Vehicle-mounted charger control method and system and vehicle controller

Abstract

The invention provides a vehicle-mounted charger control method and system and a vehicle controller, and is used for providing sweep frequency current required by electrochemical impedance spectroscopy detection for a power battery under the condition that a vehicle-mounted charger is not connected with an alternating current power grid. Acquiring target sweep frequency current information; and an isolation DC / DC circuit is driven according to the target sweep frequency current information, so that the sweep frequency current can flow bidirectionally between the intermediate bus capacitor and the power battery. According to the invention, the starting scene of the EIS detection function can be effectively expanded, and the EIS detection function is allowed to be started in the scene of not inserting a charging gun and a discharging gun or not connecting an in-vehicle alternating current load.

Description

Technical Field

[0001] The present invention relates to the technical field of new energy vehicles, and particularly relates to a control method, a system and a vehicle controller for an on-vehicle charger. Background Art

[0002] Please refer to Figure 1 , Figure 1 which is a structural diagram of a common on-vehicle charger. As Figure 1 shown, in an electric vehicle, an on-vehicle charger 100 (On Board Charger, OBC) is connected to a power battery 200 (Power battery). When the vehicle is parked and connected to an AC power grid 300, the on-vehicle charger 100 absorbs electric energy from the AC power grid 300 and performs electric energy conversion, and finally transmits stable direct current to the power battery 200. A common on-vehicle charger 100 may have a two-stage structure as Figure 1 shown. Its front stage is a PFC (Power Factor Correction) circuit 110, and its rear stage is an isolated DC / DC circuit 130. A relatively large intermediate bus capacitor 120, generally an electrolytic capacitor, is selected between the two-stage circuits to balance the instantaneous power difference between the AC side and the DC side of the PFC circuit 110. Generally, a high-voltage DC bus capacitor 610 is also connected in parallel to the power battery 200 for voltage stabilization. Further, as Figure 1 shown, an AC relay 400 is also connected in series on the AC side of the PFC circuit 110 to achieve functions such as automatic adjustment, safety protection, and conversion circuit.

[0003] Electrochemical Impedance Spectroscopy (EIS) detection of the power battery refers to injecting a current with a certain amplitude and variable frequency within a certain range (for example, 1 Hz to 1 kHz) (hereinafter referred to as "sweeping current") into the power battery 200 through an external circuit, and at the same time, the Battery Management System (BMS) detects the spectral components of the current and voltage of the power battery 200, so as to calculate the battery electrochemical impedance spectrum for functions such as battery health state estimation and safety state estimation. In the prior art, some on-vehicle chargers 100 can provide the sweeping current required for EIS detection by improving the control loop design, as Figure 2a and Figure 2b shown, where U DClink represents the intermediate bus voltage, U Ac represents the AC side voltage, I Ac represents the AC side current, I Obc represents the sweeping current (that is, the output current of the on-vehicle charger 100), U batIndicates the battery voltage. Its characteristics are as follows: The intermediate bus voltage U is stabilized by the PFC circuit 110 DClink and the output of the target value of the swept-frequency current I is realized by the isolated DC / DC circuit 130. Finally, the on-vehicle charger 100 can inject the swept-frequency current into the power battery 200. Obc

[0004] The prior art has the following deficiencies:

[0005] 1. Since the energy always flows unidirectionally (from the AC side to the battery side), the vehicle must be connected to the AC power grid 300, that is, the charging gun must be plugged in, which limits the scenarios where the EIS detection function can be enabled;

[0006] 2. When using conventional closed-loop control (such as PID control), when the frequency of the swept-frequency current is relatively high, due to the frequency attenuation characteristic of the conventional closed-loop control, the amplitude of the actually output swept-frequency current will be less than expected, affecting the EIS detection accuracy;

[0007] 3. Due to the existence of the high-voltage DC bus capacitor 610, when the frequency of the swept-frequency current is relatively high, after the swept-frequency current I Obc is filtered by the capacitor, the amplitude of the current I bat injected into the power battery 200 will further decrease, affecting the EIS detection accuracy.

[0008] It should be noted that the information disclosed in the background art part of this invention is only intended to deepen the understanding of the general background art of this invention, and should not be regarded as an admission or any form of implication that this information constitutes the prior art known to those skilled in the art. Summary of the Invention

[0009] The purpose of this invention is to provide a control method, system and vehicle controller for an on-vehicle charger, which can effectively expand the scenarios where the EIS detection function can be enabled, and allow the EIS detection function to be enabled in scenarios where the charging gun, discharging gun is not plugged in or the in-vehicle AC load is not connected.

[0010] To achieve the above object, the present invention provides a method for controlling an on-vehicle charger, which is used to provide a swept-frequency current required for detecting the electrochemical impedance spectrum of a power battery when the on-vehicle charger is not connected to an AC power grid. The on-vehicle charger includes a PFC circuit, an intermediate bus capacitor, and an isolated DC / DC circuit. The intermediate bus capacitor and the isolated DC / DC circuit are connected in parallel on the DC side of the PFC circuit, and the intermediate bus capacitor is located between the PFC circuit and the isolated DC / DC circuit. The control method includes: obtaining target swept-frequency current information according to a received instruction for detecting the electrochemical impedance spectrum of the power battery; driving the isolated DC / DC circuit according to the target swept-frequency current information so that the swept-frequency current can flow bidirectionally between the intermediate bus capacitor and the power battery.

