阅读说明：本技术 基于ss拓扑耦合机构的无线充电全工况协调控制方法 (Wireless charging full-working-condition coordination control method based on SS (service system) topology coupling mechanism ) 是由 刘普 梁燕 申永鹏 杨小亮 金楠 郭磊磊 武杰 杨存祥 王延峰 于 2019-12-04 设计创作，主要内容包括：本发明公开了一种基于SS拓扑耦合机构的无线充电全工况协调控制方法,涉及无线充电技术领域,包括计算车端BOOST电路高低压侧电压比范围；记录充电系统的工运参数；实时电量信息无线传输；采样高频逆变电流及PFC变流器直流电压；设定高频逆变电流指令及PFC变流器直流电压指令。本发明对车地端无线通讯速率要求低,无需额外增加硬件模块即可实现,简单易行,提升了充电系统运行稳定性。随着电池电压宽范围变化,地端协调控制各环节工作点,使得整个充电系统均在其定额范围内稳定运行。(The invention discloses a wireless charging full-working-condition coordination control method based on an SS (system-to-service) topological coupling mechanism, which relates to the technical field of wireless charging and comprises the steps of calculating the voltage ratio range of a high-low voltage side of a vehicle-end BOOST (BOOST open circuit); recording the industrial operation parameters of the charging system; real-time electric quantity information is wirelessly transmitted; sampling high-frequency inverter current and direct-current voltage of a PFC converter; and setting a high-frequency inverter current command and a PFC converter direct-current voltage command. The invention has low requirement on the wireless communication speed of the vehicle ground end, can be realized without additionally adding a hardware module, is simple and easy to implement, and improves the operation stability of the charging system. Along with the wide range change of the battery voltage, the ground end coordinately controls the working points of all links, so that the whole charging system stably operates in the rated range.)

1. A wireless charging full-working-condition coordination control method based on an SS topological coupling mechanism is characterized by comprising the following steps:

s1, the power transmission controller obtains the duty Ratio range of the vehicle-end BOOST circuit, and determines the voltage Ratio range (Ratio) of the high-low voltage side of the vehicle-end BOOST circuit according to the duty Ratio range_min，Ratio_max)；

S2, recording charging work and operation parameters of the charging system in real time by the vehicle-ground coordination controller;

the charging work parameters comprise a rated value of ground-end high-frequency inverter current and a direct-current voltage range (U) of the PFC converter capable of operating at full power_{pfc_min}，U_{pfc_max}) Maximum charging power of system and current quota I at low-voltage side of BOOST circuit at vehicle end_{dc_low_max}；

S3, the vehicle end control system transmits the real-time electric quantity information of the vehicle end to the vehicle ground end coordination controller; the real-time electric quantity information of the vehicle end comprises a battery charging voltage and current and a sampling value of the voltage of the low-voltage side of the BOOST circuit of the vehicle end;

s4, the high-frequency inversion controller acquires a high-frequency inversion current sampling value in real time, and the PFC controller acquires a PFC converter direct-current voltage sampling value in real time;

s5, the vehicle-ground coordination controller according to the voltage Ratio range (Ratio) of the high-low voltage side of the vehicle-end BOOST circuit_min，Ratio_max) Determining a high-frequency inverter current instruction according to the charging work operation parameters and the vehicle-end real-time electric quantity information, and transmitting the high-frequency inverter current instruction to a high-frequency inverter controller, wherein the high-frequency inverter controller carries out high-frequency inverter current closed-loop regulation according to the high-frequency inverter current instruction and the high-frequency inverter current sampling value;

s6, the high-frequency inverter controller acquires a phase shift angle dynamic value of the high-frequency inverter;

the vehicle ground end coordination controller determines the direct current voltage instruction change direction of the PFC converter according to the phase shift angle dynamic value of the high-frequency inverter; determining a direct-current voltage instruction of the PFC converter in the next period according to the direct-current voltage instruction change direction of the PFC converter and the direct-current voltage instruction of the PFC converter in the current period;

the vehicle-ground-end coordination controller transmits a PFC converter direct-current voltage instruction to the PFC controller, and the PFC controller performs PFC converter direct-current voltage closed-loop regulation according to the PFC converter direct-current voltage instruction and a PFC converter direct-current voltage sampling value;

in the system charging process, the power transmission controller adjusts the system charging power within the range of the maximum charging power of the system in real time according to the charging voltage and current of the battery.

