second end of the PFC circuit;

The second end of the primary switch circuit is connected to the primary winding of the transformer;

The first secondary winding of the transformer is connected to the first end of the secondary high voltage switch circuit, and the second end of the secondary high voltage switch circuit is used to connect the high voltage battery;

The second secondary winding of the transformer is connected to the first end of the secondary low-voltage switch circuit, and the second end of the secondary low-voltage switch circuit is used to connect the low-voltage battery;

The controller is specifically configured to control the secondary-side low-voltage switch circuit to provide the energy of the low-voltage battery to the second secondary winding of the transformer, so that the DC-DC circuit provides the power from the low-voltage battery After the electric energy is converted, the DC bus capacitor is charged.
A charging system, characterized by comprising: a charger and power supply equipment;

The power supply device is configured to send charging start request information to the charger before providing electric energy to the charger;

The charger includes a DC bus capacitor for energy storage and filtering, and the charger is used to send a request to the power supply device to the power supply device when the voltage of the DC bus capacitor reaches a preset voltage. Feedback;

The power supply device is also used to provide electrical energy to the charger after receiving the feedback information.
The charging system according to claim 10, wherein the charger is the charger according to any one of claims 7-9.
A precharging method, characterized in that the method is applied to a first device, the first device includes a power converter and a storage battery, the power converter includes a DC bus capacitor for energy storage and filtering, and Methods include:

Receiving charging start request information sent by the power supply device;

In response to the charging start request information, use the electric energy provided by the battery to charge the DC bus capacitor;

When the voltage of the DC bus capacitor reaches a preset voltage, sending feedback information of the charging start request information to the power supply device, so that the power supply device provides electrical energy to the charger through the power supply interface.