阅读说明：本技术 电动汽车的逆变器svpwm控制方法、装置及电动汽车 (SVPWM control method and device for inverter of electric automobile and electric automobile ) 是由 李庆国 张�杰 陈士刚 陈亚莉 舒晖 杭孟荀 沙文瀚 刘琳 于 2021-01-05 设计创作，主要内容包括：本申请公开了一种电动汽车的逆变器SVPWM控制方法、装置及电动汽车,其中,方法包括：检测电动汽车的交流电机的实际转速；检测实际转速所处的转速区间；若转速区间为预设低速区间,则以第一段式SVPWM调制值和第一开关频率控制交流电机；若转速区间为预设中速区间,则以第二段式SVPWM调制值和第二开关频率控制交流电机；若转速区间为预设高速区间,则以第三段式SVPWM调制值和第三开关频率控制交流电机；其中,第一至第三段式SVPWM调制值分别为五段式SVPWM调制、五段式SVPWM调制和七段式SVPWM调制,第一至第三开关频率分别为2KHz、5KHz和10KHz开关频率。由此,解决了目前SVPWM控制方式存在逆变器的损耗高、效率低等问题。(The application discloses an SVPWM control method and device for an inverter of an electric automobile and the electric automobile, wherein the method comprises the following steps: detecting the actual rotating speed of an alternating current motor of the electric automobile; detecting a rotating speed interval where the actual rotating speed is located; if the rotating speed interval is a preset low-speed interval, controlling the alternating current motor by using a first-section SVPWM modulation value and a first switching frequency; if the rotating speed interval is a preset intermediate speed interval, controlling the alternating current motor by using a second-section SVPWM modulation value and a second switching frequency; if the rotating speed interval is a preset high-speed interval, controlling the alternating current motor by using a third-section SVPWM modulation value and a third switching frequency; the first-third-stage SVPWM modulation values are five-stage SVPWM modulation, five-stage SVPWM modulation and seven-stage SVPWM modulation respectively, and the first-third switching frequencies are 2KHz, 5KHz and 10KHz switching frequencies respectively. Therefore, the problems of high loss, low efficiency and the like of the inverter in the conventional SVPWM control mode are solved.)

1. An SVPWM control method of an inverter of an electric automobile is characterized by comprising the following steps:

detecting the actual rotating speed of an alternating current motor of the electric automobile;

detecting a rotating speed interval where the actual rotating speed is located; and

if the rotating speed interval is a preset low-speed interval, controlling the alternating current motor by using a first-section SVPWM modulation value and a first switching frequency, wherein the first-section SVPWM modulation value and the first switching frequency are respectively five-section SVPWM modulation and 2KHz switching frequency;

if the rotating speed interval is a preset intermediate speed interval, controlling the alternating current motor by using a second-section SVPWM modulation value and a second switching frequency, wherein the second-section SVPWM modulation value and the second switching frequency are the five-section SVPWM modulation and the 5KHz switching frequency respectively;

and if the rotating speed interval is a preset high-speed interval, controlling the alternating current motor by using a third-section SVPWM modulation value and a third switching frequency, wherein the third-section SVPWM modulation value and the third switching frequency are seven-section SVPWM modulation and 10KHz switching frequency respectively.

2. The method according to claim 1, wherein the preset low speed interval is [0, 200] rpm, the preset medium speed interval is [200, 3000] rpm, and the preset high speed interval is more than 3000 rpm.

3. The method according to claim 1, further comprising, before detecting a rotation speed interval in which the actual rotation speed is located:

collecting vehicle parameters of the electric automobile;

and determining the preset low-speed interval, the preset medium-speed interval and the preset high-speed interval according to the vehicle parameters.

