CN115923551A - A DCDC boost charging system and method based on a new energy vehicle motor controller - Google Patents

Abstract

The invention discloses a DCDC boost charging system and method based on a new energy automobile motor controller. The problem of among the prior art high-voltage platform framework vehicle and the difficult matching of middling pressure direct current charging pile, increase with high costs, heavy, occupation space that boost circuit brought is solved. The system comprises a quick charging interface, a driving charging controller and a battery manager, wherein the quick charging interface is connected with the driving charging controller, the driving charging controller is in communication connection with the battery manager, and the battery manager is in communication connection with the quick charging interface. The driving charging controller comprises a third change-over switch, a battery and a permanent magnet motor, when the driving charging controller works in a boosting charging mode, the third change-over switch is controlled to be closed, the upper bridge of the three-phase full-bridge inverter circuit is switched off, an equivalent direct current boosting circuit is formed by the upper bridge freewheeling diode, the lower bridge and the permanent magnet motor three-phase inductance together, and the DCDC boosting quick charging function of the high-voltage platform framework vehicle is realized.

Description

A DCDC boost charging system and method based on a new energy vehicle motor controller

technical field

The invention relates to the technical field of electric vehicles, in particular to a DCDC boost charging system and method based on a new energy vehicle motor controller.

Background technique

With the increasing demand for charging of new energy vehicle users for acute and long-distance travel, increasing the charging speed has become an urgent problem to be solved by the new energy industry. At present, the most mainstream solution is high-power DC fast charging. The general power of the current DC fast charging mode is 60KW, and the maximum DC output voltage is 650V. The charging time of 10%-80% SOC is generally more than 40 minutes. In order to further shorten the charging time and improve the power performance of the vehicle, the 800V high-voltage electrical architecture has become a future trend. The charging power of a single gun equipped with 800V DC fast charging can be increased to more than 350kw, and the charging time can be further shortened.

The 800V high-voltage electrical architecture platform needs to be upgraded simultaneously at the vehicle end and the charging end, and DC charging piles have developed rapidly in recent years. The matching of vehicles with 800V high-voltage platform architecture and 400V DC charging piles has also become a major technical issue. At present, the most simple and direct way is to add a DC-DC boost circuit on the vehicle side, and adding a boost circuit means increasing the cost, and it will also bring problems to the lightweight design and space layout of the vehicle.

Contents of the invention

The present invention mainly solves the problems of high cost, heavy weight, and occupied space caused by the high-voltage platform structure vehicle and the medium-voltage DC charging pile in the prior art, and provides a new energy vehicle based on A DCDC step-up charging system and method for a motor controller.

The above-mentioned technical problems of the present invention are mainly solved by the following technical solutions: a DCDC boost charging system based on a new energy vehicle motor controller, including a fast charging interface, a drive charging controller and a battery manager, and a fast charging interface Connect the drive charge controller, the drive charge controller communicates with the battery manager, and the battery manager communicates with the fast charging interface;

The fast charging interface is used to connect the charging gun. After the fast charging interface is connected to the charging gun, it sends a fast charging connection signal to the battery manager;

The battery manager judges the connection status of the charging gun according to the fast charging interface signal, and after confirming that the charging gun is connected normally, powers on the vehicle at high voltage, controls the drive charging controller to switch to the boost charging mode; controls the drive charging Determine whether the charger is ready for charging. After confirming that the charging is ready, notify the fast charging charging device to allow charging through can communication, and drive the charging controller to perform boost control;

