Vehicle controller current sine balance degree analysis method

Abstract

The invention discloses a current sine balance degree analysis method for a vehicle controller. The method comprises the following steps: 1) collecting time domain data of three-way current of the vehicle controller; 2) performing discrete Fourier transform of three-way current; 3) carrying out fundamental frequency harmonic analysis on the three-way current; 4) carrying out multiple frequency harmonic analysis on the three-way current; 5) carrying out symmetric harmonic analysis on the three-way current 10000 Hz; (6) symmetric harmonic analysis of three-way current 20000Hz is carried out; and 7) analyzing the current sine balance degree of the vehicle controller. According to the method, analysis of the sine degree and the balance degree of the current of the controller is achieved through a very small amount of test data and simple calculation, rapid analysis of the endurance mileage of a power battery and the noise of a whole vehicle driving motor is achieved under the condition that no whole vehicle exists, and the success rate of a boarding efficiency test and a vibration noise test is greatly increased; repeated iterative optimization is avoided; the project development period is shortened and the project development cost is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of new energy vehicle electric drive system controllers, and particularly relates to a method for analyzing the sinusoidal balance degree of the current of a vehicle controller. Background Art

[0002] The electric drive system of a new energy vehicle is the core of the vehicle's power output, responsible for converting electrical energy into mechanical energy to drive the vehicle. Its performance directly affects the vehicle's power performance, efficiency, cruising range, and driving experience.

[0003] The electric drive system of a new energy vehicle mainly includes a drive motor, a controller, a power battery, etc. Among them, the controller in the electric drive system of a new energy vehicle is one of the most important components of the whole vehicle. It can achieve the purpose of switching the steady-state direct current provided by the power battery into three-phase alternating current for the drive motor to work.

[0004] During the process of current switching, the sinusoidal degree and balance degree of the three-phase alternating current actually output by the controller will directly affect the cruising range and vibration and noise performance of the new energy vehicle. Therefore, how to efficiently analyze the sinusoidal balance degree of the controller current is particularly important. However, there is currently no method for analyzing the sinusoidal balance degree of the controller current in the industry. Summary of the Invention

[0005] Aiming at the above deficiencies existing in the prior art, the technical problem to be solved by the present invention is: how to provide a method that can quickly and efficiently analyze the sinusoidal balance degree of the controller current, so as to realize the analysis of the sinusoidal degree and balance degree of the controller current with a very small amount of test data and simple calculations, and realize the rapid analysis of the cruising range of the power battery and the noise of the vehicle drive motor without the condition of a whole vehicle, greatly improving the success rate of the on-vehicle efficiency test and the vibration and noise test; avoiding repeated iterative optimization; shortening the project development cycle and reducing the project development cost.

[0006] To solve the above technical problems, the present invention adopts the following technical solutions:

[0007] A method for analyzing the sinusoidal balance degree of the current of a vehicle controller, comprising the following steps:

[0008] Step 1) Collect the time-domain data of the three-phase current of the vehicle controller;

[0009] Step 2) Perform discrete Fourier transform on the three-phase current of the vehicle controller;

[0010] Step 3) Perform fundamental frequency harmonic analysis on the three-phase current of the vehicle controller;

[0011] Step 4) Perform multiple frequency harmonic analysis on the three-phase current of the vehicle controller;

[0012] Step 5) Conduct symmetric harmonic analysis of the three-phase current of the vehicle controller at 10,000 Hz.

[0013] Step 6) Conduct symmetric harmonic analysis of the three-phase current of the vehicle controller at 20,000 Hz.

[0014] Step 7) Conduct analysis of the sinusoidal balance of the current of the vehicle controller.

[0015] Preferably, step 1) includes the following steps:

[0016] Step 1.1) Apply a stable load of a first torque to the drive motor, and apply a current clamp to each of the three wires between the controller and the drive motor.

[0017] Step 1.2) Use the current clamps to respectively collect the time-domain data of the three-phase current under various set rotational speed conditions when the rotational speed of the drive motor is stable. The set rotational speeds are i p rpm, p = 1, 2, 3,..., M, the sampling frequency is set to 50k; the data collection time is more than 10 s.

[0018] Preferably, in step 2), the following formula is used to perform discrete Fourier transform on the time-domain data of the U-phase current collected in step 1) under various set rotational speed conditions:

[0019]

[0020] In the formula: represents the result of the discrete Fourier transform of the U-phase current when the rotational speed of the drive motor is i p rpm; ω represents the frequency after discrete Fourier transform; represents the time-domain data of the U-phase current when the rotational speed of the drive motor is i p rpm, and N represents the total amount of data collected;

[0021] The following formula is used to perform discrete Fourier transform on the time-domain data of the V-phase current collected in step 1) under various set rotational speed conditions:

[0022]

[0023] In the formula: represents the result of the discrete Fourier transform of the V-phase current when the rotational speed of the drive motor is i p rpm; represents the time-domain data of the V-phase current when the rotational speed of the drive motor is i p rpm;

[0024] The following formula is used to perform discrete Fourier transform on the time-domain data of the W-phase current collected in step 1) under various set rotational speed conditions:

[0025]

[0026] Wherein: represents the discrete Fourier transform result of the current in the W direction when the rotational speed of the drive motor is i p rpm; ω represents the frequency after discrete Fourier transform, represents the time-domain data of the current in the W direction when the rotational speed of the drive motor is i p rpm.

[0027] Preferably, step 3) includes the following steps:

[0028] Step 3.1) Calculate the fundamental frequency harmonic amplitudes of the currents in the three directions of U, V, and W under the condition of each set rotational speed i p rpm:

[0029]

[0030] Wherein: represents the fundamental frequency harmonic amplitude of the current in the U direction when the rotational speed of the drive motor is i p rpm; represents the fundamental frequency harmonic amplitude of the current in the V direction when the rotational speed of the drive motor is i p rpm; represents the fundamental frequency harmonic amplitude of the current in the W direction when the rotational speed of the drive motor is i p rpm;

[0031] Step 3.2) Calculate the fundamental frequency harmonic balance degrees of the currents in the three directions of U, V, and W under the condition of each set rotational speed i p rpm:

[0032]

[0033] Wherein: represents the fundamental frequency harmonic balance degree of the currents in the three directions when the rotational speed of the drive motor is i p rpm;

[0034] Step 3.3) Calculate the average fundamental frequency harmonic balance degree of the three-phase currents

[0035]

[0036] Wherein: A J_avg represents the average fundamental frequency harmonic balance degree of the three-phase currents.

[0037] Preferably, step 4) includes the following steps: Step 4) includes the following steps:

[0038] Step 4.1) Calculate the proportion of multiple-frequency harmonics in the U-direction, V-direction, and W-direction at each set rotational speed condition;

[0039] Step 4.2) Calculate the total proportion of multiple-frequency harmonics of the three-phase current;

[0040] Step 4.3) Calculate the harmonic balance degrees of the 5th, 7th, 11th, and 13th harmonics of the three-phase current at each set rotational speed condition;

[0041] Step 4.4) Calculate the total harmonic balance degree of the multiple-frequency harmonics of the three-phase current.

