CN112688585B

CN112688585B - Inverter control method, storage medium, and electronic device

Info

Publication number: CN112688585B
Application number: CN202011607807.3A
Authority: CN
Inventors: 李超
Original assignee: Dongfeng Motor Co Ltd
Current assignee: Dongfeng Motor Co Ltd
Priority date: 2020-12-30
Filing date: 2020-12-30
Publication date: 2022-07-08
Anticipated expiration: 2040-12-30
Also published as: CN112688585A

Abstract

The invention provides an inverter control method, a storage medium and an electronic device, wherein the method comprises the following steps: when a target torque instruction is received, acquiring the current input voltage, the current output current and the current motor rotating speed of the inverter; in a dq coordinate system, acquiring a D-axis current and a Q-axis current corresponding to a target torque according to the current input voltage, the current output current and the current motor rotating speed; calculating the real-time duty ratio of the insulated gate bipolar transistor according to the D-axis current and the Q-axis current; acquiring a preset duty ratio threshold corresponding to the target torque; and controlling the on or off of the insulated gate bipolar transistor according to the real-time duty ratio and the duty ratio threshold value. By implementing the invention, the inverter can be prevented from falsely reporting the IGBT desaturation fault, the safety is improved, the harmonic wave of the output current of the inverter can be reduced, and the NVH problem of a vehicle is reduced.

Description

Inverter control method, storage medium, and electronic device

Technical Field

The present invention relates to the field of automotive technologies, and in particular, to an inverter control method, a storage medium, and an electronic device.

Background

The inverter is a converter which converts direct current electric energy (batteries and storage batteries) into constant-frequency constant-voltage or frequency-modulation voltage-regulation alternating current (generally 220V,50Hz sine wave). Insulated Gate Bipolar Transistor (IGBT) is a key device for converting direct current into alternating current in an electric vehicle inverter. The IGBT is particularly sensitive to temperature, and when the current flowing through the IGBT exceeds a predetermined value, the temperature of the IGBT rises sharply, which causes the IGBT to be damaged, so in order to protect the IGBT, a circuit for detecting a short-circuit (desaturation) failure of the IGBT is generally provided inside the inverter, and when the IGBT is short-circuited (desaturated), the inverter needs to be able to quickly detect the failure so as to turn off the IGBT in time and prevent the IGBT from being damaged by overheating.

At present, in an existing inverter Control method, an IGBT switching command (PWM wave) at the time is calculated according to a target torque given by a Vehicle Control Module (VCM) and a current operating state of a motor, and then the IGBT strictly switches according to the output switching command to output a required current. However, when the vehicle speed is high (about 130km/h or more), the inverter generally has a maximum switching frequency (10K or more) and the inverter outputs a current having a high frequency (700 Hz or more), so that pulses having extremely small on/off times may occur in each cycle. Because the IGBT belongs to a semiconductor device, it takes a certain time to turn on and off, and if the pulse width of turn-on/turn-off given in the control is less than the time required for turn-on/turn-off, it will cause the IGBT to turn on/turn off incompletely, also called "false turn-on/false turn-off".

As shown in fig. 1, normally, the collector-emitter voltage Vce of the IGBT should rise when the base-emitter voltage Vge falls (IGBT is off) and fall when Vge rises (IGBT is on). As shown in fig. 2, when "false on/false off" occurs, the Vce voltage does not rise in time when Vge falls, but rises when Vge rises (IGBT is turned on), and the logic for determining IGBT desaturation fault is that "Vce rise is detected when IGBT is turned on", and according to the semiconductor characteristics of IGBT, when the current flowing through IGBT is smaller (less than 10A) and the temperature of IGBT is higher (higher than 65 ℃), the time required for turn-on/turn-off is longer, the Vce fluctuation caused by "false on/false off" is larger, and when Vce fluctuation caused by "false on/false off" is larger and exceeds the threshold of desaturation fault, the "IGBT desaturation fault" is triggered by mistake, so as to cut off power and affect the driving safety.

