Vehicle charger and control method thereof

Abstract

The present application provides an on-board charger and a control method thereof. Since the transformer side of the AC / AC conversion circuit is connected to the AC side of the AC / DC conversion circuit via a transformer, the on-board charger has a single-stage structure. Furthermore, since the instantaneous sampling value of the grid-side current is equal to its instantaneous reference value when stable, and the instantaneous reference value of the grid-side current is determined by the phase of the instantaneous sampling value of the grid-side voltage and the reference peak value of the grid-side current, the on-board charger has a PFC function. Furthermore, since the battery-side charging power can be indirectly controlled by controlling the grid-side current, the on-board charger has a battery-side voltage and current control function. Furthermore, since phase shift control is performed on the two conversion circuits, and the phase shift control enables soft switching of the power devices in the two conversion circuits, and the single-stage structure reduces the current flowing through the devices, efficiency is improved. Therefore, the single-stage structure efficiently implements the PFC and battery-side voltage and current control functions of the two-stage isolated on-board charger.

Description

Technical Field

[0001] The present invention relates to the technical field of power electronics, and in particular to an on-board charger and a control method thereof. Background Art

[0002] At present, the market generally adopts two-stage isolated car charger, which can also be called two-stage structure. Its specific structure can be found in Figure 1 In the two-stage isolation type, it includes: PFC (Power Factor Correction) circuit and isolated DC / DC conversion circuit; among them, the PFC circuit is responsible for correcting the power factor of the grid current and maintaining the stability of the bipolar voltage of the DC bus Cbus. The isolated DC / DC conversion circuit controls the battery side voltage or current of the on-board charger to complete the battery charging process.

[0003] Generally speaking, since a two-stage isolated on-board charger requires more power devices, the overall cost of the on-board charger increases. To reduce the overall cost of the on-board charger, a single-stage isolated on-board charger, also known as a single-stage structure, can be used.

[0004] Therefore, how to use a single-stage isolated on-board charger to efficiently implement the PFC function and battery-side voltage and current control function of a two-stage isolated on-board charger is a technical problem that needs to be solved urgently. Summary of the Invention

[0005] In view of this, the present invention provides an on-board charger and a control method thereof, so as to efficiently implement the PFC function and battery-side voltage and current control function of a two-stage isolated on-board charger by utilizing a single-stage isolated on-board charger.

[0006] To achieve the above objectives, the embodiments of the present invention provide the following technical solutions:

[0007] In one aspect, the present application provides a method for controlling an on-board charger, wherein a transformer side of a bridge-type controllable AC / AC conversion circuit is connected to an AC side of a bridge-type controllable AC / DC conversion circuit via a transformer. The method for controlling the on-board charger includes:

[0008] adjusting a reference peak value of the grid-side current of the on-board charger according to a deviation of the sampled value of the battery-side voltage relative to a reference value of the battery-side voltage;

[0009] Converting the reference peak value of the grid-side current into the instantaneous reference value of the grid-side current according to the obtained phase of the instantaneous sampling value of the grid-side voltage of the on-board charger;

[0010] performing phase shift control on the two conversion circuits according to the instantaneous reference value of the grid-side current, the instantaneous sampled value of the grid-side voltage, and the sampled value of the battery-side voltage; the phase shift control enables the power devices in the two conversion circuits to achieve soft switching;

[0011] The phase shift control is corrected according to a deviation of the instantaneous sampling value of the grid-side current relative to the instantaneous reference value of the grid-side current.

[0012] Optionally, the phase shift control includes:

[0013] Determining a phase shift angle of the transformer-side output voltage of the AC / AC conversion circuit and a phase shift angle of the AC-side output voltage of the AC / DC conversion circuit based on the instantaneous reference value of the grid-side current, the instantaneous sampled value of the grid-side voltage, the sampled value of the battery-side voltage, and in combination with the switching frequency of the on-board charger and the equivalent total reactance of all passive components in the on-board charger;

[0014] generating driving signals for two conversion circuits respectively according to the two phase shift angles;

[0015] According to the driving signal of each conversion circuit, each conversion circuit is driven to perform power conversion.