[0042] Preferably, Step 4.1) includes the following steps:

[0043] Step 4.1.1) Calculate the amplitudes of the 5th, 7th, 11th, and 13th frequency harmonics of the U-phase, V-phase, and W-phase currents respectively when the rotational speed of the drive motor is i p rpm;

[0044] Among them, the calculation formulas for the amplitudes of the 5th, 7th, 11th, and 13th frequency harmonics of the U-phase current are respectively:

[0045]

[0046] In the formula: represents the amplitude of the 5th frequency harmonic of the U-phase current when the rotational speed of the drive motor is i p rpm; represents the amplitude of the 7th frequency harmonic of the U-phase current when the rotational speed of the drive motor is i p rpm; represents the amplitude of the 11th frequency harmonic of the U-phase current when the rotational speed of the drive motor is i p rpm; represents the amplitude of the 13th frequency harmonic of the U-phase current when the rotational speed of the drive motor is i p rpm;

[0047] The calculation formulas for the amplitudes of the 5th, 7th, 11th, and 13th frequency harmonics of the V-phase current are respectively:

[0048]

[0049] In the formula: represents the amplitude of the 5th frequency harmonic of the V-phase current when the rotational speed of the drive motor is i p rpm; represents the amplitude of the 7th frequency harmonic of the V-phase current when the rotational speed of the drive motor is i p rpm; represents the amplitude of the 11th frequency harmonic of the V-phase current when the rotational speed of the drive motor is i p rpm; represents the rotational speed of the drive motor at ip rpm, the harmonic amplitude of 13 times the frequency of the V-phase current;

[0050] The calculation formulas for the harmonic amplitudes of 5 times, 7 times, 11 times, and 13 times the frequency of the W-phase current are as follows:

[0051]

[0052] In the formula: represents the rotational speed of the drive motor at i p rpm, the harmonic amplitude of 5 times the frequency of the W-phase current; represents the rotational speed of the drive motor at i p rpm, the harmonic amplitude of 7 times the frequency of the W-phase current; represents the rotational speed of the drive motor at i p rpm, the harmonic amplitude of 11 times the frequency of the W-phase current; represents the rotational speed of the drive motor at i p rpm, the harmonic amplitude of 13 times the frequency of the W-phase current;

[0053] Step 4.1.2) Calculate the proportion of the multiple-frequency harmonics of the U-phase, V-phase, and W-phase currents when the rotational speed of the drive motor is at i p rpm respectively;

[0054] Among them, when the rotational speed of the drive motor is at i p rpm, the calculation formula for the proportion of the multiple-frequency harmonics of the U-phase current is:

[0055]

[0056] In the formula: represents the proportion of the multiple-frequency harmonics of the U-phase current when the rotational speed of the drive motor is at i p rpm;

[0057] When the rotational speed of the drive motor is at i p rpm, the calculation formula for the proportion of the multiple-frequency harmonics of the V-phase current is:

[0058]

[0059] In the formula: represents the proportion of the multiple-frequency harmonics of the V-phase current when the rotational speed of the drive motor is at i p rpm;

[0060] When the rotational speed of the drive motor is at i p rpm, the calculation formula for the proportion of the multiple-frequency harmonics of the W-phase current is:

[0061]

[0062] In the formula: Indicates the proportion of the multiple - frequency harmonic of the current in the W - direction when the rotational speed of the drive motor is i p rpm;

[0063] In step 4.2), calculate the total proportion of the multiple - frequency harmonics of the three - phase current according to the following formula

[0064]

[0065] In the formula: Indicates the total proportion of the multiple - frequency harmonics of the three - phase current;

[0066] In step 4.3), calculate the balance degrees of the 5 - times, 7 - times, 11 - times, and 13 - times frequency harmonics of the three - phase current when the rotational speed of the drive motor is i p rpm as follows:

[0067]

[0068] In the formula: Indicates the balance degree of the 5 - times frequency harmonic of the three - phase current when the rotational speed of the drive motor is i p rpm; Indicates the balance degree of the 7 - times frequency harmonic of the three - phase current when the rotational speed of the drive motor is i p rpm; Indicates the balance degree of the 11 - times frequency harmonic of the three - phase current when the rotational speed of the drive motor is i p rpm; Indicates the balance degree of the 13 - times frequency harmonic of the three - phase current when the rotational speed of the drive motor is i p rpm;

[0069] In step 4.4), calculate the total balance degree of the multiple - frequency harmonics of the three - phase current according to the following formula:

[0070]

[0071] In the formula: A XXJ Indicates the total balance degree of the multiple - frequency harmonics of the three - phase current.

[0072] Preferably, step 5) includes the following steps:

[0073] Step 5.1) Calculate the symmetrical harmonic amplitudes of the U - phase, V - phase, and W - phase currents at 10000 Hz when the rotational speed of the drive motor is i p rpm;

[0074] Among them, when the rotational speed of the drive motor is i p rpm, the calculation formula for the symmetrical harmonic amplitude of the U - phase current at 10000 Hz is:

[0075]

[0076] In the formula: represents the symmetric harmonic amplitude of the U-phase current at 10000 Hz when the driving motor speed is i p rpm;

[0077] When the driving motor speed is i p rpm, the calculation formula for the symmetric harmonic amplitude of the V-phase current at 10000 Hz is:

[0078]

[0079] In the formula: represents the symmetric harmonic amplitude of the V-phase current at 10000 Hz when the driving motor speed is i p rpm;

[0080] When the driving motor speed is i p rpm, the calculation formula for the symmetric harmonic amplitude of the W-phase current at 10000 Hz is:

[0081]

[0082] In the formula: represents the symmetric harmonic amplitude of the W-phase current at 10000 Hz when the driving motor speed is i p rpm;

[0083] Step 5.2) Calculate the total symmetric harmonic amplitude of the three-phase current at 10000 Hz according to the following formula:

[0084]

[0085] In the formula: A 10000Jzt represents the total symmetric harmonic amplitude of the three-phase current at 10000 Hz.

[0086] Preferably, it is characterized in that step 6) includes the following steps:

[0087] Step 6.1) Calculate the symmetric harmonic amplitudes of the U-phase, V-phase, and W-phase currents at 20000 Hz when the driving motor speed is i p rpm;

[0088] Among them, when the driving motor speed is i p rpm, the calculation formula for the symmetric harmonic amplitude of the U-phase current at 20000 Hz is:

[0089]

[0090] In the formula: represents the symmetric harmonic amplitude of the U-phase current at 20000 Hz when the driving motor speed is i p rpm;

[0091] When the rotational speed of the drive motor is i p rpm, the calculation formula for the symmetrical harmonic amplitude of the V-phase current at 20000 Hz is:

[0092]

[0093] In the formula: represents the symmetrical harmonic amplitude of the V-phase current at 20000 Hz when the rotational speed of the drive motor is i p rpm;

[0094] When the rotational speed of the drive motor is i p rpm, the calculation formula for the symmetrical harmonic amplitude of the W-phase current at 20000 Hz is:

[0095]

[0096] In the formula: represents the symmetrical harmonic amplitude of the W-phase current at 20000 Hz when the rotational speed of the drive motor is i p rpm;

[0097] Step 6.2) Calculate the total symmetrical harmonic amplitude of the three-phase current at 20000 Hz according to the following formula:

[0098]

[0099] In the formula: A 20000Jzt represents the total symmetrical harmonic amplitude of the three-phase current at 20000 Hz.

[0100] Preferably, in step 7), calculate the sinusoidal balance degree of the three-phase current of the controller according to the following formula:

[0101]

[0102] In the formula: A s is the sinusoidal balance degree of the three-phase current of the controller;

[0103] Score the sinusoidal balance degree of the three-phase current of the controller according to the calculated sinusoidal balance degree of the three-phase current of the controller.

[0104] Compared with the prior art, the present invention provides a method capable of quickly and efficiently analyzing the sinusoidal balance degree of the controller current, realizing the analysis of the sinusoidal degree and balance degree of the controller current with a very small amount of test data and simple calculations, realizing the rapid analysis of the power battery endurance mileage and the vehicle drive motor noise without a complete vehicle, greatly improving the success rate of the on-vehicle efficiency test and the vibration and noise test; avoiding repeated iterative optimization; shortening the project development cycle and reducing the project development cost. Description of the Drawings

[0105] Attached Figure 1 is a flowchart of the method for analyzing the current sine balance degree of the vehicle controller of the present invention;

[0106] Attached Figure 2 is the time-domain data of the three-phase current specifically collected by using the method for analyzing the current sine balance degree of the vehicle controller of the present invention (the driving motor speed is 1000 rpm);

[0107] Attached Figure 3 is the result after the discrete Fourier transform of the three-phase current (the driving motor speed is 1000 rpm) in the method for analyzing the current sine balance degree of the vehicle controller of the present invention. Detailed Embodiment

[0108] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Components of the embodiments of the present invention usually described and illustrated in the accompanying drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed present invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0109] In this specific embodiment, a method for analyzing the current sine balance degree of a vehicle controller is provided. As shown in the attached Figure 1 , it includes the following steps:

[0110] Step 1) Collect the time-domain data of the three-phase current of the vehicle controller;

[0111] Step 2) Perform the discrete Fourier transform of the three-phase current of the vehicle controller;

[0112] Step 3) Perform the fundamental frequency harmonic analysis of the three-phase current of the vehicle controller;

[0113] Step 4) Perform the multiple frequency harmonic analysis of the three-phase current of the vehicle controller;

[0114] Step 5) Perform the symmetric harmonic analysis of the three-phase current of the vehicle controller at 10000 Hz;

[0115] Step 6) Perform the symmetric harmonic analysis of the three-phase current of the vehicle controller at 20000 Hz;

[0116] Step 7) Perform the analysis of the current sine balance degree of the vehicle controller.

