Charger control method and device, charger, and vehicle

Abstract

A charger control method and device, a charger, and a vehicle. The method is applicable to a charger that is an on-board charger or a charging pile charger. The method includes determining a target AC side current value according to a current voltage and a target steady-state current on the AC side of the charger, correcting the target current value using an AC side current correction amount, and controlling the AC side current according to the corrected target current value, the current voltage, the AC side current, and the bus capacitor voltage so that the AC side current conforms to the collected target current value. In this way, deviation of the AC side positive half-cycle current from the AC side negative half-cycle current is avoided, thereby achieving the ultimate goal of adjusting the balance of the actual AC side current, i.e., achieving dynamic AC balance.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This disclosure claims priority to and the benefit of Chinese Patent Application No. 202211049272.1, entitled "CHARGER CONTROL METHOD AND DEVICE, CHARGER AND VEHICLE," filed on August 30, 2022. The entire contents of the above-referenced application are hereby incorporated by reference.

[0002] The present disclosure relates to the field of vehicle technology, and in particular to a charger control method and apparatus, a charger, and a vehicle. [Background technology]

[0003] An on-board charger is an electronic device that converts AC to DC and is used as an on-board charging device for electric vehicles to power the battery. Existing on-board chargers typically use a two-stage topology, with the front-stage circuit being a power factor correction circuit and the back-stage circuit being an isolated DC / DC circuit (i.e., an LCC circuit (resonant circuit)), and the instantaneous power difference between the AC and DC sides is balanced through a bus capacitor between the two stages.

[0004] The on-board charger controls charging according to the sampled voltage and current of the AC side collected by the sampling circuit on the AC side. However, due to the hardware sampling error in the sampling circuit, there may be a deviation between the current of the positive half cycle and the current of the negative half cycle on the AC side, i.e., the AC may be unbalanced. Summary of the Invention [Problem to be solved by the invention]

[0005] To overcome the problems existing in the related art, the present disclosure provides a charger control method and apparatus, a charger, and a vehicle. [Means for solving the problem]

[0006] To achieve the above object, according to a first aspect, the present disclosure provides a charger control method. The method is applied to a charger, and the charger is an on-board charger or a charging pile charger. The method includes: Determining a target current value on the AC side according to a current voltage and a steady-state target current on the AC side of the charger; correcting the target current value by using the current correction amount on the AC side; and controlling the current on the AC side according to the corrected target current value, the current voltage, the current current on the AC side, and the voltage of the bus capacitor, so that the current on the AC side conforms to the corrected target current value.

[0007] Optionally, the current correction amount on the AC side is: continuously collecting a first preset amount of current on the AC side according to a first sampling period; and determining a current correction amount on the AC side according to a first preset amount of current on the AC side.

[0008] Optionally, determining a current correction amount on the AC side in response to a first preset amount of current on the AC side comprises: Determining an average value of the first preset amount of current on the AC side as a current correction amount on the AC side.

[0009] Optionally, the first preset amount is an integer multiple of the quotient of the AC side current period and the first sampling period, where the first sampling period is significantly less than the AC side current period.

[0010] Optionally, the present voltage and present current on the AC side of the charger are: determining a current voltage on the AC side according to a current voltage AD value on the AC side of the charger collected by the AC side sampling circuit; and determining a current current on the AC side according to a current current AD value on the AC side collected by the AC side sampling circuit; The method comprises: The method further includes performing zero point correction in the AC side sampling circuit when the charger is powered on.

[0011] Optionally, zero point correction can be performed on the AC sampling circuit. The method includes correcting the sampled voltage AD value and / or the sampled current AD value of the sampling circuit on the AC side to perform zero point correction in the sampling circuit on the AC side.

[0012] Optionally, correcting the sampled voltage AD value and / or the sampled current AD value of the AC side sampling circuit includes: continuously collecting a second preset amount of voltage AD values ​​and / or current AD values ​​on the AC side according to a second sampling period; determining a correction amount for the sampled voltage AD value of the AC side sampling circuit according to the second preset amount of voltage AD value on the AC side, and / or determining a correction amount for the sampled current AD value of the AC side sampling circuit according to the second preset amount of current AD value on the AC side; Correcting the sampled voltage AD value according to the correction amount of the sampled voltage AD value, and / or correcting the sampled current AD value according to the correction amount of the sampled current AD value.