2. The wireless charging full-condition coordination control method based on the SS topology coupling mechanism according to claim 1, wherein the step of calculating the high-frequency inverter current command in S5 comprises:

s51, the power transmission controller obtains the range of the voltage at the low-voltage side of the vehicle-end BOOST circuit according to the duty ratio range of the vehicle-end BOOST circuit as follows: (Ratio)_min×U_battery，Ratio_max×U_battery)，U_batteryAnd if the current battery voltage value is obtained, the high-frequency inverter current range is as follows:

in the formula of omega₀The frequency is the resonance frequency of the coupling mechanism and is the control frequency of the current high-frequency inverter; m is the inductance mutual inductance;

s52, combining the vehicle ground end coordination controller with the PFC converter, the DC voltage range (U) capable of operating at full power_{pfc_min}，U_{pfc_max}) And the current charging power P of the system to obtain a high-frequency inverter current I_acA minimum value;

in the formula_maxThe maximum value of the phase shift angle of the high-frequency inverter is obtained;

s53, combining the vehicle-ground coordination controller with the vehicle-end BOOSLow-voltage side current rating I of T circuit_{dc_low_max}Obtaining the minimum value of the voltage at the low-voltage side of the BOOST circuit at the vehicle end according to the current charging power P of the system, and obtaining the corresponding high-frequency inverter current I according to the following formula_acA minimum value;

s54, combining the vehicle ground-end coordinating controller with the various types in S51, S52 and S53 and the ground-end high-frequency inverter current quota limit value, calculating to obtain the high-frequency inverter current instruction range (I)_{ac_ref_min}，I_{ac_ref_max})。

3. The wireless charging full-condition coordination control method based on the SS topology coupling mechanism according to claim 1, wherein the step of determining the voltage command of the PFC converter in S6 comprises:

s61, the high-frequency inversion controller determines the phase shift angle control range (sigma) of the closed-loop control of the high-frequency inverter_min，σ_max) The value range of the phase shift angle is (0, pi)

Wherein, the phase shift angle control range is smaller than the value range of the phase shift angle;

s62, in the high-frequency inverter current control process, the vehicle-ground coordination controller correspondingly adjusts the direct-current voltage instruction of the PFC converter according to the phase shift angle control range;

when the phase shift angle of the inverter is larger than the upper limit of the phase shift angle, raising a direct-current voltage instruction of the PFC converter;

when the phase shift angle of the inverter is smaller than the lower limit of the phase shift angle, the direct-current voltage instruction of the PFC converter is adjusted downwards;

when the phase shift angle of the inverter is between the upper limit and the lower limit, the direct-current voltage instruction of the PFC converter is unchanged;

and when the direct-current voltage instruction of the PFC converter exceeds the full-power voltage range of the PFC converter, maintaining the operation of the upper limit or the lower limit of the direct-current voltage of the PFC converter, and not adjusting.

4. The wireless charging full-working-condition coordination control method based on the SS topology coupling mechanism according to claim 1, characterized in that at the initial starting stage of the charging system, the vehicle-ground-end coordination controller obtains the theoretical mutual inductance value of the vehicle-ground-end coupling mechanism;

when the vehicle ground end coupling mechanism deviates, the vehicle ground end coordination controller reversely calculates an actual mutual inductance value of the vehicle ground end coupling mechanism according to a vehicle end BOOST circuit low-voltage side voltage sampling value and a high-frequency inverter current real-time sampling value and by combining the following formula; the vehicle-ground-end coordination controller performs deviation adjustment on the vehicle-ground-end coupling mechanism according to the theoretical mutual inductance value and the actual mutual inductance value;

wherein, U_{dc_low}Is the low-voltage side voltage of the vehicle-end BOOST circuit.