[0117] The following is a further detailed description of each step:

[0118] Step 1) Collect the time-domain data of the three-phase current of the vehicle controller.

[0119] Step 1) includes the following steps:

[0120] Step 1.1) Apply a stable load of a first torque to the drive motor, and apply a current clamp to each of the three wires between the controller and the drive motor. Specifically, on the motor test bench, apply a stable load of 100 Nm to the drive motor, and apply a current clamp to each of the three wires (three-phase current, which is customarily called U-phase, V-phase, and W-phase in the industry) between the controller and the drive motor.

[0121] Step 1.2) Use the current clamps to collect the time-domain data of the three-phase current when the rotational speed of the drive motor is stable at each set rotational speed condition. The set rotational speeds are i p rpm, p = 1, 2, 3,..., M, and the sampling frequency is set to 50 k; the data collection time is more than 10 s. Specifically, collect the time-domain data of the three-phase current when the rotational speed of the drive motor is stable at 1000 rpm; 2000 rpm; 3000 rpm; 4000 rpm; 5000 rpm. Therefore, in this specific embodiment, i p = 1000, 2000, 3000, 4000, 5000. The specific time-domain data of the three-phase current (when the rotational speed of the drive motor is 1000 rpm) is as shown in the appendix Figure 2 as follows.

[0122] Step 2) Perform the discrete Fourier transform of the three-phase current of the vehicle controller;

[0123] Use the following formula to perform the discrete Fourier transform on the U-phase current time-domain data collected in Step 1) under each set rotational speed condition:

[0124]

[0125] In the formula: represents the result of the discrete Fourier transform of the U-phase current when the rotational speed of the drive motor is i p rpm, ω represents the frequency after the discrete Fourier transform; represents the rotational speed of the drive motor at i pAt rpm, the U-phase current time-domain data, N represents the total amount of collected data; ω is determined according to the rotational speed of the driving motor. For example, if the rotational speed of the driving motor is 6000 rpm, then the driving motor rotates 6000 / 60 = 100 revolutions per second at this time. The change of the driving motor current per second is 100 * 4 = 400 times. At this time, the fundamental frequency harmonic is 400 Hz, and the 5th harmonic is 400 * 5 = 2000 Hz. Here, ω can be the fundamental frequency harmonic or any multiple harmonic. According to the above formula, the discrete Fourier transform result A of the U-phase current when the rotational speed of the driving motor is 1000 rpm is calculated respectively u_1000 (ω), the discrete Fourier transform result A of the U-phase current when the rotational speed of the driving motor is 2000 rpm u_2000 (ω), the discrete Fourier transform result A of the U-phase current when the rotational speed of the driving motor is 3000 rpm u_3000 (ω), the discrete Fourier transform result A of the U-phase current when the rotational speed of the driving motor is 4000 rpm u_4000 (ω), the discrete Fourier transform result A of the U-phase current when the rotational speed of the driving motor is 5000 rpm u_5000 (ω).

[0126] The following formula is used to perform discrete Fourier transform on the V-phase current time-domain data collected under various set rotational speed conditions in step 1):

[0127]

[0128] In the formula: represents the discrete Fourier transform result of the V-phase current when the rotational speed of the driving motor is i p rpm; ω represents the frequency after discrete Fourier transform; represents the V-phase current time-domain data when the rotational speed of the driving motor is i p rpm; According to the above formula, the discrete Fourier transform result A of the V-phase current when the rotational speed of the driving motor is 1000 rpm is calculated respectively v_1000 (ω), the discrete Fourier transform result A of the V-phase current when the rotational speed of the driving motor is 2000 rpm v_2000 (ω), the discrete Fourier transform result A of the V-phase current when the rotational speed of the driving motor is 3000 rpm v_3000 (ω), the discrete Fourier transform result A of the V-phase current when the rotational speed of the driving motor is 4000 rpm v_4000 (ω), the discrete Fourier transform result A of the V-phase current when the rotational speed of the driving motor is 5000 rpm v_5000 (ω).

[0129] The following formula is used to perform discrete Fourier transform on the W-phase current time-domain data collected under various set rotational speed conditions in step 1):

[0130]

[0131] wherein: represents the discrete Fourier transform result of the W-phase current when the driving motor speed is i p rpm; represents the time-domain data of the W-phase current when the driving motor speed is i p rpm; Calculate the discrete Fourier transform results A w_1000 (ω) of the W-phase current when the driving motor speed is 1000 rpm, the discrete Fourier transform results A w_2000 (ω) of the W-phase current when the driving motor speed is 2000 rpm, the discrete Fourier transform results A w_3000 (ω) of the W-phase current when the driving motor speed is 3000 rpm, the discrete Fourier transform results A w_4000 (ω) of the W-phase current when the driving motor speed is 4000 rpm, the discrete Fourier transform results A w_5000 (ω) of the W-phase current when the driving motor speed is 5000 rpm.

[0132] The results of the discrete Fourier transform of the three-phase current (when the driving motor speed is 1000 rpm) are as shown in the appendix Figure 3 as follows.

[0133] Step 3) Perform the fundamental frequency harmonic analysis of the three-phase current of the vehicle controller.

[0134] Step 3.1) Calculate the fundamental frequency harmonic amplitudes of the U-phase, V-phase, and W-phase currents under the condition of each set speed i p rpm:

[0135]

[0136] wherein: represents the fundamental frequency harmonic amplitude of the U-phase current when the driving motor speed is i p rpm; represents the fundamental frequency harmonic amplitude of the V-phase current when the driving motor speed is i p rpm; represents the fundamental frequency harmonic amplitude of the W-phase current when the driving motor speed is i p rpm; Calculate the fundamental frequency harmonic amplitudes A J_u_1000 of the U-phase current, A J_v_1000 of the V-phase current, and A J_w_1000 of the W-phase current when the driving motor speed is 1000 rpm; the fundamental frequency harmonic amplitudes A J_u_2000, the fundamental frequency harmonic amplitude A of the V-phase current J_v_2000 , the fundamental frequency harmonic amplitude A of the W-phase current J_w_2000 ; the fundamental frequency harmonic amplitude A of the U-phase current when the driving motor speed is 3000 rpm J_u_3000 , the fundamental frequency harmonic amplitude A of the V-phase current J_v_3000 , the fundamental frequency harmonic amplitude A of the W-phase current J_w_3000 ; the fundamental frequency harmonic amplitude A of the U-phase current when the driving motor speed is 4000 rpm J_u_4000 , the fundamental frequency harmonic amplitude A of the V-phase current J_v_4000 , the fundamental frequency harmonic amplitude A of the W-phase current J_w_4000 ; the fundamental frequency harmonic amplitude A of the U-phase current when the driving motor speed is 5000 rpm J_u_5000 , the fundamental frequency harmonic amplitude A of the V-phase current J_v_5000 , the fundamental frequency harmonic amplitude A of the W-phase current J_w_5000 . The fundamental frequency harmonic amplitudes of the three-phase current at different speeds calculated are shown in Table 1.

