A method for detecting open phase of a three-phase motor
By using a high-speed permanent magnet synchronous motor and its controller, and utilizing a two-phase current sensor and a half-bridge PWM square wave difference to detect phase loss in a three-phase motor, the problems of resource waste and long detection time in existing technologies are solved, and simplified control and rapid detection are achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- TIANJIN YUNQU TECH CO LTD
- Filing Date
- 2023-04-25
- Publication Date
- 2026-05-19
AI Technical Summary
Existing methods for detecting phase loss in three-phase motors require current acquisition, which wastes resources, involves complex control algorithms, and results in long detection times.
A high-speed permanent magnet synchronous motor and its controller are adopted. Phase loss is detected by two-phase current sensors and half-bridge PWM square wave difference, which simplifies the control algorithm and reduces resource utilization.
It achieves simplified control algorithms, reduced resource consumption, improved detection speed, strong adaptability, and high anti-snagging capability.
Smart Images
Figure CN116482450B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of motor phase loss detection technology, and in particular to a method for detecting phase loss in a three-phase motor. Background Technology
[0002] Current methods for detecting phase loss in three-phase motors mainly employ constant current detection. This involves supplying a small-amplitude constant current excitation source to the three-phase motor and using current sensors to detect various current values. By analyzing and calculating the acquired current values, it is determined whether the three-phase motor is experiencing a phase loss. This method requires simultaneous current acquisition functions (U / V / W) on all three-phase output circuits, resulting in resource waste. Furthermore, the constant current excitation source control algorithm of this method is relatively complex, leading to high system resource occupancy and long detection time. Therefore, this application proposes a new method for detecting phase loss in three-phase motors to address the aforementioned problems of complex control algorithms, resource waste, high system resource occupancy, and long detection time. Summary of the Invention
[0003] In view of the above-mentioned defects or deficiencies in the prior art, it is desirable to provide a method for detecting phase loss in a three-phase motor.
[0004] This invention provides a method for detecting phase loss in a three-phase motor. The method utilizes a high-speed permanent magnet synchronous motor and its controller to achieve phase loss detection. The controller includes an electrically connected data processing module, a three-phase full-bridge module, a current acquisition module, a communication module, a host computer control terminal, a low-voltage power supply module, and a high-voltage power supply. The detection method includes the following steps:
[0005] 1) Connect the controller to the high-speed permanent magnet synchronous motor, power supply, and communication hardware lines. After checking that everything is correct, supply power.
[0006] 2) The host computer control terminal obtains the high-voltage power supply voltage and fault status data information fed back by the controller through the communication module. After confirming that the data is correct, it proceeds to the next step.
[0007] 3) The host computer control terminal sends a phase loss detection start command to the controller. After receiving the command, the controller executes the phase loss detection function.
[0008] The execution flow of the phase loss detection function is as follows: the controller defaults to shutting down PWM1, PWM2, PWM3, PWM4, PWM5, and PWM6 bridge arms, at which point no current signal flows through the current sensor; and the upper and lower bridge arms of the half-bridge adopt complementary control logic; the complementary control logic is to turn on PWM1 bridge arm and turn off PWM2 bridge arm to avoid the upper and lower bridge arms from being directly connected and burning out the circuit; the principle of PWM3 and PWM4 and PWM5 and PWM6 is the same as that of PWM1 and PWM2.
[0009] The execution flow of the phase loss detection function includes the following steps:
[0010] 31) Turn off PWM5 and PWM6 bridge arms to prevent current from flowing through this half-bridge; obtain the current value taria of the current sensor flowing through phase Ia as the previous comparison value; the controller controls PWM1 bridge arm to output a 50% duty cycle square wave and PWM3 bridge arm to output a 48% duty cycle square wave, which is equivalent to a 2% duty cycle bus voltage acting on the motor. Obtain the current value curia of the current sensor for phase Ia. By calculating the difference between curia and taria, determine whether there is a phase loss problem in the U / V phases. If the difference is less than the safe value, it is determined to be a phase loss; otherwise, it is normal.
[0011] 32) Turn off PWM1 and PWM2 bridge arms to prevent current from flowing through this half-bridge; obtain the current value taric of the Ic phase current sensor as the previous comparison value; the controller controls the PWM5 bridge arm to output a 50% duty cycle square wave and the PWM3 bridge arm to output a 48% duty cycle square wave, which is equivalent to the bus voltage with a 2% duty cycle acting on the motor. Obtain the current value curic of the Ic phase current sensor. By calculating the difference between curic and taric, determine whether there is a phase loss problem in the W / V phases. If the difference is less than the safety value, it is determined to be a phase loss; otherwise, it is normal.
[0012] 33) Determine whether there is a phase loss problem in the three phases U, V and W. The controller will feed back the detection results to the host computer control terminal through the communication module.