Technical Field

The invention relates to the technical field of wireless charging, in particular to a wireless charging full-working-condition coordination control method based on an SS (service system) topological coupling mechanism.

Background

With the explosion of oil crisis and environmental problems, people are concerned more and more about the consumption of fossil energy by automobiles and the influence of the exhaust gas discharged by the automobiles on the environment. The electric vehicle is a good substitute for the traditional internal combustion engine vehicle, does not need to consume fossil energy, and does not emit exhaust gas, so the research of the electric vehicle becomes an important subject of the research of automobile manufacturers at the present stage and an important direction of the development of the automobile industry. Traditional electric automobile charging mode is for inserting electric formula, receives electric interface and fills electric pile quantity restriction, and the same time can only charge for one or several electric automobile. The wireless power transmission technology (WPT) has the advantages of high safety, strong operability and intellectualization, and effectively overcomes the defects of the plug-in charging device. Electric vehicle charging equipment based on a wireless charging electric energy transmission technology becomes a hotspot of research of power equipment manufacturers and colleges and universities.

In the current wireless charging system, the battery voltage range is wide, and due to the characteristic limitation of the coupling mechanism, along with the change of the battery voltage and the charging power, if the high-frequency inversion input voltage and current of the coupling mechanism are not adjusted in time, the system cannot be ensured to operate in the full working condition range. Therefore, the timely adjustment of the high-frequency inversion input voltage and current along with the change of the charging working condition in the charging process is very important for meeting the operation of the system under the full working condition.

Disclosure of Invention

In order to solve the problems in the prior art, the invention provides a wireless charging full-working-condition coordination control method based on an SS topology coupling mechanism, so as to solve the problem that the current wireless charging system has a wider battery voltage range, and if the high-frequency inversion input voltage and current of the coupling mechanism are not adjusted in time along with the change of the battery voltage and the charging power due to the characteristic limitation of the coupling mechanism, the system cannot be ensured to operate in the full-working-condition range. The control object of the method is an electric automobile wireless charging system, the wireless charging system adopts a series resonance (SS topology) coupling mechanism, and the coupling mechanism can effectively realize wireless transmission of electric energy.

The technical scheme of the invention is as follows:

a wireless charging full-working-condition coordination control method based on an SS topological coupling mechanism comprises the following steps:

s1, the power transmission controller obtains the duty Ratio range of the vehicle-end BOOST circuit, and determines the voltage Ratio range (Ratio) of the high-low voltage side of the vehicle-end BOOST circuit according to the duty Ratio range_min，Ratio_max)；

S2, recording charging work and operation parameters of the charging system in real time by the vehicle-ground coordination controller;

the charging work parameters comprise a rated value of ground-end high-frequency inverter current and a direct-current voltage range (U) of the PFC converter capable of operating at full power_{pfc_min}，U_{pfc_max}) Maximum charging power of system and current quota I at low-voltage side of BOOST circuit at vehicle end_{dc_low_max}；

S3, the vehicle end control system transmits the real-time electric quantity information of the vehicle end to the vehicle ground end coordination controller; the real-time electric quantity information of the vehicle end comprises a battery charging voltage and current and a sampling value of the voltage of the low-voltage side of the BOOST circuit of the vehicle end;

s4, the high-frequency inversion controller acquires a high-frequency inversion current sampling value in real time, and the PFC controller acquires a PFC converter direct-current voltage sampling value in real time;

s5, vehicle and groundThe end coordination controller is used for controlling the voltage Ratio range (Ratio) of the high-voltage side and the low-voltage side of the vehicle-end BOOST circuit_min，Ratio_max) Determining a high-frequency inverter current instruction according to the charging work operation parameters and the vehicle-end real-time electric quantity information, and transmitting the high-frequency inverter current instruction to a high-frequency inverter controller, wherein the high-frequency inverter controller carries out high-frequency inverter current closed-loop regulation according to the high-frequency inverter current instruction and the high-frequency inverter current sampling value;