[0016] Optionally, determining the phase shift angle of the transformer-side output voltage of the AC / AC conversion circuit and the phase shift angle of the AC-side output voltage of the AC / DC conversion circuit includes:

[0017] Determining a phase shift angle of a transformer-side output voltage of the AC / AC conversion circuit and a relationship between the two phase shift angles based on the instantaneous reference value of the grid-side current, the instantaneous sampled value of the grid-side voltage, and the sampled value of the battery-side voltage, in combination with the switching frequency of the on-board charger and the equivalent total reactance of all passive components in the on-board charger; the phase shift angle of the transformer-side output voltage of the AC / AC conversion circuit being within a range of values ​​that enables soft switching of power devices in the two conversion circuits;

[0018] The phase shift angle of the AC side output voltage of the AC / DC conversion circuit is determined according to the phase shift angle of the transformer side output voltage of the AC / AC conversion circuit and the relationship between the two phase shift angles.

[0019] Optionally, the phase shift control is corrected according to a deviation of the instantaneous sampling value of the grid-side current relative to the instantaneous reference value of the grid-side current, including:

[0020] At least one phase shift angle in the phase shift control is corrected.

[0021] Optionally, the reference value of the battery side voltage is equal to the charging voltage of the battery connected to the vehicle charger under constant voltage trickle charging conditions.

[0022] Optionally, adjusting a reference peak value of the grid-side current of the on-board charger according to a deviation of the sampled value of the battery-side voltage relative to a reference value of the battery-side voltage includes:

[0023] adjusting the reference value of the battery side current according to a deviation of the sampled value of the battery side voltage relative to the reference value of the battery side voltage;

[0024] The reference peak value of the grid-side current is adjusted according to a deviation of the sampled value of the battery-side current relative to the reference value of the power-side current.

[0025] Optionally, the reference value of the battery-side current is less than or equal to the charging current of the battery connected to the on-board charger under constant current charging conditions.

[0026] Optionally, the charging current of the battery under constant current charging conditions is determined according to the working state of the on-board charger and user instructions.

[0027] Another aspect of the present application provides a vehicle charger, comprising: a controller, a transformer, at least one passive component, and a bridge-type controllable AC / AC conversion circuit and an AC / DC conversion circuit; wherein:

[0028] The transformer side of the AC / AC conversion circuit is connected to the AC side of the AC / DC conversion circuit through the transformer; the grid side of the AC / AC conversion circuit serves as the grid side of the on-board charger, and the DC side of the AC / DC conversion circuit serves as the battery side of the on-board charger;

[0029] The passive components are arranged on the primary side and / or the secondary side of the transformer, and each of the passive components includes at least an inductor;

[0030] The AC / AC conversion circuit and the AC / DC conversion circuit are both controlled by the controller, and the controller is used to execute the control method of the vehicle charger as described in any one of the above aspects of the present application.

[0031] Optionally, the AC / AC conversion circuit is a half-bridge topology or a full-bridge topology;

[0032] The AC / DC conversion circuit is a half-bridge topology or a full-bridge topology.

[0033] Optionally, the passive component includes: an inductor branch; the inductor branch includes: at least one inductor; wherein:

[0034] If the number of the inductors is greater than 1, the inductors are connected in series, in parallel, or in series and parallel.

[0035] Optionally, the passive device further includes: a capacitor branch, the capacitor branch being connected in series or in parallel with the inductor branch;

[0036] The capacitor branch includes at least one capacitor; wherein:

[0037] If the number of the capacitors is greater than 1, the capacitors are connected in series, in parallel, or in series and parallel.

[0038] Optionally, the switching frequency of the on-board charger is greater than the resonant frequency of the resonant cavity in the on-board charger.

[0039] Optionally, it further includes: two filters; wherein:

[0040] One of the filters is arranged on the grid side of the AC / AC conversion circuit, and the other filter is arranged on the DC side of the AC / DC conversion circuit.

[0041] As can be seen from the above technical solution, the present invention provides a control method for an on-board charger. In this control method, since the transformer side of the AC / AC conversion circuit is connected to the AC side of the AC / DC conversion circuit via a transformer, the on-board charger is a single-stage isolated on-board charger. Furthermore, since the instantaneous sampling value of the grid-side current is equal to its instantaneous reference value during stability, and the instantaneous reference value of the grid-side current is determined by the phase of the instantaneous sampling value of the grid-side voltage and the reference peak value of the grid-side current, the on-board charger has a power factor control (PFC) function. Furthermore, since the battery-side charging power can be indirectly controlled by controlling the grid-side current, the on-board charger has a battery-side voltage and current control function. Furthermore, since the two conversion circuits are phase-shifted, the phase-shift control enables soft switching of the power devices in the two conversion circuits, and the single-stage isolated on-board charger reduces the number of devices through which the current flows, thereby improving the efficiency of the on-board charger. In summary, this control method can efficiently implement the PFC function and battery-side voltage and current control functions of a two-stage isolated on-board charger using a single-stage isolated on-board charger. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0043] Figure 1 This is a schematic diagram of the structure of a two-stage isolated on-board charger in the prior art;