[0013] According to a second aspect, the present disclosure provides a charger control device, the charger control device comprising: a memory having a computer program stored therein; and a control device that, when executing a computer program, performs the steps of the charger control method according to the first aspect of the present disclosure.

[0014] According to a third aspect, the present disclosure provides a charger including a power factor correction circuit, a bus capacitor, and an LLC circuit, connected in sequence. The present disclosure further includes a charger control device according to a second aspect, the charger control device being separately connected to the power factor correction circuit and the LLC circuit.

[0015] According to a fourth aspect, the present disclosure provides a vehicle including a battery and a charger according to the third aspect of the disclosure.

[0016] In the aforementioned technical solution, the target current value on the AC side is determined according to the charger's AC side current voltage and steady-state target current. The target current value is then corrected using a current correction variable. Finally, the AC side current is controlled according to the corrected target current value, AC side current voltage, AC side current, and bus capacitor voltage to make the AC side current follow the corrected target current value, thereby achieving power factor correction. The target current value is corrected using a current correction variable, thereby ensuring the accuracy of the corrected target current value and allowing the AC side current to precisely follow the corrected target current value, thereby avoiding deviations between the positive and negative half-cycle currents on the AC side and achieving the ultimate goal of balancing the actual current on the AC side, i.e., achieving dynamic AC balance.

[0017] Other features and advantages of the present disclosure are described in detail in the following specific implementations.

[0018] For a further understanding of the present disclosure, the accompanying drawings are provided and constitute a part of this specification, and are used to illustrate the present disclosure in conjunction with specific implementations and do not constitute limitations thereon. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 1 is a structural block diagram of a charger according to an exemplary embodiment. [Figure 2] FIG. 2 is a diagram of a circuit topology structure of a charger in accordance with an exemplary embodiment. [Figure 3] 4 is a flowchart of a charger control method according to an exemplary embodiment. [Figure 4] 1 is a schematic diagram of a charger control method according to an exemplary embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0020] Specific implementations of the present disclosure will be described in detail below with reference to the accompanying drawings. It will be understood that the specific implementations described herein are merely used to explain and detail the present disclosure, but are not intended to limit the present disclosure.

[0021] 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 employ the same circuit topology structure (as shown in FIG. 2). As shown in FIG. 1, the charger 100 includes a charger controller 5, a power factor correction circuit 2, a bus capacitor C1, and an LLC circuit 3, which are connected in sequence. The power factor correction circuit 2 is connected to a power grid 1, the LLC circuit 3 is configured to be connected to a battery 4, and the bus capacitor C1 may be an electrolytic capacitor, a thin-film capacitor, a ceramic capacitor, or the like, and may be configured to filter a DC voltage.

[0022] The charger control device 5 is separately connected to the power factor correction circuit 2 and the LLC circuit 3 to control them to operate to charge the battery, and is configured to execute a charger control method applied to the charger. The power factor correction circuit 2 is configured to perform power factor correction on an input signal from a power grid and to output a current signal obtained by the power factor correction, and the LLC circuit 3 is configured to perform DC conversion on the current signal obtained by the power factor correction to obtain DC for charging the vehicle battery.

[0023] As shown in FIG. 2, the power factor correction circuit 2 may include a third phase bridge arm formed by a first switch tube T1 and a second switch tube T2, and a fourth phase bridge arm formed by a third switch tube T3 and a fourth switch tube T4, where the midpoint of the third phase bridge arm is connected to the positive pole of the power grid 1 through an inductor L1, the midpoint of the fourth phase bridge arm is connected to the negative pole of the power grid 1, the third bus ends of the third phase bridge arm and the fourth phase bridge arm are connected to one end of a bus capacitor C1, and the fourth bus ends of the third phase bridge arm and the fourth phase bridge arm are connected to the other end of the bus capacitor C1.

