Patent Application
20250192684
The present disclosure relates to the field of vehicle technologies, and particularly, to a charger control method and apparatus, a charger, and a vehicle.
A charger is an electronic device converting an alternating current into a direct current and is used as a charging device of an electric vehicle to supply power to a battery. A two-stage topological structure is usually used in existing chargers, where a pre-stage circuit is a power factor calibration circuit, and a post-stage circuit is an isolated DCDC circuit (that is, an LCC circuit (resonant circuit)), and an instantaneous power difference between an alternating-current side and a direct-current side is balanced through a bus capacitor between the two-stage circuits.
At present, in a working process of the charger, upper and lower bridge arms of bridge arms of the isolated DCDC circuit are turned on complementarily, to supply power to the battery of the vehicle. However, when a voltage on the alternating-current side of the charger is high but a voltage of the battery is low, an uncontrollable rectified current is generated, leading to existence of a risk in the charger.
To overcome problems existing in the related art, the present disclosure provides a charger control method and apparatus, a charger, and a vehicle.
According to a first aspect, the present disclosure provides a charger control method. The method is applicable to a charger, the charger is an on-board charger or a charging pile charger, the charger includes an LLC circuit, and the LLC circuit is connected to a battery. The method includes:
In an embodiment, the determining a target working mode of the LLC circuit according to a first voltage includes:
In an embodiment, the LLC circuit includes an inverter circuit, a resonant circuit, and a rectifier circuit that are connected to each other, where the inverter circuit includes a first-phase bridge arm and a second-phase bridge arm; and
In an embodiment, the charger further includes a bus capacitor, a first bus end of the first-phase bridge arm and a first bus end of the second-phase bridge arm are connected to a first end of the bus capacitor, and a second bus end of the first-phase bridge arm and a second bus end of the second-phase bridge arm are connected to a second end of the bus capacitor; and
In an embodiment, the controlling the LLC circuit to work according to the target working mode further includes:
In an embodiment, the charger further includes a power factor calibration circuit and the bus capacitor, where the power factor calibration circuit is connected to the LLC circuit through the bus capacitor; and
In an embodiment, the determining a steady-state target current on the alternating-current side includes:
According to a second aspect, the present disclosure provides a charger control apparatus. The charger control apparatus includes:
According to a third aspect, the present disclosure provides a charger. The charger includes a power factor calibration circuit, a bus capacitor, and an LLC circuit that are connected to each other. The charger further includes:
According to a fourth aspect, the present disclosure provides a vehicle, including a battery and the charger according to the third aspect of the present disclosure.
In the foregoing technical solutions, the target working mode of the LLC circuit may be determined according to the voltage of the battery, and the LLC circuit is further controlled to work according to the target working mode. The target working mode is a full-bridge mode or a half-bridge mode. Therefore, dynamic switching of the working mode of the LLC circuit can be achieved according to the voltage of the battery, avoiding generation of an uncontrollable rectified current, so that the charger works safely, stably, and reliably in various working conditions, and a control mode is simple and efficient.
Other features and advantages of the present disclosure will be described in detail in the following implementations.
The accompanying drawings are provided to further understand the present disclosure, and they constitute a part of the specification. The accompanying drawings, along with the implementations, are used to explain the present disclosure, and constitute no limitation on the present disclosure.
The following describes the implementations of the present disclosure in detail with reference to the accompanying drawings. It should be understood that the implementations described herein are merely used to describe and explain the present disclosure, but are not to limit the present disclosure.
The present disclosure provides a charger. The charger may be an on-board charger or a charging pile charger, and the charging pile charger and the on-board charger may adopt a same circuit topology structure (as shown in
The charger control apparatus 5 is connected to both the power factor calibration circuit 2 and the LLC circuit 3, and is configured to perform a charger control method applicable to the charger, to control the power factor calibration circuit 2 and the LLC circuit 3 to work, so as to charge the battery. The power factor calibration circuit 2 is configured to perform power factor calibration on an input signal of the power grid and output a current signal obtained through the power factor calibration; and the LLC circuit 3 is configured to perform direct current conversion on the current signal obtained through the power factor calibration, to obtain a direct current so as to charge the battery of a vehicle.
As shown in
A present voltage on an alternating-current side of the charger is ua, a present current on the alternating-current side of the charger is ia, and a voltage between two ends of the bus capacitor C1 is Ubus (that is, a second voltage).
