Device for detecting loss of synchronization in synchronous motor and method therefor

Abstract

The present invention relates to a device and a method for detecting loss of synchronization in a synchronous motor. The device for detecting loss of synchronization in a synchronous motor according to the present invention: calculates a rotor position command value by using an operation command frequency of a motor; calculates a magnetic flux on a stationary coordinate system by using a voltage and a current on the stationary coordinate system; calculates an active flux by using the magnetic flux on the stationary coordinate system and the current on the stationary coordinate system; calculates a rotor position estimation value by using the active flux; and determines that the motor is in loss of synchronization when the difference between the calculated rotor position command value and the rotor position estimation value is equal to or greater than a first threshold value.

Description

Synchronous motor out-of-synchronization detection device and method

[0001] The present invention relates to electric motor control technology, and more particularly to a technology for detecting loss of synchronization during the control of a synchronous motor.

[0002] Synchronous motors are widely used across various industries, such as in fans, pumps, and blowers, due to their high power density, efficiency, and excellent speed responsiveness.

[0003] In a synchronous motor, rotational force is generated by the interaction and synchronization of the magnetic fields of the stator and the rotor. However, unlike induction motors, synchronous motors do not have rotor windings, so the applied frequency and the rotor frequency may not be synchronized during initial starting or a sudden increase in load, which can result in loss of synchronization.

[0004] When loss of synchronization occurs, heat can be generated due to mechanical vibration and overcurrent, which can cause physical damage to the motor drive system.

[0005] One method for detecting out-of-synchronization is a detection method utilizing the motor's back EMF; this method compares the output voltage during normal operation with the instantaneous output voltage and determines that out-of-synchronization has occurred if the output voltage is not suitable for the operating speed.

[0006] However, this method has a problem in that its detection performance depends on motor parameters (back EMF constant), making it difficult to detect out-of-synchronization in low-speed regions with low voltage.

[0007] The inventors of the present invention have made research efforts to solve the problems of the conventional out-of-synchronization detection technology. After much effort to provide a synchronous motor out-of-synchronization detection device and method capable of estimating the rotor position without a sensor using active flux and determining out-of-synchronization even at low speeds, the present invention has been completed.

[0008] The objective of the present invention is to provide a device and method for detecting loss of synchronization that can prevent physical damage to the motor drive system and improve the stability of the drive system by early detection of loss of synchronization caused by rapid acceleration or rapid load increase during the control of a synchronous motor.

[0009] In addition, another objective of the present invention is to detect loss of synchronization of a synchronous motor without performance degradation even during low-speed operation by detecting loss of synchronization without using a back EMF constant.

[0010] Meanwhile, other unspecified objects of the present invention will be further considered to the extent that they can be easily inferred from the following detailed description and effects.

[0011] The synchronous motor out-of-synchronization detection device according to the present invention is characterized by calculating a rotor position command value based on the motor's operating command frequency, calculating a stationary coordinate system magnetic flux using a stationary coordinate system voltage and current, calculating an active flux using the stationary coordinate system magnetic flux and the stationary coordinate system current, calculating an estimated rotor position value using the active flux, and determining that the motor is out of sync if the difference between the calculated rotor position command value and the estimated rotor position value is greater than or equal to a first threshold value.

[0012] The above processor is characterized by calculating the magnetic flux in the stationary coordinate system by integrating the value obtained by subtracting the voltage drop due to resistance from the voltage in the stationary coordinate system.

[0013] The above processor is characterized by calculating the active flux by subtracting the magnetic flux due to the current in the stationary coordinate system from the magnetic flux in the stationary coordinate system.

[0014] The above processor is characterized by calculating the magnetic flux due to the stationary coordinate system current by multiplying the stationary coordinate system current and the q-axis inductance.

[0015] The above motor is characterized by being a Surface Mounted Permanent Magnet Synchronous Motor (SPSM), an Interior Permanent Magnet Synchronous Motor (IPSM), or a Synchronous Reluctance Motor (SynRM).

[0016] The above active flux is characterized by being defined as the value obtained by adding the magnetic flux linkage by the motor permanent magnet and the value obtained by multiplying the d-axis current by the value obtained by subtracting the q-axis inductance from the d-axis inductance in the dq coordinate system.

[0017] The above processor is characterized by calculating the rotor position estimate value by the value obtained by taking the arctangent of the active flux.