s6, the high-frequency inverter controller acquires a phase shift angle dynamic value of the high-frequency inverter;

the vehicle ground end coordination controller determines the direct current voltage instruction change direction of the PFC converter according to the phase shift angle dynamic value of the high-frequency inverter; determining a direct-current voltage instruction of the PFC converter in the next period according to the direct-current voltage instruction change direction of the PFC converter and the direct-current voltage instruction of the PFC converter in the current period;

the vehicle-ground-end coordination controller transmits a PFC converter direct-current voltage instruction to the PFC controller, and the PFC controller performs PFC converter direct-current voltage closed-loop regulation according to the PFC converter direct-current voltage instruction and a PFC converter direct-current voltage sampling value;

in the system charging process, the power transmission controller adjusts the system charging power within the range of the maximum charging power of the system in real time according to the charging voltage and current of the battery.

Further, the step of calculating the high-frequency inverter current command in S5 includes:

s51, the power transmission controller obtains the range of the voltage at the low-voltage side of the vehicle-end BOOST circuit according to the duty ratio range of the vehicle-end BOOST circuit as follows: (Ratio)_min×U_battery，Ratio_max×U_battery)，U_batteryAnd if the current battery voltage value is obtained, the high-frequency inverter current range is as follows:

in the formula of omega₀The frequency is the resonance frequency of the coupling mechanism and is the control frequency of the current high-frequency inverter; m is the inductance mutual inductance;

s52, combining the vehicle-ground coordination controller with PFC converterDC voltage range (U) for full power operation of the device_{pfc_min}，U_{pfc_max}) And the current charging power P of the system to obtain a high-frequency inverter current I_acA minimum value;

in the formula_maxThe maximum value of the phase shift angle of the high-frequency inverter is obtained;

s53, combining the vehicle-ground coordination controller with the vehicle-end BOOST circuit low-voltage side current quota I_{dc_low_max}Obtaining the minimum value of the voltage at the low-voltage side of the BOOST circuit at the vehicle end according to the current charging power P of the system, and obtaining the corresponding high-frequency inverter current I according to the following formula_acA minimum value;

s54, combining the vehicle ground-end coordinating controller with the various types in S51, S52 and S53 and the ground-end high-frequency inverter current quota limit value, calculating to obtain the high-frequency inverter current instruction range (I)_{ac_ref_min}，I_{ac_ref_max})。

Further, the step of determining the voltage command of the PFC converter in S6 includes:

s61, the high-frequency inversion controller determines the phase shift angle control range (sigma) of the closed-loop control of the high-frequency inverter_min，σ_max) The value range of the phase shift angle is (0, pi);

wherein, the phase shift angle control range is smaller than the value range of the phase shift angle;

s62, in the high-frequency inverter current control process, the vehicle-ground coordination controller correspondingly adjusts the direct-current voltage instruction of the PFC converter according to the phase shift angle control range;

when the phase shift angle of the inverter is larger than the upper limit of the phase shift angle, raising a direct-current voltage instruction of the PFC converter;

when the phase shift angle of the inverter is smaller than the lower limit of the phase shift angle, the direct-current voltage instruction of the PFC converter is adjusted downwards;

when the phase shift angle of the inverter is between the upper limit and the lower limit, the direct-current voltage instruction of the PFC converter is unchanged;

and when the direct-current voltage instruction of the PFC converter exceeds the full-power voltage range of the PFC converter, maintaining the operation of the upper limit or the lower limit of the direct-current voltage of the PFC converter, and not adjusting.

Further, at the initial stage of starting the charging system, the vehicle-ground coordination controller acquires a theoretical mutual inductance value of the vehicle-ground coupling mechanism;

when the vehicle ground end coupling mechanism deviates, the vehicle ground end coordination controller reversely calculates an actual mutual inductance value of the vehicle ground end coupling mechanism according to a vehicle end BOOST circuit low-voltage side voltage sampling value and a high-frequency inverter current real-time sampling value and by combining the following formula; the vehicle-ground-end coordination controller performs deviation adjustment on the vehicle-ground-end coupling mechanism according to the theoretical mutual inductance value and the actual mutual inductance value;

wherein, U_{dc_low}Is the low-voltage side voltage of the vehicle-end BOOST circuit.

