Air suspension system and its motor stall protection method and motor controller

Abstract

This invention discloses an air suspension system, its motor stall protection method, and a motor controller. The air suspension system includes an air suspension motor and a frequency converter driving the air suspension motor. The method includes: acquiring temperature change information of the frequency converter when the air suspension system is started; acquiring rotor position change information of the air suspension motor when an abnormal temperature rise of the frequency converter is determined based on the temperature change information; and controlling the air suspension system to stop when a stall occurs in the air suspension motor based on the rotor position change information. The motor stall protection method of this invention determines whether the air suspension motor is stalled based on the temperature change information of the frequency converter and the rotor position change information of the air suspension motor, thereby improving the accuracy of determining air suspension motor stall, and is simple to operate and has a fast protection response.

Description

Technical Field

[0001] This invention relates to the field of motor control technology, and in particular to a method for motor stall protection in an air suspension system, a computer-readable storage medium, a motor controller, and an air suspension system. Background Technology

[0002] Air-bearing frequency converters use refrigerant cooling. The refrigerant cooling only kicks in when the air-bearing motor's speed increases, allowing the frequency converter to cool down. Specifically, if an internal fault in the air-bearing motor causes the rotor to seize, the frequency converter continuously outputs current. Since cooling is ineffective at this time, the internal temperature of the power devices, IGBTs (Insulated Gate Bipolar Transistors), continues to rise and eventually damages them. Therefore, stall protection is essential for air-bearing systems.

[0003] Current technologies calculate the real-time back EMF voltage using the motor's voltage equation and compare it with the theoretical design value. This method is effective only if the voltage equation is accurate, meaning the motor must be operating at medium-to-high speeds with closed-loop speed and current control. However, stalling typically occurs when the motor is stationary, making this method less effective for stall protection and prone to false alarms.

[0004] Furthermore, when implementing over-temperature protection for IGBT power devices, the IGBT can be shut down when the actual detected temperature exceeds the over-temperature setpoint. However, in the event of a true stall, the internal temperature of the IGBT rises rapidly and exceeds the external sampling point temperature, making timely protection impossible and still posing a risk of damaging the IGBT. Summary of the Invention

[0005] This invention aims to at least partially solve one of the technical problems in related technologies. Therefore, the first objective of this invention is to propose a method for motor stall protection in an air-suspension system. This method determines whether the air-suspension motor has stalled based on temperature change information from the frequency converter and rotor position change information from the air-suspension motor. This improves the accuracy of detecting air-suspension motor stall and is simple to operate with a fast protection response.

[0006] A second objective of this invention is to provide a computer-readable storage medium.

[0007] The third objective of this invention is to provide a motor controller.

[0008] The fourth objective of this invention is to provide an air suspension system.

[0009] To achieve the above objectives, a first aspect of the present invention provides a method for motor stall protection in an air suspension system. The air suspension system includes an air suspension motor and a frequency converter driving the air suspension motor. The method includes: acquiring temperature change information of the frequency converter when the air suspension system is started; acquiring rotor position change information of the air suspension motor when the temperature rise of the frequency converter is determined to be abnormal based on the temperature change information; and controlling the air suspension system to stop when the air suspension motor is determined to be stalled based on the rotor position change information.

[0010] According to an embodiment of the present invention, the motor stall protection method for an air suspension system first acquires the temperature change information of the frequency converter when the air suspension system is started. Then, when an abnormal temperature rise of the frequency converter is determined based on the temperature change information, the rotor position change information of the air suspension motor is acquired. Finally, when a stall of the air suspension motor is determined based on the rotor position change information, the air suspension system is controlled to stop. Therefore, this method determines whether the air suspension motor is stalled based on the temperature change information of the frequency converter and the rotor position change information of the air suspension motor, thereby improving the accuracy of determining whether the air suspension motor is stalled. Furthermore, it is simple to operate and has a fast protection response.

[0011] In addition, the motor stall protection method for the air suspension system according to the above embodiments of the present invention may also have the following additional technical features:

[0012] According to one embodiment of the present invention, obtaining temperature change information of the frequency converter includes: obtaining the ambient temperature when the air suspension system is turned on, and obtaining the frequency converter temperature at first preset time intervals; determining the temperature change information of the frequency converter based on the ambient temperature and the obtained multiple frequency converter temperatures.