[0018] A synchronous motor out-of-synchronization detection method according to another embodiment of the present invention comprises: a step of calculating a rotor position command value based on the motor's operating command frequency; a step of calculating a magnetic flux in a stationary coordinate system using a voltage and current in a stationary coordinate system; a step of calculating an active flux using the magnetic flux in the stationary coordinate system and the current in the stationary coordinate system; a step of calculating an estimated rotor position value using the active flux; and a step of determining that the motor is out of sync if the difference between the calculated rotor position command value and the estimated rotor position value is greater than or equal to a first threshold value.

[0019] According to the present invention, by detecting loss of synchronization early during the operation of a synchronous motor, it is possible to prevent damage to the motor operating system caused by heat generation, etc.

[0020] In addition, by using active flux instead of the motor's back EMF constant to detect loss of synchronization in a synchronous motor, it has the advantage of effectively detecting loss of synchronization even during low-speed operation of the motor.

[0021] Meanwhile, it should be added that even if an effect is not explicitly mentioned here, the effects described in the following specification and the provisional effects expected by the technical features of the present invention are treated as described in the specification of the present invention.

[0022] FIG. 1 is a schematic structural diagram of a synchronous motor out-of-sync detection device according to a preferred embodiment of the present invention.

[0023] FIG. 2 is a more detailed structural diagram of a processor of a synchronous motor out-of-sync detection device according to a preferred embodiment of the present invention.

[0024] FIG. 3 is a more detailed structural diagram of the rotor position calculation unit of a synchronous motor out-of-synchronization detection device according to a preferred embodiment of the present invention.

[0025] FIG. 4 is a more detailed structural diagram of the flux calculation unit, active flux calculation unit, and rotor position estimation unit of a synchronous motor out-of-synchronization detection device according to a preferred embodiment of the present invention.

[0026] FIG. 5 is a schematic flowchart of a synchronous motor out-of-sync detection method according to another preferred embodiment of the present invention.

[0027] FIG. 6 is a drawing for illustrating a computing environment including a computing device according to another preferred embodiment of the present invention.

[0028] ※ It should be noted that the attached drawings are provided as examples for reference to help understand the technical concept of the present invention, and the scope of the rights of the present invention is not limited by them.

[0029] Hereinafter, specific embodiments according to the embodiments of the present disclosure will be described with reference to the drawings. The following detailed description is provided to facilitate a comprehensive understanding of the methods, apparatus, and / or systems described herein. However, this is merely illustrative and the present invention is not limited thereto.

[0030] In describing the embodiments of the present disclosure, detailed descriptions of known technologies related to the present invention are omitted if it is determined that such detailed descriptions would unnecessarily obscure the essence of the embodiments. Furthermore, terms used below are defined with consideration of their functions in the present invention, and these may vary depending on the intentions or practices of the user or operator. Therefore, such definitions should be based on the content throughout this specification. Terms used in the detailed description are intended merely to describe specific embodiments and should not be limiting. Unless explicitly stated otherwise, expressions in the singular form include the meaning of the plural form. In this description, expressions such as "include" or "comprise" are intended to refer to certain characteristics, numbers, steps, actions, elements, parts thereof, or combinations thereof, and should not be interpreted to exclude the existence or possibility of one or more other characteristics, numbers, steps, actions, elements, parts thereof, or combinations thereof other than those described. Additionally, terms such as "...part," "...unit," "module," and "block" described in the specification refer to a unit that processes at least one function or operation, and this may be implemented in hardware, software, or a combination of hardware and software.

[0031] FIG. 1 is a schematic structural diagram of a synchronous motor out-of-sync detection device according to a preferred embodiment of the present invention.

[0032] The synchronous motor out-of-synchronization detection device (10) according to the present invention may include one or more processors (11), memory (12), and sensors (13).

[0033] The synchronous motor out-of-synchronization detection device (10) is intended to detect motor out-of-synchronization by estimating the position of the motor using active flux when controlling the synchronous motor V / f (voltage / frequency).

[0034] At this time, the motor may be a Surface Mounted Permanent Magnet Synchronous Motor (SPSM), an Interior Permanent Magnet Synchronous Motor (IPSM), or a Synchronous Reluctance Motor (SynRM).

[0035] The synchronous motor out-of-synchronization detection device (10) may be a computing terminal. For example, the synchronous motor out-of-synchronization detection device (10) may be a general-purpose computing system such as a desktop PC, laptop PC, tablet PC, netbook computer, workstation, PDA, smartphone, smart pad, or mobile phone, or a dedicated embedded system implemented based on Embedded Linux, but is not limited thereto.