[0024] The current voltage on the AC side of the charger is u a and the current on the AC side of the charger is i a and the voltage on the bus capacitor is Ubus.

[0025] As shown in FIG. 2, the LLC circuit 3 includes an inverter circuit 31, a resonant circuit 32, and a rectifier circuit 33, which are connected in sequence.

[0026] The inverter circuit 31 includes a first phase bridge arm formed by a fifth switch tube T5 and a sixth switch tube T6, and a second phase bridge arm formed by a seventh switch tube T7 and an eighth switch tube T8, and the first bus ends of the first phase bridge arm and the second phase bridge arm are separately connected to one end and a third bus end of the bus capacitor C1, and the second bus ends of the first phase bridge arm and the second phase bridge arm are separately connected to the other end and a fourth bus end of the bus capacitor C1.

[0027] The resonant circuit 32 employs an LLC resonant cavity and includes a resonant inductor L2, a resonant capacitor C2, and a transformer M1. One end of the resonant inductor L2 is connected to the midpoint of the first phase bridge arm, and the other end is connected to a first input terminal of the primary side of the transformer M1. The resonant inductor L2 may be magnetically integrated with the transformer M1 to participate in the resonance of the resonant circuit. The resonant capacitor C2 has one end connected to the midpoint of the second phase bridge arm, and the other end is connected to a second input terminal of the primary side of the transformer M1. The resonant capacitor C2 may be a thin-film capacitor or a ceramic capacitor to prevent DC offset of the transformer M1 and participate in the resonance of the resonant circuit. The transformer M1 may be a tapped transformer and configured for isolated electrical energy transmission.

[0028] 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. The midpoint of the fifth phase bridge arm is connected to a first input terminal of the secondary side of the transformer M1, and the midpoint of the sixth phase bridge arm is connected to a second input terminal of the secondary side of the transformer M1. The fifth bus terminals of the fifth phase bridge arm and the sixth phase bridge arm are separately connected to one end of the filter capacitor C3 and the positive terminal of the battery 4, and the sixth bus terminals of the fifth phase bridge arm and the sixth phase bridge arm are separately connected to the other end of the filter capacitor C3 and the negative terminal of the battery 4. The filter capacitor C3 is a battery-side capacitor configured to filter the DC voltage on the battery side.

[0029] Additionally, it should be noted that the rectifier circuit 33 may use a switch tube device (as shown in FIG. 2) or a rectifier diode to implement the electrical energy transmission.

[0030] The charger control method applied to the charger will be described in detail below. As shown in Figure 3, the method may include S301 to S303.

[0031] S301 The target current value on the AC side is determined according to the current voltage and steady-state target current on the AC side of the charger.

[0032] In the present disclosure, the AC side current voltage may be determined according to a current voltage analog-to-digital (AD) value of the AC side of the charger collected by an AC side sampling circuit, where the voltage AD value is a corresponding digital signal value obtained through conversion by an analog-to-digital converter (ADC).

[0033] In one implementation, the current voltage corresponding to the current voltage AD value may be determined according to a conversion relationship between the voltage on the AC side and the voltage AD value.

[0034] For example, the voltage on the AC side is equal to the sum of b1 and the product of k1 and the value of the voltage AD on the AC side.

[0035] Additionally, the steady state target current is the current value that corresponds to the AC side of the charger when the charger is operating in a stable, efficient, and optimal state.

[0036] Specifically, the phase of the AC output by the power grid is determined by the current voltage u a (i.e., the voltage of the current output by the power grid). For example, the product of the steady-state target current and the phase of the AC current output by the power grid may be determined as the target current value. As shown in FIG. 4, when the steady-state target current is I a_ref and the phase of the AC output by the power grid and determined based on a phase locked loop is cos wt, then I a_ref × cos wt is the target current value I a_ref1 It may be determined as:

[0037] S302 The target current value is corrected by using the current correction amount on the AC side.