[0013] According to one embodiment of the present invention, the temperature change information of the frequency converter includes the temperature difference between the first frequency converter temperature and the ambient temperature, and the temperature difference between two adjacent frequency converter temperatures.

[0014] According to one embodiment of the present invention, determining the temperature rise anomaly of the frequency converter based on temperature change information includes: determining the temperature rise anomaly of the frequency converter when multiple temperature differences are all greater than the corresponding temperature rise threshold.

[0015] According to one embodiment of the present invention, obtaining rotor position change information of an air-bearing motor includes: obtaining the first motor rotor position when the air-bearing system is started, and identifying the rotor position of the air-bearing motor when the inverter temperature rises abnormally to obtain the second motor rotor position; and determining rotor position change information based on the first motor rotor position and the second motor rotor position.

[0016] According to one embodiment of the present invention, when the temperature rise of the frequency converter is abnormal, the frequency converter is controlled to stop, and the rotor position of the air suspension motor is identified by voltage vector injection method.

[0017] According to one embodiment of the present invention, determining that the air suspension motor has stalled based on rotor position change information includes: determining that the air suspension motor has stalled when it is determined from the rotor position change information that the rotor position of the air suspension motor has not changed.

[0018] To achieve the above objectives, a second aspect of the present invention provides a computer-readable storage medium storing a motor stall protection program for an air suspension system, which, when executed by a processor, implements the aforementioned motor stall protection method for an air suspension system.

[0019] The computer-readable storage medium of this invention, by executing the above-described motor stall protection method for air suspension systems, can improve the accuracy of judging motor stall, and is simple to operate and has a fast protection response.

[0020] To achieve the above objectives, a third aspect of the present invention provides a motor controller, comprising: a memory, a processor, and a motor stall protection program for an air suspension system stored in the memory and executable on the processor. When the processor executes the motor stall protection program for the air suspension system, the above-described motor stall protection method for the air suspension system is implemented.

[0021] According to the embodiments of the present invention, the motor controller can improve the accuracy of judging the stall of the air suspension motor by executing the above-described motor stall protection method of the air suspension system, and is simple to operate and has a fast protection response.

[0022] To achieve the above objectives, a fourth aspect of the present invention provides an air suspension system, comprising: an air suspension motor; and a motor controller, the motor controller including a frequency converter for driving the air suspension motor, and performing stall protection control on the air suspension motor by executing the above-described motor stall protection method for the air suspension system.

[0023] According to the air suspension system of the present invention, the frequency converter of the air suspension motor is driven by the motor controller, and the motor stall protection method of the air suspension system described above is executed, which can improve the accuracy of judging the stall of the air suspension motor, and the operation is simple and the protection response is fast.

[0024] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0025] Figure 1 This is a flowchart of a motor stall protection method for an air suspension system according to an embodiment of the present invention;

[0026] Figure 2A flowchart illustrating a motor stall protection method for an air suspension system according to a specific example of the present invention;

[0027] Figure 3 This is a block diagram of a motor controller according to an embodiment of the present invention;

[0028] Figure 4 This is a block diagram of an air suspension system according to an embodiment of the present invention. Detailed Implementation

[0029] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0030] The following description, with reference to the accompanying drawings, outlines the motor stall protection method, computer-readable storage medium, motor controller, and air suspension system proposed in this invention.

[0031] like Figure 1 As shown, the motor stall protection method of the air suspension system in this embodiment of the invention may include the following steps:

[0032] S1 acquires the temperature change information of the frequency converter when the air suspension system is turned on.

[0033] According to one embodiment of the present invention, obtaining temperature change information of the frequency converter includes: obtaining the ambient temperature when the air suspension system is started, and obtaining the frequency converter temperature at first preset time intervals; determining the temperature change information of the frequency converter based on the ambient temperature and the obtained multiple frequency converter temperatures. The first preset time interval can be determined according to actual conditions; for example, the first preset time interval can be 5 seconds.

[0034] According to one embodiment of the present invention, the temperature change information of the frequency converter includes the temperature difference between the first frequency converter temperature and the ambient temperature, and the temperature difference between two adjacent frequency converter temperatures.