4. An SVPWM control device of an inverter of an electric vehicle is characterized by comprising:

the first detection module is used for detecting the actual rotating speed of an alternating current motor of the electric automobile;

the second detection module is used for detecting a rotating speed interval where the actual rotating speed is located; and

the first control module is used for controlling the alternating current motor by using a first-section SVPWM modulation value and a first switching frequency when the rotating speed interval is a preset low-speed interval, wherein the first-section SVPWM modulation value and the first switching frequency are respectively five-section SVPWM modulation and 2KHz switching frequency;

the second control module is used for controlling the alternating current motor by using a second-section SVPWM modulation value and a second switching frequency when the rotating speed interval is a preset intermediate speed interval, wherein the second-section SVPWM modulation value and the second switching frequency are the five-section SVPWM modulation and the 5KHz switching frequency respectively;

and the third control module is used for controlling the alternating current motor by using a third-section SVPWM modulation value and a third switching frequency when the rotating speed interval is a preset high-speed interval, wherein the third-section SVPWM modulation value and the third switching frequency are respectively seven-section SVPWM modulation and 10KHz switching frequency.

5. The apparatus according to claim 4, wherein the preset low speed interval is [0, 200] rpm, the preset medium speed interval is [200, 3000] rpm, and the preset high speed interval is more than 3000 rpm.

6. The apparatus of claim 5, further comprising:

the acquisition module is used for acquiring vehicle parameters of the electric vehicle before detecting a rotating speed interval where the actual rotating speed is located;

and the determining module is used for determining the preset low-speed interval, the preset medium-speed interval and the preset high-speed interval according to the vehicle parameters.

7. An electric vehicle comprising the inverter SVPWM control apparatus of the electric vehicle according to any one of claims 4 to 6.

Technical Field

The application relates to the technical field of electric automobiles, in particular to an SVPWM (Space Vector Pulse Width Modulation) control method and device for an inverter of an electric automobile and the electric automobile.

Background

The main control methods of the ac motor are divided into SPWM (Sinusoidal Pulse Width Modulation) control and SVPWM control. The PWM (Pulse width modulation) control technique is to convert a direct current into an alternating current Pulse sequence by turning on and off semiconductors (Insulated Gate Bipolar transistors ) or MOSFETs (Metal-Oxide-Semiconductor Field Effect transistors) in different combination states. SVPWM is an optimized PWM technology, has been widely applied to an electric vehicle electric driving system, can reduce harmonic waves of output current of an inverter, reduce torque fluctuation, improve system precision, improve the utilization rate of direct-current voltage of the inverter, expand a weak magnetic range, and improve the efficiency of a driving system in a high-speed area. The SVPWM control mode system has good dynamic performance, the control mode can be conveniently realized through digitalization, and the SVPWM control mode system is the mainstream control mode of the alternating current motor at present.

However, the existing SVPWM control method has the problems of high loss, low efficiency and the like of the inverter, so that the endurance mileage of the electric vehicle is greatly reduced, and a solution is urgently needed.

Content of application

The application provides an SVPWM control method and device for an inverter of an electric automobile and the electric automobile, which aim to solve the problems of high loss, low efficiency and the like of the inverter in the existing SVPWM control mode.

The embodiment of the first aspect of the application provides an inverter SVPWM control method of an electric automobile, which comprises the following steps: detecting the actual rotating speed of an alternating current motor of the electric automobile; detecting a rotating speed interval where the actual rotating speed is located; if the rotating speed interval is a preset low-speed interval, controlling the alternating current motor by using a first-section SVPWM modulation value and a first switching frequency, wherein the first-section SVPWM modulation value and the first switching frequency are respectively five-section SVPWM modulation and 2KHz switching frequency; if the rotating speed interval is a preset intermediate speed interval, controlling the alternating current motor by using a second-section SVPWM modulation value and a second switching frequency, wherein the second-section SVPWM modulation value and the second switching frequency are the five-section SVPWM modulation and the 5KHz switching frequency respectively; and if the rotating speed interval is a preset high-speed interval, controlling the alternating current motor by using a third-section SVPWM modulation value and a third switching frequency, wherein the third-section SVPWM modulation value and the third switching frequency are seven-section SVPWM modulation and 10KHz switching frequency respectively.

Further, the preset low-speed interval is [0, 200] rpm, the preset medium-speed interval is [200, 3000] rpm, and the preset high-speed interval is more than 3000 rpm.