[0038] For example, as shown in Figure 4, the target current value I a_ref1 and the current correction amount IacAjust, the corrected target current value I a_ref2 It may be determined as:

[0039] S303 According to the corrected target current value, the current voltage, the current current on the AC side, and the voltage of the bus capacitor, the current on the AC side is controlled to make the current on the AC side follow the corrected target current value.

[0040] In the present disclosure, the AC-side present current may be determined according to an AC-side present current analog-to-digital (AD) value collected by an AC-side sampling circuit.

[0041] In one implementation, the current corresponding to the current AD value may be determined according to a conversion relationship between the current on the AC side and the current AD value, where the current AD value is a digital signal value obtained through conversion by an ADC.

[0042] For example, the current on the AC side is equal to the sum of b2 and the product of k2 and the value of the AC side current AD.

[0043] Specifically, as shown in Figure 4, the bus capacitor voltage Ubus and the current voltage u a is the feedforward amount u of the closed-loop control result. a This may be input to a divider to obtain the corrected target current value I a_ref2 and the current i ais input to the control device to obtain a feedback quantity of the closed-loop control result, and the difference between the feedforward quantity and the feedback quantity is used as a modulating wave to obtain the duty cycle of the power factor correction (PFC) circuit, and is transmitted to the PWM generator together with the carrier, so that the current on the AC side may follow the corrected target current value to adjust the duty cycle of the PFC circuit to perform power factor correction.

[0044] In the aforementioned technical solution, the target current value on the AC side is determined according to the charger's AC side current voltage and steady-state target current. The target current value is then corrected using a current correction variable. Finally, the AC side current is controlled according to the corrected target current value, AC side current voltage, AC side current, and bus capacitor voltage to make the AC side current follow the corrected target current value, thereby achieving power factor correction. The target current value is corrected using a current correction variable, thereby ensuring the accuracy of the corrected target current value and allowing the AC side current to precisely follow the corrected target current value, thereby avoiding deviations between the positive and negative half-cycle currents on the AC side and achieving the ultimate goal of balancing the actual current on the AC side, i.e., achieving dynamic AC balance.

[0045] A specific method for determining the steady-state target current on the AC side will be described in detail below. Specifically, the method can be performed through the following steps (1) and (2).

[0046] (1) The target charging power on the AC side is determined.

[0047] In the present disclosure, the target charging power is the power on the AC side of the charger when the charger is in a stable and efficient optimal operating state. Specifically, the target charging power is determined based on the minimum maximum output power of the power grid, the current output power of the power grid, the maximum charging power of the battery allowed by the battery management system, the maximum power allowed by the wire, and the maximum charging power of the charger.

[0048] For example, the maximum output power of the power grid and the maximum power allowed by the wires may be determined in accordance with the contents of the national standard GBT18487.1-2015, the current output power of the power grid may be determined by a power sensor previously installed in the power grid, the maximum charging power of the battery allowed by the battery management system may be determined according to relevant parameter information of the battery, and the maximum charging power of the charger may be determined according to the hardware device selection of the charger, i.e., it may belong to the charger's inherent attribute parameters. The powers to be selected include the respective maximum powers corresponding to the power grid, battery, wire, and charger, as well as the current output power of the power grid. Therefore, by selecting the lowest value as the target charging power, it is possible to ensure that the power grid and battery connected to the charger and the wires connecting various components are all in a safe operating state while the charger is operating, thereby reducing the possibility of damage to electronic elements in the related circuits. In addition, it is possible to ensure that the AC power of the charger reaches its maximum value while ensuring operational safety. Therefore, when the AC power of the charger is at the target charging power, the charger can be in a stable and efficient optimal operating state.

[0049] (2) The steady-state target current on the AC side is determined according to the target charging power.

[0050] In the present disclosure, the steady-state target current on the AC side is a current value determined according to the target charging power, which can be determined by the quotient of the target charging power and the effective value of the AC voltage output by the power grid.

[0051] A specific method for determining the AC side current correction amount will be described in detail below. Specifically, the steps can be performed through the following steps [1] and [2].

[0052] [1] According to a first sampling period, a first preset amount of current on the AC side is continuously collected.