Meanwhile, due to the fact that the IGBT is switched on and off in a false on/false off manner, the IGBT cannot be switched on and off in accordance with a control command strictly, so that an error occurs between an actual output current and a command value, and an output current harmonic of the inverter is increased, thereby causing Noise, Vibration, and Harshness (NVH) and efficiency of the vehicle to be deteriorated.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides an inverter control method, a storage medium and electronic equipment, which can prevent an inverter from mistakenly reporting an IGBT desaturation fault, improve the safety, reduce the harmonic wave of the output current of the inverter and reduce the NVH problem of a vehicle.

The technical scheme of the invention provides an inverter control method, which comprises the following steps:

when a target torque instruction is received, acquiring the current input voltage, the current output current and the current motor rotating speed of the inverter;

in a dq coordinate system, acquiring a D-axis current and a Q-axis current corresponding to a target torque according to the current input voltage, the current output current and the current motor rotating speed;

calculating the real-time duty ratio of the insulated gate bipolar transistor according to the D-axis current and the Q-axis current;

acquiring a preset duty ratio threshold corresponding to the target torque;

and controlling the on or off of the insulated gate bipolar transistor according to the real-time duty ratio and the duty ratio threshold value.

Further, the real-time duty ratio includes a real-time on duty ratio, and the controlling the on or off of the insulated gate bipolar transistor according to the real-time duty ratio and the duty ratio threshold includes:

when the real-time switching-on duty ratio is smaller than or equal to the duty ratio threshold value, the duty ratio threshold value is modified into the real-time switching-on duty ratio;

and controlling the turn-on of the insulated gate bipolar transistor according to the real-time turn-on duty ratio.

Further, the real-time duty cycle further includes a real-time turn-off duty cycle, and the controlling the turn-on or turn-off of the insulated gate bipolar transistor according to the real-time duty cycle and the duty cycle threshold includes:

when the real-time turn-off duty ratio is smaller than or equal to the duty ratio threshold value, modifying the duty ratio threshold value into the real-time turn-off duty ratio;

and controlling the turn-off of the insulated gate bipolar transistor according to the real-time turn-off duty ratio.

Further, the calculating the real-time duty ratio of the insulated gate bipolar transistor according to the D-axis current and the Q-axis current includes:

acquiring a preset D-axis given current corresponding to the D-axis current and a preset Q-axis given current corresponding to the Q-axis current;

calculating a D-axis current difference value of the D-axis given current and the D-axis current and a Q-axis current difference value of the Q-axis given current and the Q-axis current;

the D-axis current difference value and the Q-axis current difference value are subjected to current regulators to obtain D-axis voltage and Q-axis voltage;

performing park transformation on the D-axis voltage and the Q-axis voltage to obtain a voltage vector under an alpha-beta coordinate system;

and calculating the real-time duty ratio according to the voltage vector by using a space vector pulse width modulation algorithm.

Further, the obtaining a preset duty ratio threshold corresponding to the target torque includes:

acquiring a preset switching frequency corresponding to the target torque;

and calculating the duty ratio threshold according to the switching frequency.

Further, the calculating the duty threshold according to the switching frequency includes:

calculating the duty cycle threshold using:

D＝t*f*0.000001。

wherein D is the duty cycle threshold; t is a preset minimum time value when the insulated gate bipolar transistor is conducted; f is the switching frequency.

The technical solution of the present invention also provides a storage medium, which stores computer instructions for executing all the steps of the inverter control method as described above when a computer executes the computer instructions.