Further, before detecting a rotation speed interval in which the actual rotation speed is located, the method further includes: collecting vehicle parameters of the electric automobile; and determining the preset low-speed interval, the preset medium-speed interval and the preset high-speed interval according to the vehicle parameters.

The embodiment of the second aspect of the application provides an inverter SVPWM control apparatus for an electric vehicle, comprising: the first detection module is used for detecting the actual rotating speed of an alternating current motor of the electric automobile; the second detection module is used for detecting a rotating speed interval where the actual rotating speed is located; the first control module is used for controlling the alternating current motor by using a first-section SVPWM modulation value and a first switching frequency when the rotating speed interval is a preset low-speed interval, wherein the first-section SVPWM modulation value and the first switching frequency are respectively five-section SVPWM modulation and 2KHz switching frequency; the second control module is used for controlling the alternating current motor by using a second-section SVPWM modulation value and a second switching frequency when the rotating speed interval is a preset intermediate speed interval, wherein the second-section SVPWM modulation value and the second switching frequency are the five-section SVPWM modulation and the 5KHz switching frequency respectively; and the third control module is used for controlling the alternating current motor by using a third-section SVPWM modulation value and a third switching frequency when the rotating speed interval is a preset high-speed interval, wherein the third-section SVPWM modulation value and the third switching frequency are respectively seven-section SVPWM modulation and 10KHz switching frequency.

Further, the preset low-speed interval is [0, 200] rpm, the preset medium-speed interval is [200, 3000] rpm, and the preset high-speed interval is more than 3000 rpm.

Further, still include: the acquisition module is used for acquiring vehicle parameters of the electric vehicle before detecting a rotating speed interval where the actual rotating speed is located; and the determining module is used for determining the preset low-speed interval, the preset medium-speed interval and the preset high-speed interval according to the vehicle parameters.

An embodiment of a third aspect of the present application provides an electric vehicle, including the inverter SVPWM control apparatus of the electric vehicle according to the above embodiment.

Adopt different SVPWM modulation and switching frequency to control according to alternating current motor's different rotational speeds, when alternating current motor rotational speed is low rotational speed, adopt five-segment formula SVPWM modulation and 2KHz switching frequency, when alternating current motor rotational speed is well rotational speed, adopt five-segment formula SVPWM modulation and 5KHz switching frequency, when alternating current motor rotational speed is high rotational speed, adopt seven-segment formula SVPWM modulation and 10KHz switching frequency, thereby can accurate control switching frequency and different SVPWM modulation mode, improve inverter efficiency, reduce whole car energy consumption, effectively prolong electric automobile continuation of the journey mileage, reduce whole car battery capacity, reduce cost, and satisfy the requirement of actuating system to moment of torsion precision and noise, improve and use experience. Therefore, the problems of high loss, low efficiency and the like of the inverter in the conventional SVPWM control mode are solved.

Additional aspects and advantages of the present application will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the present application.

Drawings

The foregoing and/or additional aspects and advantages of the present application will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 is a schematic diagram of an inverter operation;

FIG. 2 is a basic voltage space vector diagram;

FIG. 3 is a diagram of a regular hexagonal stator flux linkage trajectory;

FIG. 4 is a target voltage vector composition diagram;

FIG. 5 is a five-segment basis vector function sequence diagram;

FIG. 6 is a seven-segment basis vector action sequence diagram;

fig. 7 is a schematic flowchart of an inverter SVPWM control method of an electric vehicle according to an embodiment of the present application;

fig. 8 is an exemplary diagram of an inverter SVPWM control apparatus of an electric vehicle according to an embodiment of the present application.

Detailed Description

Reference will now be made in detail to embodiments of the present application, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are exemplary and intended to be used for explaining the present application and should not be construed as limiting the present application.