[0053] In the present disclosure, the first preset amount may be any set value, for example, 100, or may be an integer multiple of the quotient of the current period of the AC side and the first sampling period, where the first sampling period is significantly less than the current period of the AC side.

[0054] [2] A current correction amount on the AC side is determined according to a first preset amount of current on the AC side.

[0055] In one implementation, an average value of the first preset amount of current on the AC side may be determined as the current correction amount on the AC side.

[0056] In addition, analysis based on the principles of the AC sampling circuit reveals that the main factors affecting sampling include the resistance of the sampling Hall or operational amplifier sampling circuit and the power supply divider resistor. While differences in the divider resistor's resistance can be compensated for by sampling compensation, the output characteristics of the Hall or operational amplifier may be affected by the board-level power supply. AC voltage and current are AC values, so zero-crossing detection is crucial. If the power supply voltage deviates, the sampling zero-point reference will deviate, leading to control errors and deviations between the positive and negative half-cycle currents, resulting in AC imbalance.

[0057] Therefore, in order to further improve the dynamic balance of AC, in addition to correcting the target current value during the operation of the charger, a zero point correction can also be performed on the sampling circuit on the AC side before the charger starts to operate, in order to avoid the zero point deviation caused by the unstable voltage, thereby improving the dynamic balance of AC. Specifically, the method includes the following steps: The method may further include a step of performing zero point correction in the AC side sampling circuit when the charger is powered on.

[0058] In this disclosure, the charger includes three processes: power-on, running, and power-off. The AC voltage (i.e., power grid) is connected to the charger to power it on, and the charger is powered off when the AC voltage is interrupted, and the process in which the charger charges the vehicle's battery is the running process.

[0059] Specifically, zero point correction may be performed in the AC side sampling circuit using a plurality of methods.

[0060] In one implementation, the sampled voltage AD value of the AC side sampling circuit is corrected to perform zero point correction on the AC side sampling circuit.

[0061] Specifically, a second preset amount of voltage AD values ​​on the AC side may be continuously collected according to a second sampling period, then a correction amount of the sampled voltage AD values ​​of the AC side sampling circuit is determined according to the second preset amount of voltage AD values ​​on the AC side, and finally, the sampled voltage AD values ​​are corrected according to the correction amount of the sampled voltage AD values.

[0062] The second preset amount may be any set value, for example 100, or may be an integer multiple of the quotient of the current period of the AC side and the second sampling period, where the second sampling period is significantly less than the current period of the AC side.

[0063] For example, an average value of the second preset amount of voltage AD values ​​on the AC side may be determined as a correction amount of the sampled voltage AD values ​​of the sampling circuit on the AC side, and a difference between the sampled voltage AD value and the correction amount of the sampled voltage AD value is determined as a corrected sampled voltage AD value.

[0064] In another implementation, the sampled current AD value of the AC side sampling circuit is corrected, and zero point correction is performed on the AC side sampling circuit.

[0065] Specifically, the second preset amount of current AD values ​​on the AC side may be continuously collected according to a second sampling period, then the correction amount of the sampled current AD values ​​of the sampling circuit on the AC side is determined according to the second preset amount of current AD values ​​on the AC side, and finally the sampled current AD values ​​are corrected according to the correction amount of the sampled current AD values.

[0066] For example, an average value of the second preset amount of current AD values ​​on the AC side may be determined as a correction amount of the sampled current AD values ​​of the sampling circuit on the AC side, and a difference between the sampled current AD value and the correction amount of the sampled current AD value is determined as a corrected sampled current AD value.

[0067] In yet another implementation, the sampled voltage AD values ​​and sampled current AD values ​​of the AC side sampling circuit are corrected to perform zero point correction on the AC side sampling circuit.

[0068] Specifically, a second preset amount of voltage AD values ​​and a second preset amount of current AD values ​​on the AC side may be continuously collected according to a second sampling period, a correction amount for the sampled voltage AD values ​​of the AC side sampling circuit is determined according to the second preset amount of voltage AD values ​​on the AC side, a correction amount for the sampled current AD values ​​of the AC side sampling circuit is determined according to the second preset amount of current AD values ​​on the AC side, and finally, the sampled voltage AD values ​​are corrected according to the correction amount for the sampled voltage AD values, and the sampled current AD values ​​are corrected according to the correction amount for the sampled current AD values.