[0044] Figure 2 A schematic structural diagram of an embodiment of a vehicle charger provided in an embodiment of the present application;

[0045] Figure 3 and Figure 4 Flowcharts showing two implementation methods of the control method of the vehicle charger provided in the embodiments of the present application;

[0046] Figure 5 A schematic diagram of an implementation of a control loop for an on-board charger;

[0047] Figure 6 The fundamental wave equivalent circuit of the on-board charger provided in the embodiment of the present application;

[0048] Figure 7 for Figure 6 Power transfer vector diagram;

[0049] Figure 8a and Figure 8b The following are schematic diagrams of simulation test results of grid-side voltage and grid-side current respectively;

[0050] Figure 8c and Figure 8d The following are schematic diagrams of simulation test results of battery side voltage and battery side current;

[0051] Figure 9 A flow chart of a specific implementation of the phase shift control provided in this application;

[0052] Figure 10 A schematic diagram of another embodiment of a control loop of an on-board charger;

[0053] Figure 11a Schematic diagram of driving signals of two conversion circuits in one embodiment of an on-board charger during the positive half cycle of the power grid;

[0054] Figure 11b Schematic diagram of driving signals of two conversion circuits of an on-board charger in a negative half cycle of the power grid;

[0055] Figure 12a Schematic diagram of driving signals of two conversion circuits in another embodiment of an on-board charger during the positive half cycle of the power grid;

[0056] Figure 12b Schematic diagram of driving signals of two conversion circuits in another embodiment of an on-board charger during the negative half cycle of the power grid;

[0057] Figure 13a and Figure 13b The following are the structural diagrams of the half-bridge cycloconversion circuit and the full-bridge cycloconversion circuit respectively;

[0058] Figure 13c and Figure 13d The following are the structural diagrams of the half-bridge rectifier circuit and the full-bridge rectifier circuit respectively;

[0059] Figure 14 A flow chart of another specific implementation of the phase shift control provided in this application;

[0060] Figure 15 A schematic structural diagram of another embodiment of the vehicle charger provided in the present application. DETAILED DESCRIPTION

[0061] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0062] In this application, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus comprising the element.

[0063] In order to improve the efficiency of a single-stage isolated on-board charger and enable the single-stage isolated on-board charger to have a PFC function, an embodiment of the present application provides a control method for the on-board charger.

[0064] like Figure 2As shown, the on-board charger includes a transformer 10, an AC / AC conversion circuit 30, and an AC / DC conversion circuit 40. The transformer side of the AC / AC conversion circuit 30 is connected to the AC side of the AC / DC conversion circuit 40 through the transformer 10, and passive components 20 are provided on the primary side and / or the secondary side of the transformer 10. Each passive component 20 includes at least an inductor. The AC / AC conversion circuit 30 and the AC / DC conversion circuit 40 both have a bridge-type controllable topology.

[0065] The control method of the vehicle charger is as follows: Figure 3 As shown, the specific steps include:

[0066] S110 : Adjusting a reference peak value of a grid-side current of the vehicle charger according to a deviation of a sampled value of the battery-side voltage relative to a reference value of the battery-side voltage.

[0067] The reference peak value of the grid-side current is the reference value of the peak value of the grid-side current; the reference value of the battery-side voltage is equal to the charging voltage of the battery connected to the vehicle charger under constant-voltage trickle charging conditions; it should be noted that, under normal circumstances, the above-mentioned charging voltage is not adjusted.

[0068] In practical applications, such as Figure 4 As shown, the specific implementation of step S110 includes the following steps:

[0069] S210 : Adjusting a reference value for adjusting the battery-side current according to a deviation of the sampled value of the battery-side voltage relative to a reference value of the battery-side voltage.

[0070] Among them, the reference value of the battery side current is less than or equal to the charging current of the battery connected to the vehicle charger under constant current charging conditions; in actual application, the above charging current is determined according to the working status of the vehicle charger and user instructions, and therefore the above charging current can be adjusted according to the working status of the vehicle charger and user instructions.

[0071] In practical applications, the control loop corresponding to step S210 is as follows: Figure 5 01 in the figure specifically includes: a first PI controller and a limiter, and the limit value of the limiter is the charging current under the constant current charging condition; wherein, Vdc_ref is the reference value of the battery side voltage, Vdc is the sampled value of the battery side voltage, and Idc_ref is the reference value of the battery side current.

