阅读说明：本技术 一种电机控制器的直流母线电流估算方法 (Direct current bus current estimation method of motor controller ) 是由 舒晖 陈士刚 王瑛 钱兆刚 陶文勇 杭孟荀 于 2020-03-31 设计创作，主要内容包括：本发明涉及母线电流技术领域,提供了一种电机控制器的母线电流估算方法,包括：S1、将指定母线电压、指定母线电压下的各转速点及各转速点下的扭矩点组成一系列的测点；S2、检测电机控制器在各测点下的母线电流值；S3、计算对应测点的母线电流相关数；S4、基于各扭矩区间内两测量点的母线电流测量值及对应的母线电流相关数建立对应扭矩区间的映射参数；S5、计算对应扭矩区间内各预估点的母线电流值,称为母线电流估算值；S6、基于差值法计算不同母线电压下不同转矩及转速下的母线电流值,即为母线电流估算值。采用估算方法计算母线电流,可以减少一个电流传感器,降低电机控制器的硬件成本,同时可以实现电机控制器的小型化、轻量化。(The invention relates to the technical field of bus current, and provides a bus current estimation method of a motor controller, which comprises the following steps: s1, forming a series of measuring points by the appointed bus voltage, each rotating speed point under the appointed bus voltage and the torque point under each rotating speed point; s2, detecting the bus current value of the motor controller at each measuring point; s3, calculating the bus current correlation number of the corresponding measuring point; s4, establishing mapping parameters corresponding to the torque intervals based on the bus current measurement values of the two measurement points in each torque interval and the corresponding bus current correlation numbers; s5, calculating the bus current value of each estimated point in the corresponding torque interval, namely the bus current estimated value; and S6, calculating the bus current values under different bus voltages and different torques and rotating speeds based on a difference method, namely the bus current estimated value. The bus current is calculated by adopting the estimation method, so that a current sensor can be reduced, the hardware cost of the motor controller is reduced, and the motor controller can be miniaturized and lightened.)

1. A bus current estimation method of a motor controller is characterized by specifically comprising the following steps:

s1, forming a series of measuring points by the appointed bus voltage, each rotating speed point under the appointed bus voltage and the torque point under each rotating speed point;

s2, detecting the bus current value of the motor controller at each measuring point through the rack, namely the bus current measured value I_dc-c；

S3, calculating the bus current correlation number of the corresponding measuring point based on the motor torque and the rotating speed in the measuring point and the bus voltage value of the motor controller;

s4, selecting torque fixing points in the torque points according to a set step length, forming a torque interval by two adjacent torque fixing points, adopting the common identification of the designated bus voltage and current point in the torque interval, and based on the bus current measurement value I of two measurement points in each torque interval_dc-cEstablishing a mapping parameter corresponding to the torque interval according to the corresponding bus current correlation number;

s5, calculating the bus current value of each estimated point in the corresponding torque interval based on the mapping parameter of the torque interval, namely the bus current estimated value I_dc-gThe estimated point is a point outside the measuring point in the torque interval;

s6, calculating the bus current value under different bus voltages and different torques and rotating speeds based on the difference method, namely the bus current estimated value I_dc-g。

2. The method of estimating a bus current of a motor controller according to claim 1, wherein the bus current correlation number x is calculated by: x is N.T/U_dcWherein N isThe rotation speed of the motor to be tested, T is the torque of the motor to be tested, U_dcIs the bus voltage of the tested motor controller.

3. The method for estimating bus current of a motor controller according to claim 1, wherein the calculation formula of the mapping parameters a, b, and c of the torque interval is specifically as follows:

I_dc-c＝ax²+bx+c

wherein, I_dc-cThe bus current measured value of a measuring point in the torque interval is shown, and x is the bus current correlation number of the measuring point in the torque interval.

4. The method of claim 1, wherein the bus current estimation I is performed at different speeds and torques for a given bus voltage_dc-gThe calculation formula of (a) is specifically as follows:

I_dc-g＝ax²+bx+c

a. b and c are mapping parameters of a torque interval, and x is a bus current correlation number of an estimated point in the torque interval.