[0011] Optionally, the driving the isolated DC / DC circuit according to the target swept-frequency current information includes: driving the isolated DC / DC circuit with the average value of the swept-frequency current being zero as the target according to the target swept-frequency current information.

[0012] Optionally, the driving the isolated DC / DC circuit with the average value of the swept-frequency current being zero as the target according to the target swept-frequency current information includes: within each swept-frequency period, driving the isolated DC / DC circuit to output a reverse swept-frequency current to the intermediate bus capacitor according to the target swept-frequency current information first, and then driving the isolated DC / DC circuit to output a forward swept-frequency current to the power battery.

[0013] Optionally, the driving the isolated DC / DC circuit with the average value of the swept-frequency current being zero as the target according to the target swept-frequency current information includes: driving the isolated DC / DC circuit to pre-charge the intermediate bus capacitor to raise the voltage of the intermediate bus capacitor to a preset value; within each swept-frequency period, driving the isolated DC / DC circuit to output a forward swept-frequency current to the power battery according to the target swept-frequency current information first, and then driving the isolated DC / DC circuit to output a reverse swept-frequency current to the intermediate bus capacitor.

[0014] Optionally, the target swept-frequency current information includes the target amplitude and target frequency of the swept-frequency current.

[0015] The driving the isolated DC / DC circuit to output a forward swept-frequency current to the power battery includes: driving the isolated DC / DC circuit to output a forward swept-frequency current to the power battery according to a strategy that the swept-frequency current gradually increases from zero to half of the target amplitude and then gradually decreases to zero.

[0016] Driving the isolated DC / DC circuit to output a reverse swept-frequency current to the intermediate bus capacitor includes: driving the isolated DC / DC circuit to output a reverse swept-frequency current to the intermediate bus capacitor according to a strategy that the absolute value of the swept-frequency current gradually increases from zero to half of the target amplitude and then gradually decreases to zero.

[0017] Optionally, driving the isolated DC / DC circuit according to the target swept-frequency current information includes: driving the isolated DC / DC circuit by using a closed-loop control method according to the target swept-frequency current information and the actually collected real-time swept-frequency current information.

[0018] Optionally, driving the isolated DC / DC circuit by using a closed-loop control method according to the target swept-frequency current information and the actually collected real-time swept-frequency current information includes: obtaining swept-frequency current deviation information according to the target swept-frequency current information and the actually collected real-time swept-frequency current information; adjusting the swept-frequency current deviation information by using a PI controller and a PR controller to obtain isolated DC / DC circuit control information; modulating the isolated DC / DC circuit control information to obtain a PWM signal; and driving the isolated DC / DC circuit according to the PWM signal.

[0019] Optionally, the on-vehicle charger control method provided by the present invention further includes: adjusting the resonance frequency and resonance coefficient of the PR controller in real time according to the target swept-frequency current information.

[0020] Optionally, variable high-voltage DC bus capacitors are connected in parallel on both sides of the power battery, and the control method further includes: after receiving a power battery electrochemical impedance spectrum detection requirement instruction, controlling the capacitance of the variable high-voltage DC bus capacitor to decrease, or controlling the variable high-voltage DC bus capacitor to be completely disconnected.

[0021] To achieve the above object, the present invention further provides a vehicle controller, which includes a processor and a memory. A computer program is stored on the memory. When the computer program is executed by the processor, the on-vehicle charger control method described above is implemented.

[0022] To achieve the above object, the present invention further provides an on-vehicle charger control system, which includes an on-vehicle charger and the vehicle controller described above.

[0023] Compared with the prior art, the on-vehicle charger control method, system and vehicle controller provided by the present invention have the following beneficial effects:

[0024] The on-vehicle charger control method provided by the present invention first obtains target swept-frequency current information according to the received instruction for detecting the electrochemical impedance spectrum of the power battery when the on-vehicle charger is not connected to the AC power grid; then drives the isolated DC / DC circuit according to the target swept-frequency current information, so that the swept-frequency current can flow bidirectionally between the intermediate bus capacitor and the power battery. Since the intermediate bus capacitor can completely store the energy required for sweeping, the PFC circuit can be controlled not to work (i.e., the PFC circuit is turned off), and only the isolated DC / DC circuit is controlled to work bidirectionally to provide a bidirectional swept-frequency current. Thus, the EIS detection function can be enabled even when the on-vehicle charger is not connected to the AC power grid and is also not connected to the in-vehicle AC load, and further, the scenarios for enabling the EIS detection function can be effectively extended, allowing the EIS detection function to be enabled in scenarios where the charging gun, discharging gun is not plugged in or the in-vehicle AC load is not connected.