[0036] The memory (12) may store instructions, data structures, and program code that can be read by the processor (11). In embodiments, at least the operations performed by the processor (11) may be implemented by executing the instructions or code of the program stored in the memory (12).

[0037] The memory (12) may include a flash memory type, a hard disk type, a multimedia card micro type, a card type memory (e.g., SD or XD memory, etc.), a non-volatile memory including at least one of ROM (Read-Only Memory), EEPROM (Electrically Erasable Programmable Read-Only Memory), PROM (Programmable Read-Only Memory), magnetic memory, a magnetic disk, and an optical disk, and a volatile memory such as RAM (Random Access Memory) or SRAM (Static Random Access Memory).

[0038] The memory (12) can store one or more instructions or programs that the synchronous motor out-of-synchronization detection device (10) can use to estimate the rotor position of the motor and use it to detect out-of-synchronization.

[0039] The processor (11) controls the overall operations of the synchronous motor out-of-synchronism detection device (10). For example, the processor (11) can control the overall operation of the synchronous motor out-of-synchronism detection device (10) to detect motor out-of-synchronism using active flux by executing one or more instructions stored in memory (12).

[0040] The processor (11) may be composed of at least one of, for example, a Central Processing Unit, a microprocessor, a Graphic Processing Unit, ASICs (Application Specific Integrated Circuits), DSPs (Digital Signal Processors), DSPDs (Digital Signal Processing Devices), PLDs (Programmable Logic Devices), FPGAs (Field Programmable Gate Arrays), an Application Processor, a Neural Processing Unit, or an AI-dedicated processor designed with a hardware structure specialized for processing AI models, but is not limited thereto.

[0041] The sensor (13) may include a voltage sensor or a current sensor for measuring the voltage and current of the motor, but is not limited thereto.

[0042] FIG. 2 is a more detailed structural diagram of a processor of a synchronous motor out-of-sync detection device according to a preferred embodiment of the present invention.

[0043] The processor (11) may include a rotor position calculation unit (21), a stationary coordinate system flux calculation unit (22), an active flux calculation unit (23), a rotor position estimation unit (24), and a loss of synchronization determination unit (25).

[0044] The processor (11) compares the rotor position calculated by the rotor position calculation unit (21) with the rotor position estimated by the rotor position estimation unit (24) to determine the loss of synchronization in the loss of synchronization determination unit (25).

[0045] FIG. 3 is a more detailed structural diagram of the rotor position calculation unit of a synchronous motor out-of-synchronization detection device according to a preferred embodiment of the present invention.

[0046] The rotor position calculation unit (21) is the motor's operating command frequency ( ) is integrated by the integrator (31) ) to obtain the rotor position command value( Calculate )

[0047] At this time, a stabilization component to supplement the driving command frequency ( A stabilizer (32) for calculating ) may be further included. The configuration of the stabilizer (32) is a known technique and is omitted from this detailed description.

[0048] FIG. 4 is a more detailed structural diagram of the flux calculation unit, active flux calculation unit, and rotor position estimation unit of a synchronous motor out-of-synchronization detection device according to a preferred embodiment of the present invention.

[0049] The processor (11) calculates the active flux of the motor to estimate the rotor position, and the active flux ( ) can be defined from the torque equation on the dq axis of the synchronous coordinate system according to the type of motor as follows.

[0050]

[0051]

[0052] Equation (1) is the magnetic flux linkage due to a permanent magnet (PM), and , represents the inductance of the d-axis and q-axis, respectively, and represents the d-axis current. In Equation (1), the subscripts SPMSM, IPMSM, and SynRM represent a surface-mounted permanent magnet synchronous motor, an embedded permanent magnet synchronous motor, and a reluctance synchronous motor, respectively.

[0053] Using the concept of active flux, the magnetic flux of an IPMSM can be expressed as follows.

[0054] (2)

[0055] If this equation is converted from the dq coordinate system to the α-β stationary coordinate system, it is as follows.

[0056] (3)

[0057] This is active flux ( When rearranged for ), it is as follows.

[0058] (4)

[0059] Therefore, to calculate the active flux, the stationary coordinate system flux (22) is first calculated by the stationary coordinate system flux calculation unit (22). Calculate ). The magnetic flux in the stationary coordinate system can be calculated as follows using the magnetic flux voltage model.

