Smart control device of motor applied to blower and hydraulic device

Abstract

The present invention relates to a control device of a motor. The present invention proposes a control device that, in an environment in which a blower or a hydraulic device is applied to various manufacturing processes, optimizes the efficiency and minimizes the power consumption of a motor for starting the blower or the hydraulic device. The smart control device of a motor applied to a blower and a hydraulic device according to a preferred embodiment of the present invention includes a control panel having a control mode setting function for a plurality of control modes including an auto chasing control mode.

Description

Smart control device for electric motors applied to blowers and hydraulic systems

[0001] The present invention relates to a control device for an electric motor.

[0002] Motor control units are systems that control and regulate the operation of electric motors and are essential in various industries and mechanical equipment. An electric motor is a device that converts electrical energy into mechanical energy, and to efficiently manage its output, control is required to regulate speed, direction, torque, and other parameters. Motor control units perform this control, which typically includes speed control, position control, and acceleration and deceleration control.

[0003] For example, power conversion devices such as inverters or converters can be used to regulate the speed or output of AC and DC motors, thereby increasing energy efficiency and reducing maintenance costs. Motor control technology is essential in various applications, including automation processes, robots, elevators, and HVAC systems.

[0004] The present invention proposes a control device that optimizes the efficiency of an electric motor (motor) that starts a blower or hydraulic device and minimizes power consumption in an environment where the blower or hydraulic device is applied in various manufacturing processes.

[0005] A smart control device for an electric motor applied to a blower and a hydraulic machine according to a preferred embodiment of the present invention comprises a control panel having a control mode setting function for a plurality of control modes, including an automatic chasing control method.

[0006] Here, a main processor is further included, and in a first control mode, the main processor continuously monitors the inverter output apparent current value and determines whether the apparent power calculated through the inverter output apparent current value is greater than the active power calculated through the inverter output active current value within a preset reference value, and if it is determined that the apparent power calculated through the inverter output apparent current value is greater than the active power calculated through the inverter output active current value within a preset reference value, the main processor can prevent the torque command unit from changing the current torque command value.

[0007] In addition, if it is determined that the apparent power calculated through the inverter output apparent current value is greater than the active power calculated through the inverter output active current value by exceeding a preset reference value, the main processor performs an operation to generate a new torque command value, and the main processor can generate a new torque command value that causes the inverter to output a power torque greater than the active power calculated through the current inverter output active current value by a preset reference value.

[0008] Additionally, the system further includes a main processor, wherein the main processor continuously monitors the inverter output apparent current value in a second control mode, and if it is determined that the apparent power calculated through the inverter output apparent current value is greater than the active power calculated through the inverter output active current value by exceeding a preset reference value, the main processor generates a new torque command value, determines whether the inverter output apparent power based on the new torque command value is between the upper apparent power and the lower apparent power, and if it is determined that the inverter output apparent power based on the new torque command value is between the upper apparent power and the lower apparent power, transmits the new torque command value to a torque command unit, and if it is determined that the inverter output apparent power based on the new torque command value is not between the upper apparent power and the lower apparent power, determines whether the inverter output apparent power based on the new torque command value is greater than or equal to the upper apparent power, and if the inverter output apparent power based on the new torque command value is greater than or equal to the upper apparent power If it is determined that the upper limit torque command value is transmitted to the torque command device, and if it is determined that the inverter output apparent power based on the new torque command value is not greater than or equal to the upper limit apparent power, the lower limit torque command value can be transmitted to the torque command device.

[0009] The present invention can optimize the efficiency of the electric motor that starts the blower or hydraulic machine and minimize power consumption in an environment where the blower or hydraulic machine is applied in various manufacturing processes.

[0010] FIG. 1 is a schematic diagram of an electric motor and an electric motor control device according to one embodiment of the present invention.

[0011] Figure 2 is a flowchart for the first control method performed by the main processor in the first control mode.

[0012] Figure 3 is a flowchart for the second control method performed by the main processor in the second control mode.

[0013] Figure 4 is a diagram illustrating the inverter output apparent current values ​​collected during a set work process cycle for a plurality of set work process cycles.

[0014] The present invention is capable of various modifications and may have various embodiments, and specific embodiments are illustrated in the drawings and described in detail in the detailed description. However, this is not intended to limit the present invention to specific embodiments, and it should be understood that it includes all modifications, equivalents, and substitutions that fall within the spirit and scope of the invention.

[0015] In describing each drawing, similar reference numerals have been used for similar components. In describing the present invention, detailed descriptions of related prior art are omitted if it is determined that such detailed descriptions could obscure the essence of the invention.

[0016] Terms such as "first," "second," etc., may be used to describe various components, but said components should not be limited by said terms. These terms are used solely for the purpose of distinguishing one component from another.

[0017] For example, without departing from the scope of the rights of the present invention, the first component may be named the second component, and similarly, the second component may be named the first component.

[0018] The term "and / or" includes a combination of multiple related listed items or any of the multiple related listed items.

[0019] The terms used in this application are used merely to describe specific embodiments and are not intended to limit the invention.

[0020] The singular expression includes the plural expression unless the context clearly indicates otherwise. In this application, terms such as “comprising” or “having” are intended to specify the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should not be understood as precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0021] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as generally understood by those skilled in the art to which this invention pertains.

[0022] Terms such as those defined in commonly used dictionaries should be interpreted as having meanings consistent with their meanings in the context of the relevant technology, and should not be interpreted in an ideal or overly formal sense unless explicitly defined in this application.

[0023]

[0024] Hereinafter, with reference to FIGS. 1 to 4, a smart control device for an electric motor (hereinafter referred to as the "smart control device") applied to a blower and hydraulic machine of the present invention will be described.

[0025] Referring to FIG. 1, a smart control device (10) can be connected to a motor (2) to control the operation of the motor (2). Here, the motor (2) may be a motor (2) installed in a blower or a hydraulic device.

[0026] The smart control device (10) may include a main power supply unit (1), an inverter (3), a torque command unit (4), a main processor (5), a load current detection unit (6), an auxiliary processor (7), and a control panel (8).

[0027] The inverter (3) can convert the three-phase power supplied by the main power supply unit (1) to supply operating power to the motor (2). For example, the inverter (3) can output voltage using the Pulse Width Modulation (PWM) method. The inverter (3) can adjust the speed or torque of the motor (2) by adjusting the duty cycle of the output voltage. In other words, the inverter (3) can control the shaft power of the motor (2) by adjusting the duty cycle of the output voltage.

[0028] The torque command unit (4) can provide a command value that is used by the inverter (3) to adjust the output voltage. The inverter (3) can output a PWM voltage pulse corresponding to the command value received from the torque command unit (4). The shaft power of the motor (2) can be controlled by the command value of the torque command unit (4).

[0029]

[0030] The general formula for device efficiency is as follows.

[0031]

[0032]

[0033] And, from an electrical perspective, the efficiency formula of the device is as follows.

[0034]

[0035] Electrical efficiency can also be referred to as power factor.

[0036]

[0037] The shaft power of the pump is given by the following mathematical formula.

[0038]

[0039] Q: Flow rate (㎥ / min)

[0040] H : Pressure (m)

[0041] Pump efficiency

[0042] : Motor efficiency

[0043] Inverter efficiency

[0044]

[0045] The formula for the shaft power of the blower is the mathematical equation below.

[0046]

[0047] Q: Flow rate (㎥ / min)

[0048] H : Pressure (m)

[0049] : Blower efficiency

[0050] : Motor efficiency

[0051] Inverter efficiency

[0052]

[0053] Since the pump and blower act as loads to the inverter (3), the shaft power of the pump and the shaft power of the blower can be referred to as load torque (TL).

[0054]

[0055] The shaft power supplied by the inverter (3) can be referred to as power holding torque or power torque (TO).

[0056] The general formula for device efficiency is as follows.

[0057]

[0058]

[0059] In the above mathematical formula, power torque (TO) is 'energy supplied (electrical energy)', and the amount of work done by the machine is 'shaft power of the pump and shaft power of the blower (load torque (TL))'.

[0060]

[0061]

[0062] In the above mathematical formula, power torque (TO) is 'apparent power', and the amount of work done by the machine is 'active power (load torque (TL))'.

[0063]

[0064] The efficiency and power factor of the inverter (3) can be varied for various reasons, such as the output level of the inverter (3), the aging of the motor (2), changes in the load of the motor (2), and changes in the impedance of the motor (2).

[0065] Therefore, if the motor (2) is feedback controlled (e.g., sensor feedback control) based on the apparent power output by the inverter (3) in a fragmentary manner, power loss may increase.

[0066]

[0067] The present invention determines the output of the inverter (3) based on the active power output by the inverter (3).

[0068] An inverter output current sensing means (20, CT: Current Transformer) may be installed on the output terminal side where the inverter (3) outputs voltage to the motor (2).

[0069] The inverter output current sensing means (20) can sense the current (apparent current) that the inverter (3) outputs to the motor (2).

[0070] The load current sensing unit (6) can output a digital value (hereinafter, inverter output apparent current value) corresponding to the value sensed by the inverter output current sensing means (20) to the main processor (5) and the auxiliary processor (7). The inverter output apparent current value may be the apparent current value of the current output by the inverter.

[0071]

[0072] The main processor (5) can control the inverter (3) in the first control mode and the second control mode using the inverter output apparent current value.

[0073]

[0074] Below, the first control mode of the main processor (5) will be described. The first control mode may be a method that tracks active power.

[0075]

[0076] Referring to FIG. 2, the main processor (5) can output a torque command value corresponding to the power torque (T0, apparent power) for starting the initial motor (2) to the torque command device (4) (S21). Here, the torque command value may be a preset value. At this time, the torque command device (4) can output a signal corresponding to the torque command value received from the main processor (5) to the inverter (3) so that the inverter (3) outputs the power torque (TO, apparent power) for starting the initial motor.

[0077] And, the main processor (5) can continuously monitor the inverter output apparent current value. At this time, the main processor (5) can extract an effective current value (hereinafter, inverter output effective current value) from the inverter output apparent current value. The main processor (5) can receive information regarding the phase, magnitude, pulse width, and frequency of the inverter output voltage from the inverter (3), and can calculate the inverter output effective current value and the inverter output effective power using this information. The main processor (5) can extract the inverter output effective current value from the inverter output apparent current value at a preset period (e.g., 1 μsec). And, the main processor (5) can determine whether the apparent power calculated through the inverter output apparent current value is greater than the effective power calculated through the inverter output effective current value by a preset reference value (S22). Here, the preset reference value may be a value of 0.4% of the effective power calculated through the inverter output effective current value.

[0078] If it is determined that the apparent power calculated through the inverter output apparent current value in S22 is greater than the effective power calculated through the inverter output effective current value within a preset reference value, the main processor (5) can prevent the torque command device (4) from changing the current torque command value (S23).

[0079] In contrast, if it is determined that the apparent power calculated through the inverter output apparent current value in S22 is greater than the active power calculated through the inverter output active current value by exceeding a preset reference value, the main processor (5) can perform an operation to generate a new torque command value (S24). At this time, the main processor (5) can generate a new torque command value that causes the inverter (3) to output a power torque (T0, apparent power) that is greater than the active power calculated through the current inverter output active current value by a preset reference value. Here, the preset reference value may be a value of 0.4% of the active power calculated through the inverter output active current value.

[0080] Then, the main processor (5) can transmit the generated new torque command value to the torque command unit (4) (S25). At this time, the torque command unit (4) can output a signal corresponding to the new torque command value received from the main processor (5) to the inverter (3) so that the inverter (3) can output a power torque (T0, apparent power) that is greater than the active power calculated through the current inverter output active current value by a preset reference value.

[0081] The above operation can be repeated continuously while the motor (2) is running. As described above. The present invention can limit the apparent power (T0, power torque) calculated through the inverter output apparent current value so that it does not exceed a value larger than the active power (TL, load torque) calculated through the real-time inverter output active current value by a preset reference value. When the smart control device (10) of the present invention is installed and tested at the site, the power torque (T0, apparent power) for initial startup and the preset reference value can be set to sufficiently satisfy the requirements of the site or process applied to the blower and hydraulic machine. That is, the present invention can maximize power saving while sufficiently satisfying the requirements of the site or process applied to the blower and hydraulic machine. If the power torque (T0, apparent power) for initial startup and the preset reference value are optimally designed, the blower and hydraulic machine can be operated stably at a power factor of 99% or higher.

[0082]

[0083] Below, the second control mode of the main processor (5) will be described. The second control mode may be an Auto Chasing Control method.

[0084]

[0085] Referring to FIG. 3, the main processor (5) can output a torque command value corresponding to the power torque (T0, apparent power) for initial startup to the torque command unit (4) (S31). Here, the torque command value may be a preset value. At this time, the torque command unit (4) can output a signal corresponding to the torque command value received from the main processor (5) to the inverter (3) so that the inverter (3) outputs the power torque (TO, apparent power) for initial startup.

[0086] And, the main processor (5) can continuously monitor the inverter output apparent current value. At this time, the main processor (5) can extract an effective current value (hereinafter, inverter output effective current value) from the inverter output apparent current value. The main processor (5) can receive information regarding the phase, magnitude, pulse width, and frequency of the inverter output voltage from the inverter, and can calculate the inverter output effective current value and inverter output effective power using this information. The main processor (5) can extract the inverter output effective current value from the inverter output apparent current value at a preset period (e.g., 1 μ sec). And, the main processor (5) can determine whether the apparent power calculated through the inverter output apparent current value is greater than the effective power calculated through the inverter output effective current value within a preset reference value (S32). Here, the preset reference value may be a value of 0.4% of the effective power calculated through the inverter output effective current value.

[0087] If it is determined that the apparent power calculated through the inverter output apparent current value in S22 is greater than the effective power calculated through the inverter output effective current value within a preset reference value, the main processor (5) can prevent the torque command device (4) from changing the current torque command value (S33).

[0088] In contrast, if it is determined that the apparent power calculated through the inverter output apparent current value in S22 is greater than the active power calculated through the inverter output active current value by exceeding a preset reference value, the main processor (5) can perform the operation of generating a new torque command value (S34). At this time, the main processor (5) can generate a new torque command value that causes the inverter (3) to output a power torque (T0, apparent power) that is greater than the active power calculated through the current inverter output active current value by a preset reference value. Here, the preset reference value may be a value of 0.4% of the active power calculated through the inverter output active current value.

[0089] And, the main processor (5) can determine whether the inverter output apparent power based on the new torque command value is between the upper apparent power described later and the lower apparent power described later (S35).

[0090] When entering the second control mode, the auxiliary processor (7) can collect the apparent current value of the inverter output during a preset work process cycle through the load current detection unit (6). And, the collection can be repeated for every preset work process cycle. For example, the preset work process cycle may be 1 minute, 2 minutes, or 3 minutes. Here, the preset work process cycle may be appropriately selected by considering the characteristics of the work according to the work site where the motor (2) is applied.

[0091] Figure 4 shows the change in the inverter output apparent current value (P) for a preset work process cycle of 1 minute and 2 cycles. Each waveform represents the change in the inverter output apparent current value for each work process cycle.

[0092] The change in the apparent current value of the inverter output has a pulse shape and may have multiple positive (+) peak values ​​and multiple negative (-) peak values. The minimum value among the multiple positive (+) peak values ​​is information used to calculate the upper torque command value, and the minimum value among the multiple negative (-) peak values ​​is information used to calculate the lower torque command value.

[0093] Depending on the work site where the motor (2) is applied, the apparent current value (or apparent power) of the inverter output may change in various ways. For example, the apparent current value (or apparent power) of the inverter output may change due to changes in the production process itself and tube resistance. Tube resistance may occur due to vapor lock (bubble formation), cavitation (cavitation phenomenon), surging (pulsation phenomenon), etc. When tube resistance occurs, efficiency degradation occurs, such as a decrease in active power and an increase in power consumption (apparent power). To address this efficiency degradation, the present invention aims to limit the power torque (T0, apparent power) based on the minimum value of the positive (+) peak value (information used to calculate the upper limit of the torque command value) and the minimum value of the negative (-) peak value (information used to calculate the lower limit of the torque command value) among the inverter output apparent current values ​​collected during a plurality of preset work process cycles, so as not to cause excessive efficiency degradation.

[0094] To this end, in the second control mode, the auxiliary processor (7) can calculate an upper torque command value and a lower torque command value using the inverter output apparent current value collected during the preset work process cycle for a plurality of preset work process cycles.

[0095] At this time, the auxiliary processor (7) can calculate the apparent power (hereinafter referred to as 'upper apparent power') corresponding to the minimum value of the positive (+) peak value in the inverter output apparent current value collected during the set work process cycle for a plurality of set work process cycles. And, the auxiliary processor (7) can calculate the apparent power (hereinafter referred to as 'lower apparent power') corresponding to the minimum value of the negative (-) peak value in the inverter output apparent current value collected during the set work process cycle for a plurality of set work process cycles.

[0096] Additionally, the auxiliary processor (7) can calculate an upper torque command value that causes the inverter (3) to output an upper apparent power. Additionally, the auxiliary processor (7) can calculate a lower torque command value that causes the inverter (3) to output a lower peak power.

[0097]

[0098] The auxiliary processor (7) may be a processor that is hardware-separated from the main processor (5). In the second control mode, the auxiliary processor (7) may provide at least one of the upper apparent power, lower apparent power, upper torque command value, and lower torque command value to the main processor (7) in real time. By doing so, the main processor (7) may adjust the torque command value using at least one of the upper apparent power, lower apparent power, upper torque command value, and lower torque command value. Furthermore, since the auxiliary processor (7) is responsible for the calculation of the upper apparent power, lower apparent power, upper torque command value, and lower torque command value, the load on the main processor (7) may be reduced. In the first control mode, the calculation operation of the upper apparent power, lower apparent power, upper torque command value, and lower torque command value of the auxiliary processor (7) may not be performed. At this time, the operation of the load current detection unit (6) providing the inverter output apparent current value to the auxiliary processor (7) may not be performed.

[0099] In S35, if it is determined that the inverter output apparent power based on the new torque command value is between the upper apparent power and the lower apparent power described later, the main processor (7) can transmit the new torque command value generated in S34 to the torque command unit (4) (S36). At this time, the torque command unit (4) can output a signal corresponding to the new torque command value received from the main processor (5) to the inverter (3) so that the inverter (3) can output a power torque (T0, apparent power) that is greater than the inverter output effective power calculated using the effective current extracted from the current inverter output apparent current value by a preset reference value.

[0100] In S35, if it is determined that the apparent power of the inverter output due to the new torque command value is not between the upper apparent power and the lower apparent power described later, the main processor (5) can determine whether the apparent power of the inverter output due to the new torque command value is greater than or equal to the upper apparent power (S37).

[0101] In S37, if it is determined that the apparent power of the inverter output based on the new torque command value is greater than or equal to the upper apparent power, the main processor (5) can transmit the upper torque command value to the torque command unit (4) (S38). At this time, the torque command unit (4) can output a signal corresponding to the upper torque command value received from the main processor (5) to the inverter (3) so that the inverter (3) outputs a power torque (TO, upper apparent power) corresponding to the upper torque command value.

[0102] In S37, if it is determined that the apparent power of the inverter output based on the new torque command value is not greater than or equal to the upper apparent power (in other words, that the apparent power of the inverter output based on the new torque command value is less than or equal to the lower apparent power), the main processor (5) can transmit the lower torque command value to the torque command device (4) (S39). At this time, the torque command device (4) can output a signal corresponding to the lower torque command value received from the main processor (5) to the inverter (3) so that the inverter (3) outputs a power torque (TO, lower apparent power) corresponding to the lower torque command value.

[0103] The Auto Chasing Control method can limit the power torque (TO) between the upper apparent power and the lower apparent power in environments where the motor load or motor impedance fluctuates excessively. By doing so, it is possible to prevent the degradation of the inverter and motor life caused by responding to excessive load fluctuations, while simultaneously preventing power waste from the motor.

[0104] The smart control device (10) of the present invention can be installed at the site and the upper apparent power and lower apparent power can be flexibly and automatically set in real time while operating the motor in the process. By doing so, it is possible to maximize energy saving while sufficiently satisfying the requirements of the site or process applied to the blower and hydraulic machine in an environment where the real-time motor load fluctuates excessively.

[0105]

[0106] An operator or installer can set a control mode of the smart control device (10) to suit the site or process. A first control mode may be suitable for a site or process where the motor load fluctuates below a first level. And, a second control mode may be suitable for a site or process where the motor load fluctuates above a first level.

[0107] The control panel (8) may provide an interface for setting the control mode of the smart control device (10). Through the control panel (8), the control mode of the smart control device (10) may be selected as either the first control mode or the second control mode. Of course, the smart control device (10) may additionally have a control mode other than the first and second control modes.

[0108] The smart control device (10) can perform control operations as described above according to one of the first control mode and the second control mode selected.

Claims

1. A smart control device for an electric motor applied to a blower and a hydraulic machine, equipped with a control panel having a control mode setting function for multiple control modes, including an auto chasing control method.

2. In Paragraph 1, Includes more main processors, In the first control mode, the above main processor, Continuously monitor the inverter output apparent current value, and It determines whether the apparent power calculated through the inverter output apparent current value is greater than the active power calculated through the inverter output active current value within a preset reference value, and A smart control device for an electric motor applied to a blower and a hydraulic machine, characterized in that if it is determined that the apparent power calculated through the inverter output apparent current value is greater than the active power calculated through the inverter output active current value within a preset reference value, the main processor prevents the torque command unit from changing the current torque command value.

3. In Paragraph 2, If it is determined that the apparent power calculated through the inverter output apparent current value is greater than the active power calculated through the inverter output active current value by exceeding a preset reference value, the main processor performs the operation of generating a new torque command value, and A smart control device for an electric motor applied to a blower and a hydraulic machine, characterized in that the main processor generates a new torque command value that causes the inverter to output a power torque greater than the active power calculated through the current inverter output active current value by a preset reference value.

4. In Paragraph 1, Includes more main processors, In the second control mode, the above main processor, Continuously monitor the inverter output apparent current value, and If it is determined that the apparent power calculated through the inverter output apparent current value is greater than the active power calculated through the inverter output active current value by exceeding a preset reference value, the main processor generates a new torque command value, and Determining whether the inverter output apparent power based on the above new torque command value is a value between the upper apparent power and the lower apparent power, and The inverter output apparent power based on the above new torque command value is the above upper limit apparent power If it is determined that the value is between the power and the lower limit apparent power, the new torque command value is transmitted to the torque command device, and If it is determined that the apparent power of the inverter output due to the new torque command value is not a value between the upper apparent power and the lower apparent power, then it is determined whether the apparent power of the inverter output due to the new torque command value is greater than or equal to the upper apparent power. A smart control device for an electric motor applied to a blower and a hydraulic machine, characterized by transmitting the upper torque command value to the torque command unit when it is determined that the inverter output apparent power based on the new torque command value is greater than or equal to the upper apparent power, and transmitting the lower torque command value to the torque command unit when it is determined that the inverter output apparent power based on the new torque command value is not greater than or equal to the upper apparent power.

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