The technical solution of the present invention also provides an electronic device, including:

at least one processor; and the number of the first and second groups,

a memory communicatively coupled to the at least one processor; wherein the content of the first and second substances,

the memory stores instructions executable by the at least one processor to cause the at least one processor to:

acquiring a preset duty ratio threshold corresponding to the target torque;

Further, the real-time duty cycle further includes a real-time off duty cycle, and the controlling the on or off of the insulated gate bipolar transistor according to the real-time duty cycle and the duty cycle threshold includes:

After adopting above-mentioned technical scheme, have following beneficial effect: when a target torque instruction sent by a VCM is received, the current input voltage, the current output current and the current motor rotating speed of an inverter are obtained, the real-time duty ratio is calculated according to the current input voltage, the current output current and the current motor rotating speed, the preset duty ratio threshold value corresponding to the target torque is obtained, and the on-off time of the IGBT is controlled according to the comparison between the real-time duty ratio and the duty ratio threshold value, so that the on-off pulse width of the IGBT is limited, the abnormal rise of Vce caused by false turn-off of the IGBT in the on period is prevented, false alarm desaturation faults are avoided, and current harmonics caused by false turn-on and false turn-off are eliminated.

Drawings

The disclosure of the present invention will become more readily understood by reference to the drawings. It should be understood that: these drawings are for illustrative purposes only and are not intended to limit the scope of the present disclosure. In the figure:

fig. 1 is a schematic diagram of a voltage variation structure of a conventional IGBT in turn-on and turn-off under normal conditions;

fig. 2 is a schematic diagram of a voltage variation structure of turn-on and turn-off when the conventional IGBT is in false turn-on/false turn-off;

fig. 3 is a flowchart illustrating an inverter control method according to an embodiment of the present invention;

fig. 4 is a flowchart illustrating an inverter control method according to another embodiment of the present invention;

fig. 5 is a schematic diagram of a hardware structure of an electronic device for inverter control according to an embodiment of the present invention.

Detailed Description

The following further describes embodiments of the present invention with reference to the accompanying drawings.

It is easily understood that according to the technical solution of the present invention, those skilled in the art can substitute various structures and implementation manners without changing the spirit of the present invention. Therefore, the following detailed description and the accompanying drawings are merely illustrative of the technical aspects of the present invention, and should not be construed as limiting or restricting the technical aspects of the present invention.

The terms of orientation of up, down, left, right, front, back, top, bottom, and the like referred to or may be referred to in this specification are defined relative to the configuration shown in the drawings, and are relative terms, and thus may be changed correspondingly according to the position and the use state of the device. Therefore, these and other directional terms should not be construed as limiting terms.

As shown in fig. 3, fig. 3 is a flowchart of an inverter control method according to an embodiment of the present invention, including:

step S101, when a target torque instruction is received, acquiring the current input voltage, the current output current and the current motor rotating speed of an inverter;

step S102, obtaining a D-axis current and a Q-axis current corresponding to a target torque in a dq coordinate system according to the current input voltage, the current output current and the current motor rotating speed;

step S103, calculating the real-time duty ratio of the insulated gate bipolar transistor according to the D-axis current and the Q-axis current;

step S104, acquiring a preset duty ratio threshold corresponding to the target torque;

and S105, controlling the on or off of the insulated gate bipolar transistor according to the real-time duty ratio and the duty ratio threshold value.

Specifically, the target torque command may be sent by the VCM, and when the controller receives the target torque command, it triggers step S101 to obtain the current input voltage and the current output current of the inverter; then, step S102 is executed to obtain components of current output current on a D axis and a Q axis respectively in a dq coordinate system according to the current input voltage and the current output current, namely D axis current and Q axis current, and step S103 is executed to calculate the real-time duty ratio of the IGBT; then, step S104 is executed to obtain a preset duty ratio threshold value corresponding to the target torque; and finally, step S105 is executed to control the on-off time of the IGBT according to the comparison between the real-time duty ratio and the duty ratio threshold value, so that the on-off pulse width of the IGBT is limited, the abnormal rise of Vce caused by false turn-off of the IGBT in the on-period is prevented, the false alarm and desaturation fault is avoided, and the current harmonic wave caused by false turn-on and false turn-off is eliminated.

Preferably, the duty cycle threshold is a narrow pulse width duty cycle threshold.

The sequence of steps S102 to S103 and S104 in this embodiment is only for convenience of description, and does not limit the claims, and those skilled in the art should understand that the sequence of steps S102 to S103 and S104 can be exchanged or synchronized without affecting the actual effect.