Compared with the prior art, the invention has the beneficial effects that:

1. the invention has low requirement on the wireless communication speed of the vehicle ground end, can be realized without additionally adding a hardware module, is simple and easy to implement, improves the operation stability of the charging system, and leads the ground end to coordinate and control the working points of all links along with the wide range change of the voltage of the battery so that the whole charging system can stably operate in the rated range.

2. The BOOST circuit topology adopted by the vehicle end is also suitable for other circuit topologies adopting controllable DC/DC conversion at the vehicle end; in addition, the invention is not only suitable for the charging steady-state control stage of the charging system, but also suitable for the starting stage of the charging system, so that the system control is simple and easy to implement.

Drawings

FIG. 1 is a flow chart of the present invention;

FIG. 2 is a control structure diagram of the wireless charging system according to the present invention;

fig. 3 is an ac equivalent circuit diagram of the SS resonant system of the present invention.

Detailed Description

The technical solutions of the embodiments of the present invention are clearly and completely described below with reference to the drawings in the present invention, and it is obvious that the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, shall fall within the scope of protection of the present invention.

The control object of the invention is an electric vehicle wireless charging system, which adopts a series resonance (SS topology) coupling mechanism as shown in figure 1. The wireless charging system comprises a ground end system and a vehicle end system, wherein the ground end system comprises a ground end power transmitting end and a ground end control system, and the vehicle end system comprises a vehicle end power transmitting end and a vehicle end control system. The ground end transmitting coil and the vehicle end receiving coil form a coupling mechanism, and the coupling mechanism is used for realizing wireless transmission of electric energy.

The ground power transmitting terminal comprises a PFC (power Factor correction) converter, a high-frequency inverter and a transmitting coil. The PFC converter is used for converting alternating current electric energy into direct current electric energy and simultaneously realizing unit power factor control of an alternating current access end of the PFC converter; the high-frequency inverter is in a full-control H-bridge topology, and the output direct-current voltage of the vehicle-end high-frequency rectifier is controlled by controlling the high-frequency inverter.

The vehicle-end power receiving end comprises a high-frequency rectifier and a DC/DC converter. The vehicle-end high-frequency rectifier is a diode rectifier bridge topology and is used for converting high-frequency alternating current electric energy into direct current electric energy; the DC/DC converter, here exemplified by a BOOST type BOOST circuit, is used to implement a battery power transfer control function.

The vehicle-end control system is in wireless communication connection with the ground-end control system. The ground control system comprises a vehicle ground coordination controller, a PFC system controller and a high-frequency inverter controller; the vehicle ground end coordination controller controls the PFC system controller to coordinate and control the DC voltage of the PFC converter according to the vehicle end operation condition; the vehicle ground end coordination controller coordinates the high-frequency inverter to adjust the high-frequency inverter current by controlling the high-frequency inverter controller so as to control the high-frequency rectifier to output direct-current voltage. The vehicle-end control system includes a power transfer controller. The power transmission controller samples the battery current and the BOOST high-low voltage side voltage, and feeds back the sampled vehicle end electric quantity information to the ground end control system for corresponding processing, so that a closed feedback system is formed, and the charging system is kept to stably operate in a quota range.

Fig. 2 shows an equivalent circuit diagram of a series resonance (SS topology) coupling mechanism, where L1 and C1 are a self-inductance and a resonance capacitance of a transmitting coil, L2 and C2 are a self-inductance and a resonance capacitance of a receiving coil, U1 and IL1 are a high-frequency inverted ac voltage and current of the transmitting coil, and U2 and IL2 are a high-frequency rectified ac voltage and current of the receiving coil, respectively. The following can be written according to fig. 2:

based on the system, the resonant frequency of the primary side system is equal to that of the secondary side system, and the system frequency is at a resonant point, neglecting R₁And R₂The influence of (a) can be given by:

in formula 2,. omega₀The system resonant frequency.

