Load line recognition method for motor driver and power element protection device thereof

Abstract

This invention discloses a load resistance identification method for a motor driver and a power element protection device thereof. First, it detects the motor's rotational speed. If the speed is less than a first value, it indicates the load is blocked. If the speed is greater than the first value but less than a second value, it indicates the load is not completely blocked. Next, it detects the phase current of the three-phase power element. If the phase current is greater than the first phase current value, a blocking weight value or an incomplete blocking weight value is calculated based on the phase current magnitude. A blocking target temperature value or an incomplete blocking target temperature value is also calculated based on the phase current magnitude. Finally, it detects the temperature of the motor driver. If the temperature is greater than the blocking target temperature value or the incomplete blocking target temperature value, it determines whether the blocking weight value or the incomplete blocking weight value exceeds the accumulated weight value. If so, it shuts off a power supply to the motor driver to protect the power element and ensures that the electric vehicle will not mistakenly stop operation due to excessive current when encountering a slope.

Description

Technical Field

[0001] This invention relates to a load resistance identification method for a motor driver and a power element protection device thereof, particularly to a power element control system for an electric vehicle (EV) motor driver, which has an identification method and protection device capable of identifying that the vehicle is blocked due to road resistance, thereby protecting the power element from damage. Background Technology

[0002] In most electric vehicle motor drive applications, the power components of the motor driver are used to drive the load. In some cases, road resistance can cause load blockage, leading to excessive temperature rise of the motor driver and potential danger. Currently, to avoid damage to the power components due to overheating, existing applications often use motor speed and phase current to detect load blockage. However, this method is prone to misjudgment when the electric vehicle is on a slope due to overly stringent criteria, while lowering the criteria can easily cause the power components to overheat and be damaged. Summary of the Invention

[0003] To address the shortcomings of the prior art, the present invention aims to develop a load resistance identification method for a motor drive of an electric vehicle and a power component protection device thereof. This method can identify the vehicle's condition when encountering road resistance, thereby preventing damage to the power components of the motor drive due to overheating when the load is blocked. Furthermore, it ensures that the electric vehicle will not misjudge and stop operating when encountering a slope due to overly stringent judgment criteria.

[0004] To achieve the above objectives, the present invention provides a load resistance identification method for a motor driver. First, the motor speed is detected. If the speed is less than a first speed value, it indicates that the load is blocked. If the speed is greater than the first speed value but less than a second speed value, it indicates that the load is not completely blocked. Next, the phase current of the three-phase power element is detected. If the phase current is greater than the first phase current value, a blocking weight value or an incomplete blocking weight value is calculated based on the phase current magnitude. A blocking target temperature value or an incomplete blocking target temperature value is also calculated based on the phase current magnitude. Finally, the temperature of the motor driver is detected. If the temperature is greater than the blocking target temperature value or the incomplete blocking target temperature value, it is determined whether the blocking weight value or the incomplete blocking weight value exceeds the accumulated weight value. If so, a power supply to the motor driver is shut off to protect the power element.

[0005] To achieve the above objectives, the present invention also provides a power element protection device for a motor driver, comprising a three-phase power element, a speed detection unit, a phase current detection unit, and a temperature detection unit, wherein the three-phase power element drives a motor to drive a load; the speed detection unit detects the speed of the motor, and if it is less than a first speed value, it indicates that the load is blocked; if it is greater than the first speed value and less than a second speed value, it indicates that the load is not completely blocked; the phase current detection unit detects the phase current of the three-phase power element, and if it is greater than the first phase current value, it calculates a blocking weight value or an incomplete blocking weight value, and calculates a blocking target temperature value or an incomplete blocking target temperature value; the temperature detection unit detects the temperature of the motor driver, and if it is greater than the blocking target temperature value or the incomplete blocking target temperature value, it determines whether the blocking weight value or the incomplete blocking weight value exceeds the accumulated weight value; if so, it shuts off a power supply to the motor driver to protect the power element. Attached Figure Description

[0006] Figure 1 This is a schematic diagram of the system block diagram of the present invention.

[0007] Figure 2 This is a block diagram of the motor driver of the present invention.

[0008] Figure 3 This is a flowchart of the system startup process of the present invention.

[0009] Figure 4 This is a schematic diagram of the load blockage protection process of the present invention.

[0010] Figure 5 This is a graph showing the phase current versus weighting value of the present invention.

[0011] Figure 6 This is a graph showing the phase current versus target temperature of the present invention.

[0012] Figure 7 This is a phase current-temperature-weighting curve for an embodiment of the present invention where the load is not completely blocked.