[0060] The stationary coordinate system flux calculation unit (22) is the stationary coordinate system voltage ( Voltage drop due to resistance in ) The value obtained by subtracting ) is integrated by an integrator (41) and a high-pass filter (HPF) (42) is applied to obtain the magnetic flux in the stationary coordinate system.

[0061] A high-pass filter (42) is applied to remove the effects of the measured current, such as DC offset.

[0062] The active flux calculation unit (23) calculates the active flux from the stationary coordinate system flux as defined above.

[0063] The active flux calculation unit (23) is a stationary coordinate system magnetic flux ( q-axis inductance ( ) and stationary coordinate system current( By subtracting the component multiplied by ), the active flux in the stationary coordinate system ( You can obtain ).

[0064] Finally, the rotor position estimation unit (24) is the active flux of the stationary coordinate system ( By taking the arctangent function of ) to obtain the rotor position estimate as shown in the following equation ( You can obtain ).

[0065] (5)

[0066] The processor (11) determines whether the motor has lost synchronization by comparing the rotor position estimate value, which was estimated in this way by the loss-setting determination unit (25), with the rotor position command value calculated earlier.

[0067] The out-of-synchronization judgment unit (25) determines whether the motor has lost synchronization by comparing the rotor position estimate value and the rotor position command value.

[0068] If the difference between the rotor position command value and the rotor position estimate value is greater than or equal to the first threshold value, it can be determined that the motor has lost synchronization.

[0069] For example, the first threshold value may be 180 degrees. If there is a difference of 180 degrees between the rotor position command value and the position estimate value, the interaction between the magnetic flux of the motor stator and the rotor acts in reverse, making it impossible to generate torque any further. Therefore, if the difference is greater than 180 degrees, it is determined that the motor has lost synchronization.

[0070] The first threshold value may vary depending on the motor operating conditions.

[0071] FIG. 5 is a schematic flowchart of a synchronous motor out-of-sync detection method according to another preferred embodiment of the present invention.

[0072] The synchronous motor out-of-synchronization detection method according to the present invention can be performed by a synchronous motor out-of-synchronization detection device comprising one or more processors and a memory.

[0073] To detect synchronous motor out-of-sync, first calculate the rotor position command value (S11).

[0074] The rotor position command value can be obtained by integrating the motor's operating command frequency. In this case, a stabilization component may be additionally included to complement the operating command frequency.

[0075] Next, calculate the magnetic flux in the stationary coordinate system (S12).

[0076] The magnetic flux in the stationary coordinate system can be calculated by integrating the value obtained by subtracting the voltage drop component due to the current in the stationary coordinate system from the voltage in the stationary coordinate system and applying a high-pass filter.

[0077] A high-pass filter is applied to eliminate the effects of the measured current, such as DC offset.

[0078] The active flux is calculated based on the relationship between the magnetic flux in the stationary coordinate system and the active flux (S13).

[0079] The active flux in the stationary coordinate system can be obtained by subtracting the component obtained by multiplying the q-axis inductance and the stationary coordinate system current from the magnetic flux in the stationary coordinate system.

[0080] The rotor position estimate can be calculated by taking the arctangent function of the calculated active flux (S14).

[0081] Finally, the rotor position estimate and the rotor position command value are compared to determine if the motor has lost synchronization (S15).

[0082] If the difference between the rotor position command value and the rotor position estimate value is greater than or equal to the first threshold value, it can be determined that the motor has lost synchronization.

[0083] By estimating the rotor position using active flux to determine synchronization loss, unlike the conventional method of detecting synchronization loss using back EMF, there is an advantage in being able to detect synchronization loss early even in low-voltage, low-speed driving sections.

[0084]

[0085] FIG. 6 is a drawing for illustrating a computing environment including a computing device according to another preferred embodiment of the present invention.

[0086] In the illustrated embodiments, each component may have different functions and capabilities in addition to those described below, and may include additional components in addition to those not described below. The illustrated computing environment (60) may include a computing device (61) to perform the synchronous motor out-of-sync detection method illustrated in FIG. 5. In one embodiment, the computing device (61) may be one or more components included in the synchronous motor out-of-sync detection device illustrated in FIG. 1.