[0025] Since the on-vehicle charger control system and the vehicle controller provided by the present invention belong to the same inventive concept as the on-vehicle charger control method provided by the present invention, the on-vehicle charger control system and the vehicle controller provided by the present invention at least have all the beneficial effects of the on-vehicle charger control method provided by the present invention. Specifically, reference can be made to the relevant description of the beneficial effects of the on-vehicle charger control method provided by the present invention in the above text, and no further elaboration will be made here. Description of the Drawings

[0026] Figure 1 is a structural diagram of a common on-vehicle charger;

[0027] Figure 2a is a control schematic diagram of the PFC circuit during sweeping in the prior art;

[0028] Figure 2b is a control schematic diagram of the isolated DC / DC circuit during sweeping in the prior art;

[0029] Figure 3 is an application scenario diagram of the on-vehicle charger control method provided by an embodiment of the present invention;

[0030] Figure 4 is a flowchart of the on-vehicle charger control method provided by an embodiment of the present invention;

[0031] Figure 5 is a schematic diagram of the on-vehicle charger control method provided by an embodiment of the present invention when the isolated DC / DC circuit works alone;

[0032] Figure 6 is a closed-loop control schematic diagram of the isolated DC / DC circuit provided by an embodiment of the present invention;

[0033] Figure 7The overall flowchart of the on-vehicle charger control method provided by an embodiment of the present invention;

[0034] Figure 8 The block structure diagram of the vehicle controller provided by an embodiment of the present invention.

[0035] Among them, the reference numerals are explained as follows:

[0036] On-vehicle charger - 100; PFC circuit - 110; Intermediate bus capacitor - 120; Isolated DC / DC circuit - 130; Power battery - 200; AC power grid - 300; AC relay - 400; High-voltage DC bus capacitor - 610; Variable high-voltage DC bus capacitor - 620; Processor - 710; Communication interface - 720; Memory - 730; Communication bus - 740. Specific embodiments

[0037] The on-vehicle charger control method, system and vehicle controller proposed by the present invention are further described in detail below in conjunction with the accompanying drawings and specific embodiments. According to the following description, the advantages and features of the present invention will be clearer. It should be noted that the accompanying drawings are in a very simplified form and all use non-precise scales, only for the convenience of clearly assisting in explaining the purpose provided by the present invention. In order to make the purpose, features and advantages of the present invention more obvious and understandable, please refer to the accompanying drawings. It should be noted that the structures, scales, sizes, etc. shown in the drawings of this specification are only used to cooperate with the content disclosed in the specification for those familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention. Any modification of the structure, change of the proportional relationship or adjustment of the size, under the condition of being the same or approximate to the effect that the present invention can produce and the purpose that can be achieved, should still fall within the scope covered by the technical content disclosed by the present invention.

[0038] It should be noted that in this text, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprising", "including" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising one..." does not exclude the presence of additional identical elements in the process, method, article or device comprising the said element. The singular forms "a", "an" and "the" include plural objects, the term "or" is generally used in the sense of including "and / or", the term "several" is generally used in the sense of including "at least one", the term "at least two" is generally used in the sense of including "two or more", and in addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features.

[0039] In addition, in the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in connection with the said embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0040] The core idea of the present invention is to provide a vehicle-mounted charger control method, system and vehicle controller, which can not only effectively expand the scenarios for enabling the EIS detection function, allowing the EIS detection function to be enabled in scenarios where the charging gun, discharging gun is not plugged in or the in-vehicle AC load is not connected, but also effectively improve the detection accuracy of the EIS, thereby improving the accuracy of the power battery health state detection and safety state detection.

[0041] It should be noted that the on-vehicle charger control method, system, and vehicle controller provided by the present invention can be applied to new energy vehicles, which include passenger vehicles such as sports utility vehicles (SUVs), buses, trucks, and various commercial vehicles, and also include hybrid vehicles, pure electric vehicles, plug-in hybrid electric vehicles, etc. It should also be noted that, as can be understood by those skilled in the art, the on-vehicle charger control method provided by the present invention can not only be applied to the scenario where the on-vehicle charger is not connected to the AC grid and is also not connected to the in-vehicle AC load, but can also be further applied to the scenario where the on-vehicle charger is connected to the in-vehicle AC load.

[0042] To achieve the above idea, the present invention provides an on-vehicle charger control method for providing a swept-frequency current required for electrochemical impedance spectroscopy (EIS) detection of a power battery when the on-vehicle charger is not connected to the AC grid. Please refer to Figure 3 , which is an application scenario diagram of the on-vehicle charger control method provided by an embodiment of the present invention. As Figure 3 shown, the on-vehicle charger 100 includes a PFC circuit 110, an intermediate bus capacitor 120, and an isolated DC / DC circuit 130. The intermediate bus capacitor 120 and the isolated DC / DC circuit 130 are connected in parallel on the DC side of the PFC circuit 110, and the intermediate bus capacitor 120 is located between the PFC circuit 110 and the isolated DC / DC circuit 130. Further, the capacitance of the intermediate bus capacitor 120 is large enough to be able to completely store the energy required for sweeping the frequency.