[0035] Specifically, when the air suspension system is started, the ambient temperature at that time is acquired. For example, the ambient temperature at the start of the air suspension system can be measured by a temperature sensor and denoted as T0. After the air suspension system is started and running, the frequency converter adjusts the voltage and frequency of the output power supply by switching its internal IGBTs, continuously outputting an appropriate current to drive the air suspension motor. While the air suspension motor is running, the frequency converter temperature can be acquired at first preset intervals. For example, the frequency converter temperature at the fifth second after the air suspension system starts and running can be acquired by a temperature sensor and denoted as T1 (the first frequency converter temperature); the frequency converter temperature at the tenth second after the air suspension system starts and running (five seconds after the first frequency converter temperature) can be acquired by a temperature sensor and denoted as T2 (the second frequency converter temperature); and the frequency converter temperature at the fifteenth second after the air suspension system starts and running (five seconds after the second frequency converter temperature) can be acquired by a temperature sensor and denoted as T3. After obtaining the inverter temperatures at different times, the inverter temperature change information can be determined based on the ambient temperature T0 and the temperatures of multiple inverters (T1, T2, and T3). Specifically, the inverter temperature change information is the temperature difference between the first inverter temperature T1 and the ambient temperature T0, denoted as DeltaT1, where DeltaT1 = T1 - T0; the temperature difference between the first and second inverter temperatures, denoted as DeltaT2; and the temperature difference between the second and third inverter temperatures, denoted as DeltaT3, where DeltaT2 = T2 - T1 and DeltaT3 = T3 - T2.

[0036] S2, when the temperature rise of the frequency converter is abnormal based on the temperature change information, obtain the rotor position change information of the air suspension motor.

[0037] According to one embodiment of the present invention, determining the temperature rise anomaly of the frequency converter based on temperature change information includes: determining the temperature rise anomaly of the frequency converter when multiple temperature differences are all greater than the corresponding temperature rise threshold.

[0038] Specifically, through the above step S1, the temperature change information of the frequency converter can be obtained, and whether the temperature rise of the frequency converter is abnormal can be determined based on the temperature change information of the frequency converter. When multiple temperature differences are greater than their corresponding temperature rise thresholds, for example, when DeltaT1>DeltaT1_norm, DeltaT2>DeltaT2_norm, and DeltaT3>DeltaT3_norm, it is determined that the temperature rise of the frequency converter is abnormal, and the motor may be in a stalled state. Here, DeltaT1_norm is the temperature rise threshold of the frequency converter within 0 - 5 seconds when the air suspension system starts up and runs normally, DeltaT2_norm is the temperature rise threshold of the frequency converter within 5 - 10 seconds when the air suspension system starts up and runs normally, DeltaT3_norm is the temperature rise threshold of the frequency converter within 10 - 15 seconds when the air suspension system starts up and runs normally. The values of DeltaT1_norm, DeltaT2_norm, and DeltaT3_norm can be determined through a large amount of test data. For example, the average value can be taken through multiple tests in the same time period to determine the temperature rise threshold within a certain time period. When one of the temperature differences is less than its corresponding temperature rise threshold, for example, when DeltaT1<DeltaT1_norm, or DeltaT2<DeltaT2_norm, or DeltaT3<DeltaT3_norm, or when multiple temperature differences are less than their corresponding temperature rise thresholds, for example, when DeltaT1<DeltaT1_norm and DeltaT2<DeltaT2_norm, or DeltaT1<DeltaT1_norm and DeltaT3<DeltaT3_norm, or DeltaT2<DeltaT2_norm and DeltaT3<DeltaT3_norm, or DeltaT1<DeltaT1_norm, DeltaT2<DeltaT2_norm, and DeltaT3<DeltaT3_norm, it can be determined that the temperature rise of the frequency converter is normal, the motor has not stalled, and the air suspension system is running normally.

[0039] According to an embodiment of the present invention, obtaining the rotor position change information of the air suspension motor includes: obtaining the first motor rotor position when the air suspension system is powered on, and identifying the rotor position of the air suspension motor when the temperature rise of the frequency converter is abnormal to obtain the second motor rotor position; determining the rotor position change information based on the first motor rotor position and the second motor rotor position.

[0040] According to an embodiment of the present invention, when the temperature rise of the frequency converter is abnormal, control the frequency converter to stop, and use the voltage vector injection method to identify the rotor position of the air suspension motor.