[0013] Preferably, the communication module is a CAN communication module.
[0014] Compared with the prior art, the beneficial effects of the present invention are:
[0015] The three-phase motor phase loss detection method of the present invention uses a two-phase current sensor (U / W) and controls the phase current flowing through the three-phase motor through two sets of half-bridge PWM square wave difference. The control algorithm is simple, has low resource consumption, and short detection time. The voltage control method using PWM square wave difference has strong signal anti-winding capability, and the system is not limited by the difference of the power supply voltage system, so it has high adaptability.
[0016] It should be understood that the description in the Summary of the Invention is not intended to limit the key or essential features of the embodiments of the present invention, nor is it intended to restrict the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description
[0017] Other features, objects, and advantages of the invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:
[0018] Figure 1 This is a circuit diagram for phase loss detection in a three-phase motor. Detailed Implementation
[0019] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings.
[0020] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.
[0021] This invention adds a phase loss detection algorithm to the existing position vector control of a high-speed permanent magnet synchronous motor. This algorithm is used to solve the problem that phase loss detection cannot be achieved due to the limitations of internal hardware resources and space in the controller. The algorithm realizes the phase loss detection function of the motor by leveraging the existing platform.
[0022] Please refer to Figure 1 The present invention provides a method for detecting phase loss in a three-phase motor. The method uses a high-speed permanent magnet synchronous motor and its controller to realize the phase loss detection function of the three-phase motor. The controller includes a data processing module, a three-phase full-bridge module, a current acquisition module, a communication module, a host computer control terminal, a low-voltage power supply module, and a high-voltage power supply.
[0023] The data processing module is responsible for collecting and processing data information and executing corresponding control actions. It uses the TMS320F28335 chip as the core processing unit and is responsible for coordinating the CAN communication module parsing, three-phase output current signal acquisition, high-voltage input voltage acquisition, and enhanced pulse debugging module ePWM module signal output control.
[0024] The three-phase full-bridge module is responsible for controlling the phase-to-phase energizing sequence of the high-speed permanent magnet synchronous motor. It uses high-speed silicon carbide (SiC) as the power device and adopts a single-tube parallel process mode to form a three-phase full-bridge circuit. This circuit controls the output current direction by controlling the on / off state of the bridge arms.
[0025] The current acquisition module is responsible for acquiring the line current of the high-speed permanent magnet synchronous motor; the current acquisition module uses voltage output Hall devices to accurately acquire the three-phase output current signal;
[0026] The communication module is responsible for communication between the host computer control terminal and the data processing module, and completes the transmission of communication protocol commands. The communication module adopts a high-speed isolated CAN communication scheme, which has strong anti-interference ability and good data stability.
[0027] The host computer control terminal is responsible for initiating the phase loss detection command and feeding back the execution result to the host computer control terminal; the host computer control terminal is written in industrial control software LabVIEW and uses a CAN communication module to realize information interaction with the control unit;
[0028] The low-voltage power supply module is responsible for voltage conversion between low-voltage components in the system; the low-voltage power supply module is responsible for supplying power to the low-voltage components in the control system, converting the supply voltage DC24 to DC±15V, DC12V, DC3.3V, DC1.9V and other voltages.
[0029] The high-voltage power supply is responsible for supplying power to the high-voltage power supply section of the system; the high-voltage power supply is responsible for providing high-voltage power to the three-phase full-bridge circuit, with the voltage set to DC500V.
[0030] The detection method includes the following steps:
[0031] 1) Connect the controller to the high-speed permanent magnet synchronous motor, power supply, communication and other hardware lines, and power on after checking that everything is correct;
[0032] 2) The host computer control terminal obtains data information such as high voltage supply voltage and fault status fed back by the controller through the communication module. After confirming that the data is correct, it proceeds to the next step.
[0033] 3) The host computer control terminal sends a phase loss detection start command to the controller. After receiving the command, the controller executes the phase loss detection function.
[0034] The execution flow of the phase loss detection function is as follows: the controller defaults to shutting down PWM1, PWM2, PWM3, PWM4, PWM5, and PWM6 bridge arms, at which point no current signal flows through the current sensor; and the upper and lower bridge arms of the half-bridge adopt complementary control logic; the complementary control logic is to turn on PWM1 bridge arm and turn off PWM2 bridge arm to avoid the upper and lower bridge arms from being directly connected and burning out the circuit; the principle of PWM3 and PWM4 and PWM5 and PWM6 is the same as that of PWM1 and PWM2.
