阅读说明：本技术 一种车载充电机控制电路、方法、充电机及电动汽车 (Vehicle-mounted charger control circuit and method, charger and electric vehicle ) 是由 孔凡勇 赵洪振 李漫漫 于为珍 韩东 孙迎宾 马义勇 李宏伟 薛燕 于 2019-09-09 设计创作，主要内容包括：本公开提供了一种车载充电机控制电路、方法、充电机及电动汽车,包括滤波与整流模块、功率因数校正模块、半桥LLC谐振变换模块和主控模块,滤波与整流模块用于将输入的交流电信号滤除电磁干扰信号后转换为直流电信号；半桥LLC谐振变换模块用于使得开关管工作在零电压状态以实现充电机充电时的零电压开通；主控模块用于实时采集半桥LLC谐振变换模块的谐振电流过零点和半桥LLC谐振变换模块中点电压的电压过零点,通过比较两过零点的电位差,实现对半桥LLC谐振变换模的谐振网络输入阻抗的检测以保证半桥LLC谐振变换模块工作在感性区,无论是负载变化或是输入电压变化都能保证充电机工作在零电压工作区,进而降低充电机充电时的谐波污染。(The invention provides a vehicle-mounted charger control circuit, a vehicle-mounted charger control method, a charger and an electric vehicle, wherein the vehicle-mounted charger control circuit comprises a filtering and rectifying module, a power factor correction module, a half-bridge LLC resonance conversion module and a main control module, wherein the filtering and rectifying module is used for filtering an input alternating current signal to remove an electromagnetic interference signal and then converting the electromagnetic interference signal into a direct current signal; the half-bridge LLC resonance conversion module is used for enabling the switching tube to work in a zero-voltage state so as to realize zero-voltage switching-on when the charger is charged; the main control module is used for acquiring the zero crossing point of the resonant current of the half-bridge LLC resonant conversion module and the zero crossing point of the voltage of the midpoint voltage of the half-bridge LLC resonant conversion module in real time, and by comparing the potential difference of the two zero crossing points, the detection of the resonant network input impedance of the half-bridge LLC resonant conversion module is realized to ensure that the half-bridge LLC resonant conversion module works in an inductive area, so that the charger can work in a zero-voltage working area no matter the load changes or the input voltage changes, and further the harmonic pollution when the charger is charged is reduced.)

1. The vehicle-mounted charger control circuit for the electric automobile is characterized by comprising a filtering and rectifying module, a power factor correction module, a half-bridge LLC resonance conversion module and a main control module, wherein the filtering and rectifying module is used for filtering an electromagnetic interference signal from an input alternating current signal and converting the electromagnetic interference signal into a direct current signal;

the power factor correction module is used for removing harmonic components in the direct current signal and outputting a direct current voltage signal to a load through the half-bridge LLC resonance conversion module, and the half-bridge LLC resonance conversion module is used for enabling the switching tube to work in a zero-voltage state so as to realize zero-voltage switching-on when the charger is charged;

the main control module is used for acquiring the output voltage of the half-bridge LLC resonant conversion module in real time, outputting a PWM control signal to the half-bridge LLC resonant conversion module according to the acquired output voltage data, and stabilizing the output voltage of the half-bridge LLC resonant conversion module by controlling the on and off of a switch tube in the half-bridge LLC resonant conversion module;

the main control module is also used for acquiring the zero crossing point of the resonant current of the half-bridge LLC resonant conversion module and the zero crossing point of the voltage of the midpoint of the half-bridge LLC resonant conversion module in real time, and detecting the input impedance of the resonant network of the half-bridge LLC resonant conversion module by comparing the phases of the two zero crossing points so as to ensure that the half-bridge LLC resonant conversion module works in an inductive area;

the main control module is also used for collecting various parameters of the battery in real time and controlling the half-bridge LLC resonance conversion module according to the collected parameters to realize conversion of protection charging, constant current charging, constant voltage charging and trickle charging.

2. The vehicle-mounted charger control circuit for the electric automobile according to claim 1, wherein the half-bridge LLC resonance conversion module comprises a half-bridge structure, a resonance network, a transformer, a rectification circuit and a filter circuit, and the primary side of the transformer comprises a first switching tube, a second switching tube, a resonance inductor, an excitation inductor and a resonance capacitor;

the first switch tube and the second switch tube respectively comprise a first parasitic capacitor and a second parasitic capacitor, the secondary winding of the transformer adopts a center tap mode, and the rectifying and filtering circuit comprises a first diode, a second diode and a first filtering capacitor.