Before introducing the SVPWM control method of the inverter of the electric vehicle according to the embodiment of the present application, a common SVPWM modulation method is introduced, wherein the common SVPWM modulation method mainly includes a seven-segment type and a five-segment type, the switching frequency is 2KHz, 5KHz, and 10KHz, and the specific process is as follows:

as shown in fig. 1, the inverter mainly inverts a direct current into three phases to supply power to an alternating current motor, and the inverter has three bridge arms and outputs three-phase voltage A, B, C. Each phase controls the voltage vector by 2 power devices (IGBTs), for a total of 6 power devices (IGBTs). To show its principle in a simple way, the power device (IGBT) is replaced by a switch. Only one of the upper bridge arm and the lower bridge arm can be switched on and the other can be switched off at any time, and in each bridge arm, the upper bridge arm is switched on and the lower bridge arm is switched off to be defined as '1'; the lower arm is turned on, and the upper arm is turned off and defined as "0". Sa is used for the phase A bridge arm state; the B-phase bridge arm state is represented by Sb; the C-phase bridge arm state is represented by Sc. Sa, Sb, Sc for a total of eight switching states, six active workspace voltage vectors U1-U6. Two zero vectors U0 and U7, Ul (001), U2(010), U3(011), U4(100), U5(101), U6(110), U0(000), U7 (111). Through Clack constant amplitude transformation, a voltage amplitude of 2Udc/3 can be obtained, as shown in Table 1.

TABLE 1

	Sa	Sb	Sc	Amplitude value
					U0	0	0	0	2Udc/3
U1	1	0	0	2Udc/3
					U2	1	1	0	2Udc/3
U3	0	1	0	2Udc/3
					U4	0	1	1	2Udc/3
U5	0	0	1	2Udc/3
					U6	1	0	1	2Udc/3
U7	1	1	1	2Udc/3

The adjacent space voltage vectors are separated by 60 degrees as shown in fig. 2, two zero vectors (U0, U7) have zero amplitude and are positioned at the center, and the voltage space vector diagram is shown in fig. 2.

The six effective working vectors are made to work in the order of U1-U6. In the first sector, inverter switch state bit 100, space voltage vector U1, flux linkage vector Ψ 1. Entering the second sector, the inverter switching state is 110, the space vector is U2, the flux linkage vector is Ψ 2, and the flux linkage motion trajectory in the first sector is Δ Ψ 12 in FIG. 3. And by analogy, each effective working vector acts on pi/3 radian, and six effective working vectors complete one period. Six Δ Ψ are connected end to end and the stator flux linkage vector is a closed hexagon as shown in fig. 3. Since the switch is switched 6 times in one period, the circuit is a regular hexagon. A nearly circular flux linkage vector cannot be formed.

Only one switch state is generated in each period, a regular hexagonal rotating magnetic field is generated, the difference between the regular hexagonal rotating magnetic field and a circular magnetic field is large, and the torque ripple is large. Torque ripple is reduced in order to make the flux linkage vector as close to a circle as possible. Therefore, the inverter switches on and off states in each sector, and the time of each state is different by combining eight states. The expected output vector can be synthesized by two adjacent effective working vectors according to the space parallelogram synthesis rule, so that the magnetic chain of the synthesized vector is close to a circle as much as possible. For example, in the first sector, the voltage vector Uout is synthesized by the spatial basis vectors U1 and U2. Uout is t1/t × U1+ t1/t × U2. Where t1 and t2 are the U1 and U2 action times, respectively, in a cycle, as shown in FIG. 4, t > t1+ t2, and the rest of the time can be supplemented with zero vectors (U0, U7). The action time t0 of the zero vector is t-t1-t 2. At this time, the action times of U1, U2, U0(U7) have been determined, but the action order is not determined, leaving a large space for SVPWM vector control. Generally, two methods are used: the first and zero vectors are realized in a centralized way, and the second and zero vectors are realized in a dispersed way. Two ways are described below, taking the first sector as an example:

zero vector centralized insertion mode (five-segment mode). A period (t) is divided into 5 parts, and after t1 and t2 are divided equally, zero vectors are respectively placed in the middle of the switching period at the head end and the tail end of the switching period, and the selection principle of the zero vectors is that the switching period is the minimum, so that the loss is reduced. As shown in fig. 5, a switching pattern of the SVPWM wave is given. The action sequence is t1/2, t2/2, t7, t2/2 and t 2/2.