As shown in
The inverter circuit 31 includes: a first-phase bridge arm formed by a fifth transistor T5 and a sixth transistor T6, and a second-phase bridge arm formed by a seventh transistor T7 and an eighth transistor T8, where a first bus end of the first-phase bridge arm and the second-phase bridge arm is connected to the end of the bus capacitor C1 and the third bus end, and a second bus end of the first-phase bridge arm and the second-phase bridge arm is connected to the another end of the bus capacitor C1 and the fourth bus end.
The resonant circuit 32 adopts an LLC resonant cavity, and includes a resonant inductor L2, a resonant capacitor C2, and a transformer M1. An end of the resonant inductor L2 is connected to a midpoint of the first-phase bridge arm, and another end is connected to a first input end on a primary side of the transformer M1, where the resonant inductor L2 may be magnetically integrated with the transformer M1 to participate in resonance in the resonant circuit. An end of the resonant capacitor C2 is connected to a midpoint of the second-phase bridge arm, and another end is connected to a second input end on the primary side of the transformer M1, where the resonant capacitor C2 may be a film capacitor or a ceramic capacitor, to prevent a direct-current offset of the transformer M1 and participate in resonance in the resonant circuit. The transformer M1 may be a tapped transformer and configured for electric energy isolation transmission.
The rectifier circuit 33 includes a fifth-phase bridge arm formed by a first diode D1 and a second diode D2, a sixth-phase bridge arm formed by a third diode D3 and a fourth diode D4, and a filter capacitor C3. A midpoint of the fifth-phase bridge arm is connected to a first input end on a secondary side of the transformer M1, and a midpoint of the sixth-phase bridge arm is connected to a second input end on the secondary side of the transformer M1. A fifth bus end of the fifth-phase bridge arm and the sixth-phase bridge arm is connected to an end of the filter capacitor C3 and the positive electrode of the battery 4, and a sixth bus end of the fifth-phase bridge arm and the sixth-phase bridge arm is connected to another end of the filter capacitor C3 and the negative electrode of the battery 4. The filter capacitor C3 is a capacitor on a battery side and is configured to filter a direct present voltage on the battery side.
In addition, it should be noted that, the rectifier circuit 33 may use a transistor device or a rectifier diode (as shown in
The following describes charger control method in detail. As shown in
S301: A target working mode of an LLC circuit is determined according to a first voltage of a battery.
In the present disclosure, the first voltage of the battery is a voltage between two ends of the battery and is a voltage on a direct-current side. The first voltage may be obtained through sampling by using a voltage sensor, or may be obtained in a vehicle packet communication manner.
The target working mode is a full-bridge mode or a half-bridge mode.
S302: The LLC circuit is controlled to work according to the target working mode.
In the foregoing technical solutions, the target working mode of the LLC circuit may be determined according to the voltage of the battery, and the LLC circuit is further controlled to work according to the target working mode. The target working mode is a full-bridge mode or a half-bridge mode. Therefore, dynamic switching of the working mode of the LLC circuit can be achieved according to the voltage of the battery, avoiding generation of an uncontrollable rectified current, so that the charger works safely, stably, and reliably in various working conditions, and a control mode is simple and efficient.
The following describes an implementation of determining the target working mode of the LLC circuit according to the first voltage of the battery in S301.
In an embodiment, if the first voltage is less than a first preset voltage, the target working mode is determined as the half-bridge mode; and if the first voltage is greater than or equal to the first preset voltage, the target working mode is determined as the full-bridge mode.
As can be known according to a circuit principle of the circuit topology shown in
Therefore, the first preset voltage may be set to √{square root over (2)}*UacMax/K. That is, when the first voltage of the battery is less than √{square root over (2)}*UacMax/K, the LLC circuit works in the half-bridge mode, implementing a characteristic of a half-bridge LLC; and when the first voltage of the battery is greater than or equal to √{square root over (2)}*UacMax/K, the LLC circuit works in the full-bridge mode, implementing a characteristic of a full-bridge LLC, where K is a turn ratio of the transformer in the resonant circuit (that is, a ratio of turns on the primary side to turns on the secondary side in the transformer).
When the first voltage of the battery changes from being greater than or equal to √{square root over (2)}*UacMax/K to being less than √{square root over (2)}*UacMax/K, the working mode of the LLC circuit is switched from the full-bridge mode to the half-bridge mode, that is, a characteristic of the LLC circuit changes. In this case, an input and output characteristic changes to a relationship of 2:1, that is, Ubus=2*K*Udc. In this way, when the working mode of the LLC circuit is switched from the full-bridge mode to the half-bridge mode, Ubus is far greater than √{square root over (2)}*UacMax, so that a risk of an uncontrollable rectified current in the charger when a voltage on the alternating-current side is high can be eliminated. Udc is the first voltage of the battery.