3. The vehicle-mounted charger control circuit for the electric automobile according to claim 2, wherein the turn ratio n of the transformer is determined in a manner that:

wherein, V_{in_nom}Is the rated input voltage, V, of the resonant network_oIs the output voltage, V, of a half-bridge LLC resonant conversion module_dThe voltage drop of the rectifier tube conducting tube.

4. The vehicle-mounted charger control circuit for the electric automobile according to claim 3, wherein a transformer transformation ratio n determines a maximum direct current gain G of a half-bridge LLC resonant conversion module_maxAnd minimum DC gain G_minRespectively is as follows:

。

5. the vehicle-mounted charger control circuit for the electric automobile according to claim 4, wherein the normalized frequency f of the half-bridge LLC resonant conversion module_n＝f/f_rWhen f is_nWhen the value is 1, the working frequency f of the half-bridge LLC resonant conversion module is equal to the resonant frequency f_rAt the moment, the direct current gain of the half-bridge LLC resonant conversion module is 1 and is not influenced by a load, ZVS is realized by a primary side switch tube of the half-bridge LLC resonant conversion module, ZCS is realized by a secondary side rectifier tube diode, and the half-bridge LLC resonant conversion module works in an optimal state;

by maximum value of DC gain G_maxDetermining minimum operating frequency f of half-bridge LLC resonant conversion module_min；

By a minimum value of DC gain G_minDetermining maximum operating frequency f of half-bridge LLC resonant conversion module_max；

Further, the operating frequency f of the half-bridge LLC resonant conversion module is in the range: f. of_min<f<f_max；

Wherein k is an inductance ratio, and the value of the inductance ratio k is 1/3.

6. The control circuit of the vehicle-mounted charger for the electric automobile according to claim 5, wherein the maximum quality factor that can be obtained when the half-bridge LLC resonant conversion module works in an inductive range is as follows:

in order to ensure that the half-bridge LLC resonant conversion module can work in an inductive region in a full-load range, the quality factor Q of the half-bridge LLC resonant conversion module is lower than Q_max；

Further, Q is (90% to 95%) Q_max。

7. The control circuit of the vehicle-mounted charger for the electric automobile according to claim 5, characterized in that,

the values of the resonance inductance are:

the value of the resonance capacitance is:

the value of the excitation inductance is:

wherein R is_acIs an equivalent load resistance value.

8. A control method of a vehicle-mounted charger for an electric vehicle is characterized in that the control circuit of any one of claims 1 to 7 is utilized, and the steps are as follows:

after the battery is connected to a charger, detecting the voltage of the battery to be charged, and judging whether protective charging needs to be carried out for a period of time to activate reaction substances;

various parameters of the battery and the half-bridge LLC resonant conversion module are collected in real time, and the half-bridge LLC resonant conversion module is controlled according to the collected parameters to realize conversion of protection charging, constant-current charging, constant-voltage charging and trickle charging;

further, the output voltage of the half-bridge LLC resonant conversion module is collected in real time, a PWM control signal is output to the half-bridge LLC resonant conversion module according to the collected output voltage data, and the output voltage of the half-bridge LLC resonant conversion module is stabilized by controlling the on and off of a switch tube in the half-bridge LLC resonant conversion module;

furthermore, the zero crossing point of the resonant current of the half-bridge LLC resonant conversion module and the zero crossing point of the voltage of the midpoint of the half-bridge LLC resonant conversion module are acquired in real time, the detection of the input impedance of the resonant network of the half-bridge LLC resonant conversion module is realized by comparing the phases of the two zero crossing points, and a PWM control signal is sent to the half-bridge LLC resonant conversion module according to the detection result to ensure that the phase of the zero crossing point of the voltage of the midpoint of the half-bridge LLC resonant conversion module is ahead of the phase of the zero crossing point of the resonant current of the half-bridge LLC resonant conversion module so as to realize that the.

9. A vehicle-mounted charger for an electric automobile, which is characterized by comprising the control circuit of the vehicle-mounted charger for the electric automobile according to any one of claims 1 to 7.

10. An electric vehicle, comprising the vehicle-mounted charger control circuit for the electric vehicle of any one of claims 1 to 7;

or, include the on-vehicle machine that charges of electric automobile of claim 9.

Technical Field

The disclosure relates to the technical field of electric automobiles, in particular to a control circuit and a control method for a vehicle-mounted charger, the charger and an electric automobile.

Background

The statements in this section merely provide background information related to the present disclosure and may not necessarily constitute prior art.