Zero vector scatter-insert approach (seven-segment approach). One period (t) is divided into 7 parts distributed at the beginning, the end and the middle of the switching period, as shown in fig. 6. The time of the basic voltages U1 and U2 is divided in half and inserted between zero vectors. The action sequence is based on the principle of less switching times and less loss.

According to the SVPWM seven-segment and five-segment principles, the five-segment has less switching times in one period than the seven-segment, and thus the loss of the power device of the inverter is small. The seven-segment zero vector has flexible action time and can be inserted in multiple points, so that the current harmonic wave is small, the torque fluctuation is small and the precision is high. The seven-section type switching times are relatively more, and the loss of the inverter power device is large.

The PWM switching time is obtained by comparing the carrier wave with the modulated wave. The frequency fc (2KHz, 5KHz, 10KHz) of the carrier wave is generally much larger than that of the modulated wave. When the amplitude of the modulation wave is larger than the amplitude of the carrier wave, the PWM wave is at a high level, the amplitude of the modulation wave is smaller than the amplitude of the carrier wave, and the PWM is at a low level. The frequency fr of the modulated wave is related to the motor speed by n which is 60fr/p, the motor speed of n, the frequency fr of the modulated wave and the number p of pole pairs of the motor. The carrier ratio N is defined as fc/fr. The carrier ratio is large, and the output waveform is relatively good.

At present, the switching frequency of a general power device (IGBT) for an electric automobile is 10KHz at most, and the switching frequency can be adjusted through software, and the switching frequency is set to be 2KHz, 5KHz and 10KHz in the embodiment of the application.

At present, an electric automobile provides driving force through a motor, an energy storage device is mainly a high-voltage direct-current battery, and therefore an inverter is inevitably needed to convert direct current into alternating current. The inverter realizes the conversion function by switching on and off the power device, the switching on and off of the power device inevitably has energy loss, and if the efficiency of the inverter can be improved in a control mode, the inverter has great significance for improving the endurance mileage of the electric automobile.

Therefore, the present invention provides an inverter SVPWM control method and apparatus for an electric vehicle, and the inverter SVPWM control method and apparatus for an electric vehicle and the electric vehicle according to the present invention are described below with reference to the accompanying drawings. Aiming at the problems of high loss and low efficiency of the inverter in the prior SVPWM control mode mentioned in the above background technology center, the application provides an SVPWM control method of an electric vehicle inverter, in the method, different SVPWM modulation and switching frequency are adopted for control according to different rotating speeds of an alternating current motor, when the rotating speed of the alternating current motor is low, five-segment SVPWM modulation and 2KHz switching frequency are adopted, when the rotating speed of the alternating current motor is medium, five-segment SVPWM modulation and 5KHz switching frequency are adopted, when the rotating speed of the alternating current motor is high, seven-segment SVPWM modulation and 10KHz switching frequency are adopted, thereby the switching frequency and different SVPWM modulation modes can be accurately controlled, the inverter efficiency is improved, the whole vehicle energy consumption is reduced, the electric vehicle endurance mileage is effectively prolonged, the whole vehicle battery capacity is reduced, the cost is reduced, and the requirements of a driving system on torque precision and noise are met, the use experience is improved. Therefore, the problems of high loss, low efficiency and the like of the inverter in the conventional SVPWM control mode are solved.

Specifically, fig. 7 is a schematic flowchart of an inverter SVPWM control method of an electric vehicle according to an embodiment of the present application.

As shown in fig. 7, the SVPWM control method of the inverter of the electric vehicle includes the steps of:

in step S101, the actual rotational speed of the ac motor of the electric vehicle is detected.

The main body of the inverter SVPWM control method for the electric vehicle may be the electric vehicle. The inverter SVPWM control method of the electric vehicle according to the embodiment of the present application may be executed by the inverter SVPWM control apparatus of the electric vehicle according to the embodiment of the present application, and the inverter SVPWM control apparatus of the electric vehicle according to the embodiment of the present application may be configured in any electric vehicle to execute the inverter SVPWM control method of the electric vehicle according to the embodiment of the present application.

