Device and method for self-calibration of offline Hall current sensor of vehicle motor controller

Abstract

The present invention belongs to the field of sensor calibration technology and provides a device and method for self-calibrating an offline Hall effect current sensor of a vehicle motor controller. The device comprises: a test host, a high-voltage DC power supply, a motor controller, an NI acquisition card, a three-phase inductor, and a plurality of relay switches; the high-voltage DC power supply is used to supply power to the three-phase inductor via the motor controller; the motor controller and the plurality of relay switches are used to control the conduction and disconnection of the three-phase inductor; the motor controller is provided with an internal current sensor, which is used to detect the current value of the three-phase inductor; the NI acquisition card is used to collect the current value of each phase of the Hall effect current sensor; the test host is connected to the motor controller, the NI acquisition card, and the high-voltage DC power supply. The present invention implements the entire current sensor self-calibration and automatic detection process through the test host software and the lower computer software of the motor controller under test.

Description

Technical Field

[0001] The present invention belongs to the technical field of sensor calibration, and in particular relates to a self-calibration device and method for an offline Hall effect current sensor of a vehicle motor controller. Background Art

[0002] There are two common methods for calibrating current sensor coefficients. The first relies on modular current sensors with high accuracy and reliability, using a standard power supply to calculate and utilize a single set of current coefficients. This method eliminates the need for self-calibration, but it ignores the impact of current sensor design and installation variations on measurement accuracy, particularly for non-modular current sensors. Furthermore, modular current sensors are expensive. The second method utilizes various self-calibration algorithms to calibrate the current sensor, including linear regression of single or multiple data points at varying temperatures, amplitudes, and frequencies. The main difference between these two methods lies in the design and implementation of the self-calibration algorithm, which can be categorized as simple or complex. The simple method directly calculates the unique coefficients of the Hall effect sensor within the motor controller by first calculating and then reading out the stored actual phase current data and phase current AD data. This method is fast and low-cost, but suffers from poor reliability and consistency. The complex method considers multiple coefficient influencing factors, collects more measurement data, and estimates the coefficients using polynomial regression models or neural networks. This method is used for end-of-line testing and calibration, but the overall system is complex and the equipment cost is high. Summary of the Invention

[0003] In view of the shortcomings of the prior art, the present invention provides a self-calibration device for an offline Hall effect current sensor of a vehicle motor controller, comprising:

[0004] A test host, a high-voltage DC power supply, a motor controller, an NI acquisition card, a three-phase inductor coil, and several relay switches; the Hall current sensor is configured to collect the current value of the three-phase inductor coil;

[0005] The high-voltage DC power supply is used to supply power to the three-phase inductor coil through the motor controller;

[0006] The motor controller and the plurality of relay switches are used to control the conduction and disconnection of the three-phase inductor coil;

[0007] The motor controller is provided with an internal current sensor, and the internal current sensor is used to detect the current value of the three-phase inductor coil;

[0008] The NI acquisition card is used to collect the current values ​​of each phase of the Hall current sensor;

[0009] The test host and the motor controller 、The NI acquisition card is connected to a high-voltage DC power supply, and calibrates the Hall current sensor according to the current value of the internal current sensor fed back by the motor controller and the current value of the Hall current sensor acquired by the NI acquisition card.

[0010] Furthermore, the CAN bus is used to upload the current values ​​of each phase collected by the NI acquisition card to the test host.

[0011] Furthermore, the test host controls the motor controller via a CAN bus.

[0012] Another embodiment of the present invention provides a method for self-calibration of an offline Hall effect current sensor of a vehicle motor controller, comprising:

[0013] The motor controller is powered by a high-voltage DC power supply, and the motor controller and several relay switches control the three-phase inductor coil to be turned on or off;

[0014] The Hall current sensor collects the current value of the three-phase inductor coil, and the current sensor inside the motor controller detects the current value of the three-phase inductor coil;

[0015] The test host calibrates the Hall current sensor according to the current value of the internal current sensor fed back by the motor controller and the current value of the Hall current sensor collected by the Hall current sensor.

[0016] Furthermore, the NI acquisition card collects the current value of each phase of the Hall current sensor.

[0017] Furthermore, the current values ​​of each phase collected by the NI acquisition card are uploaded to the test host via the CAN bus.