The controller according to the embodiment of the present invention is preferably an on-vehicle Electronic Control Unit (ECU).

According to the inverter control method provided by the invention, when a target torque instruction sent by a VCM is received, the current input voltage, the current output current and the current motor rotating speed of the inverter are obtained, the real-time duty ratio is calculated according to the current input voltage, the current output current and the current motor rotating speed, the preset duty ratio threshold value corresponding to the target torque is obtained, and the on-off time of the IGBT is controlled according to the comparison between the real-time duty ratio and the duty ratio threshold value, so that the on-off pulse width of the IGBT is limited, the abnormal rise of Vce in the on-off period caused by false turn-off of the IGBT is prevented, the false alarm desaturation fault is avoided, and the current harmonic wave brought by false turn-on and false turn-off is eliminated.

As shown in fig. 4, fig. 4 is a flowchart of an inverter control method according to another embodiment of the present invention, including:

step S201, when a target torque instruction is received, acquiring the current input voltage, the current output current and the current motor rotating speed of an inverter;

step S202, in a dq coordinate system, obtaining D-axis current and Q-axis current corresponding to target torque according to current input voltage, current output current and current motor rotating speed;

step S203, calculating the real-time duty ratio of the insulated gate bipolar transistor according to the D-axis current and the Q-axis current;

step S204, acquiring a preset switching frequency corresponding to the target torque;

step S205, calculating a duty ratio threshold value according to the switching frequency;

step S206, judging whether the real-time opening duty ratio is less than or equal to the duty ratio threshold value;

step S207, the duty ratio threshold value is modified into a real-time opening duty ratio;

step S208, judging whether the real-time turn-off duty ratio is less than or equal to a duty ratio threshold value;

step S209, the duty ratio threshold value is modified into a real-time turn-off duty ratio;

and S210, controlling the on or off of the insulated gate bipolar transistor according to the real-time duty ratio.

Specifically, when a target torque command sent by the VCM is received, the controller executes step S201 to acquire a current input voltage, a current output current, and a current motor speed of the inverter, and executes steps S202 to S203 to calculate a real-time duty ratio, where the real-time duty ratio includes a real-time on duty ratio Ton and a real-time off duty ratio Toff; then, step S204 is executed to inquire a preset motor rotating speed/torque/switching frequency table according to the target torque to obtain the target torque, and a duty ratio threshold value is calculated according to the relation between the frequency and the duty ratio; and then, executing a step S206 to judge whether the real-time turn-on duty ratio Ton is less than or equal to a duty ratio threshold, if so, executing a step S207 to modify the duty ratio threshold into the real-time turn-on duty ratio Ton, otherwise, executing a step S208 to judge whether the real-time turn-off duty ratio Toff is less than or equal to the duty ratio threshold, if so, executing a step S209 to modify the duty ratio threshold into the real-time turn-off duty ratio Toff, otherwise, executing a step S210 to control the turn-on or turn-off of the IGBT according to the real-time duty ratio, thereby judging whether the real-time turn-on duty ratio or the real-time turn-off duty ratio of the IGBT is a narrow pulse width, limiting the turn-on or turn-off pulse width of the IGBT, preventing Vce caused by 'false turn-off' of the IGBT from abnormally rising in a turn-on period, avoiding false turn-off saturation faults, and eliminating current harmonics caused by 'false turn-on and false turn-off'.

In one embodiment, to facilitate calculation of the real-time duty ratio, the calculating of the real-time duty ratio of the igbt according to the D-axis current and the Q-axis current includes:

acquiring preset D-axis given current corresponding to the D-axis current and preset Q-axis given current corresponding to the Q-axis current;

the D-axis current difference value and the Q-axis current difference value are subjected to current regulators to obtain a D-axis voltage and a Q-axis voltage;

carrying out park transformation on the D-axis voltage and the Q-axis voltage to obtain a voltage vector under an alpha-beta coordinate system;

In one embodiment, to facilitate calculating the duty threshold, the calculating the duty threshold according to the switching frequency includes:

calculating the duty cycle threshold using:

D＝t*f*0.000001。

wherein D is a duty cycle threshold; t is a preset minimum time value when the IGBT is conducted; f is the switching frequency.