The drive charge controller includes a third switch, a battery, and a permanent magnet motor. The battery is connected to the permanent magnet motor through a three-phase full-bridge inverter circuit. The third switch is connected to the output end of the fast charge interface and the input end of the drive charge controller. Among them, the neutral point of the stator winding of the permanent magnet motor is connected to the third switch as the positive input terminal, and the negative pole of the busbar of the three-phase full-bridge inverter circuit is connected to the third switch as the negative input terminal. When working in the boost charging mode, The third switching switch is controlled to close, the upper bridge of the three-phase full-bridge inverter circuit is turned off, the lower bridge of the three-phase full-bridge inverter circuit is repeatedly turned on and off at a fixed frequency, and the three-phase power supply of the upper bridge freewheeling diode, the lower bridge, and the permanent magnet motor The inductors together form an equivalent DC boost circuit. The third switch includes a positive input terminal, a negative input terminal, a positive output terminal, and a negative output terminal, wherein the positive input terminal and the negative input terminal of the third switch are connected to the output terminal of the fast charging interface, and the positive output terminal and the negative output terminal of the third switch are The terminals are respectively connected to the positive input terminal and the negative input terminal of the drive charge controller.

The present invention utilizes the existing circuit of the new energy vehicle for improvement, extracts the neutral point of the three-phase winding of the permanent magnet motor as the positive input end of the charging DC voltage, and utilizes the three-phase inductance of the stator winding and the three-phase full-bridge inverter circuit, through Control the structure of the three-phase full-bridge inverter circuit, which is equivalent to a boost circuit, control the boosted DC side voltage, and reversely charge the battery. There is no need to add a DC-DC step-up circuit, which not only reduces the cost, but also facilitates the lightweight and space layout of the vehicle. For the DCDC boost charging system based on the drive charge controller, it also includes a fast charge interface, a battery manager, a drive charge controller, and the interaction logic between them.

In the boost charging mode, the neutral point of the permanent magnet motor is used as the DC positive input terminal, the three-phase inductance of the stator winding of the permanent magnet motor is used as the energy storage inductance of the boost circuit, and the upper bridge of the three-phase full-bridge inverter circuit is turned off. The freewheeling diode and the lower bridge are used to form a boost circuit with three DC boost circuits connected in parallel, and its control principle is the same as that of the common boost circuit.

The interaction between the battery manager and the drive charge controller is connected through can communication, and the fast charging interface is connected with the battery manager through can communication.

As a preferred solution, the DC boost circuit includes three-phase inductors La, Lb, Lc, diode D1, diode D3, diode D5, transistor S2, transistor S4, and transistor S6, and one end of the three-phase inductors La, Lb, and Lc are connected to each other. As the positive input terminal, the other ends of the three-phase inductors La, Lb, and Lc are respectively connected to the positive poles of diode D1, diode D3, and diode D5, and the negative poles of diode D1, diode D3, and diode D5 are connected to each other and connected to the positive terminal of the battery. The collector of S2 is connected to the anode of diode D1, the collector of transistor S4 is connected to the anode of diode D3, the collector of transistor S6 is connected to the anode of diode D5, the emitters of transistor S2, transistor S4, and transistor S6 are respectively grounded, and the bases of transistor S2, transistor S4, and transistor S6 Both poles are input with the same fixed frequency control signal.

In this scheme, the neutral point of the permanent magnet motor is used as the DC positive input terminal, the three-phase inductance La, Lb, and Lc of the stator winding of the permanent magnet motor are used as the energy storage inductance of the boost circuit, and the upper bridge of the three-phase full-bridge inverter circuit is normally On and off, use the freewheeling diodes D1, D3, D5 and the lower arm transistors S2, S4, S6 of the three-phase full-bridge inverter circuit to form a boost circuit consisting of three DC boost circuits connected in parallel. Its control is the same as the basic principle of ordinary boost circuit, and the specific control is as follows:

Control transistors S2, S4, S6 to turn on and off repeatedly at the same fixed frequency, in three-phase inductance Lx (x=a, b, c), transistor Sy (y=2, 4, 6) and diode Dz (z=1 , 3, 5) The intermediate node generates a series of pulses, and the three-phase inductance and capacitor C form an output filter to filter the electric pulses, thereby obtaining a DC output voltage Vout.