Formula 1 is simplified to obtain:

the mutual conductance gain and mutual resistance gain of the resonant network are irrelevant to the load resistance, and when the system frequency is at a resonant frequency point, the specific expression is as follows: the following were used:

wherein G is_ivssFor mutual conductance gain, G_vissFor the mutual resistance gain, k is the coupling coefficient of the coupling coil, and the expression is as follows:

in this embodiment, the battery charging is divided into the following stages:

when the battery voltage is lower, a constant current charging mode is adopted (the current instruction is set as the maximum current);

when the voltage of the battery reaches a certain value, the charging power is larger than the maximum charging power of the charging system due to the continuous charging with the maximum current, and the system is switched to a constant (limited) power charging mode;

when the battery voltage reaches its maximum charge voltage, the system will stop charging. The full working condition range of the battery charging is obtained as above.

In the whole charging process, the vehicle-end BOOST circuit can normally operate and needs to ensure that the voltage of the high-low voltage side is in a proper range, namely, the following requirement is met:

D＝(U_high-U_low)/U_high,(D_min≤D≤D_max) (formula 6)

In order to meet the requirement of the system operating in the full voltage range, the voltage of the low-voltage side of the vehicle-end BOOST circuit should change along with the voltage change of the high-voltage side of the vehicle-end BOOST circuit, so as to ensure that the vehicle-end BOOST circuit can normally work.

In addition, each link of the system device has the quota requirement. In the process of charging the battery, along with the change of the voltage and the charging power of the battery, the corresponding change of the system needs to be controlled in time to ensure that each link of the charging system is in the voltage and current quota range.

As shown in fig. 3, the invention provides a wireless charging full-operating-condition coordination control method based on an SS topology coupling mechanism, which specifically includes the following implementation steps:

s1, the power transmission controller obtains the duty Ratio range of the vehicle-end BOOST circuit, and determines the voltage Ratio range (Ratio) of the high-low voltage side of the vehicle-end BOOST circuit according to the duty Ratio range_min，Ratio_max)；

S2, recording charging work and operation parameters of the charging system in real time by the vehicle-ground coordination controller;

the charging work parameters comprise a rated value of ground-end high-frequency inverter current and a direct-current voltage range (U) of the PFC converter capable of operating at full power_{pfc_min}，U_{pfc_max}) Maximum charging power of system and current quota I at low-voltage side of BOOST circuit at vehicle end_{dc_low_max}；

S3, the vehicle end control system transmits the real-time electric quantity information of the vehicle end to the vehicle ground end coordination controller; the real-time electric quantity information of the vehicle end comprises a battery charging voltage and current and a sampling value of the voltage of the low-voltage side of the BOOST circuit of the vehicle end;

s4, the high-frequency inversion controller acquires a high-frequency inversion current sampling value in real time, and the PFC controller acquires a PFC converter direct-current voltage sampling value in real time;

s5, the vehicle-ground coordination controller according to the voltage Ratio range (Ratio) of the high-low voltage side of the vehicle-end BOOST circuit_min，Ratio_max) Determining a high-frequency inverter current instruction according to the charging work operation parameters and the vehicle-end real-time electric quantity information, and transmitting the high-frequency inverter current instruction to a high-frequency inverter controller, wherein the high-frequency inverter controller carries out high-frequency inverter current closed-loop regulation according to the high-frequency inverter current instruction and the high-frequency inverter current sampling value;

s6, the high-frequency inverter controller acquires a phase shift angle dynamic value of the high-frequency inverter;

the vehicle ground end coordination controller determines the direct current voltage instruction change direction of the PFC converter according to the phase shift angle dynamic value of the high-frequency inverter; determining a direct-current voltage instruction of the PFC converter in the next period according to the direct-current voltage instruction change direction of the PFC converter and the direct-current voltage instruction of the PFC converter in the current period;

the vehicle-ground-end coordination controller transmits a PFC converter direct-current voltage instruction to the PFC controller, and the PFC controller performs PFC converter direct-current voltage closed-loop regulation according to the PFC converter direct-current voltage instruction and a PFC converter direct-current voltage sampling value;

in the system charging process, the power transmission controller adjusts the system charging power within the range of the maximum charging power of the system in real time according to the charging voltage and current of the battery.