It can be understood that, in the embodiment of the present application, different switching frequencies and SVPWM modulation methods are adopted according to different motor rotation speeds, and therefore, in the embodiment of the present application, the actual rotation speed of the ac motor is firstly collected to perform subsequent control.

In step S102, a rotation speed section in which the actual rotation speed is located is detected.

It can be understood that, in order to reduce the inverter loss and meet the requirements of new energy vehicles on noise and torque accuracy, different switching frequencies and SVPWM modulation modes are adopted in different rotation speed intervals according to different numbers of the embodiments. Therefore, after the actual rotating speed is acquired, the section where the actual rotating speed is located needs to be further determined.

In this embodiment, before detecting the rotation speed interval where the actual rotation speed is located, the method further includes: collecting vehicle parameters of the electric vehicle; and determining a preset low-speed interval, a preset medium-speed interval and a preset high-speed interval according to the vehicle parameters.

The method and the device for controlling the electric vehicle speed can be determined according to specific parameters of the electric vehicle, such as the motor speed, and specifically preset a low-speed range, a middle-speed range and a high-speed range.

For example, the motor rotation speed is n, and the rotation speed (absolute value) is divided into three sections: the method comprises the following steps of presetting a low-speed interval I, a middle-speed interval II and a high-speed interval III. According to practical conditions, a low-speed interval I can be defined: the rotating speed is 0-200 rpm; and a medium-speed interval II: 200-: above 3000 rpm.

In step S103, if the rotation speed interval is the preset low speed interval, the ac motor is controlled by the first segment SVPWM modulation value and the first switching frequency, where the first segment SVPWM modulation value and the first switching frequency are the five-segment SVPWM modulation and the 2KHz switching frequency, respectively.

It can be understood that, when the ac motor speed is in a low speed, the embodiment of the present application employs a five-segment SVPWM modulation and a 2KHz switching frequency, where, when the speed interval is a low speed interval, the modulation wave frequency is 13.3KHz, the carrier wave is 2KHz, and the carrier wave ratio N is fc/fr 2000/13.3 is 150.3.

As can be seen from the carrier ratio, the requirement can be met by adopting 2KHz at a low-speed stage, so that the switching loss can be reduced, and meanwhile, the torque precision and the noise are considered. Meanwhile, although the tube opening frequency is reduced in the low-speed area, the carrier ratio has no great influence, the sine influence on current output is small, and the torque precision of the system can be met.

In step S104, if the rotation speed interval is the preset intermediate speed interval, the ac motor is controlled by the second-stage SVPWM modulation value and the second switching frequency, where the second-stage SVPWM modulation value and the second switching frequency are the five-stage SVPWM modulation and the 5KHz switching frequency, respectively.

It can be understood that when the rotating speed of the alternating current motor is in a middle rotating speed, five-segment SVPWM modulation and 5KHz switching frequency are adopted, wherein when the rotating speed region is in a middle-speed region, the modulation wave frequency is 200KHz, the carrier wave is at 5KHz, and the carrier wave ratio N is 5000/200 is 25.

In step S105, if the rotation speed interval is the preset high speed interval, the ac motor is controlled by the third segment SVPWM modulation value and the third switching frequency, wherein the third segment SVPWM modulation value and the third switching frequency are the seven segment SVPWM modulation and the 10KHz switching frequency, respectively.

It can be understood that when the rotating speed of the alternating current motor is in a high rotating speed, seven-segment SVPWM modulation and 10KHz switching frequency are adopted, wherein when the rotating speed region is a high-speed region, the modulation wave frequency is 466.6KHz, the carrier wave is 10KHz, and the carrier wave ratio N is 10000/466.6 which is 21.