[0072] S220 : Adjust the reference peak value of the grid-side current according to the deviation of the sampled value of the battery-side current relative to the reference value of the power-side current.

[0073] In practical applications, the control loop corresponding to step S220 is as follows: Figure 502 in the embodiment specifically includes: a second PI controller; wherein Idc is a sampled value of the battery side current, and Ig_ref is a reference peak value of the grid side current.

[0074] It can be seen from step S210 and step S220 that in the initial stage of charging, the battery is more depleted and the terminal voltage of the battery is lower. Therefore, the sampling value of the battery side voltage is always much smaller than the reference value of the battery side voltage, so that the reference value of the adjusted battery side current is always equal to the charging current of the battery under the constant current charging condition, so that the battery is in the constant current charging condition; as the battery is gradually fully charged, the terminal voltage of the battery continues to rise and is slightly greater than the reference value of the battery side voltage, and the adjusted reference value of the battery side current begins to be less than the charging current under the constant current charging condition and gradually decreases. Finally, the sampling value of the battery side voltage stabilizes at the reference value of the battery side voltage, so that the battery is in the constant voltage trickle charging condition.

[0075] S120 : Convert the reference peak value of the grid-side current into an instantaneous reference value of the grid-side current according to the obtained phase of the instantaneous sampling value of the grid-side voltage of the vehicle charger.

[0076] The instantaneous reference value of the grid-side current is a reference value of the instantaneous value of the grid-side current.

[0077] In practical applications, the control loop corresponding to step S120 is as follows: Figure 5 03 in the figure specifically includes: PLL (Phase Locked Loop) and parameter conversion link; wherein vg is the instantaneous sampling value of the grid-side voltage, θ is the phase of the instantaneous sampling value of the grid-side voltage, sinθ is the transfer function of the parameter conversion link, and ig_ref is the instantaneous reference value of the grid-side current.

[0078] S130 , performing phase shift control on the two conversion circuits according to the instantaneous reference value of the grid-side current, the instantaneous sampling value of the grid-side voltage, and the sampling value of the battery-side voltage.

[0079] Phase-shift control controls the power transmission of the on-board charger by adjusting the phase-shift angle of the transformer-side output voltage of the AC / AC conversion circuit and the phase-shift angle of the AC-side output voltage of the AC / DC conversion circuit, that is, by adjusting the phase difference between the two output voltages. Furthermore, during this adjustment, the power devices in the two conversion circuits can achieve soft switching. The following embodiments will explain phase-shift control in detail and will not be repeated here.

[0080] In practical applications, the control loop corresponding to step S130 is as follows: Figure 5 04 in the control loop, the specific control process of the control loop will be described in detail in the following embodiments and will not be repeated here.

[0081] The following describes in detail how to control the power transmission of the on-board charger through the two phase differences mentioned above:

[0082] By performing fundamental wave equivalent analysis on the on-board charger, its equivalent circuit is obtained, such as Figure 6 shown; in Figure 6 In the AC / AC conversion circuit, the transformer side output voltage is fundamental component of Characterizes the output voltage of the transformer side of the AC / AC conversion circuit, and the output voltage of the AC side of the AC / DC conversion circuit fundamental component of Characterizes the AC side output voltage of the AC / DC conversion circuit. In practical applications, Among them, β / 2 is the fundamental component The phase shift angle is α, which is the phase shift angle of the output voltage on the transformer side of the AC / AC conversion circuit, and β is the phase shift angle of the output voltage on the AC side of the AC / DC conversion circuit.

[0083] In addition, Figure 6 middle, is the equivalent total reactance of all passive components, specifically: It represents the current on the above-mentioned equivalent total reactance, that is, the current on the transformer.

[0084] According to the above equivalent circuit, we can draw Figure 7 The power transfer vector diagram shown is composed of Figure 7 It can be seen that as α and β change, the voltage across the equivalent total reactance The modulus and argument of The modulus and argument of the vehicle's current will also change accordingly. Therefore, by adjusting α and β, the magnitude and direction of the current on the equivalent total reactance can be controlled, thereby controlling the direction and magnitude of the transmission power of the vehicle charger, that is, controlling the power transmission of the vehicle charger.