Specifically, a preset minimum time value t when the IGBT is turned on may be set according to a user requirement, and the setting of the value t is related to the carrier frequency of the IGBT.

Preferably, the preset minimum time value when the IGBT is turned on is 4 μ s, so that the turn-on or turn-off time of the IGBT can be further ensured, the voltage Vce between the collector and the emitter is prevented from abnormally rising in the turn-on period due to "false turn-off" of the IGBT, the IGBT desaturation failure is prevented from being mistakenly reported, and current harmonics caused by "false turn-on/false turn-off" are reduced.

An embodiment of the present invention provides a storage medium for storing computer instructions for performing all the steps of the inverter control method in any one of the method embodiments as described above, when the computer instructions are executed by a computer.

As shown in fig. 5, a schematic diagram of a hardware structure of an electronic device for inverter control according to an embodiment of the present invention includes:

at least one processor 501; and (c) a second step of,

a memory 502 communicatively coupled to the at least one processor 501; wherein the content of the first and second substances,

the memory 502 stores instructions executable by the at least one processor 501, the instructions being executable by the at least one processor 501 to enable the at least one processor 501 to:

acquiring a preset duty ratio threshold corresponding to the target torque;

Fig. 5 illustrates an example of a processor 501.

The Electronic device is preferably an Electronic Control Unit (ECU).

The electronic device may further include: an input device 503 and an output device 504.

The processor 501, the memory 502, the input device 503 and the output device 504 may be connected by a bus or other means, and are illustrated as being connected by a bus.

The memory 502, which is a non-volatile computer-readable storage medium, may be used to store non-volatile software programs, non-volatile computer-executable programs, and modules, such as program instructions/modules corresponding to the inverter control method in the embodiments of the present application, for example, the method flows shown in fig. 3-4. The processor 501 executes various functional applications and data processing by executing nonvolatile software programs, instructions, and modules stored in the memory 502, that is, implements the inverter control method in the above-described embodiments.

The memory 502 may include a storage program area and a storage data area, wherein the storage program area may store an operating system, an application program required for at least one function; the storage data area may store data created according to the use of the inverter control method, and the like. Further, the memory 502 may include high speed random access memory, and may also include non-volatile memory, such as at least one magnetic disk storage device, flash memory device, or other non-volatile solid state storage device. In some embodiments, the memory 502 may optionally include a memory remotely located from the processor 501, and these remote memories may be connected through a network to a device that performs the inverter control method. Examples of such networks include, but are not limited to, the internet, intranets, local area networks, mobile communication networks, and combinations thereof.

The input device 503 may receive input user clicks and generate signal inputs related to user settings and function control of the inverter control method. The output device 504 may include a display device such as a display screen.

The inverter control method of any of the method embodiments described above is performed when the one or more modules are stored in the memory 502, when executed by the one or more processors 501.

In one embodiment, the real-time duty cycle includes a real-time on duty cycle, and the controlling the on or off of the igbt according to the real-time duty cycle and the duty cycle threshold includes:

In one embodiment, the real-time duty cycle further includes a real-time off duty cycle, and the controlling the on or off of the igbt according to the real-time duty cycle and the duty cycle threshold includes:

The product can execute the method provided by the embodiment of the application, and has the corresponding functional modules and beneficial effects of the execution method. For technical details that are not described in detail in this embodiment, reference may be made to the methods provided in the embodiments of the present application.

The electronic device of embodiments of the present invention exists in a variety of forms, including but not limited to:

(1) an Electronic Control Unit (ECU) is also called a "traveling computer" or a "vehicle-mounted computer". The digital signal processor mainly comprises a microprocessor (CPU), a memory (ROM and RAM), an input/output interface (I/O), an analog-to-digital converter (A/D), a shaping circuit, a driving circuit and other large-scale integrated circuits.