[0043] Please continue to refer to Figure 4 , which is a flowchart of the on-vehicle charger control method provided by an embodiment of the present invention. As Figure 4 shown, the on-vehicle charger control method provided by the present invention includes the following steps:

[0044] Step S100: Obtain target swept-frequency current information according to the received EIS detection requirement instruction of the power battery 200;

[0045] Step S200: Drive the isolated DC / DC circuit 130 according to the target swept-frequency current information so that the swept-frequency current can flow bidirectionally between the intermediate bus capacitor 120 and the power battery 200.

[0046] It can be seen that the present invention can effectively expand the scenario for enabling the EIS detection function, allowing the EIS detection function to be enabled in the scenario where the charging gun, discharging gun are not inserted and the in-vehicle AC load is not connected.

[0047] Since the capacitance of the intermediate bus capacitor 120 is large enough, the intermediate bus capacitor 120 is sufficient to dynamically store and release the swept-frequency energy. Thus, when the on-vehicle charger is not connected to the AC grid 300 and is also not connected to the in-vehicle AC load, the PFC circuit 110 can be controlled not to work (i.e., turn off the PFC circuit 110), and only the isolated DC / DC circuit 130 is controlled to work bidirectionally to provide a bidirectional swept-frequency current (as Figure 5 shown, which is the schematic diagram of the on-vehicle charger control method provided by an embodiment of the present invention when the isolated DC / DC circuit 130 works alone), so that the scenario for enabling the EIS detection function can be effectively extended, allowing the EIS detection function to be enabled in scenarios where the charging gun, discharging gun is not plugged in or the in-vehicle AC load is not connected.

[0048] As Figure 5 shown, when the on-vehicle charger control method provided by the present invention works alone for the isolated DC / DC circuit 130, the intermediate bus capacitor 120 can dynamically store and release the swept-frequency energy without the intervention of the PFC circuit 110, and at this time, the isolated DC / DC circuit 130 works bidirectionally to directly provide a bidirectional swept-frequency current (i.e., the swept-frequency energy flows bidirectionally between the power battery 200 and the intermediate bus capacitor 120).

[0049] In some exemplary embodiments, driving the isolated DC / DC circuit 130 according to the target swept-frequency current information includes:

[0050] Driving the isolated DC / DC circuit 130 with the target of making the average value of the swept-frequency current zero according to the target swept-frequency current information.

[0051] Thus, by driving the isolated DC / DC circuit 130 with the target of making the average value of the swept-frequency current zero according to the target swept-frequency current information, it can be ensured that the positive and negative values of the bidirectional swept-frequency current are equal, so as to ensure that the net energy flow in each swept-frequency cycle tends to zero. Furthermore, the intermediate bus capacitor 120 does not need to undertake the task of large-capacity energy buffering, avoiding voltage fluctuations caused by unidirectional energy accumulation. At the same time, the dependence on the capacitance of the intermediate bus capacitor 120 can be reduced, indirectly alleviating the problem of the decrease in the current amplitude during high-frequency swept-frequency.

[0052] In some exemplary embodiments, driving the isolated DC / DC circuit 130 with the target of making the average value of the swept-frequency current zero according to the target swept-frequency current information includes:

[0053] In each swept-frequency cycle, first drive the isolated DC / DC circuit 130 to output a reverse swept-frequency current to the intermediate bus capacitor 120 according to the target swept-frequency current information, and then drive the isolated DC / DC circuit 130 to output a forward swept-frequency current to the power battery 200.

[0054] Thus, by driving the isolated DC / DC circuit 130 to output a reverse swept-frequency current to the intermediate bus capacitor 120 in each swept-frequency period, energy can be transferred from the power battery 200 to the intermediate bus capacitor 120, providing an energy reserve for subsequent output of a forward swept-frequency current.

[0055] In some exemplary embodiments, driving the isolated DC / DC circuit 130 with the swept-frequency current mean value being zero as the target according to the target swept-frequency current information includes:

[0056] Driving the isolated DC / DC circuit 130 to pre-charge the intermediate bus capacitor 120 to raise the voltage of the intermediate bus capacitor 120 to a preset value;

[0057] In each swept-frequency period, according to the target swept-frequency current information, first drive the isolated DC / DC circuit 130 to output a forward swept-frequency current to the power battery 200, and then drive the isolated DC / DC circuit 130 to output a reverse swept-frequency current to the intermediate bus capacitor 120.

[0058] Thus, after enabling the EIS detection function, by driving the isolated DC / DC circuit 130 to pre-charge the intermediate bus capacitor 120 to raise the voltage of the intermediate bus capacitor 120 to a preset value, the isolated DC / DC circuit 130 can provide bidirectional current through fast charge and discharge, and at the same time, it can also avoid shutdown protection caused by voltage over-limit due to transient energy fluctuations during the swept-frequency process.