[0013] Figure 8 This is a phase current-temperature-weighted value curve for a load-blocked embodiment of the present invention.

[0014] Figure labeling: 10-Motor driver; 20-Three-phase power element; 30-Motor; 40-Load; 50-Power supply; 11-Microcontroller unit; 12-Speed ​​detection unit; 13-Phase current detection unit; 14-Temperature detection unit; 51-Blocked weight value curve; 52-Incompletely blocked weight value curve; 61-Blocked target temperature value curve; 62-Incompletely blocked target temperature value curve. Detailed Implementation

[0015] Please refer to the following: Figure 1 and Figure 2 As shown, where Figure 1 This is a schematic diagram of the system block diagram of the present invention. Figure 2 This is a block diagram of the motor driver of the present invention. The present invention is a power system for electric vehicles (EVs) and can be used to identify the road resistance status of the EV, i.e., to determine whether the load blockage is caused by the EV being on a slope. The EV power system of the present invention is driven by a motor driver 10, which has a three-phase power element 20 that drives a motor 30. The motor 30 drives a load 40 to rotate, such as a tire. The motor driver 10 is powered by a power source 50 composed of batteries.

[0016] This invention utilizes a motor driver 10 to protect the motor from jamming during rotation; please refer to the following: Figure 2 and Figure 3 As shown, where Figure 3 This is a system startup flowchart for the present invention. The present invention controls the timing of power supply shutdown of the motor driver 10 to the power supply 50 according to the load congestion scenario, in order to protect the three-phase power components 20 from overheating damage. Figure 2 As shown, the motor driver 10 of the present invention further comprises a microcontroller unit 11, a speed detection unit 12, a phase current detection unit 13, and a temperature detection unit 14. Figure 3 As shown, when the motor driver 10 starts (S310), the microcontroller unit 11 will determine whether the load is blocked (S320). If so, the power supply 50 of the motor driver 10 will be turned off (S330).

[0017] The speed detection unit 12 is connected to the motor 30 and the microcontroller unit 11. Under the control of the microcontroller unit 11, it detects the motor speed and transmits the data to the microcontroller unit 11. The phase current detection unit 13 is connected to the three-phase power element 20 and the microcontroller unit 11. Under the control of the microcontroller unit 11, it detects the magnitude of the phase current of the three-phase power element 20 and transmits the data to the microcontroller unit 11. The temperature detection unit 14 is connected to the three-phase power element 20 and the microcontroller unit 11. Under the control of the microcontroller unit 11, it detects the temperature of the motor driver 10 and transmits the data to the microcontroller unit 11.

[0018] Please refer to this document as well. Figure 2 and Figure 4 As shown, where Figure 4This is a schematic diagram of the load blockage protection process of the present invention. The present invention divides the load blockage situation into two modes: complete blockage and incomplete blockage, to distinguish between a sloping road surface and a road obstruction state. The method of identifying road obstruction in the present invention first uses the microcontroller unit 11 to control the speed detection unit 12 to detect whether the speed of the motor 30 is less than a first speed value. If it is, it means that the load 40 is blocked. Preferably, the first speed value is 10 rpm. In other words, when the speed is less than 10 rpm, the load 40 is blocked (S410). If the speed is greater than the first speed value and less than a second speed value, it means that the load 40 is in an incomplete blockage state. Preferably, the second speed value is 170 rpm. In other words, when the speed is greater than 10 rpm and less than 170 rpm, the load is in an incomplete blockage state (S420). The electric vehicle is on a sloping road surface.

[0019] Next, the microcontroller unit 11 controls the phase current detection unit 13 to detect whether the phase current of the three-phase power element 20 is greater than the first phase current value within each millisecond (S411, S421). Preferably, the effective value of the first phase current is 60 Arms. All subsequent phase currents are in effective value Arms. If the phase current is greater than the first phase current value of 60 Arms, a blocking weight value (S412) or an incomplete blocking weight value (S422) is calculated based on the phase current. Then, a blocking target temperature value (S413) or an incomplete blocking target temperature value (S423) is calculated based on the phase current. The calculation mode of the microcontroller unit 11 is that the larger the phase current, the larger the calculated blocking weight value or incomplete blocking weight value, and the smaller the calculated blocking target temperature value or incomplete blocking target temperature value. Conversely, the smaller the phase current, the smaller the calculated blockage weight value or incomplete blockage weight value, and the larger the calculated target temperature value or incomplete blockage target temperature value.