[0085] It should be noted that when the phase shift angle of the transformer-side output voltage of the AC / AC conversion circuit is positive, it indicates that the phase of the transformer-side output voltage of the AC / AC conversion circuit after phase shifting is ahead of the phase when the phase shift angle is zero; conversely, it indicates that the phase of the transformer-side output voltage of the AC / AC conversion circuit after phase shifting lags behind the phase when the phase shift angle is zero; when the phase shift angle of the AC-side output voltage of the AC / DC conversion circuit is negative, it indicates that the phase of the AC-side output voltage of the AC / DC conversion circuit after phase shifting lags behind the phase when the phase shift angle is zero; conversely, it indicates that the phase of the AC-side output voltage of the AC / DC conversion circuit after phase shifting is ahead of the phase when the phase shift angle is zero.

[0086] S140 . Correct the phase shift control according to a deviation of the instantaneous sampling value of the grid-side current relative to the instantaneous reference value of the grid-side current.

[0087] In practical applications, the control loop corresponding to step S140 is as follows: Figure 5 05 in the embodiment specifically includes: a resonant PI controller; wherein ig is an instantaneous sampling value of the grid-side current.

[0088] In practical applications, the phase shift control may be corrected by correcting the phase shift angle of the transformer-side output voltage of the AC / AC conversion circuit, or by correcting the phase shift angle of the AC-side output voltage of the AC / DC conversion circuit, or by correcting the phase shift angle of both the transformer-side output voltage of the AC / AC conversion circuit and the AC-side output voltage of the AC / DC conversion circuit simultaneously. The correction is not specifically limited here and may be determined according to specific circumstances.

[0089] In this on-board charger control method, since the transformer side of the AC / AC conversion circuit is connected to the AC side of the AC / DC conversion circuit via a transformer, the on-board charger is a single-stage isolated on-board charger. Furthermore, since the instantaneous sampled value of the grid-side current is equal to the instantaneous reference value of the grid-side current when the on-board charger reaches a stable state, and the instantaneous reference value of the grid-side current is determined by the phase of the instantaneous sampled value of the grid-side voltage and the reference peak value of the grid-side current, the grid-side current and the grid-side voltage are in phase, i.e., the on-board charger has a PFC function. Furthermore, since the two conversion circuits are phase-shifted, and phase-shifting control enables soft switching of the power devices in the two conversion circuits, and the single-stage isolated on-board charger reduces the number of devices through which the current flows, the efficiency of the on-board charger is improved. In summary, this control method can efficiently implement the PFC function and battery-side voltage and current control functions of a two-stage isolated on-board charger using a single-stage isolated on-board charger.

[0090] In order to verify the effectiveness of the control method of the vehicle charger provided in this application, a simulation test of the vehicle charger was carried out using the control method. The test results are as follows: Figure 8a 、 Figure 8b 、 Figure 8c and Figure 8d shown by Figure 8a and Figure 8b It can be seen that the grid side voltage and grid side current are in anti-phase, thus achieving grid side power factor and current control; Figure 8c and Figure 8d It can be seen that the vehicle charger can complete the battery charging function according to the preset battery side voltage and battery side current.

[0091] It should be noted that Figure 8a and Figure 8bThe simulated THD (Total Harmonic Distortion) is 2%.

[0092] It is worth noting that since the on-board charger includes a transformer and a bridge-type controllable AC / AC conversion circuit and an AC / DC conversion circuit, and the transformer side of the AC / AC conversion circuit is connected to the AC side of the AC / DC conversion circuit through the transformer, the power devices included in the on-board charger are reduced, thereby reducing the overall cost of the on-board charger; in addition, the power devices included in the on-board charger are reduced, so the corresponding control investment is also reduced, thereby reducing the control cost of the on-board charger; in addition, in the on-board charger, there is no need to set a bus electrolytic capacitor, so the overall cost of the on-board charger can be further reduced, and the overall volume of the on-board charger is also reduced and the service life of the on-board charger is extended.

[0093] Another embodiment of the present application describes in detail the specific process of phase shift output control, and the process is as follows: Figure 9 As shown, the specific steps include:

[0094] S310. Determine the phase shift angle of the transformer-side output voltage of the AC / AC conversion circuit and the phase shift angle of the AC-side output voltage of the AC / DC conversion circuit based on the instantaneous reference value of the grid-side current, the instantaneous sampled value of the grid-side voltage, the sampled value of the battery-side voltage, the switching frequency of the on-board charger, and the equivalent total reactance of all passive components in the on-board charger.

[0095] The switching frequency of the on-board charger is the operating frequency of the switching tubes of the two conversion circuits in the on-board charger.