[0087] The computing device (61) includes at least one processor (62), a computer-readable storage medium (63), and a communication bus (65). The processor (62) may enable the computing device (61) to operate according to the exemplary embodiment described above. For example, the processor (62) may execute one or more programs (64) stored in the computer-readable storage medium (63). The one or more programs (64) may include one or more computer-executable instructions, and the computer-executable instructions may be configured to enable the computing device (61) to perform operations according to the exemplary embodiment when executed by the processor (62).

[0088] The communication bus (65) interconnects various other components of the computing device (61), including the processor (62) and the computer-readable storage medium (63).

[0089] The computing device (61) may also include one or more input / output interfaces (66) and one or more communication interfaces (67) that provide an interface for one or more input / output devices (68). The input / output interfaces (66) and the communication interfaces (67) are connected to a communication bus (65). The input / output devices (68) may be connected to other components of the computing device (61) through the input / output interfaces (66). An exemplary input / output device (68) may include input devices such as a pointing device (such as a mouse or trackpad), a keyboard, a touch input device (such as a touchpad or touchscreen), a voice or sound input device, various types of sensor devices and / or imaging devices, and / or output devices such as a display device, a printer, a speaker and / or a network card. An exemplary input / output device (68) may be included inside the computing device (61) as a component constituting the computing device (61), or it may be connected to the computing device (61) as a separate device distinct from the computing device (61).

[0090]

[0091] According to the synchronous motor out-of-synchronization detection device and method of the present invention as described above, out-of-synchronization can be detected early without a motor position sensor, thereby preventing damage to the motor or motor drive system caused by out-of-synchronization in advance.

[0092]

[0093] The scope of protection of the present invention is not limited to the description and expression of the embodiments explicitly described above. Furthermore, it is added once again that the scope of protection of the present invention cannot be limited by obvious changes or substitutions in the technical field to which the present invention belongs.

Claims

1. Memory containing one or more instructions; and A processor that executes one or more instructions stored in the memory above; Includes, The above processor is, Calculate the rotor position command value based on the motor's operating command frequency, and Calculate the magnetic flux in the stationary coordinate system using the voltage and current in the stationary coordinate system, and The active flux is calculated using the above stationary coordinate system magnetic flux and stationary coordinate system current, and Calculate the rotor position estimate using the above active flux, and A synchronous motor out-of-synchronization detection device characterized by determining that the motor is out of sync when the difference between the above-calculated rotor position command value and the rotor position estimate value is greater than or equal to a first threshold value.

2. In Paragraph 1, A synchronous motor out-of-synchronization detection device characterized by the processor calculating the magnetic flux in the stationary coordinate system by integrating the value obtained by subtracting the voltage drop due to resistance from the voltage in the stationary coordinate system.

3. In Paragraph 1, A synchronous motor out-of-synchronization detection device characterized by the processor calculating the active flux by subtracting the magnetic flux due to the current in the stationary coordinate system from the magnetic flux in the stationary coordinate system.

4. In Paragraph 3, A synchronous motor out-of-synchronization detection device characterized by the processor calculating the magnetic flux caused by the stationary coordinate system current by the value obtained by multiplying the stationary coordinate system current and the q-axis inductance.

5. In Paragraph 1, A synchronous motor out-of-synchronization detection device characterized in that the motor is a Surface Mounted Permanent Magnet Synchronous Motor (SPSM), an Interior Permanent Magnet Synchronous Motor (IPSM), or a Synchronous Reluctance Motor (SynRM).

6. In Paragraph 1, A synchronous motor out-of-synchronization detection device characterized in that the above active flux is defined as the magnetic flux linkage by the motor permanent magnet and the value obtained by multiplying the d-axis current by the value obtained by subtracting the q-axis inductance from the d-axis inductance in the d-axis coordinate system.

7. In Paragraph 1, A synchronous motor out-of-synchronization detection device characterized by the processor calculating the rotor position estimate value by taking the arctangent of the active flux.

8. A method for detecting synchronous motor out-of-synchronism performed by a synchronous motor out-of-synchronism detection device comprising one or more processors and memory: A step of calculating a rotor position command value based on the motor's operating command frequency; A step of calculating the magnetic flux in the stationary coordinate system using the voltage and current in the stationary coordinate system; A step of calculating the active flux using the above stationary coordinate system magnetic flux and stationary coordinate system current; A step of calculating an estimated rotor position value using the above active flux; and A step of determining that the motor is out of sync if the difference between the above-calculated rotor position command value and the rotor position estimate value is greater than or equal to a first threshold value; A method for detecting synchronous motor loss of synchronization, characterized by including

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