[0020] Please refer to the embodiment of the calculation of the weight value of this invention. Figure 5 As shown, this is a curve of phase current versus weight value according to the present invention. The blocked weight value or the incomplete blocked weight value is a weight value curve table. This weight value curve table is based on the actual experimental confirmation of the time each phase current can withstand, and is converted into a weight value to be accumulated every millisecond. The blocked weight value is greater than the incomplete blocked weight value. When the load 40 is in a blocked state, the microcontroller unit 11 calculates a smaller blocked weight value based on the larger the phase current value detected by the phase current detection unit 13. When the phase current is 180 Arms, the calculated blocked weight value is 33; when the phase current is 160 Arms, the blocked weight value is 29; when the phase current is 140 Arms, the blocked weight value is 25… and so on. When the phase current is 60 Arms, the blocked weight value is 7, and so on. Figure 5 The curve showing the blocking weight value is 51.

[0021] Similarly, when load 40 is in a partially blocked state, the larger the phase current value, the smaller the incomplete blockage weight calculated by the microcontroller 11. When the phase current is 180 Arms, the calculated incomplete blockage weight is 24; when the phase current is 160 Arms, the incomplete blockage weight is 21; when the phase current is 140 Arms, the incomplete blockage weight is 18… and so on. When the phase current is 60 Arms, the blockage weight is 5. Figure 5 The incompletely blocked weight value curve 52 is shown.

[0022] Please refer to the embodiment of the calculation of the target temperature value of the present invention. Figure 6 As shown, this is a phase current versus target temperature curve of the present invention. The microcontroller unit 11 of the present invention determines the temperature at which the motor driver 10 needs to intervene based on the phase current magnitude versus the temperature curve of the motor driver 10. The target temperature curve table is a set of target temperature values, where the time each phase current can withstand is determined based on actual experiments and converted into a weighted value to be accumulated every millisecond. Furthermore, the target temperature curve table for phase current is less than the target temperature curve for partial phase current.

[0023] When load 40 is in a blocked state, the smaller the phase current value detected by the phase current detection unit 13, the larger the calculated blockage target temperature value. When the phase current is 180 Arms, the calculated blockage target temperature value is 36; when the phase current is 160 Arms, the blockage target temperature value is 40; when the phase current is 140 Arms, the blockage target temperature value is 44… and so on. When the phase current is 60 Arms, the blockage target temperature value is 60. Figure 6 The target temperature value curve shown is 61.

[0024] Similarly, when load 40 is in a partially blocked state, the smaller the phase current value, the higher the incomplete blockage target temperature calculated by the microcontroller 11. When the phase current is 180 Arms, the calculated incomplete blockage target temperature is 60; when the phase current is 160 Arms, the incomplete blockage target temperature is 64; when the phase current is 140 Arms, the incomplete blockage target temperature is 69… and so on. When the phase current is 60 Arms, the blockage target temperature is 86. Figure 6 The target temperature value curve shown is 62, indicating incomplete blockage.

[0025] Please refer to this document as well. Figure 2 and Figure 4As shown, the microcontroller unit 11 controls the temperature detection unit 14 to detect the temperature of the motor driver 10 and compare it with the target temperature value of complete blockage or the target temperature value of incomplete blockage. If the motor driver temperature is greater than the target temperature value of complete blockage (S414) or greater than the target temperature value of incomplete blockage (S424), it is then determined whether the weight value of complete blockage or the weight value of incomplete blockage exceeds an accumulated weight value (S430). Preferably, the accumulated weight value is 20000. If so, the power supply to the motor driver 10 is turned off to protect the power element.

[0026] When the load is in a blocked state, if the speed detection unit 12 detects that the motor speed is not less than the first speed value, that is, the speed is greater than 10 rpm, then the microcontroller unit 11 deducts the accumulated weight value of the blocked state (S415). When the load is in a partially blocked state, if the speed detection unit 12 detects that the motor speed is not less than the second speed value, that is, the speed is greater than 170 rpm, then the microcontroller unit 11 deducts the accumulated weight value of the partially blocked state (S425).

[0027] When the load is in a blocked state, if the phase current detection unit 13 detects that the phase current of the three-phase power element 20 and the motor speed is less than the first phase current value, that is, the phase current is less than 60 Arms, then the microcontroller unit 11 deducts the accumulated weight value of the blocked state (S415). When the load is in a partially blocked state, if the phase current detection unit 13 detects that the phase current of the three-phase power element 20 and the motor speed is less than the first phase current value, that is, the phase current is less than 60 Arms, then the microcontroller unit 11 deducts the accumulated weight value of the partially blocked state (S425).