[0059] It should be noted that as can be understood by those skilled in the art, after raising the voltage of the intermediate bus capacitor 120 to the preset value, in each swept-frequency period, according to the target swept-frequency current information, the isolated DC / DC circuit 130 can also be first driven to output a reverse swept-frequency current to the intermediate bus capacitor 120, and then the isolated DC / DC circuit 130 is driven to output a forward swept-frequency current to the power battery 200.

[0060] Furthermore, the preset value is the average of the safety upper limit and the safety lower limit corresponding to the intermediate bus capacitor 120. Thus, after enabling the EIS detection function, by pre-charging the voltage of the intermediate bus capacitor 120 to near the average of the safety upper limit and the safety lower limit, it can be ensured that the isolated DC / DC circuit 130 can provide bidirectional current through fast charge and discharge.

[0061] In some exemplary embodiments, the target swept-frequency current information includes the target amplitude and the target frequency of the swept-frequency current.

[0062] Driving the isolated DC / DC circuit 130 to output a forward swept-frequency current to the power battery 200 includes:

[0063] Drive the isolated DC / DC circuit 130 to output a forward swept-frequency current to the power battery 200 according to a strategy that the swept-frequency current gradually increases from zero to half of the target amplitude and then gradually decreases to zero.

[0064] Thus, by driving the isolated DC / DC circuit 130 to output a forward swept-frequency current according to a strategy that the swept-frequency current gradually increases from zero to half of the target amplitude and then gradually decreases to zero, the step mutation of the swept-frequency current can be avoided, and the instantaneous current stress on the power battery 200 can be significantly reduced.

[0065] In some exemplary embodiments, driving the isolated DC / DC circuit to output a reverse swept-frequency current to the intermediate bus capacitor includes:

[0066] Drive the isolated DC / DC circuit 130 to output a reverse swept-frequency current to the intermediate bus capacitor 120 according to a strategy that the absolute value of the swept-frequency current gradually increases from zero to half of the target amplitude and then gradually decreases to zero.

[0067] Thus, by driving the isolated DC / DC circuit 130 to output a reverse swept-frequency current according to a strategy that the absolute value of the swept-frequency current gradually increases from zero to half of the target amplitude and then gradually decreases to zero, the voltage mutation caused by the instantaneous large current impact can be avoided, and the bus voltage fluctuation can be reduced.

[0068] In some exemplary embodiments, driving the isolated DC / DC circuit 130 according to the target swept-frequency current information includes:

[0069] Drive the isolated DC / DC circuit 130 by using a closed-loop control method according to the target swept-frequency current information and the actually collected real-time swept-frequency current information.

[0070] Thus, by driving the isolated DC / DC circuit 130 by using a closed-loop control method according to the target swept-frequency current information and the actually collected real-time swept-frequency current information, precise control of the isolated DC / DC circuit 130 can be achieved, thereby effectively improving the EIS detection accuracy, and further effectively improving the accuracy of the health state detection and safety state detection of the power battery 200.

[0071] In some exemplary embodiments, driving the isolated DC / DC circuit 130 by using a closed-loop control method according to the target swept-frequency current information and the actually collected real-time swept-frequency current information includes:

[0072] Obtain the swept-frequency current deviation information according to the target swept-frequency current information and the actually collected real-time swept-frequency current information;

[0073] The sweep current deviation information is adjusted by using a PI controller and a PR controller to obtain the isolated DC / DC circuit control information;

[0074] The isolated DC / DC circuit control information is modulated to obtain a PWM signal;

[0075] The isolated DC / DC circuit 130 is driven according to the PWM signal.

[0076] Since the PI controller can effectively suppress the steady-state error and the PR controller can compensate for the amplitude attenuation through the resonance peak, by adjusting the sweep current deviation information by using the PI controller and the PR controller, the control accuracy of the isolated DC / DC circuit 130 can be further improved, thereby further effectively improving the EIS detection accuracy.

[0077] It should be noted that, as can be understood by those skilled in the art, in addition to using the PI controller and the PR controller to implement the closed-loop control of the isolated DC / DC circuit 130, the closed-loop control such as model predictive closed-loop control and feedforward + feedback closed-loop control can also be used to implement the closed-loop control of the isolated DC / DC circuit 130. For more content about the model predictive closed-loop control and the feedforward + feedback closed-loop control, reference can be made to the relevant content known to those skilled in the art for adaptive understanding, and details will not be elaborated here one by one.

[0078] In some exemplary embodiments, the on-vehicle charger control method provided by the present invention further includes:

[0079] The resonance frequency and resonance coefficient of the PR controller are adjusted in real time according to the target sweep current information.

[0080] Thus, by adjusting the resonance frequency and resonance coefficient of the PR controller in real time according to the target sweep current information (specifically, the frequency of the target sweep current), the amplitude attenuation of the sweep current caused by the circuit attenuation characteristics can be effectively compensated, so that the amplitude of the actually output sweep current can effectively reach the target value, thereby effectively improving the EIS detection accuracy and ensuring the accuracy of the battery health state detection and the safety state detection.