The following describes an implementation of controlling the LLC circuit to work according to the target working mode in S302.
In an embodiment, if the target working mode is the half-bridge mode, an upper bridge arm and a lower bridge arm of the first-phase bridge arm are controlled to be turned on complementarily through a first duty cycle, and an upper bridge arm of the second-phase bridge arm is controlled to be turned off and a lower bridge arm of the second-phase bridge arm is controlled to be turned on; and if the target working mode is the full-bridge mode, the upper bridge arm and the lower bridge arm of the first-phase bridge arm are controlled to be turned on complementarily through the first duty cycle, and the upper bridge arm and the lower bridge arm of the second-phase bridge arm are controlled to be turned on complementarily through the first duty cycle, where the upper bridge arm of the first-phase bridge arm and the lower bridge arm of the second-phase bridge arm are turned on simultaneously, and the lower bridge arm of the first-phase bridge arm and the upper bridge arm of the second-phase bridge arm are turned on simultaneously.
For example, the LLC circuit is shown in
In addition, according to abnormality analysis, the working mode of the LLC circuit is distinguished by using the first preset voltage as a critical point. Therefore, it can be deduced that, the voltages Ubus between the two ends of the bus capacitor C1 in the two working modes (that is, the full-bridge mode and the half-bridge mode) are greatly different, where in the half-bridge mode, Ubus=2*K*Udc, and in the full-bridge mode, Ubus=K*Udc. In this way, when the LLC circuit is switched from the half-bridge mode to the full-bridge mode, an input voltage (that is, Ubus) of the LLC circuit is excessively high, leading to generation of an extremely large current in the resonant cavity, and the charger has a risk of being damaged. For the same on time, a higher input voltage of the LLC circuit indicates a larger current flowing through the resonant circuit.
To avoid the generation of a large current in the resonant cavity when the LLC circuit is switched from the half-bridge mode to the full-bridge mode, the following method is proposed:
To ensure that the charger works in a safe range, it needs to be ensured that the voltage between the two ends of the bus capacitor C1 meets Ubus≥√{square root over (2)}*UacMax, otherwise, an uncontrollable rectified current will be generated. That is, whether an uncontrollable rectified current is generated is distinguished by using √{square root over (2)}*UacMax (that is, a second preset voltage) as a critical point of the voltage between the two ends of the bus capacitor CL. When working of the LLC circuit in the half-bridge mode ends, that is, when the LLC circuit is switched from the half-bridge mode to the full-bridge mode, a relationship between the voltage Ubus between the two ends of the bus capacitor C1 and the second preset voltage needs to be determined. When Ubus is less than (slightly less than herein) the second preset voltage, the LLC circuit may be directly switched from the half-bridge mode to the full-bridge mode. When Ubus is greater than or equal to the second preset voltage, the LLC circuit is not directly switched from the half-bridge mode to the full-bridge mode. Instead, upper bridge arms and lower bridge arms of phase bridge arms in the inverter circuit are controlled to be turned on complementarily through a duty cycle less than the foregoing first duty cycle, to discharge the voltage of the bus capacitor through an open loop, and until Ubus is less than the second preset voltage, the LLC circuit is controlled to work in the full-bridge mode (that is, the upper bridge arm and the lower bridge arm of the first-phase bridge arm are controlled to be turned on complementarily through the first duty cycle, and the upper bridge arm and the lower bridge arm of the second-phase bridge arm are controlled to be turned on complementarily through the first duty cycle, where the upper bridge arm of the first-phase bridge arm and the lower bridge arm of the second-phase bridge arm are turned on simultaneously, and the lower bridge arm of the first-phase bridge arm and the upper bridge arm of the second-phase bridge arm are turned on simultaneously).
In an embodiment, in a case that the target working mode is the full-bridge mode, before the step that the upper bridge arm and the lower bridge arm of the first-phase bridge arm are controlled to be turned on complementarily through the first duty cycle, that the LLC circuit is controlled to work according to the target working mode (S302) may further include the following steps:
In the foregoing implementation, when Ubus is greater than or equal to the second preset voltage, the LLC circuit is not directly switched from the half-bridge mode to the full-bridge mode. Instead, the upper bridge arms and the lower bridge arms of the phase bridge arms in the inverter circuit are controlled to be turned on complementarily through the duty cycle less than the foregoing first duty cycle, so that on duty cycles of the upper bridge arms and the lower bridge arms of the phase bridge arms in the inverter circuit are limited, that is, on time of the upper bridge arms and the lower bridge arms of the phase bridge arms in the inverter circuit is reduced. Therefore, a current in the resonant cavity is effectively suppressed, and generation of a large current in the resonant cavity when the LLC circuit is switched from the half-bridge mode to the full-bridge mode is further avoided, thereby improving the safety and stability of the charger.