When the transistor Sy is in the on state, the three-phase inductor Lx stores energy, the rising slope of the inductor current is Vin/Lx, the diode Dz reverses blocking, and the capacitor C and the pre-charging resistor R form a discharge circuit to output current.

When the transistor Sy is in the off state, the three-phase inductor Lx is discharged, and the slope of the inductor current is (Vout-Vin)/Lx. The diode Dz conducts forward, and the three-phase inductance Lx shunts in parallel to generate three currents Ix (x=a, b, c), which provides the current Iout for the pre-charging resistor R and charges the capacitor C.

When the boost circuit operates continuously in the steady state of the CCM mode, the relationship between the input voltage and the output voltage is: Vout/Vin=1/(1-D), where D is the duty cycle of the input control signal.

As a preferred solution, the third switch includes a first switch and a second switch, one end of the first switch is connected to the positive output end of the drive charging controller, and one end of the second switch is connected to the negative output end of the drive charge controller. The negative input terminal of the controller is connected, the other end of the first switch is the positive input terminal, the other end of the second switch is the negative input terminal, the positive input terminal of the first switch and the negative input terminal of the second switch are respectively connected to the positive output terminal of the fast charging interface and the negative output terminal. The third switching switch is used to connect and shut off the fast charging interface and the driving charging controller. The third switching switch is arranged in the high voltage control box, that is, the driving charging controller and the fast charging interface are connected through the high voltage control box.

As a preferred solution, the battery also includes a pre-charging circuit. The pre-charging circuit includes a pre-charging resistor R, a first switch K1, a second switch K2, and a capacitor C. The first terminal and the second terminal of the capacitor C are respectively connected to the battery Positive and negative poles, one end of the pre-charging resistor R is connected to the positive pole of the battery, the other end of the pre-charging resistor R is connected to one end of the first switch K1, the other end of the first switch K1 is connected to the first end of the capacitor C, and the other end of the first switch K1 The positive connection point is formed to be connected to the positive output end of the DC boost circuit, the second switch K2 is connected in parallel to the circuit in which the pre-charging resistance R and the first switch K1 are connected in series, and the second terminal of the capacitor C forms a negative connection point to connect with the DC boost circuit Negative output connection. Specifically, in this solution, the first end of the capacitor C is respectively connected to the cathode of the diode D1, the cathode of the diode D3, the cathode of the diode D5, the other end of the first switch K1, and one end of the second switch K2, and the second end of the capacitor C is respectively connected to Battery negative pole, three-phase full-bridge inverter circuit bus negative pole. Wherein the first switch K1, the second switch K2, the pre-charging resistor R, and the capacitor C together constitute a pre-charging circuit.

A DCDC boost charging control method based on a new energy vehicle motor controller, comprising the following steps:

S1. Detect the connection status between the fast charging interface and the charging gun;

S2. After the connection between the fast charging interface and the vehicle charging is completed, drive the charging controller to switch to the boost charging mode. The process is to close the third switch, turn off the upper bridge of the three-phase full-bridge inverter circuit, and turn off the The lower bridge of the transformer circuit is repeatedly switched on and off at a fixed frequency, and an equivalent DC boost circuit is composed of the freewheeling diode of the upper bridge, the lower bridge, and the three-phase inductance of the permanent magnet motor;

S3. Confirm that the charging preparation is normal, drive the charging controller to perform boost control, and adjust the output voltage to the target voltage.

As a preferred solution, the specific process of step S1 includes:

S11. The fast charging interface detects whether it is connected to the charging gun, and the fast charging interface sends a fast charging connection signal to the battery manager;

S12. The battery manager judges whether the connection is normal according to the fast charging connection signal, if normal, enters the next step, and reports a charging fault signal if not normal;

S13. The battery manager controls the first switch and the second switch to power on the whole vehicle with high voltage. The process includes opening the second switching switch, closing the first switching switch, a pre-charging circuit composed of a battery, a capacitor C and a pre-charging resistor R for pre-charging, and after the pre-charging is completed, the first switching switch is controlled to be turned off, and the second switching switch is closed. switch.