[0137] Table 1: Fundamental frequency harmonic amplitudes of the three-phase current at different speeds

[0138] 1000 rpm 2000 rpm 3000 rpm 4000 rpm 5000 rpm U direction 233.9 232.3 226.4 239.7 187.7 V direction 235.8 233.6 226.5 239.2 186.6 W direction 235.2 234.5 225.6 237.5 187.2

[0139] Step 3.2) Calculate the fundamental frequency harmonic balance degrees of the three-phase current in the U-phase, V-phase, and W-phase under each set speed i p rpm working condition;

[0140]

[0141] In the formula: represents the fundamental frequency harmonic balance degree of the three-phase current when the driving motor speed is i p rpm working condition; Specifically, calculate the fundamental frequency harmonic balance degree A of the three-phase current when the driving motor speed is 1000 rpm according to the above formula J_1000 ; the fundamental frequency harmonic balance degree A of the three-phase current when the driving motor speed is 2000 rpm J_2000 ; the fundamental frequency harmonic balance degree A of the three-phase current when the driving motor speed is 3000 rpm J_3000 ; the fundamental frequency harmonic balance degree A of the three-phase current when the driving motor speed is 4000 rpm J_4000 ; the fundamental frequency harmonic balance degree A of the three-phase current when the driving motor speed is 5000 rpm J_5000 .

[0142] Step 3.3) Calculate the average fundamental frequency harmonic balance degree of the three-phase current

[0143]

[0144] Where: A J_avg represents the harmonic balance degree of the average three-phase current fundamental frequency.

[0145] In this specific embodiment,

[0146] A J_avg = A J_1000 + A J_2000 + A J_3000 + A J_4000 + A J_5000

[0147] The calculated harmonic balance degrees of the three-phase current fundamental frequency and the values of the average harmonic balance degree of the three-phase current fundamental frequency at different rotational speeds are shown in Table 2.

[0148] Table 2: Harmonic balance degrees of the three-phase current fundamental frequency and values of the average harmonic balance degree of the three-phase current fundamental frequency at different rotational speeds

[0149] <![CDATA[A J_1000 > <![CDATA[A J_2000 > <![CDATA[A J_3000 > <![CDATA[A J_4000 > <![CDATA[A J_5000 > <![CDATA[A J_avg > 0.81％ 0.94％ 0.40％ 0.92％ 0.59％ 3.65％

[0150] Step 4) Conduct the multiple-frequency harmonic analysis of the three-phase current of the vehicle controller.

[0151] Step 4.1) Calculate the proportion of multiple-frequency harmonics in the U-phase, V-phase, and W-phase at each set rotational speed condition.

[0152] Step 4.1.1) Calculate the harmonic amplitudes of the 5th, 7th, 11th, and 13th frequencies of the U-phase, V-phase, and W-phase currents respectively when the rotational speed of the drive motor is i p rpm.

[0153] Among them, the calculation formulas for the harmonic amplitudes of the 5th, 7th, 11th, and 13th frequencies of the U-phase current are as follows:

[0154]

[0155] Where: represents the harmonic amplitude of the 5th frequency of the U-phase current when the rotational speed of the drive motor is i p rpm; represents the harmonic amplitude of the 7th frequency of the U-phase current when the rotational speed of the drive motor is i p rpm; represents the harmonic amplitude of the 11th frequency of the U-phase current when the rotational speed of the drive motor is i p rpm; represents the harmonic amplitude of the 13th frequency of the U-phase current when the rotational speed of the drive motor is i p rpm. Calculate the harmonic amplitude of the 5th frequency of the U-phase current A 5_u_1000, the amplitude A of the 7th - harmonic frequency 7_u_1000 , the amplitude A of the 11th - harmonic frequency 11_u_1000 , the amplitude A of the 13th - harmonic frequency 13_u_1000 ; Calculate the amplitude A of the 5th - harmonic frequency of the U - phase current when the driving motor speed is 2000 rpm 5_u_2000 , the amplitude A of the 7th - harmonic frequency 7_u_2000 , the amplitude A of the 11th - harmonic frequency 11_u_2000 , the amplitude A of the 13th - harmonic frequency 13_u_2000 ; Calculate the amplitude A of the 5th - harmonic frequency of the U - phase current when the driving motor speed is 3000 rpm 5_u_3000 , the amplitude A of the 7th - harmonic frequency 7_u_3000 , the amplitude A of the 11th - harmonic frequency 11_u_3000 , the amplitude A of the 13th - harmonic frequency 13_u_3000 ; Calculate the amplitude A of the 5th - harmonic frequency of the U - phase current when the driving motor speed is 4000 rpm 5_u_4000 , the amplitude A of the 7th - harmonic frequency 7_u_4000 , the amplitude A of the 11th - harmonic frequency 11_u_4000 , the amplitude A of the 13th - harmonic frequency 13_u_4000 ; Calculate the amplitude A of the 5th - harmonic frequency of the U - phase current when the driving motor speed is 5000 rpm 5_u_5000 , the amplitude A of the 7th - harmonic frequency 7_u_5000 , the amplitude A of the 11th - harmonic frequency 11_u_5000 , the amplitude A of the 13th - harmonic frequency 13_u_5000 .

[0156] The calculation formulas for the amplitudes of the 5th -, 7th -, 11th -, and 13th - harmonic frequencies of the V - phase current are as follows:

[0157]

[0158] In the formula: represents the amplitude of the 5th - harmonic frequency of the V - phase current when the driving motor speed is i p rpm; represents the amplitude of the 7th - harmonic frequency of the V - phase current when the driving motor speed is i p rpm; represents the amplitude of the 11th - harmonic frequency of the V - phase current when the driving motor speed is i p rpm; represents the amplitude of the 13th - harmonic frequency of the V - phase current when the driving motor speed is i p rpm; Calculate the amplitude A of the 5th - harmonic frequency of the V - phase current when the driving motor speed is 1000 rpm according to the above formula 5_v_1000 , the amplitude A of the 7th - harmonic frequency 7_v_1000 , the amplitude A of the 11th - harmonic frequency 11_v_1000 , the amplitude A of the 13th - harmonic frequency13_v_1000 ; Calculate the amplitude A of the 5 - times - frequency harmonic of the V - phase current when the driving motor speed is 2000 rpm 5_v_2000 , the amplitude A of the 7 - times - frequency harmonic 7_v_2000 , the amplitude A of the 11 - times - frequency harmonic 11_v_2000 , the amplitude A of the 13 - times - frequency harmonic 13_v_2000 ; Calculate the amplitude A of the 5 - times - frequency harmonic of the V - phase current when the driving motor speed is 3000 rpm 5_v_3000 , the amplitude A of the 7 - times - frequency harmonic 7_v_3000 , the amplitude A of the 11 - times - frequency harmonic 11_v_3000 , the amplitude A of the 13 - times - frequency harmonic 13_v_3000 ; Calculate the amplitude A of the 5 - times - frequency harmonic of the V - phase current when the driving motor speed is 4000 rpm 5_v_4000 , the amplitude A of the 7 - times - frequency harmonic 7_v_4000 , the amplitude A of the 11 - times - frequency harmonic 11_v_4000 , the amplitude A of the 13 - times - frequency harmonic 13_v_4000 ; Calculate the amplitude A of the 5 - times - frequency harmonic of the V - phase current when the driving motor speed is 5000 rpm 5_v_5000 , the amplitude A of the 7 - times - frequency harmonic 7_v_5000 , the amplitude A of the 11 - times - frequency harmonic 11_v_5000 , the amplitude A of the 13 - times - frequency harmonic 13_v_5000 .