[0018] Furthermore, the output current value of the high-voltage current source is set to generate the motor controller CAN message.

[0019] Furthermore, an NI acquisition card is used to collect the current value of the U-phase current sensor.

[0020] Furthermore, the current value of the U-phase current sensor acquired by the NI acquisition card is subjected to least square fitting, and the test host calculates the U-phase current sensor coefficient and writes it into the CAN bus.

[0021] Furthermore, the test host sends several target currents via the CAN bus, and the current value of the U-phase current sensor is compared with the target current to determine whether the Hall current sensor is working properly. Compared with the existing technology, the present invention has the following advantages:

[0022] The device of the present invention does not require additional equipment investment. The entire current sensor self-calibration and automatic detection process is implemented through the test host software and the lower computer software of the motor controller under test. Compared with installing modular current sensors, the test results are more accurate and do not require additional equipment investment. The present invention detects the current value of the three-phase inductor coil through the current sensor inside the motor controller. The current value of the three-phase inductor coil detected by the Hall current sensor is then collected through an external detection NI acquisition card. This completes the self-calibration and detection process, thus ensuring the accuracy of the self-calibration process and the consistency of the detection results.

[0023] Other features and advantages of the present invention will be described in the following description, and in part will become apparent from the description, or will be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0025] Figure 1 The architecture diagram of the self-calibration device for the offline Hall current sensor of the vehicle motor controller is shown;

[0026] Figure 2 Shows a circuit diagram of a self-calibration device for an offline Hall current sensor of a vehicle motor controller;

[0027] Figure 3 The flowchart of the self-calibration device for the offline Hall current sensor of the vehicle motor controller is shown;

[0028] Figure 4 A scatter plot of the least squares fitting algorithm is shown. DETAILED DESCRIPTION

[0029] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0030] Specifically, the present invention discloses a self-calibration device for a Hall current sensor of an off-line motor controller for a vehicle, the self-calibration device comprising: Figure 1 As shown,

[0031] Test host, high-voltage DC power supply, low-voltage DC power supply, NI acquisition card, Hall current sensor, three-phase inductor coil, motor controller and various relay switches.

[0032] The test host is responsible for controlling the entire motor controller, Hall current sensor offline calibration and testing process. It uses serial communication through the test host software to control the low-voltage DC power supply, high-voltage DC power supply and relay switch, and communicates with the motor controller under test through the CAN bus.

[0033] The test host controls the high-voltage DC power switch, low-voltage DC power switch and high-voltage relay switch through serial communication to supply power to the motor controller;

[0034] The test host controls the motor controller via the CAN bus.

[0035] The Hall current sensor is set at the three-phase current output terminal of the motor controller. The NI acquisition card collects the current data of each phase and uploads it to the test host via CAN.

[0036] Another embodiment of the present invention provides a self-calibration method for a vehicle Hall current sensor, comprising:

[0037] The test process begins when the test host sends a command to the low-voltage DC power supply through serial communication, then turns on the high-voltage DC power supply and closes the corresponding relay according to the test process.

[0038] Standard Hall effect current sensor testing includes DC current acquisition self-calibration under a DC current source and AC current acquisition testing under a DC voltage source. The former uses a DC current source to calculate the current acquisition value of the external Hall effect current sensor and the current acquisition value of the Hall effect current sensor within the motor controller to achieve Hall effect current sensor coefficient self-calibration.

[0039] Take the U-phase current sensor test as an example. Figure 2 As shown, the high-voltage power supply is set to constant current output, and then relays K4, K3 and K6 are closed to form a DC circuit. The values ​​of the external current sensor Iu and the internal U-phase current sensor are collected and compared. At the same time, the sensor coefficient is calculated by linear fitting based on multiple sets of current values, as shown in Figure 4 As shown, after completion, calibrate the current sensors of the other two phases in the same way.

[0040] After completing DC current acquisition and self-calibration, set the high-voltage power supply to constant voltage output. The test host controls and closes all relay switches K1, K2, K3, K4, and K5, and controls the motor controller to start the inverter process of the entire circuit. Under the current closed-loop control inside the motor controller, the current sensor is detected by comparing the target current and the actual current acquisition value.