[0028] When the load is in a blocked state, if the temperature detection unit 14 detects that the temperature of the motor driver 10 is less than the blocked target temperature value, the microcontroller unit 11 deducts the accumulated weight value of the blocked state (S415). When the load is in a partially blocked state, if the temperature detection unit 14 detects that the temperature of the motor driver 10 is less than the partially blocked target temperature value, the microcontroller unit 11 deducts the accumulated weight value of the partially blocked state (S425).

[0029] Please see Figure 7 As shown, this is a phase current-temperature-weight value curve of an embodiment of the incomplete load blocking of the present invention. In the state of incomplete load blocking 40, the target temperature value for incomplete blocking is determined via the phase current; when the temperature of the motor driver 10 reaches the target temperature value for incomplete blocking, the current weight value is determined via the phase current, such as a weight of 24 for 180 Arms. The weight value is continuously accumulated until it reaches 20000, at which point protection is triggered to shut down the motor driver. Figure 7It is known that the larger the phase current, the smaller the temperature detected, and the larger the weight value at this time. In this state, it only takes 2 seconds to accumulate the weight value to reach 20000, triggering the protection to shut down the motor driver; conversely, the smaller the phase current, the larger the temperature detected, and the smaller the weight value at this time. In this state, it takes 10 seconds to accumulate the weight value to reach 20000, triggering the protection to shut down the motor driver.

[0030] Please see Figure 8 As shown, this is a phase current-temperature-weight value curve of an embodiment of the load blocking of the present invention. In the state of load 40 blocking, the target blocking temperature value to be determined is obtained through the phase current; when the temperature of the motor driver 10 reaches the target blocking temperature value, the current weight value is obtained through the phase current, such as a weight of 33 for 180 Arms. The weight value is continuously accumulated until it reaches 20000, triggering protection to shut down the motor driver. Figure 8 It is known that the larger the phase current, the smaller the temperature detected, and the larger the weight value at this time. In this state, the weight value only needs 1 second to accumulate to 20000, triggering the protection to shut down the motor driver; conversely, the smaller the phase current, the larger the temperature detected, and the smaller the weight value at this time. In this state, the weight value only needs 5 seconds to accumulate to 20000, triggering the protection to shut down the motor driver.

[0031] In summary, the advantages of this invention are that it can identify the vehicle's condition when encountering road obstructions, ensuring that the electric vehicle will not mistakenly stop the load due to excessive current when encountering a slope, and preventing damage to power components caused by overheating of the motor driver when the load is blocked. Therefore, this invention is not only innovative in its technical concept, but also enhances the aforementioned multiple benefits compared to existing technologies.

Claims

1. A load line discrimination method for a motor drive having three phase power elements driving a motor to operate a load, the method comprising the steps of: The method includes at least: ​ The motor's rotational speed is detected. If it is less than a first rotational speed value, it indicates that the load is blocked. If it is greater than the first rotational speed value and less than a second rotational speed value, it indicates that the load is not completely blocked. If the current of one phase of the three-phase power element is greater than a first phase current value, a blocking weight value or a partial blocking weight value is calculated based on the magnitude of that phase current, and a blocking target temperature value or a partial blocking target temperature value is also calculated based on the magnitude of that phase current; and If the temperature of the motor driver is detected and is greater than the target temperature for complete blockage or the target temperature for incomplete blockage, it is determined whether the blockage weight value or the incomplete blockage weight value exceeds an accumulated weight value. If so, the power supply to the motor driver is shut off to protect the power component.

2. The load line resistance discrimination method for a motor driver according to claim 1, wherein Also includes: A speed detection unit is provided and connected to the motor to detect the speed; A phase current detection unit is provided and connected to the three-phase power element to detect the magnitude of the phase current; and A temperature detection unit is provided and connected to the three-phase power element to detect the temperature.

3. The load line resistance discrimination method for a motor driver according to claim 1, wherein The first speed value is 10 rpm, and the second speed value is 170 rpm.

4. The load line resistance discrimination method for a motor driver according to claim 1, wherein The effective value of the first phase current is 60 amperes, or 60 Arms.

5. The load line resistance discrimination method for a motor driver according to claim 1, wherein The blocking weight value or the incomplete blocking weight value is calculated based on the phase current. The larger the phase current, the larger the blocking weight value or the incomplete blocking weight value, and the smaller the calculated blocking target temperature value or the incomplete blocking target temperature value. Conversely, the smaller the phase current, the smaller the blocking weight value or the incomplete blocking weight value, and the larger the calculated blocking target temperature value or the incomplete blocking target temperature value.

6. The load resistance identification method for a motor driver as described in claim 1, characterized in that, The blocked weight value or the incomplete blocked weight value is a weight value curve table. The weight value curve table is based on the actual test to confirm the time that the current of each phase can withstand, and is converted into a weight value that needs to be accumulated every millisecond. The blocked weight value is greater than the incomplete blocked weight value.