As a preferred solution, the specific process in step 2 includes:

S21. After the vehicle fast charging interface is connected to the charging gun, the battery manager notifies the drive charging controller to switch to the boost charging mode through CAN communication;

S22. Drive the charging controller to perform mode switching self-test, after the self-test is completed, switch the driving charging controller from the driving control mode to the boost charging mode;

S23. Drive the charging controller to confirm whether charging is ready, if yes, allow charging, and feed back a charging permission signal to the battery manager, if not, not allow charging, and report a charging failure signal.

As a preferred solution, the specific process of step S3 includes:

S31. After the charging controller is ready for charging, wait for the input charging voltage, and the battery manager allows charging through the can communication fast charging charging device;

S32. Drive the charging controller to detect whether the charging input terminal voltage is normal, if normal, enter the next step, if not normal, report a charging fault signal;

S33. Drive the charging controller to perform boost charging, and adjust the output voltage to the target voltage.

Therefore, the advantage of the present invention is:

1. Through the interaction between the fast charging interface, the battery manager, and the driving and charging controller, the system realizes the identification and switching of the two working modes. By switching to the high-voltage charging working mode, the high-voltage power platform architecture and the medium-voltage Matching of current charging piles.

2. The existing circuit of the new energy vehicle is used for improvement, and there is no need to add a DC-DC booster circuit, which not only reduces the cost, but also facilitates the lightweight and space layout of the vehicle.

Description of drawings

Fig. 1 is a kind of structural block diagram of the present invention;

Fig. 2 is a kind of circuit structure diagram of driving charge controller in the present invention;

Fig. 3 is a kind of flow diagram of control method of the present invention;

Fig. 4 is a kind of simulation circuit structural representation of driving charging controller in the present invention;

Fig. 5 is the oscillogram of simulation circuit input voltage and output voltage among the present invention;

Fig. 6 is a waveform diagram of the input current and output current of the simulation circuit in the present invention.

1-Quick charging interface 2-High voltage control box 3-Drive charging controller 4-Battery manager.

Detailed ways

The technical solutions of the present invention will be further specifically described below through the embodiments and in conjunction with the accompanying drawings.

Example:

In this embodiment, a DCDC boost charging system based on a new energy vehicle motor controller, as shown in FIG. 1 , includes a fast charging interface 1, a drive charging controller 3 and a battery manager 4. The drive charge controller is connected, the drive charge controller communicates with the battery manager, and the battery manager communicates with the fast charging interface.

The fast charging interface is used to connect the charging gun. After the fast charging interface is connected to the charging gun, it sends a fast charging connection signal to the battery manager;

The battery manager judges the connection status of the charging gun according to the fast charging interface signal, and after confirming that the charging gun is connected normally, powers on the vehicle at high voltage, controls the drive charging controller to switch to the boost charging mode; controls the drive charging It is judged whether the charger is ready for charging. After confirming that it is ready for charging, the fast charging charging device is notified through CAN communication to allow charging, and the charging controller is driven to perform boost control.

The drive charge controller includes a third switch K3, a battery, and a permanent magnet motor. The battery is connected to the permanent magnet motor through a three-phase full-bridge inverter circuit. The third switch is connected to the output terminal of the fast charge interface and the input of the drive charge controller. Between the terminals, the neutral point of the stator winding of the permanent magnet motor is used as the positive input terminal to connect to the third switch, and the negative pole of the busbar of the three-phase full-bridge inverter circuit is connected to the third switch as the negative input terminal. When working in the boost charging mode , control the third switching switch to close, the upper bridge of the three-phase full-bridge inverter circuit is turned off, the lower bridge of the three-phase full-bridge inverter circuit is repeatedly turned on and off at a fixed frequency, and the freewheeling diode of the upper bridge, the lower bridge and the permanent magnet motor are three The phase inductances together form an equivalent DC boost circuit.