In the face of adding new energy, the safety and reliability of a power grid are seriously checked, strict requirements are put on the safety and reliability of adding new energy into the power grid, and particularly, when an electric vehicle-mounted charger charges an electric vehicle, large harmonic pollution is easily generated, so that zero-voltage starting and zero-current switching-off are generally realized by using a resonant converter in the vehicle-mounted charger, but when general resonant converters have high input voltage, the phenomenon of overlarge switching-off current exists, and the problems of conduction loss and overhigh switching loss exist when the input voltage is wide, and the limitation limits the further improvement of the switching frequency and the efficiency of the converter.

The inventor of the present disclosure finds in research that a half-bridge LLC resonant converter can realize ZVS in a full load range and a wide input voltage range, and is very suitable for being used as a power topology of a vehicle-mounted charger, but (1) currently, a common LLC resonant converter mostly adopts analog control, and has poor expansibility and poor universality; (2) the current LLC resonant converter cannot ensure that a charger can work in a zero-voltage working area no matter load change or input voltage change, so that the new energy electric automobile is charged efficiently in a power grid and harmonic pollution is reduced; (3) the current LLC resonant converter cannot be adjusted in real time to ensure that a half-bridge LLC resonant conversion module works in an inductive area.

Disclosure of Invention

In order to solve the defects of the prior art, the disclosure provides a vehicle-mounted charger control circuit, a vehicle-mounted charger control method, a charger and an electric automobile, wherein the charger can work in a zero-voltage working area no matter load change or input voltage change, and harmonic pollution is reduced while the electric automobile with new energy is charged in a high efficiency mode in a power grid.

In order to achieve the purpose, the following technical scheme is adopted in the disclosure:

in a first aspect, the present disclosure provides a control circuit for a vehicle-mounted charger for an electric vehicle;

a vehicle-mounted charger control circuit for an electric automobile comprises a filtering and rectifying module, a power factor correction module, a half-bridge LLC resonance conversion module and a main control module, wherein the filtering and rectifying module is used for filtering electromagnetic interference signals of input alternating current signals and converting the electromagnetic interference signals into direct current signals;

the power factor correction module is used for removing harmonic components in the direct current signal and outputting a direct current voltage signal to a load through the half-bridge LLC resonance conversion module, and the half-bridge LLC resonance conversion module is used for enabling the switching tube to work in a zero-voltage state so as to realize zero-voltage switching-on when the charger is charged;

the main control module is used for acquiring the output voltage of the half-bridge LLC resonant conversion module in real time, outputting a PWM control signal to the half-bridge LLC resonant conversion module according to the acquired output voltage data, and stabilizing the output voltage of the half-bridge LLC resonant conversion module by controlling the on and off of a switch tube in the half-bridge LLC resonant conversion module;

the main control module is used for acquiring a resonant current zero crossing point of the half-bridge LLC resonant conversion module and a voltage zero crossing point of a midpoint voltage of the half-bridge LLC resonant conversion module in real time, detecting the input impedance of a resonant network of the half-bridge LLC resonant conversion module by comparing phases of the two zero crossing points, and ensuring that the half-bridge LLC resonant conversion module works in an inductive area by dynamically controlling the on-off of a switching tube in the half-bridge LLC resonant conversion module;

the main control module is also used for collecting various parameters of the battery in real time and controlling the half-bridge LLC resonance conversion module according to the collected parameters to realize conversion of protection charging, constant current charging, constant voltage charging and trickle charging.

As some possible implementation manners, the half-bridge LLC resonant conversion module includes a half-bridge structure, a resonant network, a transformer, a rectification circuit, and a filter circuit, and includes, on a primary side of the transformer, a first switching tube, a second switching tube, a resonant inductor, an excitation inductor, and a resonant capacitor;

the first switch tube and the second switch tube respectively comprise a first parasitic capacitor and a second parasitic capacitor, the secondary winding of the transformer adopts a center tap mode, and the rectifying and filtering circuit comprises a first diode, a second diode and a first filtering capacitor.

As some possible implementations, the turn ratio n of the transformer is determined by:

wherein, V_{in_nom}Is the rated input voltage, V, of the resonant network_oIs the output voltage, V, of a half-bridge LLC resonant conversion module_dThe voltage drop of the rectifier tube conducting tube.