[0035] The execution flow of the phase loss detection function includes the following steps:
[0036] 31) Turn off both PWM5 and PWM6 bridge arms to prevent current from flowing through this half-bridge; obtain the current value (taria) currently flowing through the Ia phase current sensor, and the direction of flow is as follows: Figure 1 As shown by the middle arrow ①, this is used as the initial comparison value; the controller controls the PWM1 bridge arm to output a 50% duty cycle square wave, and the PWM3 bridge arm to output a 48% duty cycle square wave. This is equivalent to a 2% duty cycle bus voltage being applied to the motor, and the resulting current flows as follows. Figure 1As shown by the middle arrow ②, obtain the current value curia of the phase Ia current sensor. By calculating the difference between curia and taria, determine whether there is a phase loss problem in the U / V phases. If the difference is less than the safe value, it is determined to be a phase loss; otherwise, it is normal.
[0037] 32) Turn off both PWM1 and PWM2 bridge arms to prevent current from flowing through this half-bridge; obtain the current value (taric) currently flowing through the Ic phase current sensor, and the flow direction is as follows: Figure 1 As shown by arrow ③, this is used as the initial comparison value; the controller controls the PWM5 bridge arm to output a 50% duty cycle square wave, and the PWM3 bridge arm to output a 48% duty cycle square wave. This is equivalent to a 2% duty cycle bus voltage being applied to the motor, and the resulting current flows as follows. Figure 1 As shown by arrow ④, the current value curic of the Ic phase current sensor is obtained. The difference between curic and taric is calculated to determine whether there is a phase loss problem in the W / V phases. If the difference is less than the safe value, it is determined to be a phase loss; otherwise, it is normal.
[0038] 33) Determine whether there is a phase loss problem in the three phases U, V and W. The controller will feed back the detection results to the host computer control terminal through the communication module.
[0039] Preferably, the communication module is a CAN communication module.
[0040] In the description of this specification, the terms "connection," "installation," and "fixing," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.
[0041] In the description of this specification, the terms "one embodiment," "some embodiments," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. 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.
[0042] The above are merely preferred embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.
Claims
1. A method for detecting phase loss in a three-phase motor, characterized in that, A three-phase motor phase loss detection function is implemented using a high-speed permanent magnet synchronous motor and its controller. The controller includes an electrically connected data processing module, a three-phase full-bridge module, a current acquisition module, a communication module, a host computer control terminal, a low-voltage power supply module, and a high-voltage power supply. The detection method includes the following steps: 1) Connect the controller to the high-speed permanent magnet synchronous motor, power supply, and communication hardware lines. After checking that everything is correct, supply power. 2) The host computer control terminal obtains the high-voltage power supply voltage and fault status data information fed back by the controller through the communication module. After confirming that the data is correct, it proceeds to the next step. 3) The host computer control terminal sends a phase loss detection start command to the controller. After receiving the command, the controller executes the phase loss detection function. The execution flow of the phase loss detection function is as follows: the controller defaults to shutting down PWM1, PWM2, PWM3, PWM4, PWM5, and PWM6 bridge arms, at which point no current signal flows through the current sensor; and the upper and lower bridge arms of the half-bridge adopt complementary control logic; the complementary control logic is to turn on PWM1 bridge arm and turn off PWM2 bridge arm to avoid the upper and lower bridge arms from being directly connected and burning out the circuit; the principle of PWM3 and PWM4 and PWM5 and PWM6 is the same as that of PWM1 and PWM2. The execution flow of the phase loss detection function includes the following steps: 31) Turn off PWM5 and PWM6 bridge arms to prevent current from flowing through this half-bridge; obtain the current value taria of the current sensor flowing through phase Ia as the previous comparison value; the controller controls PWM1 bridge arm to output a 50% duty cycle square wave and PWM3 bridge arm to output a 48% duty cycle square wave, which is equivalent to a 2% duty cycle bus voltage acting on the motor. Obtain the current value curia of the current sensor for phase Ia. By calculating the difference between curia and taria, determine whether there is a phase loss problem in the U / V phases. If the difference is less than the safe value, it is determined to be a phase loss; otherwise, it is normal. 32) Turn off PWM1 and PWM2 bridge arms to prevent current from flowing through this half-bridge; obtain the current value taric of the Ic phase current sensor as the previous comparison value; the controller controls the PWM5 bridge arm to output a 50% duty cycle square wave and the PWM3 bridge arm to output a 48% duty cycle square wave, which is equivalent to the bus voltage with a 2% duty cycle acting on the motor. Obtain the current value curic of the Ic phase current sensor. By calculating the difference between curic and taric, determine whether there is a phase loss problem in the W / V phases. If the difference is less than the safety value, it is determined to be a phase loss; otherwise, it is normal. 33) Determine whether there is a phase loss problem in the three phases U, V and W. The controller will feed back the detection results to the host computer control terminal through the communication module.
2. The method for detecting phase loss in a three-phase motor according to claim 1, characterized in that, The communication module uses a CAN communication module.