(2) Mobile communication devices, which are characterized by mobile communication capabilities and are primarily targeted at providing voice and data communications. Such terminals include smart phones (e.g., iphones), multimedia phones, functional phones, and low-end phones, among others.

(3) The ultra-mobile personal computer equipment belongs to the category of personal computers, has the functions of calculation and processing, and generally has the mobile internet access characteristic. Such terminals include PDA, MID, and UMPC devices, among others.

(4) Portable entertainment devices such devices may display and play multimedia content. Such devices include audio and video players (e.g., ipods), handheld game consoles, electronic books, as well as smart toys and portable car navigation devices.

(5) The server is similar to a general computer architecture, but has higher requirements on processing capacity, stability, reliability, safety, expandability, manageability and the like because of the need of providing high-reliability service.

(6) And other electronic devices with data interaction functions.

Furthermore, the logic instructions in the memory 502 may be implemented in software functional units and stored in a computer readable storage medium when sold or used as a stand-alone product. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a mobile terminal (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.

The above-described embodiments of the apparatus are merely illustrative, and the units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the embodiment of the present invention. One of ordinary skill in the art can understand and implement it without inventive effort.

Through the above description of the embodiments, those skilled in the art will clearly understand that each embodiment can be implemented by software plus a necessary general hardware platform, and certainly can also be implemented by hardware. With this understanding in mind, the above-described technical solutions may be embodied in the form of a software product, which can be stored in a computer-readable storage medium such as ROM/RAM, magnetic disk, optical disk, etc., and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute the methods described in the embodiments or some parts of the embodiments.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the embodiments of the present invention, and not to limit the same; although embodiments of the present invention have been described in detail with reference to the foregoing embodiments, those skilled in the art will understand that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

Claims

1. An inverter control method, characterized by comprising:

acquiring a preset duty ratio threshold corresponding to the target torque;

and controlling the on-off time of the insulated gate bipolar transistor according to the real-time duty ratio and the duty ratio threshold value.

2. The inverter control method of claim 1, wherein the real-time duty cycle comprises a real-time on duty cycle, and wherein the controlling the on or off of the insulated gate bipolar transistor according to the real-time duty cycle and the duty cycle threshold comprises:

3. The inverter control method of claim 2, wherein the real-time duty cycle further comprises a real-time off duty cycle, and wherein the controlling the on or off of the insulated gate bipolar transistor according to the real-time duty cycle and the duty cycle threshold comprises:

4. The inverter control method according to any one of claims 1 to 3, wherein the calculating a real-time duty cycle of the IGBT from the D-axis current and the Q-axis current comprises:

5. The inverter control method according to any one of claims 1 to 3, wherein the obtaining of the preset duty threshold corresponding to the target torque includes:

acquiring a preset switching frequency corresponding to the target torque;

and calculating the duty ratio threshold according to the switching frequency.

6. The inverter control method of claim 5, wherein the calculating the duty cycle threshold from the switching frequency comprises:

calculating the duty cycle threshold using:

D＝t*f*0.000001

7. A storage medium, characterized in that the storage medium stores computer instructions for performing all the steps of the inverter control method according to any one of claims 1 to 6 when the computer instructions are executed by a computer.

8. An electronic device, comprising:

at least one processor; and the number of the first and second groups,

the memory stores instructions executable by the at least one processor to enable the at least one processor to:

acquiring a preset duty ratio threshold value corresponding to the target torque;

9. The electronic device of claim 8, wherein the real-time duty cycle comprises a real-time on duty cycle, and wherein the controlling the turn-on or turn-off of the insulated gate bipolar transistor according to the real-time duty cycle and the duty cycle threshold comprises:

10. The electronic device of claim 9, wherein the real-time duty cycle further comprises a real-time off duty cycle, the controlling the turn-on or turn-off of the insulated gate bipolar transistor according to the real-time duty cycle and the duty cycle threshold value comprising: