Motor drive control system and control method thereof

Abstract

The present invention provides a motor drive control system and control method that can stably protect a motor not only when there is an overload in a high-speed drive state but also when there is an overload in a low-speed drive state by varying the applied current limiting logic depending on the drive speed of the motor. [Solution] The present invention provides a motor drive control system and control method that can stably protect the motor not only when it is overloaded in a high-speed driving state but also when it is overloaded in a low-speed driving state by varying the current limiting logic applied to a BLDC motor for a cooling fan depending on the driving speed of the motor.

Description

Technical Field

[0001] The present invention relates to a motor drive control system and a control method thereof, and more particularly, to a motor drive control system and a control method thereof that control a motor to be stably driven even under low-speed overload conditions.

Background Art

[0002] A BLDC motor for a cooling fan usually has a current limit logic applied to prevent burnout of the motor and the inverter due to overcurrent. Specifically, due to the characteristics of the cooling fan, when the driving speed of the motor increases, the required power consumption current increases accordingly. Therefore, considering the allowable current of the motor capacity, coil, wire, and other elements according to the specifications of the conventional elements without the motor, the current limit logic is set.

[0003] During normal driving, as shown in FIG. 3, since the load generated in the motor itself is within the current limit range, driving can be performed without applying the applied current limit logic. However, when sluggishness occurs, in other words, when a foreign object or the like is caught between the rotating bodies and is not completely constrained, and the state of rotating at low speed and high load occurs, the motor is applied with a current corresponding to the drive signal and continues to operate, and the power consumption current increases.

[0004] At this time, as shown in FIG. 3 a), when the drive limit power information, that is, the current rises to the current limit value corresponding to the above-described current limit logic, the current cannot increase any further, and the drive speed decreases. When the drive speed decreases, the operating efficiency decreases even when the same current is used, and excessive heat is generated, resulting in burnout due to an increase in the internal temperature due to insufficient cooling performance.

[0005] Accordingly, the present invention is for solving problems caused by overloads that occur in a low-speed driving state under semi-constrained conditions, rather than in a "high-speed driving state" corresponding to normal overloads. By varying the applied current limiting logic according to the driving speed of the motor, the present invention can stably protect the motor not only from overloads in the high-speed driving state but also from overloads in the low-speed driving state.

[0006] In this regard, Korean Patent Publication No. 10-2020-0059849 ("BLDC Motor Overload Detection Device and Method") discloses a device that measures the difference between the mechanical angle and the electrical angle of a BLDC motor to determine the presence or absence of constraint of the BLDC motor. [[Prior Art Documents]] [[Patent Documents]]

[0007] [[Patent Document 1]] Korean Patent Publication No. 10-2020-0059849 [[Summary of the Invention]] [[Problems to be Solved by the Invention]]

[0008] Therefore, the present invention has been devised to solve the problems of the prior art as described above, and the object of the present invention is to solve the problems caused by overloads that occur in a low-speed driving state under semi-constrained conditions, rather than in a "high-speed driving state" corresponding to normal overloads. By varying the applied current limiting logic according to the driving speed of the motor, the present invention provides a motor drive control system and its control method that can stably protect the motor not only from overloads in the high-speed driving state but also from overloads in the low-speed driving state. [[Means for Solving the Problems]]

[0009] To achieve the above object, the motor drive control system of the present invention preferably includes a motor drive unit 100 that provides a drive current to a motor 10 according to an input drive signal, a state calculation unit 200 that calculates information regarding the operating state of the motor 10 driven by the control of the motor drive unit 100, an analysis unit 300 that analyzes the allowable power information of the motor 10 by using the information regarding the operating state of the motor 10 calculated by the state calculation unit 200 based on preset drive limit power information, and a power control unit 400 that generates a control signal for controlling the supply current of the motor 10 by using the allowable power information of the motor 10 analyzed by the analysis unit 300 and transmits the control signal to the motor drive unit 100.

[0010] Furthermore, it is preferable that the state calculation unit 200 calculates information regarding the operating state including the current rotation speed, the current measured current, and the measured voltage of the motor 10 currently driven by the control of the motor drive unit 100.

[0011] Furthermore, it is preferable that the analysis unit 300 analyzes the heat generation state of the motor 10 according to the rotation speed and power based on the basic specifications of the elements constituting the motor 10, and sets the drive limit power information based on the rotation speed and power.

[0012] Furthermore, it is preferable that the analysis unit 300 performs a comparative analysis of the limit power according to the drive limit power information based on the current rotation speed of the motor 10 calculated by the state calculation unit 200 and the current power, and when the current power exceeds the limit power, analyzes the allowable power information according to the limit power.

[0013] Furthermore, it is preferable that the power control unit 400 controls the supply current of the motor 10 by using the allowable power information reflecting the current rotation speed of the motor 10 analyzed by the analysis unit 300 and varies the current power of the motor 10.

[0014] The motor drive control method of the present invention for achieving the above object includes a driving step (S100) in a motor drive unit to provide a driving current to a motor by an input driving signal, a current power calculation step (S200) in a state calculation unit to obtain information regarding an operating state of the motor driven by the driving step (S100) and calculate current power information, a determination step (S300) in an analysis unit to compare and determine between preset drive limit power information and the current power information of the motor by the current power calculation step (S200), an analysis step (S400) to analyze allowable power information of the motor by the drive limit power information when the current power information of the motor exceeds the drive limit power information according to the comparison and determination result of the determination step (S300), and a drive control step (S500) in a power control unit to generate a control signal for controlling a supply current of the motor using the allowable power information of the motor analyzed by the analysis step (S400). It is preferable that the method includes these steps.

[0015] Furthermore, it is preferable that the current power calculation step (S200) includes the current rotation speed, the currently measured current, and the measured voltage of the motor 10 as information regarding the operating state of the motor.

[0016] Furthermore, it is preferable that the determination step (S300) compares and determines between the drive limit power information and the current power information of the motor based on the current rotation speed of the motor 10.

[0017] Furthermore, it is preferable that the determination step (S300) analyzes a heat generation state based on the rotation speed and power of the motor according to basic specifications of elements constituting the motor in advance, and sets the drive limit power information based on the rotation speed and power.

Effects of the Invention

[0018] According to the present invention, a motor drive control system and its control method have the advantage of stably protecting a motor not only from overload in a high-speed driving state but also from overload in a low-speed driving state by varying the current limit logic applied to a BLDC motor for a cooling fan according to the driving speed of the motor. Thereby, under semi-constrained conditions, it is possible to prevent the occurrence of burnout of the motor, inverter, etc. due to the occurrence of low-speed overload. However, since power control by supply current control may cause the motor to be driven at a speed lower than the target speed corresponding to the input drive signal, when an overload condition of the current motor occurs by an external administrator or upper control means, an alarm indicating that the motor can be driven at a target speed lower than the input drive signal is generated. In addition to preventing burnout of the motor, inverter, etc., it has the advantage of being able to detect faults / abnormalities.

Brief Description of the Drawings

[0019]

Figure 1

Figure 2

Figure 3

Modes for Carrying Out the Invention

[0020] Hereinafter, a motor drive control system and its control method according to the present invention having the above-described configuration will be described in detail with reference to the accompanying drawings. Also, a system means a set of components including devices, equipment, and means that are organized to perform necessary functions and interact regularly with each other.

[0021] The motor applied to the motor drive control system and its control method according to an embodiment of the present invention is a BLDC motor for a cooling fan. Usually, a current limit logic is applied to prevent the motor and the inverter from burning due to overcurrent.

[0022] However, when sluggishness occurs during the process of driving the motor, since the rotation speed of the motor is low despite being in an overload state, the current is continuously applied. Eventually, insufficient cooling due to low-speed overload causes the temperature inside the motor to rise and burnout occurs. That is, depending on the applied current limit logic, there is a problem that it can sufficiently cope with "high-speed overload" but cannot sufficiently cope with "low-speed overload" due to conditions such as sluggishness.

[0023] Accordingly, the motor drive control system and its control method according to an embodiment of the present invention have a technical objective of stably protecting the motor not only from overload in the high-speed driving state but also from overload in the low-speed driving state by varying the applied current limit logic according to the driving speed of the motor.

[0024] FIG. 1 is a configuration exemplary diagram showing a motor drive control system according to an embodiment of the present invention. Referring to FIG. 1, the motor drive control system according to an embodiment of the present invention will be described in detail. The motor drive control system according to an embodiment of the present invention preferably includes a motor drive unit 100, a state calculation unit 200, an analysis unit 300, and a power control unit 400 as shown in FIG. 1. Each configuration preferably operates by one arithmetic processing means or is included in each arithmetic processing means.

[0025] Examining each configuration in detail, The motor drive unit 100 preferably provides a drive current to the motor 10 by a drive signal input from an external administrator or a higher-level control means. Specifically, the drive signal is configured to include a target rotation speed for driving the motor 10. As a result, in order for the motor drive unit 100 to cause the motor 10 to reach the target rotational speed included in the drive signal, a current is applied via the speed control means.

[0026] The state calculation unit 200 preferably calculates information regarding the operating state of the driven motor 10 under the control of the motor drive unit 100. Specifically, the state calculation unit 200 preferably acquires, as information regarding the operating state, information including the current rotational speed, the currently measured current, and the currently measured voltage of the currently driven motor 10 under the control of the motor drive unit 100.

[0027] Further, the state calculation unit 200 preferably calculates the current power of the motor 10 using the acquired currently measured current and currently measured voltage of the motor 10, and stores and manages it as information regarding the operating state.

[0028] The analysis unit 300 preferably analyzes the allowable power information of the motor 10 using the information regarding the operating state of the motor 10 calculated by the state calculation unit 200 based on the preset drive limit power information. Here, the preset drive limit power information means the drive limit power value by the "current limit logic" applied to the above-described motor, and the drive limit power information is based on the basic specification information of the elements constituting the motor 10. It is preferable to analyze the heat generation state according to the rotational speed and power of the motor 10, and set the drive limit power information based on the rotational speed and power as shown in FIG. 3(b).

[0029] The drive limit power value by the conventional "current limit logic" is set so that no power overload of the motor occurs regardless of the motor drive speed, as shown in FIG. 3(a). In this case, as described above, although the speed of the motor is low, the power state deviates from the normal operation range due to the semi-restraint condition. However, since the drive limit power information (drive limit power value) only considers the case of high speed, the state of the motor under the low-speed overload condition cannot be accurately recognized, and eventually, burnout may occur.

[0030] To solve this problem, the analysis unit 300 preferably analyzes the heat generation state based on the rotation speed of the motor and the current power, and sets drive limit power information. Based on the current rotation speed of the motor 10 calculated by the state calculation unit 200, the analysis unit 300 preferably compares and analyzes the limit power according to the drive limit power information and the current power. When the current power exceeds the limit power, it is preferable to analyze the allowable power information according to the limit power.

[0031] In other words, based on the current rotation speed of the motor 10 calculated by the state calculation unit 200, the analysis unit 300 compares and analyzes the limit power according to the drive limit power information and the calculated current power of the motor 10. When the current power of the motor 10 exceeds the limit power, it is determined that the motor 10 is in an overload state, and it is preferable to derive the allowable power information corresponding to the current rotation speed of the motor 10. At this time, the allowable power information is derived based on the drive limit power information, which corresponds to the upper limit value of the allowable power rather than the appropriate power.

[0032] That is to say, compared with the conventional drive limit power value, the drive limit power information of the analysis unit 300 is set so that the upper limit value of the allowable power varies according to the rotation speed of the motor. Even when the motor is overloaded despite a low speed, it can be efficiently detected and a safe driving operation can be performed.

[0033] The power control unit 400 preferably generates a control signal for controlling the supply current of the motor 10 using the allowable power information analyzed by the analysis unit 300, and transmits it to the motor drive unit 100. That is, the power control unit 400 preferably varies the current power of the motor 10 by using the allowable power information reflecting the current rotation speed of the motor 10 analyzed by the analysis unit 300, limiting the current power through the PI control means, and controlling the supply current of the motor 10.

[0034] As an example, when a low-speed overload occurs under semi-constrained conditions, the allowable power information can be derived by reflecting the current rotational speed of the motor 10 in the drive limit power information, and the current power of the motor 10 is limited low by the control signal generated using the allowable power information, and the driving speed of the motor is driven lower than the target speed, but problems such as heat generation due to overload can be prevented, and furthermore, burnout of the motor and inverter can be prevented.

[0035] FIG. 2 is a flowchart showing a motor drive control method according to an embodiment of the present invention, and a motor drive control method according to an embodiment of the present invention will be described in detail with reference to FIG. 2. As shown in FIG. 2, the motor drive control method according to an embodiment of the present invention preferably includes a drive step (S100), a current power calculation step (S200), a determination step (S300), an analysis step (S400), and a drive control step (S500).

[0036] Examining each step in detail, In the drive step (S100), in the motor drive unit 100, a drive current is provided to the motor 10 by a drive signal input from an external administrator or a higher-level control means. That is, the drive signal including the target rotational speed to drive the motor 10 is input, and in order to cause the motor 10 to reach the target rotational speed, a current is applied via a speed control means.

[0037] In the current power calculation step (S200), in the state calculation unit 200, information regarding the operating state of the motor 10 driven by the drive step (S100) is acquired, and the current power information of the motor 10 is calculated. Specifically, in the current power calculation step (S200), as the information regarding the operating state, information including the current rotational speed, the current measured current, and the current measured voltage of the motor 10 currently being driven under the control of the motor drive unit 100 is acquired, and the current power information of the motor 10 is calculated using the acquired current measured current and current measured voltage of the motor 10.

[0038] In the determination step (S300), it is preferable that the analysis unit 300 compares and determines the preset drive limit power information with the current power information of the motor 10 obtained in the current power calculation step (S200). Specifically, in the determination step (S300), based on the basic specification information of the elements constituting the motor 10 in advance, the heat generation state due to the rotation speed and power of the motor 10 is analyzed, and as shown in FIG. 3(b), the drive limit power information is set based on the rotation speed and power.

[0039] Thereby, in the determination step (S300), based on the current rotation speed of the motor 10, by comparing and analyzing the limit power according to the drive limit power information with the calculated current power of the motor 10, it is determined whether the current power of the motor 10 exceeds the limit power.

[0040] According to the determination result of the determination step (S300), if the current power of the motor 10 exceeds the limit power, it is preferably determined that the current motor 10 is in an overload state. Thereby, in the analysis step (S400), according to the comparison and determination result of the determination step (S300), if the current power of the motor 10 exceeds the limit power, the allowable power information of the motor 10 is analyzed according to the drive limit power information.

[0041] That is, by analyzing the allowable power information corresponding to the current rotation speed of the motor 10 based on the drive limit power information, the allowable power information corresponds to the upper limit value of the allowable power rather than the appropriate power.

[0042] In the drive control step (S500), the power control unit 400 generates a control signal for controlling the supply current of the motor 10 using the allowable power information of the motor 10 analyzed in the analysis step (S400), and transmits it to the motor drive unit 100. That is, in the drive control step (S500), it is preferable to vary the current power of the motor 10 by limiting the current power via the PI control means and controlling the supply current of the motor 10 using the allowable power information reflecting the current rotation speed of the motor 10 analyzed in the analysis step (S400).

[0043] At this time, the motor drive control system and its control method according to an embodiment of the present invention can prevent the occurrence of burnout of the motor, inverter, etc. due to the occurrence of low-speed overload under semi-constrained conditions. However, since it may be driven lower than the target speed according to the input drive signal, when generating the control signal based on the allowable power information of the motor 10, the power control unit 400 transmits the control signal to the motor drive unit 100 and notifies the external administrator or the upper control means that an overload condition of the current motor 10 has occurred and a control signal that can be driven at a target speed lower than the input drive signal has been further generated and transmitted. This is preferable. Thereby, not only can the burnout of the motor, inverter, etc. be prevented, but also the detection of failures / abnormalities can be performed.

[0044] The present invention is not limited to the above-described embodiments. Of course, the scope of application is diverse, and it goes without saying that various modifications can be made by those having ordinary knowledge in the field to which the present invention pertains without departing from the gist of the present invention claimed in the claims.

Explanation of Reference Numerals

[0045] 10 Motor 100 Motor drive unit 200 State calculation unit 300 Analysis unit 400 Power control unit

Claims

1. A motor drive unit 100 that provides a drive current to a motor 10 in response to an input drive signal; A state calculation unit 200 that calculates information including the current rotational speed, the current measured current, and the current measured voltage of the motor 10, which is information regarding the operating state of the motor 10 driven under the control of the motor drive unit 100, and calculates the current power of the motor 10 using the current measured current and the current measured voltage of the motor 10; An analysis unit 300 that analyzes the allowable power information of the motor 10 using the current rotational speed, the current measured current, and the current measured voltage of the motor 10, which are information regarding the operating state of the motor 10 calculated by the state calculation unit 200, based on preset drive limit power information; A power control unit 400 that generates a control signal for controlling the supply current of the motor 10 using the allowable power information of the motor 10 analyzed by the analysis unit 300 and transmits the control signal to the motor drive unit 100; comprising The drive limit power information of the analysis unit 300 analyzes the heat generation state of the motor 10 based on the rotational speed and power according to the basic specifications of the elements constituting the motor 10 and is set based on the rotational speed and power. The analysis unit 300 compares the limit power according to the drive limit power information based on the current rotational speed of the motor 10 with the current power of the motor 10, and is set such that the upper limit value of the allowable power of the motor 10 is variable, so that even when the motor 10 is overloaded despite its low speed, it can be detected. A motor drive control system characterized by this.

2. The analysis unit 300 compares and analyzes the limit power according to the drive limit power information based on the current rotational speed of the motor 10 calculated by the state calculation unit 200 with the current power, and when the current power exceeds the limit power, analyzes the allowable power information according to the limit power. The motor drive control system according to claim 1, characterized by this.

3. The power control unit 400 varies the current power of the motor 10 by controlling the supply current of the motor 10 using the allowable power information reflecting the current rotational speed of the motor 10 analyzed by the analysis unit 300. The motor drive control system according to claim 2, characterized by this. **Claim 4**: A motor drive control method that enables efficient detection and safe driving operation even when the motor is overloaded despite a low speed, comprising: a driving step (S100) in a motor drive unit that provides a drive current to the motor by an input drive signal; a current power calculation step (S200) in a state calculation unit that calculates information including the current rotation speed, current measured current, and current measured voltage of the motor, which is information regarding the operating state of the motor driven by the driving step (S100), and calculates the current power information of the motor using the current measured current and current measured voltage of the motor; a determination step (S300) in an analysis unit that compares and determines the limited power information based on preset drive limit power information and the current power information of the motor based on the current rotation speed of the motor by the current power calculation step (S200); an analysis step (S400) that, based on the comparison determination result of the determination step (S300), sets the upper limit value of the allowable power of the motor to be variable by the drive limit power information when the current power information of the motor exceeds the drive limit power information, and analyzes the allowable power information of the motor; a drive control step (S500) in a power control unit that generates a control signal for controlling the supply current of the motor using the allowable power information of the motor analyzed by the analysis step (S400); comprising: the drive limit power information of the analysis unit is set based on the rotation speed and power of the motor by analyzing the heat generation state due to the rotation speed and power of the motor based on the basic specification information of the elements constituting the motor; the analysis step (S400) is: Based on the current rotation speed of the motor by the determination step (S300), by setting the upper limit value of the allowable power of the motor to be variable according to the comparison result between the limited power by the drive limit power information and the current power information of the motor, even when the motor is overloaded despite a low speed, it is efficiently detected and a safe driving operation is performed. A motor drive control method characterized by this. **Claim 5** The determination step (S300) is: characterized by comparing and determining the drive limit power information and the current power information of the motor based on the current rotation speed of the motor. The motor drive control method according to claim 4.

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