As shown in Figure 2, the DC boost circuit formed in the drive charge controller includes three-phase inductors La, Lb, Lc, diode D1, diode D3, diode D5, transistor S2, transistor S4, transistor S6, three-phase inductor La, One end of Lb and Lc are connected as positive poles, the other ends of three-phase inductors La, Lb, and Lc are respectively connected to the positive poles of diode D1, diode D3, and diode D5, and the negative poles of diode D1, diode D3, and diode D5 are connected to each other. Connected to the battery input terminal, the collector of transistor S2 is connected to the positive pole of diode D1, the collector of transistor S4 is connected to the positive pole of diode D3, the collector of transistor S6 is connected to the positive pole of diode D5, the emitters of transistor S2, transistor S4, and transistor S6 are respectively grounded, and the transistors S2, Both the bases of the transistors S4 and S6 are input with the same fixed-frequency control signal.

The third switch K3 is set inside the high-voltage control box. The third switch K3 includes a first switch and a second switch. One end of the first switch is a positive output end connected to the positive input end of the drive charging controller, and one end of the second switch is a negative electrode. The output terminal is connected to the negative input terminal of the drive charge controller, the other terminal of the first switch is the positive input terminal, the other terminal of the second switch is the negative input terminal, the positive input terminal of the first switch and the negative input terminal of the second switch are respectively connected to the fast charging On the positive and negative output terminals of the interface.

The battery also includes a pre-charging circuit. The pre-charging circuit includes a pre-charging resistor R, a first switch K1, a second switch K2, and a capacitor C. The first terminal and the second terminal of the capacitor C are respectively connected to the positive pole and the negative pole of the battery. One end of the resistor R is connected to the positive pole of the battery, the other end of the pre-charging resistor R is connected to one end of the first switch K1, the other end of the first switch K1 is connected to the first end of the capacitor C, and the other end of the first switch K1 forms a positive connection point with the DC booster. The positive output terminal of the voltage circuit is connected, the second switching switch K2 is connected in parallel to the circuit in which the pre-charging resistor R and the first switching switch K1 are connected in series, and the second terminal of the capacitor C forms a negative connection point and is connected to the negative output terminal of the DC boost circuit.

Usually, the motor controller consists of a permanent magnet motor, a three-phase full-bridge inverter circuit and a DC side capacitor C. The DC boost circuit is improved by using the existing motor controller of the new energy vehicle. The neutral point of the permanent magnet motor is used as the DC positive input terminal, the three-phase inductance La, Lb, and Lc of the stator winding of the permanent magnet motor are used as the energy storage inductance of the boost circuit, and the upper bridge of the three-phase full-bridge inverter circuit is normally closed and turned off. The freewheeling diodes D1, D3, D5 and the lower arm transistors S2, S4, S6 of the three-phase full-bridge inverter circuit form a boost circuit with three DC boost circuits connected in parallel. Its control is the same as the basic principle of ordinary boost circuit, and the specific control is as follows:

Control transistors S2, S4, S6 to turn on and off repeatedly at the same fixed frequency, in three-phase inductance Lx (x=a, b, c), transistor Sy (y=2, 4, 6) and diode Dz (z=1 , 3, 5) The intermediate node generates a series of pulses, and the three-phase inductance and capacitor C form an output filter to filter the electric pulses, thereby obtaining a DC output voltage Vout.

When the transistor Sy is in the on state, the three-phase inductor Lx stores energy, the rising slope of the inductor current is Vin/Lx, the diode Dz reverses blocking, and the capacitor C and the pre-charging resistor R form a discharge circuit to output current.

When the transistor Sy is in the off state, the three-phase inductor Lx is discharged, and the slope of the inductor current is (Vout-Vin)/Lx. The diode Dz conducts forward, and the three-phase inductance Lx shunts in parallel to generate three currents Ix (x=a, b, c), which provides the current Iout for the pre-charging resistor R and charges the capacitor C.