Specifically, the step of calculating the high-frequency inverter current command in S5 includes:

s51 workThe range of the voltage of the low-voltage side of the vehicle-end BOOST circuit obtained by the rate transmission controller according to the duty ratio range of the vehicle-end BOOST circuit is as follows: (Ratio)_min×U_battery，Ratio_max×U_battery)，U_batteryAnd if the current battery voltage value is obtained, the high-frequency inverter current range is as follows:

in the formula of omega₀The frequency is the resonance frequency of the coupling mechanism and is the control frequency of the current high-frequency inverter; m is the inductance mutual inductance;

s52, combining the vehicle ground end coordination controller with the PFC converter, the DC voltage range (U) capable of operating at full power_{pfc_min}，U_{pfc_max}) And the current charging power P of the system to obtain a high-frequency inverter current I_acA minimum value;

in the formula_maxThe maximum value of the phase shift angle of the high-frequency inverter is obtained;

s53, combining the vehicle-ground coordination controller with the vehicle-end BOOST circuit low-voltage side current quota I_{dc_low_max}Obtaining the minimum value of the voltage at the low-voltage side of the BOOST circuit at the vehicle end according to the current charging power P of the system, and obtaining the corresponding high-frequency inverter current I according to the following formula_acA minimum value;

s54, combining the vehicle ground-end coordinating controller with the various types in S51, S52 and S53 and the ground-end high-frequency inverter current quota limit value, calculating to obtain the high-frequency inverter current instruction range (I)_{ac_ref_min}，I_{ac_ref_max})。

The step of determining the PFC converter voltage command in S6 includes:

s61, the high-frequency inversion controller determines the phase shift angle control range (sigma) of the closed-loop control of the high-frequency inverter_min，σ_max) The value range of the phase shift angle is (0, pi);

in order to ensure the stability of the closed-loop control of the inverter, the control range of the phase shift angle needs to be set slightly smaller than the value range.

S62, in the high-frequency inverter current control process, the vehicle-ground coordination controller correspondingly adjusts the direct-current voltage instruction of the PFC converter according to the phase shift angle control range;

when the phase shift angle of the inverter is larger than the upper limit of the phase shift angle, raising a direct-current voltage instruction of the PFC converter;

when the phase shift angle of the inverter is smaller than the lower limit of the phase shift angle, the direct-current voltage instruction of the PFC converter is adjusted downwards;

when the phase shift angle of the inverter is between the upper limit and the lower limit, the direct-current voltage instruction of the PFC converter is unchanged;

and when the direct-current voltage instruction of the PFC converter exceeds the full-power voltage range of the PFC converter, maintaining the operation of the upper limit or the lower limit of the direct-current voltage of the PFC converter, and not adjusting.

The entire regulation must ensure that the dc voltage of the PFC converter is within its operating range.

At the initial stage of starting the charging system, the vehicle-ground end coordination controller acquires a theoretical mutual inductance value of the vehicle-ground end coupling mechanism; when the vehicle ground end coupling mechanism deviates, the vehicle ground end coordination controller reversely calculates an actual mutual inductance value of the vehicle ground end coupling mechanism according to a vehicle end BOOST circuit low-voltage side voltage sampling value and a high-frequency inverter current real-time sampling value and by combining the following formula; the vehicle-ground-end coordination controller performs deviation adjustment on the vehicle-ground-end coupling mechanism according to the theoretical mutual inductance value and the actual mutual inductance value;

wherein, U_{dc_low}Is the low-voltage side voltage of the vehicle-end BOOST circuit.