[0159] The calculation formulas for the amplitudes of the 5 - times, 7 - times, 11 - times, and 13 - times - frequency harmonics of the W - phase current are as follows:

[0160]

[0161] In the formula: represents the 5 - times - frequency harmonic amplitude of the W - phase current when the driving motor speed is i p rpm; represents the 7 - times - frequency harmonic amplitude of the W - phase current when the driving motor speed is i p rpm; represents the 11 - times - frequency harmonic amplitude of the W - phase current when the driving motor speed is i p rpm; represents the 13 - times - frequency harmonic amplitude of the W - phase current when the driving motor speed is i p rpm. Calculate the amplitude A of the 5 - times - frequency harmonic of the W - phase current, the amplitude A of the 7 - times - frequency harmonic 5_w_1000 , the amplitude A of the 11 - times - frequency harmonic 7_w_1000 , and the amplitude A of the 13 - times - frequency harmonic of the W - phase current when the driving motor speed is 1000 rpm according to the above formula 11_w_1000 ; Calculate the amplitude A of the 5 - times - frequency harmonic of the W - phase current when the driving motor speed is 2000 rpm 13_w_1000 ; Calculate the amplitude A of the 5 - times - frequency harmonic of the W - phase current when the driving motor speed is 2000 rpm 5_w_2000, the amplitude A of the 7 - times frequency harmonic 7_w_2000 , the amplitude A of the 11 - times frequency harmonic 11_w_2000 , the amplitude A of the 13 - times frequency harmonic 13_w_2000 ; Calculate the amplitude A of the 5 - times frequency harmonic of the W - phase current when the driving motor speed is 3000 rpm 5_w_3000 , the amplitude A of the 7 - times frequency harmonic 7_w_3000 , the amplitude A of the 11 - times frequency harmonic 11_w_s000 , the amplitude A of the 13 - times frequency harmonic 13_w_3000 ; Calculate the amplitude A of the 5 - times frequency harmonic of the W - phase current when the driving motor speed is 4000 rpm 5_w_4000 , the amplitude A of the 7 - times frequency harmonic 7_w_4000 , the amplitude A of the 11 - times frequency harmonic 11_w_4000 , the amplitude A of the 13 - times frequency harmonic 13_w_4000 ; Calculate the amplitude A of the 5 - times frequency harmonic of the W - phase current when the driving motor speed is 5000 rpm 5_w_5000 , the amplitude A of the 7 - times frequency harmonic 7_w_5000 , the amplitude A of the 11 - times frequency harmonic 11_w_5000 , the amplitude A of the 13 - times frequency harmonic 13_w_5000 .

[0162] Step 4.1.2) Calculate the proportion of the multiple - frequency harmonics of the U - phase, V - phase, and W - phase currents when the driving motor speed is i p rpm respectively;

[0163] Among them, when the driving motor speed is i p rpm, the calculation formula for the proportion of the multiple - frequency harmonics of the U - phase current is:

[0164]

[0165] In the formula: represents the proportion of the multiple - frequency harmonics of the U - phase current when the driving motor speed is i p rpm; Calculate the proportion of the multiple - frequency harmonics of the U - phase current A when the driving motor speed is 1000 rpm according to the above formula Z_u_1000 ; The proportion of the multiple - frequency harmonics of the U - phase current A when the driving motor speed is 2000 rpm Z_u_2000 ; The proportion of the multiple - frequency harmonics of the U - phase current A when the driving motor speed is 3000 rpm Z_u_3000 ; The proportion of the multiple - frequency harmonics of the U - phase current A when the driving motor speed is 4000 rpm Z_u_4000 ; The proportion of the multiple - frequency harmonics of the U - phase current A when the driving motor speed is 5000 rpm Z_u_5000 .

[0166] When the driving motor speed is i pWhen the rotational speed is rpm, the calculation formula for the proportion of the multiple-frequency harmonic of the V-phase current is:

[0167]

[0168] In the formula: represents the proportion of the multiple-frequency harmonic of the V-phase current when the rotational speed of the drive motor is i p rpm; According to the above formula, calculate the proportion of the multiple-frequency harmonic of the V-phase current A Z_v_1000 when the rotational speed of the drive motor is 1000 rpm; the proportion of the multiple-frequency harmonic of the V-phase current A Z_v_2000 when the rotational speed of the drive motor is 2000 rpm; the proportion of the multiple-frequency harmonic of the V-phase current A Z_v_3000 when the rotational speed of the drive motor is 3000 rpm; the proportion of the multiple-frequency harmonic of the V-phase current A Z_v_4000 when the rotational speed of the drive motor is 4000 rpm; the proportion of the multiple-frequency harmonic of the V-phase current A Z_v_5000 .

[0169] When the rotational speed of the drive motor is i p rpm, the calculation formula for the proportion of the multiple-frequency harmonic of the W-phase current is:

[0170]

[0171] In the formula: represents the proportion of the multiple-frequency harmonic of the W-phase current when the rotational speed of the drive motor is i p rpm; According to the above formula, calculate the proportion of the multiple-frequency harmonic of the W-phase current A Z_w_1000 when the rotational speed of the drive motor is 1000 rpm; the proportion of the multiple-frequency harmonic of the W-phase current A Z_w_2000 when the rotational speed of the drive motor is 2000 rpm; the proportion of the multiple-frequency harmonic of the W-phase current A Z_w_3000 when the rotational speed of the drive motor is 3000 rpm; the proportion of the multiple-frequency harmonic of the W-phase current A Z_w_4000 when the rotational speed of the drive motor is 4000 rpm; the proportion of the multiple-frequency harmonic of the W-phase current A Z_w_5000 .

[0172] Step 4.2) Calculate the total proportion of the multiple-frequency harmonics of the three-phase current;

[0173] Calculate the total proportion of the multiple-frequency harmonics of the three-phase current according to the following formula

[0174]

[0175] In the formula: represents the total proportion of the multiple-frequency harmonics of the three-phase current;

[0176] In this specific embodiment,

[0177]

[0178] In this specific embodiment, the 5 times, 7 times, 11 times, and 13 times frequency harmonic amplitudes of the U-phase, V-phase, and W-phase currents at different rotational speeds are shown in Table 3; the percentages of the multiple-frequency harmonics of the U-phase, V-phase, and W-phase currents at different rotational speeds are shown in Table 4.

[0179] Table 3: 5 times, 7 times, 11 times, and 13 times frequency harmonic amplitudes of the U-phase, V-phase, and W-phase currents at different rotational speeds

[0180]

[0181] Table 4: Percentages of the multiple-frequency harmonics of the U-phase, V-phase, and W-phase currents at different rotational speeds

[0182]

[0183]

[0184] The total percentage of the multiple-frequency harmonics of the three-phase currents calculated based on Table 4 is: 1.73%.

[0185] Step 4.3) Calculate the 5 times, 7 times, 11 times, and 13 times frequency harmonic balance degrees of the three-phase currents under each set rotational speed condition.

[0186] Calculate according to the following formula when the rotational speed of the drive motor is i p rpm, the 5 times, 7 times, 11 times, and 13 times frequency harmonic balance degrees of the three-phase currents:

[0187]

[0188] In the formula: represents the 5 times frequency harmonic balance degree of the three-phase currents when the rotational speed of the drive motor is i p rpm; represents the 7 times frequency harmonic balance degree of the three-phase currents when the rotational speed of the drive motor is i p rpm; represents the 11 times frequency harmonic balance degree of the three-phase currents when the rotational speed of the drive motor is i p rpm; represents the 13 times frequency harmonic balance degree of the three-phase currents when the rotational speed of the drive motor is i p rpm; According to the above formula, when the rotational speed of the drive motor is 1000 rpm, the 5 times frequency harmonic balance degree A 5J_1000 of the three-phase currents, the 7 times frequency harmonic balance degree A 7J_1000, the 11 - times - frequency harmonic balance degree A of three - phase current 11J_1000 , the 13 - times - frequency harmonic balance degree A of three - phase current 13J_1000 ; Calculate the 5 - times - frequency harmonic balance degree A of three - phase current when the driving motor speed is 2000 rpm 5J_2000 , the 7 - times - frequency harmonic balance degree A of three - phase current 7J_2000 , the 11 - times - frequency harmonic balance degree A of three - phase current 11J_2000 , the 13 - times - frequency harmonic balance degree A of three - phase current 13J_2000 ; Calculate the 5 - times - frequency harmonic balance degree A of three - phase current when the driving motor speed is 3000 rpm 5J_3000 , the 7 - times - frequency harmonic balance degree A of three - phase current 7J_3000 , the 11 - times - frequency harmonic balance degree A of three - phase current 11J_3000 , the 13 - times - frequency harmonic balance degree A of three - phase current 13J_3000 ; Calculate the 5 - times - frequency harmonic balance degree A of three - phase current when the driving motor speed is 4000 rpm 5J_4000 , the 7 - times - frequency harmonic balance degree A of three - phase current 7J_4000 , the 11 - times - frequency harmonic balance degree A of three - phase current 11J_4000 , the 13 - times - frequency harmonic balance degree A of three - phase current 13J_4000 ; Calculate the 5 - times - frequency harmonic balance degree A of three - phase current when the driving motor speed is 5000 rpm 5J_5000 , the 7 - times - frequency harmonic balance degree A of three - phase current 7J_5000 , the 11 - times - frequency harmonic balance degree A of three - phase current 11J_5000 , the 13 - times - frequency harmonic balance degree A of three - phase current 13J_5000 .