When the boost circuit operates continuously in the steady state of CCM mode, the relationship between the input voltage and the output voltage is: Vout/Vin=1/(1-D), where D is the duty cycle of the input transistor control signal.

After improvement, the drive charge controller is formed, and it has two working modes through the interaction with the fast charge interface and the battery controller: drive control mode and boost charge mode.

Working in the drive control mode, the third switch is disconnected, the fast charging interface is not connected, the neutral point of the motor stator is in a short-circuit state, the working process is: the battery provides DC side voltage, and the inverter is carried out through the three-phase full-bridge inverter circuit Control, so that the stator winding generates magnetomotive force, and controls the rotation of the permanent magnet motor.

Working in the boost charging mode, the second switch and the third switch are closed, the neutral point of the permanent magnet motor is connected to the DC side Vin+ of the charging pile, and the negative pole of the charging controller is connected to the DC side Vin- of the charging pile to simulate the boost circuit. DCDC boost control, that is, the upper bridge of the three-phase full-bridge inverter circuit is turned off, using the three-phase inductance of the permanent magnet motor, the freewheeling diode of the upper bridge of the three-phase full-bridge inverter circuit and the lower bridge IGBT circuit to form a three-group The parallel boost circuit realizes the DCDC boost fast charging function of the high-voltage platform architecture vehicle.

The following uses the simulation circuit diagram to illustrate, as shown in Figure 5, the leakage inductance of the three-phase stator winding of the permanent magnet motor: La=Lb=Lc=127μH;

High voltage side capacitance: C=350μF

Analog load resistance: R=5.33Ω

Duty cycle D=0.4375

Open tube cycle: f _s =20khz

According to the design of the invention, the vehicle high-voltage architecture system requires the output voltage Vout of the DCDC boost charging control system to be 450V, and the duty cycle of the trigger pulse is calculated to be D=0.4375.

The results of input voltage and output voltage are shown in Figure 5. The input power is 120kw, ignoring the loss, and the input dynamic rate is equal to the output power, so the battery charging current Iout=P/Vout=150A. The input current and output current results are shown in Figure 6.

A DCDC boost charging control method based on a new energy vehicle motor controller, as shown in Figure 3, comprising the following steps:

S1. Detect the connection status between the fast charging interface and the charging gun; the specific process includes:

S11. The fast charging interface is connected to the charging gun, and the fast charging interface sends a fast charging connection signal to the battery manager;

S12. The battery manager judges whether the connection is normal according to the fast charging connection signal, if normal, enters the next step, and reports a charging fault signal if not normal;

S13. The battery manager controls the first switch and the second switch to power on the whole vehicle with high voltage.

S2. After the connection between the fast charging interface and the vehicle charging is completed, drive the charging controller to switch to the boost charging mode. The process is to close the third switch, turn off the upper bridge of the three-phase full-bridge inverter circuit, and turn off the The lower bridge of the variable circuit is repeatedly switched on and off at a fixed frequency, and an equivalent DC boost circuit is composed of the freewheeling diode of the upper bridge, the lower bridge, and the three-phase inductance of the permanent magnet motor; the specific process extension of step S2 includes:

S21. After the vehicle fast charging interface is connected to the charging gun, the battery manager notifies the drive charging controller to switch to the boost charging mode through CAN communication;

S22. Drive the charge controller to perform mode switching self-test. After the self-test is completed, the drive charge controller is switched from the drive control mode to the boost charge mode; that is, the process is to close the third switch, and the three-phase full-bridge inverter circuit The bridge is turned off, the lower bridge of the three-phase full-bridge inverter circuit is repeatedly switched on and off at a fixed frequency, and the equivalent DC boost circuit is composed of the freewheeling diode of the upper bridge, the lower bridge, and the three-phase inductance of the permanent magnet motor;

S23. Drive the charging controller to confirm whether charging is ready, if yes, allow charging, and feed back a charging permission signal to the battery manager, if not, not allow charging, and report a charging failure signal.