[0041] Specifically, when determining an abnormal temperature rise in the frequency converter based on temperature change information, the rotor position change information of the air-bearing motor can also be obtained. This information is used to further determine whether the air-bearing motor is stalled, thus preventing the motor from mistakenly entering stall protection and affecting the normal operation of the air-bearing system. The rotor position of the first motor at startup of the air-bearing system is obtained; for example, this can be detected by a position sensor and denoted as Pos0. When the frequency converter experiences an abnormal temperature rise, it is controlled to stop, and the motor control mode is switched to PWM (Pulse Width Modulation) control mode. The current rotor position of the air-bearing motor is detected using a voltage vector injection method. For example, by injecting a pulsed voltage vector into the synchronous shaft, the high-frequency current response caused by the rotor's salient poles is detected, and the position error signal is decoupled, thus achieving rotor position observation, denoted as Pos1. After obtaining the first motor rotor position Pos0 and the second motor rotor position Pos1, rotor position change information can be determined based on Pos0 and Pos1.

[0042] S3, when it is determined that the air suspension motor has stalled based on the rotor position change information, controls the air suspension system to stop.

[0043] According to one embodiment of the present invention, determining that the air suspension motor has stalled based on rotor position change information includes: determining that the air suspension motor has stalled when it is determined from the rotor position change information that the rotor position of the air suspension motor has not changed.

[0044] Specifically, the rotor positions Pos0 and Pos1 of the first and second motors are obtained from step S2. When the absolute value of the difference between Pos0 and Pos1 is less than PosThreshold, it is determined that the rotor position of the air-bearing motor has not changed, indicating that the air-bearing motor is stalled. The air-bearing system is then controlled to report a fault and shut down to ensure that internal components are not damaged. The value of PosThreshold is determined by the number of injected PWM pulses using the voltage vector injection method. Conversely, when the absolute value of the difference between Pos0 and Pos1 is greater than or equal to PosThreshold, it is determined that the rotor position of the air-bearing motor has changed, indicating that the air-bearing motor is not stalled, and the air-bearing system can enter the operating state.

[0045] The following is combined with Figure 2 The protection method of the present invention will be described below.

[0046] As a specific example, the motor stall protection method of the air suspension system of the present invention may include the following steps:

[0047] S101, air suspension system activated.

[0048] S102, detects ambient temperature T0 and motor rotor position Pos0.

[0049] S103, detect the inverter temperature T1 in the fifth second, and calculate the temperature difference DeltaT1=T1-T0.

[0050] S104, detect the inverter temperature T2 at the tenth second, and calculate the temperature difference DeltaT2=T2-T1.

[0051] S105, at the fifteenth second, detect the inverter temperature T3 and calculate the temperature difference DeltaT3=T3-T2.

[0052] S106, determine whether multiple temperature differences are all greater than the corresponding temperature rise threshold. If yes, proceed to step S107; if no, proceed to step S111.

[0053] S107: The inverter temperature rise is found to be abnormal, and the inverter is stopped. The motor control mode is switched to PWM control mode.

[0054] S108 uses the voltage vector injection method to detect the current motor rotor position Pos1.

[0055] S109, determine whether the absolute value of the difference between Pos1 and Pos0 is less than PosThreshold. If yes, proceed to step S110; otherwise, proceed to step S111. PosThreshold is determined by the number of injected PWM pulses in the voltage vector injection method.

[0056] S110, the air suspension motor stalled, reported a fault, and controlled the air suspension system to shut down.

[0057] S111, the air suspension motor did not stall, and the air suspension system entered the operating state.

[0058] In summary, the motor stall protection method for an air suspension system according to an embodiment of the present invention first acquires the temperature change information of the frequency converter when the air suspension system is started. Then, when an abnormal temperature rise of the frequency converter is determined based on the temperature change information, the rotor position change information of the air suspension motor is acquired. Finally, when a stall of the air suspension motor is determined based on the rotor position change information, the air suspension system is controlled to stop. Therefore, this method determines whether the air suspension motor is stalled based on the temperature change information of the frequency converter and the rotor position change information of the air suspension motor, thereby improving the accuracy of determining whether the air suspension motor is stalled. Furthermore, it is simple to operate and has a fast protection response.

[0059] Corresponding to the above embodiments, the present invention also proposes a computer-readable storage medium.

[0060] The computer-readable storage medium of this invention stores a motor stall protection program for an air suspension system. When the motor stall protection program for the air suspension system is executed by a processor, it implements the above-described motor stall protection method for the air suspension system.