[0189] In this specific embodiment, the 5 - times, 7 - times, 11 - times, and 13 - times - frequency harmonic balance degree values of three - phase current at each rotational speed are shown in Table 5.

[0190] Table 5: The 5 - times, 7 - times, 11 - times, and 13 - times - frequency harmonic balance degree values of three - phase current at each rotational speed

[0191] 1000 rpm 2000 rpm 3000 rpm 4000 rpm 5000 rpm 5 times 3.54％ 4.95％ 5.20％ 9.35％ 12.76％ 7 times 10.06％ 10.04％ 2.30％ 10.24％ 16.89％ 11 times 4.00％ 24.32％ 17.64％ 11.11％ 14.88％ 13 times 4.05％ 7.69％ 8.69％ 5.45％ 12.68％

[0192] Step 4.4) Calculate the total balance degree of the multiple - frequency harmonics of three - phase current.

[0193] Calculate the total balance degree of the multiple - frequency harmonics of three - phase current according to the following formula:

[0194]

[0195] In the formula: A XXJ represents the total balance degree of the multiple - frequency harmonics of three - phase current.

[0196] In this specific embodiment,

[0197] A XXJ = 0.01 * (A 5J_1000 + A 7J_1000 + A 11J_1000 + A 13J_1000 + A 5J_2000 + A 7J_2000 + A 11J_2000 + A 13J_2000 + A 5J_3000 + A 7J_3000 + A 11J_3000 + A 13J_3000 + A 5J_4000 + A 7J_4000 + A 11J_4000 + A 13J_4000 + A 5J_5000 + A 7J_5000 + A 11J_5000 + A 13J_5000 )

[0198] The total balance degree A of the triple - frequency harmonics of the three - phase current calculated in this specific embodiment XXJ is: 1.95%.

[0199] Step 5) Conduct a symmetrical harmonic analysis of the three - phase current of 10000 Hz for the vehicle controller.

[0200] Step 5.1) Calculate the symmetrical harmonic amplitudes of the U - phase, V - phase, and W - phase currents at 10000 Hz when the driving motor speed is i p rpm.

[0201] Among them, when the driving motor speed is i p rpm, the formula for calculating the symmetrical harmonic amplitude of the U - phase current at 10000 Hz is:

[0202]

[0203] In the formula: represents the symmetrical harmonic amplitude of the U - phase current at 10000 Hz when the driving motor speed is i p rpm; according to the above formula, when the driving motor speed is 1000 rpm, the symmetrical harmonic amplitude A 10000J_u_1000 of the U - phase current at 10000 Hz is calculated; when the driving motor speed is 2000 rpm, the symmetrical harmonic amplitude A 10000J_u_2000 of the U - phase current at 10000 Hz; when the driving motor speed is 3000 rpm, the symmetrical harmonic amplitude A 10000_u_3000 of the U - phase current at 10000 Hz; when the driving motor speed is 4000 rpm, the symmetrical harmonic amplitude A 10000_u_4000; When the driving motor speed is 5000 rpm, the symmetric harmonic amplitude A of the U-phase current at 10000 Hz 100_u_5000 。

[0204] When the driving motor speed is i p rpm, the calculation formula for the symmetric harmonic amplitude of the V-phase current at 10000 Hz is:

[0205]

[0206] In the formula: represents the symmetric harmonic amplitude of the V-phase current at 10000 Hz when the driving motor speed is i p rpm; According to the above formula, the symmetric harmonic amplitude A of the V-phase current at 10000 Hz when the driving motor speed is 1000 rpm is calculated 100_v_1000 ; The symmetric harmonic amplitude A of the V-phase current at 10000 Hz when the driving motor speed is 2000 rpm 10000J_v_2000 ; The symmetric harmonic amplitude A of the V-phase current at 10000 Hz when the driving motor speed is 3000 rpm 1000_v_3000 ; The symmetric harmonic amplitude A of the V-phase current at 10000 Hz when the driving motor speed is 4000 rpm 10000_v_4000 ; The symmetric harmonic amplitude A of the V-phase current at 10000 Hz when the driving motor speed is 5000 rpm 1000_v_5000 。

[0207] When the driving motor speed is i p rpm, the calculation formula for the symmetric harmonic amplitude of the W-phase current at 10000 Hz is:

[0208]

[0209] In the formula: represents the symmetric harmonic amplitude of the W-phase current at 10000 Hz when the driving motor speed is i p rpm; According to the above formula, the symmetric harmonic amplitude A of the W-phase current at 10000 Hz when the driving motor speed is 1000 rpm is calculated 10000J_w_1000 ; The symmetric harmonic amplitude A of the W-phase current at 10000 Hz when the driving motor speed is 2000 rpm 1000_w_2000 ; The symmetric harmonic amplitude A of the W-phase current at 10000 Hz when the driving motor speed is 3000 rpm 10000_w_3000 ; The symmetric harmonic amplitude A of the W-phase current at 10000 Hz when the driving motor speed is 4000 rpm 10000_w_4000 ; The symmetric harmonic amplitude A of the W-phase current at 10000 Hz when the driving motor speed is 5000 rpm 100_w_5000 。

[0210] In this specific embodiment, the symmetric harmonic amplitudes of the currents in the U, V, and W directions at 10,000 Hz obtained by calculation at each rotational speed are shown in Table 6.

[0211] Table 6: Symmetric harmonic amplitudes of the currents in the U, V, and W directions at 10,000 Hz at each rotational speed

[0212] 1000 rpm 2000 rpm 3000 rpm 4000 rpm 5000 rpm U direction 0.44 1.38 3.98 4.00 3.00 V direction 0.43 1.37 3.95 3.99 2.98 W direction 0.44 1.39 3.91 3.97 2.95

[0213] Step 5.2) Calculate the total symmetric harmonic amplitude of the three-phase currents at 10,000 Hz according to the following formula:

[0214]

[0215] In the formula: A 10000Jzt represents the total symmetric harmonic amplitude of the three-phase currents at 10,000 Hz.

[0216] In this specific embodiment,

[0217] A 10000Jzt = 0.01 * (A 10000J_u_1000 + A 10000_v_1000 + A 10000J_w_1000 + A 10000J_u_2000 + A 10000J_v_2000 + A 10000J_w_2000 + A 10000J_u_3000 + A 10000J_v_3000 + A 10000J_w_3000 + A 10000J_u_4000 + A 10000J_v_4000 + A 10000J_w_4000 + A 10000J_u_5000 + A 10000J_v_5000 + A 10000J_w_5000 )

[0218] The calculated A 10000Jzt in this specific embodiment is 0.29:

[0219] Step 6) Conduct a symmetric harmonic analysis of the three-phase currents of the vehicle controller at 20,000 Hz.

[0220] Step 6.1) Calculate the symmetric harmonic amplitudes of the currents in the U, V, and W directions at 20,000 Hz when the rotational speed of the drive motor is i p rpm;

[0221] Among them, when the rotational speed of the drive motor is i p rpm, the calculation formula for the symmetric harmonic amplitude of the U-phase current at 20,000 Hz is:

[0222]

[0223] In the formula: Indicates the symmetrical harmonic amplitude of the U-phase current at 20000 Hz when the driving motor speed is i p rpm; According to the above formula, the symmetrical harmonic amplitude A of the U-phase current at 20000 Hz when the driving motor speed is 1000 rpm is calculated 20000J_u_1000 ; The symmetrical harmonic amplitude A of the U-phase current at 20000 Hz when the driving motor speed is 2000 rpm 20000J_u_2000 ; The symmetrical harmonic amplitude A of the U-phase current at 20000 Hz when the driving motor speed is 3000 rpm 20000J_u_3000 ; The symmetrical harmonic amplitude A of the U-phase current at 20000 Hz when the driving motor speed is 4000 rpm 20000J_u_4000 ; The symmetrical harmonic amplitude A of the U-phase current at 20000 Hz when the driving motor speed is 5000 rpm 200_u_5000 .