By further limitation, the maximum direct current gain G of the half-bridge LLC resonant conversion module is determined by the transformer transformation ratio n_maxAnd minimum DC gain G_minRespectively is as follows:

as a further limitation, the normalized frequency f of the half-bridge LLC resonant conversion module_n＝f/f_rWhen f is_nWhen the value is 1, the working frequency f of the half-bridge LLC resonant conversion module is equal to the resonant frequency f_rAt the moment, the direct current gain of the half-bridge LLC resonant conversion module is 1 and is not influenced by a load, ZVS is realized by a primary side switch tube of the half-bridge LLC resonant conversion module, ZCS is realized by a secondary side rectifier tube diode, and the half-bridge LLC resonant conversion module works in an optimal state;

by maximum value of DC gain G_maxDetermining minimum operating frequency f of half-bridge LLC resonant conversion module_min；

By a minimum value of DC gain G_minDetermining maximum operating frequency f of half-bridge LLC resonant conversion module_max；

Further, the operating frequency f of the half-bridge LLC resonant conversion module is in the range: f. of_min<f<f_max；

Wherein k is an inductance ratio, and the value of the inductance ratio k is 1/3.

By way of further limitation, the maximum quality factor that can be obtained when the half-bridge LLC resonant conversion module operates in the inductive range is:

in order to ensure that the half-bridge LLC resonant conversion module can work in an inductive region in a full-load range, the quality factor Q of the half-bridge LLC resonant conversion module is lower than Q_max；

Further, Q is (90% to 95%) Q_max。

As a further limitation, the value of the resonant inductance is:

the value of the resonance capacitance is:

the value of the excitation inductance is:

wherein R is_acIs an equivalent load resistance value.

In a second aspect, the present disclosure provides a control method for a vehicle-mounted charger for an electric vehicle, where, by using the control circuit of the present disclosure, the steps are as follows:

after the battery is connected to a charger, detecting the voltage of the battery to be charged, and judging whether protective charging needs to be carried out for a period of time to activate reaction substances;

various parameters of the battery and the half-bridge LLC resonant conversion module are collected in real time, and the half-bridge LLC resonant conversion module is controlled according to the collected parameters to realize the conversion of constant-current charging, constant-voltage charging and trickle charging;

further, the output voltage of the half-bridge LLC resonant conversion module is collected in real time, a PWM control signal is output to the half-bridge LLC resonant conversion module according to the collected output voltage data, and the output voltage of the half-bridge LLC resonant conversion module is stabilized by controlling the on and off of a switch tube in the half-bridge LLC resonant conversion module;

furthermore, the zero crossing point of the resonant current of the half-bridge LLC resonant conversion module and the zero crossing point of the voltage of the midpoint of the half-bridge LLC resonant conversion module are acquired in real time, the detection of the input impedance of the resonant network of the half-bridge LLC resonant conversion module is realized by comparing the phases of the two zero crossing points, and a PWM control signal is sent to the half-bridge LLC resonant conversion module according to the detection result to ensure that the phase of the zero crossing point of the voltage of the midpoint of the half-bridge LLC resonant conversion module is ahead of the phase of the zero crossing point of the resonant current of the half-bridge LLC resonant conversion module so as to realize that the.

In a third aspect, the disclosure provides a vehicle-mounted charger for an electric automobile, which comprises the vehicle-mounted charger control circuit for the electric automobile.

In a fourth aspect, the present disclosure provides an electric vehicle, including the vehicle-mounted charger control circuit for an electric vehicle of the present disclosure;

in a fifth aspect, the present disclosure provides an electric vehicle, which includes the vehicle-mounted charger of the present disclosure.

Compared with the prior art, the beneficial effect of this disclosure is:

according to the charging method and device, the main control module is used for ensuring that the LLC resonant converter cannot be adjusted in real time so as to ensure that the half-bridge LLC resonant conversion module works in a sensitive area, and further, the charging machine can work in a zero-voltage working area no matter load change or input voltage change, so that the new energy electric automobile is charged efficiently in a power grid, and harmonic pollution is reduced.

The content through setting up host system, gather LLC resonant converter and treat rechargeable battery's each item parameter, realize the real-time dynamic control to the converter, stability of the output voltage of assurance converter that can be real-time has solved the poor problem of expansibility and commonality when current LLC resonant converter adopts analog control.

According to the method and the device, through effective setting and selection of all parameters of the LLC resonance conversion module, the charger can work in a zero-voltage working area no matter load change or input voltage change is guaranteed, and therefore zero-voltage starting and zero-current turning-off can be guaranteed no matter what conditions are.

Drawings

Fig. 1 is a schematic structural diagram of a vehicle-mounted charger control circuit according to embodiment 1 of the present disclosure.

Fig. 2 is a schematic structural diagram of an LLC resonant conversion module described in embodiment 1 of this disclosure.

Fig. 3 shows dc gains of the LLC resonant conversion module at different k values when Q is 0.5 according to embodiment 1 of the present disclosure.

Detailed Description

It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present disclosure. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.