[0096] In practical applications, the control loop corresponding to step S310 is as follows: Figure 10 Calculation step 06 in the figure, where f is the switching frequency of the on-board charger, Z is the equivalent total reactance, α is the phase shift angle of the output voltage on the transformer side of the AC / AC conversion circuit, and β is the phase shift angle of the output voltage on the AC side of the AC / DC conversion circuit.

[0097] S320 : Generate driving signals for two conversion circuits respectively according to the two phase shift angles, and drive each conversion circuit to perform power conversion according to the driving signal of each conversion circuit.

[0098] If the AC / AC conversion circuit is a half-bridge topology, for example, Figure 13a As shown, the driving signals of Sp1~Sp4 are as follows Figure 11a 、 Figure 11b 、 Figure 12a 、 Figure 12b As shown; in the positive half cycle of the power grid, Sp1 and Sp3 operate at high frequency, and Sp2 and Sp4 are constantly conducting, as shown Figure 11a and Figure 12a ( Figure 11a and Figure 12a All Figure 13a The driving signals of the switches Sp1 to Sp4 in the circuit shown are shown as an example); in the negative half cycle of the power grid, Sp2 and Sp4 operate at high frequency, and Sp1 and Sp3 are constantly turned on, as shown in FIG. Figure 11b and Figure 12b ( Figure 11b and Figure 12b All Figure 13a The driving signals of the switching tubes Sp1 to Sp4 in the circuit are shown as an example.

[0099] If the AC / AC conversion circuit is a full-bridge topology, for example, Figure 13b As shown, the drive of the half-bridge topology can be expanded by using the same drive signal logic for the semiconductor devices on the opposite sides of the two bridge arms (ie, the upper side of one bridge arm and the lower side of the other bridge arm).

[0100] If the AC / DC conversion circuit is a half-bridge topology, for example, Figure 13c As shown, the driving signals of Ss1 and Ss3 are as follows Figure 12a or Figure 12b ( Figure 12a and Figure 12b by Figure 13c As shown in the circuit shown, the driving signals of the switching tubes Ss1 and Ss3 are taken as an example, and Ss1 and Ss3 are alternately turned on.

[0101] If the AC / DC converter circuit is a full-bridge topology, for example, Figure 13d As shown, the driving signals of Ss1 to Ss4 are as follows Figure 11a or Figure 11b ( Figure 11a or Figure 11b by Figure 13d As shown in the circuit, the driving signals of the switches Ss1 to Ss4 are used as an example. Ss1 and Ss4, and Ss2 and Ss3, are turned on alternately, with Ss1 being turned on earlier than Ss4, and Ss3 being turned on earlier than Ss2.

[0102] In practical applications, the control loop corresponding to step S330 is as follows: Figure 10 PWM generator 07 in which K pwm is the transfer function of the PWM generator.

[0103] This embodiment also describes the specific process of step S310 in detail. Figure 14 As shown, the specific steps include:

[0104] S410. Determine the phase shift angle of the transformer-side output voltage of the AC / AC conversion circuit, and the relationship between the two phase shift angles, based on the instantaneous reference value of the grid-side current, the instantaneous sampled value of the grid-side voltage, the sampled value of the battery-side voltage, the switching frequency of the on-board charger, and the equivalent total reactance of all passive components in the on-board charger.

[0105] The phase shift angle of the transformer-side output voltage of the AC / AC conversion circuit is within a value range that enables the power devices in the two conversion circuits to achieve soft switching.

[0106] S420 : Determine the phase shift angle of the AC-side output voltage of the AC / DC conversion circuit according to the phase shift angle of the transformer-side output voltage of the AC / AC conversion circuit and the relationship between the two phase shift angles.

[0107] Another embodiment of the present application provides a vehicle charger, which has a specific structure as follows Figure 2 As shown, it specifically includes: controller (to simplify the view, Figure 2 Controller not shown), transformer 10, at least one passive device 20 ( Figure 2 Only two passive components 20 are shown as an example), as well as a bridge-type controllable AC / AC conversion circuit 30 and an AC / DC conversion circuit 40; the connection relationship between each component is as follows:

[0108] The transformer side of the AC / AC conversion circuit 30 is connected to the AC side of the AC / DC conversion circuit 40 through the transformer 10; the grid side of the AC / AC conversion circuit 30 serves as the grid side of the on-board charger and is connected to the power supply, usually connected to the power grid; the DC side of the AC / DC conversion circuit 40 serves as the battery side of the on-board charger and is connected to the charging port of the vehicle.