[0224] When the driving motor speed is i p rpm, the calculation formula for the symmetrical harmonic amplitude of the V-phase current at 20000 Hz is:

[0225]

[0226] In the formula: Indicates the symmetrical harmonic amplitude of the V-phase current at 20000 Hz when the driving motor speed is i p rpm; According to the above formula, the symmetrical harmonic amplitude A of the V-phase current at 20000 Hz when the driving motor speed is 1000 rpm is calculated 20000J_v_1000 ; The symmetrical harmonic amplitude A of the V-phase current at 20000 Hz when the driving motor speed is 2000 rpm 20000J_v_2000 ; The symmetrical harmonic amplitude A of the V-phase current at 20000 Hz when the driving motor speed is 3000 rpm 200_v_3000 ; The symmetrical harmonic amplitude A of the V-phase current at 20000 Hz when the driving motor speed is 4000 rpm 20000J_v_4000 ; The symmetrical harmonic amplitude A of the V-phase current at 20000 Hz when the driving motor speed is 5000 rpm 20000J_v_5000 .

[0227] When the driving motor speed is i p rpm, the calculation formula for the symmetrical harmonic amplitude of the W-phase current at 20000 Hz is:

[0228]

[0229] In the formula: Indicates the symmetrical harmonic amplitude of the W-phase current at 20000 Hz when the driving motor speed is i pThe symmetric harmonic amplitude of the W-phase current at 20000 Hz when the rotational speed is [rpm]; according to the above formula, the symmetric harmonic amplitude A of the W-phase current at 20000 Hz when the rotational speed of the drive motor is 1000 rpm is calculated 20000_w_1000 ; The symmetric harmonic amplitude A of the W-phase current at 20000 Hz when the rotational speed of the drive motor is 2000 rpm 20000J_w_2000 ; The symmetric harmonic amplitude A of the W-phase current at 20000 Hz when the rotational speed of the drive motor is 3000 rpm 200_w_3000 ; The symmetric harmonic amplitude A of the W-phase current at 20000 Hz when the rotational speed of the drive motor is 4000 rpm 20000J_w_4000 ; The symmetric harmonic amplitude A of the W-phase current at 20000 Hz when the rotational speed of the drive motor is 5000 rpm 20000J_w_5000 。

[0230] In this specific embodiment, the calculated symmetric harmonic amplitudes of the U-phase, V-phase, and W-phase currents at 20000 Hz for each rotational speed are shown in Table 7

[0231] Table 7: Symmetric harmonic amplitudes of the U-phase, V-phase, and W-phase currents at 20000 Hz for each rotational speed

[0232] 1000 rpm 2000 rpm 3000 rpm 4000 rpm 5000 rpm U direction 0.60 1.73 4.59 4.42 3.21 V direction 0.59 1.70 4.80 4.46 3.22 W direction 0.60 1.73 4.80 4.48 3.22

[0233] Step 6.2) Calculate the total symmetric harmonic amplitude of the three-phase currents at 20000 Hz according to the following formula

[0234]

[0235] In the formula: A 20000Jzt represents the total symmetric harmonic amplitude of the three-phase currents at 20000 Hz

[0236] In this specific embodiment

[0237]

[0238] In this specific embodiment, the calculated A 20000Jzt is: 0.44

[0239] Step 7) Analyze the current sine balance of the vehicle controller

[0240] Calculate the sine balance of the three-phase currents of the controller according to the following formula

[0241]

[0242] In the formula: A s is the sine balance of the three-phase currents of the controller; in this specific embodiment, the calculated A s is: 8.25

[0243] Score the three-phase current sine balance degree of the controller according to the calculated value. Specifically, Table 8 is the scoring table for the three-phase current sine balance degree of the controller, and score the calculated three-phase current sine balance degree of the controller according to Table 8.

[0244] Table 8: Scoring Table for Three-Phase Current Sine Balance Degree of Controller

[0245] 1 minute 2 minutes 3 minutes 4 minutes 5 minutes 6 minutes 7 minutes 8 minutes 9 minutes 10 minutes 0～2 2～4 4～6 6～8 8～10 10～12 12～14 14～18 18～20 >20 Perfect Extremely excellent Excellent Extremely good Good Average Fair Poor Bad Extremely bad

[0246] In this specific embodiment, the calculated value of A s is: 8.25, so the score is 5 points, which is good.

[0247] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit them. Those of ordinary skill in the art should understand that any modifications or equivalent replacements made to the technical solutions of the present invention without departing from the purpose and scope of the technical solutions shall be covered by the scope of the claims of the present invention.

Claims

1. A method for analyzing the current sine balance degree of a vehicle controller, characterized in that, It includes the following steps: Step 1) Collect the time-domain data of the three-phase current of the vehicle controller; Step 2) Perform discrete Fourier transform on the three-phase current of the vehicle controller; Step 3) Perform fundamental frequency harmonic analysis on the three-phase current of the vehicle controller; Step 4) Perform multiple frequency harmonic analysis on the three-phase current of the vehicle controller; Step 5) Perform symmetrical harmonic analysis on the three-phase current of the vehicle controller at 10000 Hz; Step 6) Perform symmetrical harmonic analysis on the three-phase current of the vehicle controller at 20000 Hz; Step 7) Perform analysis on the sine balance of the vehicle controller current.

2. The method for analyzing the current sine balance of a vehicle controller according to claim 1, wherein Step 1) includes the following steps: Step 1.1) Apply a stable load of a first torque to the drive motor and apply a current clamp to each of the three wires between the controller and the drive motor; Step 1.2) Use a current clamp to collect the time-domain data of the three-phase current when the driving motor speed is stable at each set speed condition. The set speeds are i p rpm, p = 1, 2, 3, … M, the sampling frequency is set to 50k; the data acquisition time is more than 10s.

3. The method for analyzing the current sine balance degree of a vehicle controller according to claim 2, characterized in that, In Step 2), the following formula is used to perform discrete Fourier transform on the U-phase current time-domain data collected in Step 1) under each set speed condition: Wherein: represents the discrete Fourier transform result of the current in the U direction when the driving motor speed is i p rpm; ω represents the frequency after discrete Fourier transform; represents the time-domain data of the current in the U direction when the driving motor speed is i p rpm, and N represents the total amount of collected data; The following formula is used to perform discrete Fourier transform on the V-phase current time-domain data collected in Step 1) under each set speed condition: Wherein: represents the discrete Fourier transform result of the current in the V direction when the driving motor speed is i p rpm; represents the time-domain data of the current in the V direction when the driving motor speed is i p rpm. The following formula is used to perform discrete Fourier transform on the W-phase current time-domain data collected in Step 1) under each set speed condition: Wherein: represents the discrete Fourier transform result of the W-phase current when the driving motor speed is i p rpm, represents the time-domain data of the W-phase current when the driving motor speed is i p rpm.

4. The method for analyzing the current sine balance of a vehicle controller according to claim 3, characterized in that Step 3) includes the following steps: Step 3.1) Calculate the fundamental frequency harmonic amplitudes of the three-phase currents in the U, V, and W directions at each set rotational speed i p rpm operating condition: In the formula: represents the fundamental frequency harmonic amplitude of the current in the U direction when the rotational speed of the drive motor is i p rpm; represents the fundamental frequency harmonic amplitude of the current in the V direction when the rotational speed of the drive motor is i p rpm; represents the fundamental frequency harmonic amplitude of the current in the W direction when the rotational speed of the drive motor is i p rpm. Step 3.2) Calculate each set rotational speed i p Under the rpm operating condition, the harmonic balance degrees of the fundamental frequencies of the three-phase currents in the U-direction, V-direction, and W-direction; Wherein: represents the three-phase current fundamental frequency harmonic balance at the operating condition where the rotational speed of the drive motor is i p rpm; Step 3.3) Calculate the average three-phase current fundamental frequency harmonic balance degree Where: A J_avg represents the harmonic balance degree of the average three-phase current fundamental frequency.