It should be noted that the switching losses of the three combinations are as follows: five-segment SVPWM modulation, 2KHz switching frequency < five-segment SVPWM modulation, 5KHz switching frequency < seven-segment SVPWM modulation and 10KHz switching frequency. In the aspect of noise, the high switching frequency is low in noise, and although the low frequency of 2KHz is noise, the use experience of a driver can still be met due to the fact that the starting stage time is short. For the torque precision, the phase current waveform of the 10K seven-segment type is good, the harmonic component is small, and therefore the torque fluctuation is small, and the precision is high. Therefore, the control method of the embodiment of the application can reduce switching loss, reduce loss of the inverter, improve the endurance of the whole vehicle, meet the requirements of a driving system on torque precision and noise, and meet the control precision.

According to the SVPWM control method of the inverter of the electric automobile provided by the embodiment of the application, different SVPWM modulation and switching frequency are adopted for control according to different rotating speeds of the alternating current motor, when the rotating speed of the alternating current motor is low, five-segment SVPWM modulation and 2KHz switching frequency are adopted, when the rotating speed of the alternating current motor is medium, five-segment SVPWM modulation and 5KHz switching frequency are adopted, when the rotating speed of the alternating current motor is high, seven-segment SVPWM modulation and 10KHz switching frequency are adopted, therefore, the switching frequency and different SVPWM modulation modes can be accurately controlled, the efficiency of the inverter is improved, the energy consumption of the whole automobile is reduced, the endurance mileage of the electric automobile is effectively prolonged, the battery capacity of the whole automobile is reduced, the cost is reduced, the requirements of a driving system on torque precision and noise are met, and the use experience is improved.

Next, an inverter SVPWM control apparatus of an electric vehicle according to an embodiment of the present application will be described with reference to the drawings.

Fig. 8 is a block schematic diagram of an inverter SVPWM control apparatus of an electric vehicle according to an embodiment of the present application.

As shown in fig. 8, the inverter SVPWM control apparatus 10 of the electric vehicle includes: a first detection module 100, a second detection module 200, a first control module 300, a second control module 400, and a third control module 500.

The first detection module 100 is used for detecting the actual rotating speed of an alternating current motor of the electric automobile; the second detection module 200 is configured to detect a rotation speed interval where an actual rotation speed is located; the first control module 300 is configured to control the ac motor according to a first SVPWM modulation value and a first switching frequency when the rotation speed interval is a preset low speed interval, where the first SVPWM modulation value and the first switching frequency are a five-segment SVPWM modulation and a 2KHz switching frequency, respectively; the second control module 400 is configured to control the ac motor according to a second SVPWM modulation value and a second switching frequency when the rotation speed interval is the preset intermediate speed interval, where the second SVPWM modulation value and the second switching frequency are five-segment SVPWM modulation and 5KHz switching frequency, respectively; the third control module 500 is configured to control the ac motor with a third SVPWM modulation value and a third switching frequency when the rotation speed interval is the preset high speed interval, wherein the third SVPWM modulation value and the third switching frequency are respectively seven SVPWM modulation and 10KHz switching frequency

Further, the preset low speed interval is [0, 200] rpm, the preset medium speed interval is [200, 3000] rpm, and the preset high speed interval is more than 3000 rpm.

Further, the apparatus 10 of the embodiment of the present application further includes: the device comprises an acquisition module and a determination module. The acquisition module is used for acquiring vehicle parameters of the electric vehicle before detecting a rotating speed interval where the actual rotating speed is located; the determining module is used for determining a preset low-speed interval, a preset medium-speed interval and a preset high-speed interval according to the vehicle parameters.

It should be noted that the foregoing explanation of the embodiment of the SVPWM control method for an inverter of an electric vehicle is also applicable to the SVPWM control apparatus for an inverter of an electric vehicle in this embodiment, and will not be repeated herein.