7. The load resistance identification method for a motor driver as described in claim 1, characterized in that, The target temperature value for complete blockage or a target temperature value for incomplete blockage is a target temperature curve table. The target temperature curve table is based on the actual test to confirm the time that the current of each phase can withstand, and is converted into the target temperature that needs to be accumulated every millisecond. The target temperature value for complete blockage is less than the target temperature value for incomplete blockage.

8. The load resistance identification method for a motor driver as described in claim 1, characterized in that, The cumulative weight value is 20000.

9. The load resistance identification method for a motor driver as described in claim 1, characterized in that, Also includes: If the detected rotational speed is greater than the second rotational speed value, the blocked weight value or the incomplete blocked weight value is deducted.

10. The load resistance identification method for a motor driver as described in claim 1, characterized in that, Also includes: When the current of a phase is less than the current of the first phase, the blocking weight value or the incomplete blocking weight value is deducted.

11. The load resistance identification method for a motor driver as described in claim 1, characterized in that, Also includes: If the detected temperature is lower than the target temperature for complete blockage or lower than the target temperature for incomplete blockage, the weight value for complete blockage or incomplete blockage shall be deducted.

12. A power element protection device for a motor driver, characterized in that, The motor drive includes: A three-phase power element drives a motor to power a load. A speed detection unit is connected to the motor to detect a speed of the motor. If the speed is less than a first speed value, it indicates that the load is blocked. If the speed is greater than the first speed value and less than a second speed value, it indicates that the load is not completely blocked. A single-phase current detection unit is connected to the three-phase power element to detect the current of one phase of the three-phase power element. If the current is greater than a first-phase current value, a blocking weight value or a partial blocking weight value is calculated based on the magnitude of the phase current, and a blocking target temperature value or a partial blocking target temperature value is calculated based on the magnitude of the phase current. A temperature detection unit is connected to the three-phase power element to detect the temperature of the motor driver. If the temperature is greater than the target temperature value for complete blockage or the target temperature value for incomplete blockage, it is determined whether the blockage weight value or the incomplete blockage weight value exceeds an accumulated weight value. If so, the power supply to the motor driver is shut off to protect the power element.

13. The power element protection device for the motor driver as described in claim 12, characterized in that, The first speed value is 10 rpm, and the second speed value is 170 rpm.

14. The power element protection device for the motor driver as described in claim 12, characterized in that, The effective value of the first phase current is 60 amperes per millisecond, or 60 Arms.

15. The power element protection device for a motor driver as described in claim 12, characterized in that, The blocking weight value or the incomplete blocking weight value is calculated based on the phase current. The larger the phase current, the larger the blocking weight value or the incomplete blocking weight value, and the smaller the calculated blocking target temperature value or the incomplete blocking target temperature value. Conversely, the smaller the phase current, the smaller the blocking weight value or the incomplete blocking weight value, and the larger the calculated blocking target temperature value or the incomplete blocking target temperature value.

16. The power element protection device for the motor driver as described in claim 12, characterized in that, The blocked weight value or the incomplete blocked weight value is a weight value curve table. The weight value curve table is based on the actual test to confirm the time that the current of each phase can withstand, and is converted into a weight value that needs to be accumulated every millisecond. The blocked weight value is greater than the incomplete blocked weight value.

17. The power element protection device for a motor driver as described in claim 12, characterized in that, The target temperature value for complete blockage or a target temperature value for incomplete blockage is a target temperature curve table. The target temperature curve table is based on the actual test to confirm the time that the current of each phase can withstand, and is converted into the target temperature that needs to be accumulated every millisecond. The target temperature value for complete blockage is less than the target temperature value for incomplete blockage.

18. The power element protection device for the motor driver as described in claim 12, characterized in that, The cumulative weight value is 20000.

19. The power element protection device for a motor driver as described in claim 12, characterized in that, If the rotational speed detection unit detects that the rotational speed is greater than the second rotational speed value, it deducts the blocking weight value or the incomplete blocking weight value.

20. The power element protection device for a motor driver as described in claim 12, characterized in that, When the phase current detection unit detects that the phase current is less than the first phase current value, it deducts the blocking weight value or the incomplete blocking weight value.

21. The power element protection device for a motor driver as described in claim 12, characterized in that, When the temperature detection unit detects that the temperature is lower than the target temperature for complete blockage or lower than the target temperature for incomplete blockage, it deducts the weight value for complete blockage or the weight value for incomplete blockage.

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