5. The method for estimating the bus current of the motor controller according to claim 1, wherein the designated bus voltage takes 3 values, which are Uhigh, Umid and Ulow, respectively, where Uhigh is a maximum voltage value under full power operation, Umid is an operating voltage value under full power operation, and Ulow is an operating voltage value under operable power.

6. The bus current estimation method of a motor controller according to claim 1, wherein a dc current sensor is provided on the motor controller of the motor to be measured, the motor speed and torque are read through the stage, and the bus current value of the motor controller is read through the dc current sensor.

7. The bus current estimation method of a motor controller according to claim 1, wherein the measuring point is formed by a method specifically including:

selecting a designated bus voltage value of the motor controller;

based on the speed interval N at a given bus voltage₁Carrying out rotating speed value taking to obtain each rotating speed point;

based on the torque interval T at each rotational speed point₁Obtaining the value of the torque to obtain each torque point;

the designated bus voltage, each rotating speed point under the designated bus voltage and the torque point under each rotating speed point form a series of measuring points.

Technical Field

The invention relates to the technical field of motor bus current calculation, and provides a bus current estimation method of a motor controller.

Background

With the slope withdrawal of the national subsidies and the cancellation of the local subsidies, the production cost of the new energy automobile needs to be continuously reduced to meet the market demand. The direct current bus current of the motor controller is used as a key parameter of the new energy automobile, the current sensor is basically adopted to collect and feed back the current to the whole automobile controller in real time, and the problem of high hardware cost exists in the mode of obtaining the bus current of the motor controller through the current sensor.

Disclosure of Invention

The invention provides a bus current estimation method of a motor controller, which is used for calculating bus current without additionally arranging a current sensor and reducing the hardware cost of the motor controller.

The invention is realized in such a way that a bus current estimation method of a motor controller specifically comprises the following steps:

s1, selecting the designated bus voltage value of the motor controller, and selecting the designated bus voltage value based on the rotating speed interval N₁Carrying out rotating speed value taking to obtain each rotating speed point, and obtaining the rotating speed point based on the torque interval T₁Obtaining torque values, acquiring each torque point, and forming a series of measuring points by the appointed bus voltage, each rotating speed point under the appointed bus voltage and the torque point under each rotating speed point;

s2, detecting the bus current value of the motor controller at each measuring point through the rack, namely the bus current measured value I_dc-c；

S3, calculating the bus current correlation number of the corresponding measuring point based on the motor torque and the rotating speed in the measuring point and the bus voltage value of the motor controller;

s4, selecting torque fixing points in the torque points according to a set step length, forming a torque interval by two adjacent torque fixing points, adopting the common identification of the designated bus voltage and current point in the torque interval, and based on the bus current measurement value I of two measurement points in each torque interval_dc-cAnd corresponding bus current correlation number establishmentMapping parameters corresponding to the torque interval;

s5, calculating the bus current value of each estimated point in the corresponding torque interval based on the mapping parameter of the torque interval, namely the bus current estimated value I_dc-gThe estimated point is a point outside the measuring point in the torque interval;

s6, calculating the bus current value under different bus voltages and different torques and rotating speeds based on the difference method, namely the bus current estimated value I_dc-g。

Further, the formula for calculating the bus current correlation number x is as follows: x is N.T/U_dcWherein N is the rotation speed of the motor to be tested, T is the torque of the motor to be tested, and U_dcIs the bus voltage of the tested motor controller.

Further, the calculation formula of the mapping parameters a, b and c of the torque interval is specifically as follows:

I_dc-c＝ax²+bx+c

wherein, I_dc-cThe bus current measured value of a measuring point in the torque interval is shown, and x is the bus current correlation number of the measuring point in the torque interval.

Further, the bus current estimated value I under different rotating speeds and torques under the designated bus voltage_dc-gThe calculation formula of (a) is specifically as follows:

I_dc-g＝ax²+bx+c

a. b and c are mapping parameters of a torque interval, and x is a bus current correlation number of an estimated point in the torque interval.

Further, the designated bus voltages take 3 values, which are Uhigh, Umid and Ulow, respectively, where Uhigh is the maximum voltage value under full power operation, Umid is the operating voltage value under full power operation, and Ulow is the operating voltage value under operable power.