S3. Confirm that the charging preparation is normal, drive the charging controller to perform boost control, and adjust the output voltage to the target voltage. The specific process includes:

S31. After the charging controller is ready for charging, wait for the input charging voltage, and the battery manager allows charging through the can communication fast charging charging device;

S32. Drive the charging controller to detect whether the charging input terminal voltage is normal, if normal, enter the next step, if not normal, report a charging fault signal;

S33. Drive the charging controller to perform boost charging, and adjust the output voltage to the target voltage.

The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art to which the present invention belongs can make various modifications or supplements to the described specific embodiments or adopt similar methods to replace them, but they will not deviate from the spirit of the present invention or go beyond the definition of the appended claims range.

Although terms such as fast charging interface, high-voltage control box, drive charging controller, and battery manager are frequently used in this article, the possibility of using other terms is not excluded. These terms are used only for the purpose of describing and explaining the essence of the present invention more conveniently; interpreting them as any kind of additional limitation is against the spirit of the present invention.

Claims (8)

1. A DCDC boost charging system based on a new energy automobile motor controller comprises a quick charging interface (1), a driving charging controller (3) and a battery manager (4), wherein the quick charging interface is connected with the driving charging controller, the driving charging controller is in communication connection with the battery manager, and the battery manager is in communication connection with the quick charging interface;

the quick charging interface is used for connecting a charging gun and sending a quick charging connection signal to the battery manager after the quick charging interface is connected with the charging gun;

the battery manager judges the connection state of the charging gun according to the quick charging interface signal, and when the charging gun is confirmed to be in a normal connection state, the whole vehicle is electrified at high voltage, and the driving charging controller is controlled to be switched into a boosting charging mode; judging whether the driving charging controller is ready for charging, informing the quick charging equipment of allowing charging through can communication after the charging is confirmed to be ready, and performing boost control by the driving charging controller;

drive charge controller, including the third change over switch, a battery, permanent-magnet machine, the battery passes through three-phase full-bridge inverter circuit and is connected with permanent-magnet machine, the third change over switch is connected between quick interface output and drive charge controller input of filling, wherein permanent-magnet machine stator winding neutral point connects the third change over switch as positive input, three-phase full-bridge inverter circuit generating line negative pole connects the third change over switch as negative input, when work is in boost charge mode, control third change over switch is closed, the bridge is shut off on the three-phase full-bridge inverter circuit, the repeated break-make of three-phase full-bridge inverter circuit lower bridge with fixed frequency, by last bridge freewheeling diode, the lower bridge, permanent-magnet machine three-phase inductance constitutes equivalent direct current boost circuit jointly.

2. The DCDC boost charging system based on the new energy automobile motor controller according to claim 1, wherein the DC boost circuit comprises three-phase inductors La, lb, lc, a diode D1, a diode D3, a diode D5, a transistor S2, a transistor S4 and a transistor S6, one ends of the three-phase inductors La, lb and Lc are connected as a positive input end, the other ends of the three-phase inductors La, lb and Lc are respectively and correspondingly connected with the positive electrodes of the diode D1, the diode D3 and the diode D5, the negative electrodes of the diode D1, the diode D3 and the diode D5 are connected and connected to the positive electrode of the battery, the collector electrode of the transistor S2 is connected with the positive electrode of the diode D1, the collector electrode of the transistor S4 is connected with the positive electrode of the diode D3, the collector electrode of the transistor S6 is connected with the positive electrode of the diode D5, the emitter electrodes of the transistor S2, the transistor S4 and the transistor S6 are respectively grounded, and the base electrodes of the transistor S2, the transistor S4 and the transistor S6 are all input the same control signals with fixed frequency.