[0081] Please continue to refer to Figure 6 , which is the schematic diagram of the closed-loop control of the isolated DC / DC circuit 130 provided by an embodiment of the present invention. As Figure 6 shown, first, according to the EIS detection requirement, the target value of the sweep current is calculated as the target value of the output current of the on-vehicle charger 100, and then the target value of the output current of the on-vehicle charger 100 (that is, Figure 6 the I in ObcDes)Take the difference from the sampled value of the output current of the on-vehicle charger 100 (i.e., the actual swept-frequency current, i.e., Figure 6 the I in Obc ) to obtain the swept-frequency current deviation I ObcErr , and input the obtained swept-frequency current deviation I ObcErr into a PI (Proportional-Integral) controller, and then input the output result of the PI controller into a PR (Proportional-Resonant) controller to output the isolated DC / DC circuit control information. After the isolated DC / DC circuit control information output by the PR controller is modulated by a modulation algorithm, a PWM (Pulse Width Modulation) signal can be obtained. According to the PWM signal, driving the isolated DC / DC circuit 130 can generate the required swept-frequency current.

[0082] It should be noted that although Figure 6 this is described by taking the series connection of the PI controller and the PR controller as an example, as those skilled in the art can understand, this does not constitute a limitation to the present invention. In some other embodiments, the PI controller and the PR controller can also be arranged in parallel. At this time, the obtained swept-frequency current deviation I ObcErr can be respectively input into the PI controller and the PR controller, and by adding the output results of the PI controller and the PR controller according to a preset weight coefficient, the isolated DC / DC circuit control information can be obtained.

[0083] Please continue to refer to Figure 3 , as Figure 3 shown, in some exemplary embodiments, variable high-voltage DC bus capacitors 620 are arranged in parallel on both sides of the power battery 200, and the on-vehicle charger control method further includes:

[0084] After receiving the electrochemical impedance spectroscopy detection requirement instruction of the power battery 200, control the capacitance of the variable high-voltage DC bus capacitor 620 to decrease, or control the variable high-voltage DC bus capacitor 620 to be completely disconnected.

[0085] Thus, by controlling the capacitance of the variable high-voltage DC bus capacitor 620 to decrease, or controlling the variable high-voltage DC bus capacitor 620 to be completely disconnected after the EIS detection function is enabled, it can effectively avoid the problem that when the swept-frequency current frequency is relatively high, the amplitude of the current I bat injected into the power battery 200 will further decrease after the swept-frequency current is filtered by the variable high-voltage DC bus capacitor 620, thereby further improving the EIS detection accuracy. It should be noted that as those skilled in the art can understand, a series of switches can be used to change the capacitance of the variable high-voltage DC bus capacitor 620.

[0086] For the sake of easy understanding, the following combinesFigure 7 The overall process of the on-vehicle charger control method provided by the present invention will be described. As Figure 7 shown, after receiving the EIS function enabling instruction, first control the isolated DC / DC circuit 130 to pre-charge the intermediate bus capacitor 120 to raise the voltage of the intermediate bus capacitor 120 to near the average value of the safe upper and lower limits; then drive the isolated DC / DC circuit 130 according to the target frequency and target amplitude of the swept-frequency current to complete the swept-frequency target. After that, according to the EIS detection requirements, change the target frequency and target amplitude of the swept-frequency current, and return to execute the above step of driving the isolated DC / DC circuit 130 until receiving the EIS function disabling instruction.

[0087] Based on the same inventive concept, the present invention also provides a vehicle controller. Please refer to Figure 8 , which is a schematic block diagram of the vehicle controller provided by an embodiment of the present invention. As Figure 8 shown, the vehicle controller includes a processor 710 and a memory 730. A computer program is stored on the memory 730. When the computer program is executed by the processor 710, the on-vehicle charger control method described above is implemented. Since the vehicle controller provided by the present invention and the on-vehicle charger control method provided by the present invention belong to the same inventive concept, the vehicle controller provided by the present invention has at least all the beneficial effects of the on-vehicle charger control method provided by the present invention. For details, reference can be made to the relevant descriptions of the beneficial effects of the on-vehicle charger control method provided by the present invention above, and no further elaboration will be made here.

[0088] It should be noted that, as can be understood by those skilled in the art, the vehicle controller provided by the present invention can not only control the on-vehicle charger 100 to provide the swept-frequency current required for the electrochemical impedance spectrum detection of the power battery 200 according to the control method provided by the present invention when the on-vehicle charger 100 is not connected to the AC power grid 300, but also control the on-vehicle charger 100 to provide the swept-frequency current required for the electrochemical impedance spectrum detection of the power battery 200 in the forward charging swept-frequency mode according to the existing technical solution when the on-vehicle charger 100 is connected to the AC power grid 300.