The wireless charging full-working-condition coordination control method based on the SS topology coupling mechanism provided by the invention has low requirements on the wireless communication speed between the train and the ground and is easy to realize. The method is suitable for each stage of wireless charging, and specifically comprises the following steps:

1. charging system start-up procedure

Calculating a direct current voltage instruction of the PFC converter, wherein in a starting stage, because the inversion is not put into use, a phase shift angle is 0, and because the phase shift angle is lower than the lowest phase shift angle value, an initial direct current voltage instruction of the PFC converter is the lowest full-load voltage U of the PFC converter_{pfc_min}；

The PFC converter direct-current voltage instruction calculation module can be continuously put into operation and operated according to a set algorithm;

the PFC converter completes the starting process of the PFC converter according to a voltage instruction and controls the direct-current voltage of the PFC converter according to the instruction to provide direct-current support for the rear-stage high-frequency inverter;

calculating an initial instruction of a high-frequency inverter current starting process: the current power, the mutual inductance value of the coupling mechanism, the maximum phase shift angle, the maximum voltage of the full-power operation of the PFC and the maximum current of the low-voltage side of the BOOST circuit at the vehicle end are brought into 7-9 to obtain a high-frequency inverter current instruction range (I)_{ac_ref_min}，I_{ac_ref_max}) And calculating to obtain a final instruction: (I)_{ac_ref_min}，I_{ac_ref_max})/2；

Starting the high-frequency inverter, and controlling the high-frequency inverter current to gradually reach an instruction, so that the end system establishes BOOST low-voltage side voltage for the vehicle end;

and starting the BOOST circuit at the vehicle end, and realizing system control according to the set system control mode and the set control instruction.

2. Steady state operation of charging system

And in the steady-state operation stage of the charging system, the PFC converter direct-current voltage instruction calculation module and the high-frequency inverter current instruction calculation module are still called to respectively generate a PFC converter direct-current voltage instruction and a high-frequency inverter current instruction so as to realize system charging control.

3. Phase shift angle range setting

The natural value range (0, pi) of the phase shift angle, the high-frequency inversion current closed-loop control, the phase shift angle as the output quantity of the controller, and the distance boundary value of the phase shift angle needs to be controlled to have certain allowance in order to avoid the controller from oscillating in a critical uncontrolled state in the control process. The value of the phase shifting angle cannot be too low, and if the value is too low, the harmonic wave of the high-frequency inverter current is large, and the system loss is large. The phase shift angle range needs to be set appropriately according to the above two principles.

4. Offset of coupling mechanism

The invention provides a wireless charging full-working-condition coordination control method based on an SS topological coupling mechanism. Due to the fact that the relative positions of the vehicle ground ends are inconsistent, the system mutual inductance is different. The mutual inductance self-detection function of the system can be increased.

From (equation 10):

when the high-frequency inverter starts to pulse, the mutual inductance of the coupling mechanism can be calculated by using a plurality of groups of high-frequency inverter current values and BOOST low-voltage side voltage values according to the formula. And then, the self-detected mutual inductance value can be used for carrying out coordination control on the ground end of the vehicle, so that the control deviation caused by the deviation of the coupling mechanism is avoided.

5. Coordinating controller control frequency

The high resonant frequency of the wireless charging system high-frequency inverter is dozens of kHz, and the system control frequency is also high. The vehicle-ground coordination control mainly follows the change of the battery voltage and the charging power through automatic coordination control, and because the change rate of the battery voltage and the power is slow in the charging process, the vehicle-ground coordination controller calculates an instruction every 1S, and the system control requirement can be met. The specific control frequency varies according to the specific system parameters. The coordination control has low requirement on the wireless communication rate of the vehicle ground end, and the coordination control method is simple and easy to implement.

According to the embodiment of the invention, vehicle end information is transmitted to the ground end controller through vehicle ground end wireless communication, and the ground end controller coordinates, controls and calculates to obtain the high-frequency inverter current instruction and the PFC converter direct-current voltage instruction according to the coupling mechanism parameters and the control system parameters of the system, so that the vehicle ground end can operate in the rated range. The method is simple and easy to implement, and ensures the stable operation of the system.

The above disclosure is only for the preferred embodiments of the present invention, but the embodiments of the present invention are not limited thereto, and any variations that can be made by those skilled in the art are intended to fall within the scope of the present invention.