[0041] like Figure 3 As shown,

[0042] S1: Supply a low-voltage 12V / 2A power supply to the motor controller, maintain shutdown mode, and enable CAN communication. Close relays K4, K3, and K6 to conduct the U-phase circuit. Set the high-voltage current source to 50A, 90A, or 125A and output the current. After waiting for 1 second, read the CAN signal from the motor controller under test and use the NI acquisition card to collect the current value of the U-phase current sensor.

[0043] S2: Disconnect relays K4, K3, and K6, and close relays K7, K3, and K5. Set the high-voltage current source to output current of -50A, -90A, or -125A, and then read the CAN message from the motor controller under test after waiting for 1 second. Use the NI acquisition card to collect the current value of the U-phase current sensor.

[0044] S3: Obtain the AD value of CAN feedback under ±50, ±90, and ±125A current source output and the U-phase current value collected by the NI acquisition card for least squares fitting, such as Figure 4 As shown, the test host calculates the current sensor coefficient and writes it into the CAN.

[0045] S4: Measure and calculate the V-phase and W-phase current sensor coefficients in the same way and write them into the CAN.

[0046] S5: The motor controller lower computer software reads the three-phase current sensor coefficients from the CAN and records them in the internal data memory; after the motor controller is powered on again at low voltage, it reads the current sensor coefficients recorded in the internal data memory and applies them to the three-phase current acquisition along with the program initialization.

[0047] S6: Set the high-voltage current source to a constant voltage of 350V and output it. Control the motor controller under test to enter the current closed-loop control mode. The test host sends multiple target currents via CAN. Use the NI acquisition card to collect the three-phase currents and compare the difference with the target currents to determine whether the three-phase current sensors are working properly.

[0048] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A self-calibration device for the offline Hall current sensor of a vehicle motor controller, characterized in that: include: A test host, a high-voltage DC power supply, a motor controller, an NI acquisition card, a three-phase inductor coil, and several relay switches; the Hall current sensor is configured to collect the current value of the three-phase inductor coil; The high-voltage DC power supply is used to supply power to the three-phase inductor coil through the motor controller; The motor controller and the plurality of relay switches are used to control the conduction and disconnection of the three-phase inductor coil; The motor controller is provided with an internal current sensor, and the internal current sensor is used to detect the current value of the three-phase inductor coil; The NI acquisition card is used to collect the current values ​​of each phase of the Hall current sensor; The test host and the motor controller 、 The NI acquisition card is connected to a high-voltage DC power supply, and calibrates the Hall current sensor according to the current value of the internal current sensor fed back by the motor controller and the current value of the Hall current sensor acquired by the NI acquisition card.

2. The self-calibration device according to claim 1, characterized in that: include, The CAN bus is used to upload the current values ​​of each phase collected by the NI acquisition card to the test host.

3. The self-calibration device according to claim 1, characterized in that: include, The test host controls the motor controller via the CAN bus.

4. A self-calibration method for the offline Hall current sensor of a vehicle motor controller, characterized in that: include, The motor controller is powered by a high-voltage DC power supply, and the motor controller and several relay switches control the three-phase inductor coil to be turned on or off; The Hall current sensor collects the current value of the three-phase inductor coil, and the current sensor inside the motor controller detects the current value of the three-phase inductor coil; The test host calibrates the Hall current sensor according to the current value of the internal current sensor fed back by the motor controller and the current value of the Hall current sensor collected by the Hall current sensor.

5. The self-calibration method according to claim 4, characterized in that: The Hall current sensor collects the current value of the three-phase inductor coil, including: The NI acquisition card collects the current value of each phase of the Hall current sensor.

6. The self-calibration method according to claim 5, characterized in that: include: The current values ​​of each phase collected by the NI acquisition card are uploaded to the test host via the CAN bus.

7. The self-calibration method according to claim 6, characterized in that: include: The output current value of the high-voltage direct current power supply is set, and the motor controller CAN message is generated.

8. The self-calibration method according to claim 7, characterized in that: include: Use the NI acquisition card to collect the current value of the U-phase current sensor.

9. The self-calibration method according to claim 8, characterized in that: include: The current value of the U-phase current sensor acquired by the NI acquisition card is subjected to least square fitting, and the test host calculates the U-phase current sensor coefficient and writes it into the CAN bus.

10. The self-calibration method according to claim 9, characterized in that: include, The test host sends several target currents through the CAN bus, and the current value of the U-phase current sensor is compared with the target current to determine whether the Hall current sensor is working properly.

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