[0069] In addition, the charger control device 5 a memory having a computer program stored therein; The present invention may also include a control device that, when executing a computer program, performs the steps of the charger control method of the present disclosure.

[0070] The present disclosure further provides a vehicle including a charger according to the present disclosure.

[0071] Although the exemplary implementations of the present disclosure have been described in detail above with reference to the accompanying drawings, the present disclosure is not limited to the specific details of the above implementations. Within the technical idea of ​​the present disclosure, various simple modifications may be made to the technical solutions of the present disclosure, and all such simple modifications shall fall within the protection scope of the present disclosure.

[0072] In addition, it should be noted that the specific technical features described in the above specific implementations may be combined in any suitable manner without conflict, and in order to avoid unnecessary repetition, the present disclosure will not further describe the various possible combinations.

[0073] In addition, various implementations of the present disclosure may be combined in any manner without departing from the spirit of the present disclosure, and such combinations shall also be considered to be part of the present disclosure.

Claims

1. A charger control method applied to a charger, the charger being an on-board charger or a charging pile charger, the method comprising: determining a target current value on the AC side of the charger according to a current voltage and a steady-state target current on the AC side of the charger; correcting the target current value by using the AC side current correction amount; and controlling a current on the AC side according to the corrected target current value, the present voltage, the present current on the AC side, and a voltage of a bus capacitor to make the current on the AC side conform to the corrected target current value.

2. The current correction amount on the AC side is as follows: continuously collecting a first preset amount of current on the AC side according to a first sampling period; and determining the current correction amount on the AC side in response to the first preset amount of current on the AC side.

3. determining the current correction amount on the AC side in response to the first preset amount of current on the AC side; 3. The method of claim 2, comprising determining an average value of the first preset amount of current on the AC side as the current correction amount on the AC side.

4. 4. The method according to claim 2 or 3, wherein the first preset amount is an integer multiple of a quotient of a current period of the AC side and the first sampling period, and the first sampling period is significantly less than the current period of the AC side.

5. The present voltage and the present current on the AC side of the charger are as follows: determining the current voltage of the AC side according to a current voltage AD value of the AC side of the charger collected by the AC side sampling circuit; and determining the current current of the AC side according to a current current AD value of the AC side collected by the AC side sampling circuit; The method comprises: The method of claim 1 , further comprising performing a zero point correction in the sampling circuit on the AC side when the charger is powered on.

6. performing the zero point correction in the sampling circuit on the AC side, 6. The method of claim 5, further comprising correcting the sampled voltage AD values ​​and / or the sampled current AD values ​​of the sampling circuit on the AC side to perform zero point correction in the sampling circuit on the AC side.

7. The correcting of the sampled voltage AD value and / or the sampled current AD value of the sampling circuit on the AC side is continuously collecting a second preset amount of voltage AD values ​​and / or current AD values ​​on the AC side according to a second sampling period; determining a correction amount for the sampled voltage AD value of the sampling circuit on the AC side according to the second preset amount of voltage AD value on the AC side, and / or determining a correction amount for the sampled current AD value of the sampling circuit on the AC side according to the second preset amount of current AD value on the AC side; 7. The method according to claim 6, further comprising: correcting the sampled voltage AD value according to the correction amount of the sampled voltage AD value; and / or correcting the sampled current AD value according to the correction amount of the sampled current AD value.

8. a memory having a computer program stored therein; A charger control device (5) comprising: a control device, the control device performing the steps of the method according to any one of claims 1 to 7 when the control device executes the computer program.

9. A charger (100) comprising a power factor correction circuit (2), a bus capacitor (C1), and an LLC circuit (3) connected in series, said charger (100) comprising: A charger (100) further comprising the charger control device (5) of claim 8, wherein the charger control device (5) is separately connected to the power factor correction circuit (2) and the LLC circuit (3).

10. A vehicle comprising a battery (4) and a charger (100) according to claim 9.

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