[0061] The computer-readable storage medium of this invention, by executing the above-described motor stall protection method for air suspension systems, can improve the accuracy of judging motor stall, and is simple to operate and has a fast protection response.

[0062] Corresponding to the above embodiments, the present invention also proposes a motor controller.

[0063] like Figure 3 As shown, the motor controller 200 of this embodiment may include: a memory 210, a processor 220, and a motor stall protection program for the air suspension system stored in the memory 210 and executable on the processor 220. When the processor 220 executes the motor stall protection program for the air suspension system, it implements the above-mentioned motor stall protection method for the air suspension system.

[0064] The motor controller of this invention, by executing the above-described motor stall protection method for the air suspension system, can improve the accuracy of judging the stall of the air suspension motor, and is simple to operate and has a fast protection response.

[0065] Corresponding to the above embodiments, the present invention also proposes an air suspension system 100.

[0066] like Figure 4 As shown, the air suspension system 100 of this embodiment may include an air suspension motor 110 and a motor controller 200. The motor controller 200 includes a frequency converter for driving the air suspension motor 110, and performs stall protection control on the air suspension motor 110 by executing the aforementioned motor stall protection method of the air suspension system 100.

[0067] According to the air suspension system proposed in the embodiments of the present invention, the frequency converter of the air suspension motor is driven by the motor controller, and the motor stall protection method of the air suspension system described above can be executed to improve the accuracy of judging the stall of the air suspension motor. Moreover, the operation is simple and the protection response is fast.

[0068] It should be noted that the logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include: an electrical connection having one or more wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Alternatively, the computer-readable medium may be paper or other suitable media on which the program can be printed, since the program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in a computer memory.

[0069] It should be understood that various parts of the present invention can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0070] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0071] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0072] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0073] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for motor stall protection in an air suspension system, characterized in that, The air suspension system includes an air suspension motor and a frequency converter that drives the air suspension motor; the method includes: When the air suspension system is turned on, the temperature change information of the frequency converter is acquired; When the temperature rise of the frequency converter is determined to be abnormal based on the temperature change information, the rotor position change information of the air suspension motor is obtained; When it is determined that the air suspension motor has stalled based on the rotor position change information, the air suspension system is controlled to stop. Obtaining the temperature change information of the frequency converter includes: The ambient temperature when the air suspension system is turned on is obtained, and the inverter temperature is obtained every first preset time interval; The temperature change information of the frequency converter is determined based on the ambient temperature and the acquired temperatures of multiple frequency converters. When the temperature rise of the frequency converter is abnormal, the frequency converter is controlled to stop, and the rotor position of the air suspension motor is identified by voltage vector injection method. The temperature change information of the frequency converter includes the temperature difference between the first frequency converter temperature and the ambient temperature, and the temperature difference between two adjacent frequency converter temperatures.

2. The method according to claim 1, characterized in that, Determining abnormal temperature rise in the frequency converter based on the temperature change information includes: When multiple temperature differences are greater than the corresponding temperature rise threshold, the temperature rise of the frequency converter is determined to be abnormal.

3. The method according to any one of claims 1-2, characterized in that, Obtaining the rotor position change information of the air-suspended motor includes: The first motor rotor position is obtained when the air suspension system is started, and the rotor position of the air suspension motor is identified when the temperature rise of the frequency converter is abnormal, so as to obtain the second motor rotor position. The rotor position change information is determined based on the rotor positions of the first motor and the second motor.

4. The method according to claim 3, characterized in that, Determining that the air-suspended motor has stalled based on the rotor position change information includes: If the rotor position of the air-suspended motor does not change based on the rotor position change information, it is determined that the air-suspended motor has stalled.

5. A computer-readable storage medium, characterized in that, It stores a motor stall protection program for an air suspension system, which, when executed by a processor, implements the motor stall protection method for an air suspension system according to any one of claims 1-4.

6. A motor controller, characterized in that, The system includes a memory, a processor, and a motor stall protection program for an air suspension system stored in the memory and executable on the processor. When the processor executes the motor stall protection program for the air suspension system, it implements the motor stall protection method for the air suspension system according to any one of claims 1-4.

7. An air suspension system, characterized in that, include: Air-suspended motor; A motor controller, comprising a frequency converter for driving the air-suspension motor, and performing stall protection control on the air-suspension motor by executing the motor stall protection method for the air-suspension system according to any one of claims 1-4.

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