[0109] Passive components 20 are provided on the primary side and / or secondary side of the transformer 10 , and each passive component 20 includes at least an inductor; the AC / AC conversion circuit 30 and the AC / DC conversion circuit 40 are both controlled by a controller, which is used to execute the control method of the vehicle charger provided in the above embodiment.

[0110] Optionally, the bridge-type controllable AC / AC conversion circuit 30 may be a half-bridge topology, such as Figure 13a The circuit shown can also be a full-bridge topology, such as Figure 13b The circuit shown here is not specifically limited and is within the scope of protection of this application; the bridge-type controllable AC / DC conversion circuit 40 can be a half-bridge topology, such as Figure 13c The circuit shown can also be a full-bridge topology, such as Figure 13d The circuit shown is not specifically limited here and is within the scope of protection of this application.

[0111] In practical applications, the bridge-type controllable AC / AC conversion circuit 30 is preferably a half-bridge cyclic conversion circuit or a full-bridge cyclic conversion circuit. In practical applications, including but not limited to this, no specific limitation is made here, and it can be determined according to the specific circumstances, all within the scope of protection of this application.

[0112] In practical applications, the bridge-type controllable AC / DC conversion circuit 40 is preferably a half-bridge rectifier circuit or a full-bridge rectifier circuit. In practical applications, including but not limited to these, no specific limitations are made here and it may depend on the specific circumstances, all within the scope of protection of this application.

[0113] This embodiment provides an implementation of a passive device 20, which specifically includes: an inductor branch; wherein the inductor branch includes: at least one inductor, if the number of inductors is greater than 1, the inductors are connected in series, in parallel, or in series and parallel.

[0114] This embodiment provides another implementation of the passive device 20, whose structure is as follows: Figure 2 ( Figure 2 As shown in the figure (only one capacitor and one inductor are used as examples to illustrate each passive component 20), on the basis of the above embodiment, it also includes: a capacitor branch; wherein the capacitor branch and the inductor branch are connected in series or in parallel; in addition, the capacitor branch includes: at least one capacitor, if the number of capacitors is greater than 1, then the capacitors are connected in series, in parallel, or in series and parallel.

[0115] In practical applications, when the passive device 20 includes both an inductor and a capacitor, that is, when the on-board charger can resonate, it is preferred to set the switching frequency of the on-board charger to be greater than the resonant frequency of the resonant cavity in the on-board charger, so as to further achieve soft switching of each switch tube in the AC / AC conversion circuit 30 and the AC / DC conversion circuit 40.

[0116] This embodiment also provides another implementation of the vehicle charger, the specific structure of which is as follows: Figure 15 As shown, based on the above embodiment, it further includes: two filters; one filter is set on the grid side of the AC / AC conversion circuit 30, and the other filter is set on the DC side of the AC / DC conversion circuit 40.

[0117] For the above description of the disclosed embodiments, the features recorded in the various embodiments in this specification can be replaced or combined with each other, so that professionals in this field can implement or use this application. The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as above with a preferred embodiment, it is not used to limit the present invention. Any technician familiar with the field can make many possible changes and modifications to the technical solution of the present invention using the methods and technical contents disclosed above without departing from the scope of the technical solution of the present invention, or modify it into an equivalent embodiment of equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the scope of protection of the technical solution of the present invention.

Claims

1. A control method for a vehicle charger, characterized in that: In the on-board charger, the transformer side of the bridge-type controllable AC / AC conversion circuit is connected to the AC side of the bridge-type controllable AC / DC conversion circuit through a transformer; the control method of the on-board charger includes: adjusting a reference peak value of the grid-side current of the on-board charger according to a deviation of a sampled value of the battery-side voltage relative to a reference value of the battery-side voltage; Converting the reference peak value of the grid-side current into the instantaneous reference value of the grid-side current according to the obtained phase of the instantaneous sampling value of the grid-side voltage of the on-board charger; performing phase shift control on the two conversion circuits according to the instantaneous reference value of the grid-side current, the instantaneous sampled value of the grid-side voltage, and the sampled value of the battery-side voltage; the phase shift control enables the power devices in the two conversion circuits to achieve soft switching; The phase shift control is corrected according to a deviation of the instantaneous sampling value of the grid-side current relative to the instantaneous reference value of the grid-side current.

2. The control method of the vehicle charger according to claim 1, characterized in that: The phase shift control includes: Determining a phase shift angle of the transformer-side output voltage of the AC / AC conversion circuit and a phase shift angle of the AC-side output voltage of the AC / DC conversion circuit based on the instantaneous reference value of the grid-side current, the instantaneous sampled value of the grid-side voltage, the sampled value of the battery-side voltage, and in combination with the switching frequency of the on-board charger and the equivalent total reactance of all passive components in the on-board charger; generating driving signals for two conversion circuits respectively according to the two phase shift angles; According to the driving signal of each conversion circuit, each conversion circuit is driven to perform power conversion.