[0089] As Figure 8As shown, the vehicle controller further includes a communication interface 720 and a communication bus 740. Among them, the processor 710, the communication interface 720, and the memory 730 complete mutual communication through the communication bus 740. The communication bus 740 includes but is not limited to a CAN bus, etc. For the convenience of representation, only a thick line is used in the figure, but it does not mean that there is only one bus or one type of bus. The communication interface 720 is used for communication between the above-mentioned vehicle controller (such as a charger controller) and other vehicle controllers (such as a vehicle controller, a motor controller, a battery management controller, etc., not shown in the figure). The communication bus 740 connects the above-mentioned vehicle controller (such as a charger controller) and other vehicle controllers (such as a vehicle controller, a motor controller, a battery management controller, etc., not shown in the figure) and other scattered nodes into a closed-loop system, enabling each vehicle controller to perform communication and data transmission in multiple working states (parking state, charging state, starting state, running state, vehicle forward and reverse states, feedback braking state, mechanical braking state, general fault state, major fault state), so as to realize the control function of the vehicle.

[0090] The processor 710 referred to in the present invention may be a central processing unit (CPU), or may also be other general-purpose processors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc. The processor 710 is the control center of the vehicle controller, and connects various parts of the entire vehicle controller through various interfaces and lines.

[0091] The memory 730 can be used to store the computer program. By running or executing the computer program stored in the memory 730 and invoking the data stored in the memory 730, the processor 710 realizes various functions of the vehicle controller. The memory 730 may include non-volatile and / or volatile memory. The non-volatile memory may include read-only memory (ROM), programmable memory (PROM), electrically programmable memory (EPROM), electrically erasable programmable memory (EEPROM), or flash memory. The volatile memory may include random access memory (RAM) or external cache memory. By way of illustration and not limitation, random access memory is available in various forms, such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous random access memory (SDRAM), double data rate synchronous random access memory (DDR SDRAM), enhanced synchronous random access memory (ESDRAM), synchronous link dynamic random access memory (SLDRAM), Rambus direct random access memory (RDRAM), direct memory bus dynamic random access memory (DRDRAM), and Rambus dynamic random access memory (RDRAM), etc.

[0092] Based on the same inventive concept, the present invention further provides a vehicle-mounted charger control system, including the vehicle-mounted charger 100 described above and the vehicle controller described above. Since the vehicle-mounted charger control system provided by the present invention includes the vehicle controller provided by the present invention, the vehicle-mounted charger control system provided by the present invention also has at least all the beneficial effects of the vehicle-mounted charger control method provided by the present invention. For details, reference can be made to the relevant descriptions of the beneficial effects of the vehicle-mounted charger control method provided by the present invention in the foregoing, and no further elaboration will be made here.

[0093] In summary, compared with the prior art, the vehicle-mounted charger control method, system, and vehicle controller provided by the present invention have the following beneficial effects:

[0094] When the on-vehicle charger 100 is not connected to the AC power grid 300, the present invention first obtains target swept-frequency current information according to the received electrochemical impedance spectroscopy (EIS) detection requirement instruction of the power battery 200; then drives the isolated DC / DC circuit 130 according to the target swept-frequency current information, so that the swept-frequency current can flow bidirectionally between the intermediate bus capacitor 120 and the power battery 200. Since the capacitance of the intermediate bus capacitor 120 is large enough, the intermediate bus capacitor 120 is sufficient to dynamically store and release the swept-frequency energy. Thus, when the on-vehicle charger is not connected to the AC power grid 300 and is also not connected to the in-vehicle AC load, the PFC circuit 110 can be controlled not to work (i.e., turn off the PFC circuit 110), and only the isolated DC / DC circuit 130 is controlled to work bidirectionally to provide a bidirectional swept-frequency current. Therefore, the EIS detection function can be enabled even when the on-vehicle charger 100 is not connected to the AC power grid 300, and further, the scenarios for enabling the EIS detection function can be effectively extended, allowing the EIS detection function to be enabled in scenarios where the charging gun, discharging gun is not plugged in or the in-vehicle AC load is not connected.

[0095] It should be noted that computer program code for performing the operations of the present invention can be written in one or more programming languages or combinations thereof. The programming languages include object-oriented programming languages such as Java, Smalltalk, C++, and also include conventional procedural programming languages such as the "C" language or similar programming languages. The program code can be executed entirely on the user's computer, partially on the user's computer, executed as an independent software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In the case of a remote computer, the remote computer can be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or can be connected to an external computer (for example, by using an Internet service provider to connect through the Internet).

[0096] It should be noted that the devices and methods disclosed in the embodiments of this article can also be implemented in other ways. The device embodiments described above are merely illustrative. For example, the flowcharts and block diagrams in the accompanying drawings show the possible architectures, functions, and operations of devices, methods, and computer program products according to multiple embodiments of this article. In this regard, each block in the flowchart or block diagram may represent a module, a program, or a part of code, and the part of the module, program segment, or code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order than that marked in the accompanying drawings. For example, two consecutive blocks can actually be executed substantially in parallel, and they can sometimes be executed in the reverse order, depending on the functions involved. It should also be noted that each block in the block diagram and / or flowchart, as well as the combination of blocks in the block diagram and / or flowchart, can be implemented by a dedicated hardware-based system for performing the specified functions or actions, or can be implemented by a combination of dedicated hardware and computer instructions. Additionally, in each embodiment of this article, the functional modules can be integrated together to form an independent part, or each module can exist separately, or two or more modules can be integrated to form an independent part.