According to the utility model provides an electric automobile's dc-to-ac converter SVPWM controlling means, adopt different SVPWM modulation and switching frequency to control according to alternating current motor's different rotational speeds, when alternating current motor rotational speed is at low rotational speed, adopt five-segment formula SVPWM modulation and 2KHz switching frequency, when alternating current motor rotational speed is at well rotational speed, adopt five-segment formula SVPWM modulation and 5KHz switching frequency, when alternating current motor rotational speed is at high rotational speed, adopt seven-segment formula SVPWM modulation and 10KHz switching frequency, thereby can accurate control switching frequency and different SVPWM modulation mode, improve inverter efficiency, reduce whole car energy consumption, effectively prolong electric automobile continuation of the journey mileage, reduce whole car battery capacity, reduce cost, and satisfy the requirement of actuating system to moment of torsion precision and noise, improve use experience.

The embodiment also provides an electric vehicle, which comprises the inverter SVPWM control device of the electric vehicle of the above embodiment. According to the electric automobile that this application embodiment provided, adopt different SVPWM modulation and switching frequency to control according to alternating current motor's different rotational speeds, when alternating current motor rotational speed is low rotational speed, adopt five-stage formula SVPWM modulation and 2KHz switching frequency, when alternating current motor rotational speed is well rotational speed, adopt five-stage formula SVPWM modulation and 5KHz switching frequency, when alternating current motor rotational speed is high rotational speed, adopt seven-stage formula SVPWM modulation and 10KHz switching frequency, thereby can accurate control switching frequency and different SVPWM modulation mode, improve inverter efficiency, reduce whole car energy consumption, effectively prolong electric automobile continuation of the journey mileage, reduce whole car battery capacity, reduce cost, and satisfy the requirement of actuating system to moment of torsion precision and noise, improve and use experience.

In the description herein, reference to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the application. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or N embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present application, "N" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

Any process or method descriptions in flow charts or otherwise described herein may be understood as representing modules, segments, or portions of code which include one or more N executable instructions for implementing steps of a custom logic function or process, and alternate implementations are included within the scope of the preferred embodiment of the present application in which functions may be executed out of order from that shown or discussed, including substantially concurrently or in reverse order, depending on the functionality involved, as would be understood by those reasonably skilled in the art of implementing the embodiments of the present application.

The logic and/or steps represented in the flowcharts or otherwise described herein, e.g., an ordered listing of executable instructions that can be considered to implement logical functions, can be embodied in any computer-readable medium for use by or in connection with an instruction execution system, apparatus, or device, such as a computer-based system, processor-containing system, or other system that can fetch the instructions from the instruction execution system, apparatus, or device and execute the instructions. For the purposes of this description, a "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transport the program for use by or in connection with the instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of the computer-readable medium would include the following: an electrical connection (electronic device) having one or N wires, a portable computer diskette (magnetic device), a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disc read-only memory (CDROM). Additionally, the computer-readable medium could even be paper or another suitable medium upon which the program is printed, as the program can be electronically captured, via for instance optical scanning of the paper or other medium, then compiled, interpreted or otherwise processed in a suitable manner if necessary, and then stored in a computer memory.

It should be understood that portions of the present application may be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, the N steps or methods may be implemented in software or firmware stored in a memory and executed by a suitable instruction execution system. If implemented in hardware, as in another embodiment, any one or combination of the following techniques, which are known in the art, may be used: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application specific integrated circuit having an appropriate combinational logic gate circuit, a Programmable Gate Array (PGA), a Field Programmable Gate Array (FPGA), or the like.

It will be understood by those skilled in the art that all or part of the steps carried by the method for implementing the above embodiments may be implemented by hardware related to instructions of a program, which may be stored in a computer readable storage medium, and when the program is executed, the program includes one or a combination of the steps of the method embodiments.

In addition, functional units in the embodiments of the present application may be integrated into one processing module, or each unit may exist alone physically, or two or more units are integrated into one module. The integrated module can be realized in a hardware mode, and can also be realized in a software functional module mode. The integrated module, if implemented in the form of a software functional module and sold or used as a stand-alone product, may also be stored in a computer readable storage medium.

The storage medium mentioned above may be a read-only memory, a magnetic or optical disk, etc. Although embodiments of the present application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present application, and that variations, modifications, substitutions and alterations may be made to the above embodiments by those of ordinary skill in the art within the scope of the present application.