In addition, the foregoing method may further include the following step (1) to step (4):
(1) Present electricity information of the alternating-current side of the charger and the second voltage of the bus capacitor are obtained.
In the present disclosure, the electricity information includes a present current and a present voltage on the alternating-current side.
For example, the present current on the alternating-current side of the charger may be obtained through a current sensor; and the present voltage on the alternating-current side of the charger and the second voltage of the bus capacitor may be obtained through a voltage sensor. In this way, the present electricity information of the alternating-current side of the charger and the second voltage of the bus capacitor may be clear, to provide a data support for current adjustment on the alternating-current side.
(2) A steady-state target current on the alternating-current side is determined.
In the present disclosure, the steady-state target current is a current value corresponding to the alternating-current side of the charger when the charger is in a stable and efficient optimal working state.
(3) A target current value on the alternating-current side is determined according to the present voltage and the steady-state target current.
For example, a phase of an alternating current outputted by the power grid may be extracted according to the present voltage ua (that is, a voltage of the current outputted by the power grid). For example, a product of the steady-state target current and the phase of the alternating current outputted by the power grid may be determined as the target current value. As shown in
(4) A power factor calibration circuit is controlled to perform power factor calibration according to the target current value, the present current, the present voltage, and the second voltage.
In an embodiment, as shown in
The following describes in detail an implementation of determining the steady-state target current on the alternating-current side in the foregoing step (2). In an embodiment, the step may be implemented through the following step (21) and step (22):
(21). A target charging power on the alternating-current side is determined.
In the present disclosure, the target charging power is a power on the alternating-current side of the charger when the charger is in a stable and efficient optimal working state. In an embodiment, a minimum value in a maximum output power of the power grid, a current output power of the power grid, a maximum charging power of the battery allowed by a battery management system, a maximum power allowed by a wire, and a maximum charging power of the charger is determined as the target charging power.
For example, the maximum output power of the power grid and the maximum power allowed by the wire may be determined according to content in the national standard GBT 18487.1-2015; the current output power of the power grid may be determined through a power sensor arranged on the power grid in advance; the maximum charging power of the battery allowed by the battery management system may be determined according to related parameter information of the battery; and the maximum charging power of the charger may be determined according to hardware device selection of the charger, that is, belong to an inherent attribute parameter of the charger. The to-be-selected powers are respectively maximum powers corresponding to the power grid, the battery, the wire, and the charger, and the current output power of the power grid. Therefore, by selecting a minimum value as the target charging power, it may be ensured that during working of the charger, the power grid and the battery connected to the charger and wires connecting various parts are all in a safe working state, thereby reducing a possibility of a damaged electronic element on a related circuit. In addition, the power on the alternating-current side of the charger may be ensured to reach a maximum value while working safety is ensured. Therefore, if the power on the alternating-current side of the charger is the target charging power, the charger may be in the stable and efficient optimal working state.
(22) The steady-state target current on the alternating-current side is determined according to the target charging power.
In the present disclosure, the steady-state target current on the alternating-current side is a current value determined according to the target charging power. The steady-state target current may be determined according to a quotient of the target charging power and a valid value of an alternating-present voltage outputted by the power grid.
In addition, the charger control apparatus 5 may include:
The present disclosure further provides a vehicle, including a battery and the charger according to the present disclosure.
Examples of implementations of the present disclosure are described in detail above with reference to the accompanying drawings, but the present disclosure is not limited to the details in the above implementations. Various simple variations may be made to the technical solutions of the present disclosure within the scope of the technical idea of the present disclosure, and such simple variations shall all fall within the protection scope of the present disclosure.
In addition, it should be noted that, technical features described in the foregoing implementations may be combined in any appropriate manner without conflict. To avoid unnecessary repetition, various possible combinations are not further described in the present disclosure.
In addition, the various implementations of the present disclosure may be combined arbitrarily without departing from the idea of the present disclosure, and such combinations shall also be considered as the content disclosed in the present disclosure.
| Number | Date | Country | Kind |
|---|---|---|---|
| 202211059072.4 | Aug 2022 | CN | national |
This application is a continuation application of International Patent Application No. PCT/CN2023/108248, filed on Jul. 19, 2023, which is based on and claims priority to and benefits of Chinese Patent Application No. 202211059072.4, filed on Aug. 30, 2022. The entire content of all of the above-referenced applications is incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/CN2023/108248 | Jul 2023 | WO |
| Child | 19059109 | US |