3. The DCDC boost charging system based on the new energy automobile motor controller as claimed in claim 2, wherein the third switch comprises a first switch and a second switch, one end of the first switch is a positive output terminal connected to the positive input terminal of the driving charging controller, one end of the second switch is a negative output terminal connected to the negative input terminal of the driving charging controller, the other end of the first switch is a positive input terminal, the other end of the second switch is a negative input terminal, and the positive input terminal of the first switch and the negative input terminal of the second switch are respectively connected to the positive output terminal and the negative output terminal of the fast charging interface.

4. The DCDC boost charging system based on the new energy automobile motor controller as claimed in claim 1, 2 or 3, wherein the battery further includes a pre-charging circuit, the pre-charging circuit includes a pre-charging resistor R, a first switch K1, a second switch K2, and a capacitor C, a first end and a second end of the capacitor C are respectively connected to the positive electrode and the negative electrode of the battery, one end of the pre-charging resistor R is connected to the positive electrode of the battery, the other end of the pre-charging resistor R is connected to one end of the first switch K1, the other end of the first switch K1 is connected to a first end of the capacitor C, the other end of the first switch K1 forms a positive electrode connection point to be connected to the positive electrode output end of the DC boost circuit, the second switch K2 is connected in parallel to a circuit in which the pre-charging resistor R and the first switch K1 are connected in series, and the second end of the capacitor C forms a negative electrode connection point to be connected to the negative electrode output end of the DC boost circuit.

5. A DCDC boost charging control method based on a new energy automobile motor controller adopts the system in any one of claims 1-4, and is characterized in that: the method comprises the following steps:

s1, detecting the connection state of a quick charging interface and a charging gun;

s2, after the quick charging interface is connected with the vehicle charging, the charging controller is driven to be switched to a boosting charging mode, the process is to close a third change-over switch, the upper bridge of the three-phase full-bridge inverter circuit is switched off, the lower bridge of the three-phase full-bridge inverter circuit is repeatedly switched on and off at a fixed frequency, and an equivalent direct-current boosting circuit is formed by an upper bridge freewheeling diode, the lower bridge and the three-phase inductance of the permanent magnet motor;

and S3, confirming that the charging preparation is normal, driving the charging controller to perform boost control, and adjusting the output voltage to a target voltage.

6. The DCDC boost charging control method based on the new energy automobile motor controller according to claim 5, wherein the step S1 comprises the following specific steps:

s11, a quick charging interface is connected with a charging gun and sends a quick charging connection signal to a battery manager;

s12, the battery manager judges whether the connection is normal according to the quick charging connection signal, if so, the next step is carried out, and if not, a charging fault signal is reported;

and S13, the battery manager controls the first change-over switch and the second change-over switch to electrify the whole vehicle at high voltage.

7. The DCDC boost charging control method based on the new energy automobile motor controller according to claim 5, characterized in that the specific process in step 2 comprises:

s21, after the vehicle quick charging interface is connected with a charging gun, the battery manager informs the driving charging controller to switch to a boosting charging mode through can communication;

s22, driving the charging controller to perform mode switching self-checking, and after the self-checking is completed, switching the driving charging controller from a driving control mode to a boosting charging mode;

and S23, driving the charging controller to confirm whether charging is ready, if so, allowing charging, feeding back a charging allowing signal to the battery manager, and if not, not allowing charging, reporting a charging fault signal.

8. The DCDC boost charging control method based on the new energy automobile motor controller according to claim 5, wherein the step S3 comprises the following steps:

s31, after the charging controller is driven to be charged, waiting for inputting of charging voltage, and allowing charging through can communication quick charging equipment by the battery manager;

s32, driving the charging controller to detect whether the voltage of the charging input end is normal or not, if the voltage is normal, entering the next step, and if the voltage is not normal, reporting a charging fault signal;

and S33, driving the charge controller to perform boost charge, and adjusting the output voltage to the target voltage.

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