Furthermore, a direct current sensor is arranged on a motor controller of the motor to be detected, the rotating speed and the torque of the motor are read through the rack, and the bus current value of the motor controller is read through the direct current sensor.

The bus current estimation method of the motor controller provided by the invention has the following beneficial technical effects: the bus current is calculated by adopting the estimation method, so that a current sensor can be reduced, the hardware cost of the motor controller is reduced, and the motor controller can be miniaturized and lightened.

Drawings

FIG. 1 is a schematic diagram of a motor rack test provided by an embodiment of the present invention;

fig. 2 is a flowchart of a bus current estimation method of a motor controller according to an embodiment of the present invention.

Detailed Description

The following description of preferred embodiments of the invention will be made in further detail with reference to the accompanying drawings.

Fig. 2 is a flowchart of a bus current estimation method of a motor controller according to an embodiment of the present invention, where the method specifically includes the following steps:

s1, selecting the designated bus voltage value of the motor controller, and selecting the designated bus voltage value based on the rotating speed interval N₁Carrying out rotating speed value taking to obtain each rotating speed point, and obtaining the rotating speed point based on the torque interval T₁Obtaining torque values, acquiring each torque point, and forming a series of measuring points by the appointed bus voltage, each rotating speed point under the appointed bus voltage and the torque point under each rotating speed point;

in the embodiment of the invention, three bus voltages are selected, namely Uhigh, Umid and Ulow, wherein Uhigh is the maximum voltage value under full-power operation, Umid is the working voltage value under full-power operation, and Ulow is the working voltage value under operable power;

the rotating speed points are as follows in sequence: n is a radical of₁、2N₁、……、nN₁(ii) a The torque points are in sequence: t is₁、2T₁、……、mT₁

S2, detecting the bus current value of the motor controller at each measuring point through the rack, namely the bus current measured value I_dc-c；

In the embodiment of the invention, a rack is built as shown in figure 1, a direct current sensor is arranged on a motor controller of a tested motor, the bus voltage of the motor controller is set based on the rack, and the rotating speed and the torque of the motor are read through the rackThe moment value is read by a direct current sensor to the bus current value of the motor controller and is called as a bus current measured value I_dc-c。

S3, calculating a bus current correlation number x of the corresponding measuring point based on the motor torque and the rotating speed in the measuring point and the bus voltage value of the motor controller;

in the embodiment of the present invention, a calculation formula of the bus current correlation number x is: x is N.T/U_dcWherein N is the rotation speed of the motor to be tested, T is the torque of the motor to be tested, and U_dcIs the bus voltage of the tested motor controller.

S4, selecting torque fixing points in the torque points according to a set step length, forming a torque interval by two adjacent torque fixing points, adopting the common identification of the designated bus voltage and current point in the torque interval, and based on the bus current measurement value I of two measurement points in each torque interval_dc-cEstablishing a mapping parameter corresponding to the torque interval according to the corresponding bus current correlation number;

in the examples of the present invention, I_dc-c＝ax²+ bx + c, wherein, I_dc-cThe measured value of the bus current of a measuring point in the torque interval is shown, x is the bus current related number of the corresponding measuring point in the torque interval, and a, b and c are mapping parameters of the torque interval.

S5, calculating the bus current value of each estimated point in the corresponding torque interval based on the mapping parameter of the torque interval, namely the bus current estimated value I_dc-gThe estimated point is a point outside the measuring point in the torque interval;

in the examples of the present invention, I_dc-g＝ax²And the + bx + c, a, b and c are mapping parameters corresponding to the torque interval, x is a bus current correlation number of an estimated point in the torque interval, and the calculation method of the bus current correlation number of the estimated point is the same as the calculation method of the bus current correlation number of the measured point.

S6, calculating the bus current value under different bus voltages and different torques and rotating speeds based on the difference method, namely the bus current estimated value I_dc-g。

The bus current estimation method of the motor controller provided by the invention has the following beneficial technical effects: the bus current is calculated by adopting the estimation method, so that a current sensor can be reduced, the hardware cost of the motor controller is reduced, and the motor controller can be miniaturized and lightened.

It is clear that the specific implementation of the invention is not restricted to the above-described embodiments, but that various insubstantial modifications of the inventive process concept and technical solutions are within the scope of protection of the invention.