3. The control method of the vehicle charger according to claim 2, characterized in that: Determining a phase shift angle of a transformer-side output voltage of the AC / AC conversion circuit and a phase shift angle of an AC-side output voltage of the AC / DC conversion circuit, comprising: Determining a phase shift angle of a transformer-side output voltage of the AC / AC conversion circuit and a relationship between the two phase shift angles based on the instantaneous reference value of the grid-side current, the instantaneous sampled value of the grid-side voltage, and the sampled value of the battery-side voltage, in combination with the switching frequency of the on-board charger and the equivalent total reactance of all passive components in the on-board charger; the phase shift angle of the transformer-side output voltage of the AC / AC conversion circuit being within a range of values ​​that enables soft switching of power devices in the two conversion circuits; The phase shift angle of the AC side output voltage of the AC / DC conversion circuit is determined according to the phase shift angle of the transformer side output voltage of the AC / AC conversion circuit and the relationship between the two phase shift angles.

4. The control method of the vehicle charger according to claim 1, characterized in that: Correcting the phase shift control according to a deviation of the instantaneous sampling value of the grid-side current relative to the instantaneous reference value of the grid-side current includes: At least one phase shift angle in the phase shift control is corrected.

5. The control method of the vehicle charger according to any one of claims 1 to 4, characterized in that: The reference value of the battery side voltage is equal to the charging voltage of the battery connected to the on-board charger under constant voltage trickle charging conditions.

6. The control method of the vehicle charger according to any one of claims 1 to 4, characterized in that: Adjusting a reference peak value of a grid-side current of the on-board charger according to a deviation of a sampled value of the battery-side voltage relative to a reference value of the battery-side voltage includes: adjusting a reference value of the battery side current according to a deviation of the sampled value of the battery side voltage relative to a reference value of the battery side voltage; The reference peak value of the grid-side current is adjusted according to a deviation of the sampled value of the battery-side current relative to a reference value of the battery-side current.

7. The control method of the vehicle charger according to claim 6, characterized in that: The reference value of the battery-side current is less than or equal to the charging current of the battery connected to the on-board charger under constant current charging conditions.

8. The control method of the vehicle charger according to claim 7, characterized in that: The charging current of the battery under constant current charging conditions is determined according to the working state of the on-board charger and user instructions.

9. A vehicle charger, characterized in that: include: A controller, a transformer, at least one passive component, and a bridge-controlled AC / AC conversion circuit and an AC / DC conversion circuit; wherein: The transformer side of the AC / AC conversion circuit is connected to the AC side of the AC / DC conversion circuit through the transformer; the grid side of the AC / AC conversion circuit serves as the grid side of the on-board charger, and the DC side of the AC / DC conversion circuit serves as the battery side of the on-board charger; The passive components are arranged on the primary side and / or the secondary side of the transformer, and each of the passive components includes at least an inductor; The AC / AC conversion circuit and the AC / DC conversion circuit are both controlled by the controller, and the controller is used to execute the control method of the vehicle charger according to any one of claims 1 to 8.

10. The vehicle charger according to claim 9, characterized in that: The AC / AC conversion circuit is a half-bridge topology or a full-bridge topology; The AC / DC conversion circuit is a half-bridge topology or a full-bridge topology.

11. The vehicle charger according to claim 9, characterized in that: The passive device includes: an inductor branch; the inductor branch includes: at least one inductor; wherein: If the number of the inductors is greater than 1, the inductors are connected in series, in parallel, or in series and parallel.

12. The vehicle charger according to claim 11, characterized in that: The passive device further includes: a capacitor branch, the capacitor branch being connected in series or in parallel with the inductor branch; The capacitor branch includes at least one capacitor; wherein: If the number of the capacitors is greater than 1, the capacitors are connected in series, in parallel, or in series and parallel.

13. The vehicle charger according to any one of claims 9 to 12, characterized in that: The switching frequency of the on-board charger is greater than the resonant frequency of the resonant cavity in the on-board charger.

14. The vehicle charger according to any one of claims 9 to 12, characterized in that: Also includes: Two filters; where: One of the filters is arranged on the grid side of the AC / AC conversion circuit, and the other filter is arranged on the DC side of the AC / DC conversion circuit.

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