[0097] It should also be noted that the above description is only a description of the preferred embodiments of the present invention, and does not limit the scope of the present invention in any way. Any changes and modifications made by those of ordinary skill in the art of the present invention based on the above disclosure belong to the protection scope of the present invention. Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations fall within the scope of the present invention and its equivalent technologies, the present invention also intends to include these modifications and variations.

Claims

1. A vehicle charger control method, characterized in that: The on-board charger is used to provide the power battery with a sweeping current required for electrochemical impedance spectroscopy detection when the on-board charger is not connected to the AC power grid. The on-board charger includes a PFC circuit, an intermediate bus capacitor and an isolated DC / DC circuit. The intermediate bus capacitor and the isolated DC / DC circuit are arranged in parallel on the DC side of the PFC circuit, and the intermediate bus capacitor is located between the PFC circuit and the isolated DC / DC circuit. The control method includes: According to the received power battery electrochemical impedance spectroscopy detection demand instruction, the target frequency sweep current information is obtained; The isolated DC / DC circuit is driven according to the target frequency sweeping current information, so that the frequency sweeping current can flow bidirectionally between the intermediate bus capacitor and the power battery.

2. The vehicle charger control method according to claim 1, characterized in that: The step of driving the isolated DC / DC circuit according to the target frequency sweep current information comprises: The isolated DC / DC circuit is driven according to the target frequency sweep current information with the frequency sweep current average being zero as a target.

3. The vehicle charger control method according to claim 2, characterized in that: The step of driving the isolated DC / DC circuit with a target of zero mean value of the swept frequency current according to the target swept frequency current information includes: In each frequency sweep cycle, the isolated DC / DC circuit is first driven to output a reverse frequency sweep current to the intermediate bus capacitor according to the target frequency sweep current information, and then the isolated DC / DC circuit is driven to output a forward frequency sweep current to the power battery.

4. The vehicle charger control method according to claim 2, characterized in that: The step of driving the isolated DC / DC circuit with a target of zero mean value of the swept frequency current according to the target swept frequency current information includes: Driving the isolated DC / DC circuit to pre-charge the intermediate bus capacitor to raise the voltage of the intermediate bus capacitor to a preset value; In each frequency sweeping cycle, the isolated DC / DC circuit is first driven to output a forward frequency sweeping current to the power battery according to the target frequency sweeping current information, and then the isolated DC / DC circuit is driven to output a reverse frequency sweeping current to the intermediate bus capacitor.

5. The vehicle charger control method according to claim 3 or 4, characterized in that: The target frequency sweeping current information includes a target amplitude and a target frequency sweeping current; The step of driving the isolated DC / DC circuit to output a forward frequency sweep current to the power battery comprises: Driving the isolated DC / DC circuit to output a forward sweep current to the power battery according to a strategy in which the sweep current gradually increases from zero to half of the target amplitude and then gradually decreases to zero; The step of driving the isolated DC / DC circuit to output a reverse frequency sweep current to the intermediate bus capacitor comprises: The isolated DC / DC circuit is driven to output a reverse frequency sweeping current to the intermediate bus capacitor according to a strategy in which the absolute value of the frequency sweeping current gradually increases from zero to half of the target amplitude and then gradually decreases to zero.

6. The vehicle charger control method according to claim 1, characterized in that: The step of driving the isolated DC / DC circuit according to the target frequency sweep current information comprises: The isolated DC / DC circuit is driven by a closed-loop control method according to the target frequency sweeping current information and the actual frequency sweeping current information collected in real time.

7. The vehicle charger control method according to claim 6, characterized in that: The method of driving the isolated DC / DC circuit by a closed-loop control method according to the target frequency sweeping current information and the actual frequency sweeping current information collected in real time includes: Acquire frequency sweeping current deviation information according to the target frequency sweeping current information and the actual frequency sweeping current information collected in real time; The PI controller and the PR controller are used to adjust the frequency sweeping current deviation information to obtain isolated DC / DC circuit control information; Modulating the isolated DC / DC circuit control information to obtain a PWM signal; The isolated DC / DC circuit is driven according to the PWM signal.

8. The vehicle charger control method according to claim 7, characterized in that: The control method further comprises: The resonant frequency and the resonant coefficient of the PR controller are adjusted in real time according to the target frequency sweeping current information.

9. The vehicle charger control method according to claim 1, characterized in that: Variable high-voltage DC bus capacitors are connected in parallel on both sides of the power battery, and the control method further includes: After receiving the power battery electrochemical impedance spectrum detection demand instruction, the capacitance of the variable high-voltage DC bus capacitor is controlled to decrease, or the variable high-voltage DC bus capacitor is controlled to be completely disconnected.

10. A vehicle controller, characterized in that: The invention comprises a processor and a memory, wherein a computer program is stored in the memory, and when the computer program is executed by the processor, the vehicle charger control method according to any one of claims 1 to 9 is implemented.

11. A vehicle charger control system, characterized in that: It comprises an on-board charger and the vehicle controller as claimed in claim 10.

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