5. The method for analyzing the current sine balance degree of a vehicle controller according to claim 4, wherein Step 4) includes the following steps: Step 4) includes the following steps: Step 4.1) Calculate the proportion of multiple frequency harmonics of the U-phase, V-phase, and W-phase under each set speed condition; Step 4.2) Calculate the total proportion of multiple frequency harmonics of the three-phase current; Step 4.3) Calculate the harmonic balance degrees of the 5th, 7th, 11th, and 13th harmonics of the three-phase current under each set speed condition; Step 4.4) Calculate the total balance degree of the multiple frequency harmonics of the three-phase current.

6. The method for analyzing the current sine balance degree of a vehicle controller according to claim 5, characterized in that, Step 4.1) includes the following steps: Step 4.1.1) Calculate the harmonic amplitudes of 5 times, 7 times, 11 times, and 13 times the frequencies of the currents in the U-phase, V-phase, and W-phase respectively when the driving motor speed is i p rpm; Among them, the calculation formulas for the amplitudes of the 5th, 7th, 11th, and 13th frequency harmonics of the U-phase current are respectively: Where: represents the amplitude of the 5th harmonic of the U-phase current at the driving motor speed of i p rpm; represents the amplitude of the 7th harmonic of the U-phase current at the driving motor speed of i p rpm; represents the amplitude of the 11th harmonic of the U-phase current at the driving motor speed of i p rpm; represents the amplitude of the 13th harmonic of the U-phase current at the driving motor speed of i p rpm. The calculation formulas for the amplitudes of the 5th, 7th, 11th, and 13th frequency harmonics of the V-phase current are respectively: In the formula: represents the 5th harmonic amplitude of the current in the V direction at the rotational speed i of the drive motor p rpm; represents the 7th harmonic amplitude of the current in the V direction at the rotational speed i of the drive motor p rpm; represents the 11th harmonic amplitude of the current in the V direction at the rotational speed i of the drive motor p rpm; represents the 13th harmonic amplitude of the current in the V direction at the rotational speed i of the drive motor p rpm. The calculation formulas for the amplitudes of the 5th, 7th, 11th, and 13th frequency harmonics of the W-phase current are respectively: In the formula: represents the 5th harmonic amplitude of the W-phase current at the drive motor speed of i p rpm; represents the 7th harmonic amplitude of the W-phase current at the drive motor speed of i p rpm; represents the 11th harmonic amplitude of the W-phase current at the drive motor speed of i p rpm; represents the 13th harmonic amplitude of the W-phase current at the drive motor speed of i p rpm. Step 4.1.2) Calculate the proportion of the multiple-frequency harmonics of the currents in the U-phase, V-phase, and W-phase at the driving motor speed of i p rpm for each; Among them, when the rotational speed of the drive motor is i p rpm, the calculation formula for the proportion of the frequency harmonic of the U-phase current multiple is: Where: represents the proportion of the multiple-frequency harmonic of the current in the U direction when the rotational speed of the drive motor is i p rpm; When the rotational speed of the drive motor is i p rpm, the calculation formula for the proportion of the frequency harmonic of the current multiple in the V direction is as follows: Wherein: represents the proportion of the multiple frequency harmonics of the current in the V direction when the rotational speed of the drive motor is i p rpm; When the driving motor speed is i p rpm, the calculation formula for the proportion of the frequency harmonic of the W-phase current multiple is as follows: Where: represents the proportion of the multiple frequency harmonics of the current in the W direction when the rotational speed of the drive motor is i p rpm; In Step 4.2), calculate the total proportion of multiple frequency harmonics of the three-phase current according to the following formula Wherein: represents the total proportion of triple-current multiple frequency harmonics.

7. The method for analyzing the current sine balance of a vehicle controller according to claim 6, characterized in that In step 4.3), calculate the 5 times, 7 times, 11 times, and 13 times harmonic balance degrees of the three-phase current when the driving motor speed is i p rpm as follows: In the formula: represents the 5 - times - frequency harmonic balance of the three - phase current when the driving motor speed is i p rpm; represents the 7 - times - frequency harmonic balance of the three - phase current when the driving motor speed is i p rpm; represents the 11 - times - frequency harmonic balance of the three - phase current when the driving motor speed is i p rpm; represents the 13 - times - frequency harmonic balance of the three - phase current when the driving motor speed is i p rpm. In Step 4.4), calculate the total balance degree of the multiple frequency harmonics of the three-phase current according to the following formula: Where: A XXJ represents the total balance degree of triple-frequency harmonics of three-phase current.

8. The method for analyzing the current sine balance degree of a vehicle controller according to claim 7, characterized in that, Step 5) includes the following steps: Step 5.1) Calculate the symmetrical harmonic amplitudes of the currents in the U-phase, V-phase, and W-phase at 10,000 Hz when the driving motor speed is i p rpm; Among them, when the rotational speed of the drive motor is i p rpm, the calculation formula for the symmetrical harmonic amplitude of the U-phase current at 10000 Hz is: Wherein: represents the symmetric harmonic amplitude of the current in the U direction at 10000 Hz when the rotational speed of the drive motor is i p rpm; When the driving motor speed is i p rpm, the calculation formula for the symmetric harmonic amplitude of the V-phase current at 10000 Hz is: Where: represents the symmetric harmonic amplitude of the current in the V direction at 10,000 Hz when the rotational speed of the drive motor is i p rpm; When the driving motor speed is i p rpm, the calculation formula for the symmetric harmonic amplitude of the W-phase current at 10000 Hz is: Wherein: represents the symmetric harmonic amplitude of the W-phase current at 10000 Hz when the driving motor speed is i p rpm; Step 5.2) Calculate the total amplitude of the symmetrical harmonics of the three-phase current at 10000 Hz according to the following formula: Where: A 10000Jzt represents the total amplitude of the symmetrical harmonic wave of the three-phase current at 10000 Hz.

9. The method for analyzing the current sine balance degree of a vehicle controller according to claim 8, characterized in that, Step 6) includes the following steps: Step 6.1) Calculate the symmetrical harmonic amplitudes of the U-phase, V-phase, and W-phase currents at 20000 Hz when the driving motor speed is i p rpm Among them, when the rotational speed of the drive motor is i p rpm, the calculation formula for the symmetrical harmonic amplitude of the U-phase current at 20000 Hz is: Wherein: represents the symmetric harmonic amplitude of the current in the U direction at 20000 Hz when the driving motor speed is i p rpm; When the rotational speed of the drive motor is i p rpm, the calculation formula for the symmetric harmonic amplitude of the V-phase current at 20000 Hz is as follows: Wherein: represents the symmetrical harmonic amplitude of the current in the V direction at 20000 Hz when the rotational speed of the drive motor is i p rpm; The rotational speed of the drive motor is at i p rpm, and the calculation formula for the symmetrical harmonic amplitude of the W-phase current at 20000 Hz is as follows: Wherein: represents the symmetric harmonic amplitude of the current in the W direction at 20000 Hz when the rotational speed of the drive motor is i p rpm; Step 6.2) Calculate the total amplitude of the symmetrical harmonics of the three-phase current at 20000 Hz according to the following formula: Where: A 20000Jzt represents the total amplitude of the symmetrical harmonics of the three-phase current at 20000 Hz.

10. The method for analyzing the current sine balance degree of a vehicle controller according to claim 9, wherein In Step 7), calculate the sine balance degree of the three-phase current of the controller according to the following formula: Where: A s is the three-phase current sine balance degree of the controller; Score the sine balance degree of the three-phase current of the controller according to the calculated sine balance degree of the three-phase current of the controller.

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