WO2011105676A1

WO2011105676A1 - Apparatus and method for controlling the speed of a wound-rotor induction motor

Info

Publication number: WO2011105676A1
Application number: PCT/KR2010/007480
Authority: WO
Inventors: 박시우; 김성완
Original assignee: 주식회사 자이벡
Priority date: 2010-02-24
Filing date: 2010-10-28
Publication date: 2011-09-01

Abstract

The present invention relates to an apparatus and method for controlling the speed of a wound-rotor induction motor. Specifically, a wound-rotor induction motor according to one embodiment of the present invention comprises: a rectifying unit receiving AC power from rotor windings of the wound-rotor induction motor and rectifying the AC power to DC power; a switching unit connected to an output end of the rectifying unit and adjusting a turn-on time in response to a switching control unit; a power storage unit receiving and storing power which is induced by a rotor of the wound-rotor induction motor during a turn-off time of the switching unit; a power regeneration unit supplying the power stored in the power storage unit to an external power system; a control unit controlling a switching operation of the switching unit such that the speed or torque of the wound-rotor induction motor is the same as that required by a user, and controlling operating conditions of the power regeneration unit.

Description

Speed control device for winding induction motor and speed control method thereof

The present invention relates to a speed control device of a wound induction motor and a speed control method thereof, wherein the speed or torque of the wound induction motor is smoothly and freely controlled, and the electrical energy induced by the rotor winding is regenerated to the power supply side. The present invention relates to a speed control device for a winding type induction motor and a speed control method for reducing energy usage.

Electric motors that are used as power transmission devices for various facilities in the industrial field are mainly induction motors. Induction motors are mainly composed of two types of squirrel cage induction motors and winding type induction motors.

Although the winding type induction motor is still widely used in the industrial field, research and development to improve the control method of the winding type induction motor has not been made well.

The wound induction motor may implement a large starting torque by controlling a current flowing through the rotor winding to adjust an equivalent resistance value of the rotor winding. Therefore, it is widely used for the purpose of starting a crane or a large inertial load which requires a large starting torque. Conventional methods for controlling torque and speed of wound induction motors include secondary resistance, stationary Servius and stationary cramers.

In the secondary resistance method, the speed of the wound induction motor is controlled stepwise by connecting the secondary resistance in each stage of the rotor winding output stage of the wound induction motor and adjusting the resistance value by sequentially shorting the mechanical switch. However, this secondary resistance method has a disadvantage of causing contact failure of the mechanical switch due to the inductance of the rotor winding.

In order to improve the frequent failure of mechanical switches, a method of using a thyristor as a switch for secondary resistance is recently used. However, the method of using a thyristor has a problem that the manufacturing cost of the device is greatly increased because a thyristor, which is an expensive three-phase semiconductor switch, must be used for each stage of the secondary resistors connected in multiple stages.

Another disadvantage of the multi-stage secondary resistance control method is that the operation is not smooth because the speed must be controlled stepwise. This is a phenomenon in which a large torque ripple occurs because the resistance value does not change linearly but changes in steps. To solve the torque ripple problem, recently, a thyristor is used to control the voltage entering the stator of the motor, thereby relatively smooth and delicate torque control. Has become possible. However, this method has a disadvantage in that maximum torque cannot be used because torque loss is inevitable.

In addition, the biggest disadvantage of the secondary resistance method is that the electrical energy induced in the rotor is wasted in the form of thermal energy through the secondary resistance. An additional disadvantage is the shortening of the lifetime of secondary resistors exposed to continuous thermal fatigue.

The stationary Serbius method regenerates and restores the battery energy obtained after the three-phase full-wave rectification of the rotor output of the wound induction motor to the three-phase power supply, but increases the price of the device, increases the weight, and reduces the installation space. There is a problem.

The stationary cramer system rectifies the rotor output of the wound induction motor by three-phase full-wave rectification, and then connects the rotor output power of the induction motor by connecting it to the commutator of a DC motor connected on the same axis as the mechanical drive of the wound induction motor. Is converted to the mechanical output of the direct current motor to help the output of the winding type induction motor by mechanical force, the system is complex and costs a lot of configuration and installation.

Accordingly, there is a need to solve the problems of the conventional method and to develop a technology for controlling the winding type induction motor economically.

The present invention has been made to solve the above problems, and provides an apparatus and method capable of continuous, stable and efficient speed and torque control without the use of secondary resistance in the winding induction motor, and in the secondary resistor It aims to prevent waste of power by returning the consumed energy to the power supply side. In addition, to improve the circuit configuration of the device for controlling the speed and torque of the wound induction motor, and to reduce the production cost to provide a speed control device economically.

Technical problems to be achieved by the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art from the description of the present invention. .

According to an aspect of the present invention, there is provided a speed control apparatus for a wound induction motor, including: a rectifier configured to receive AC power output from a rotor winding of a wound induction motor and rectify to a DC voltage; A switching unit connected to an output terminal of the rectifying unit and adjusting a turn-on time in response to a switching control signal; A power storage unit for receiving and storing electrical energy induced by a rotor of the wound induction motor during the time when the switching unit is turned off; A power regenerative unit supplying power stored in the power storage unit to an external power system; And a controller configured to adjust the switching operation of the switching unit so that the speed or torque of the wound induction motor matches the speed or torque of the wound induction motor required by the user, and adjust an operating state of the power regenerative unit. In this case, the operating state of the power regenerative unit may be a regenerative operation mode for activating the power regenerative unit to supply power to regenerative energy or a regenerative stop mode for stopping the operation of the power regenerative unit.

The rectifier may be a three-phase full-wave rectifier circuit for rectifying the three-phase AC power output from the winding of the rotor of the wound induction motor to DC, but is not limited thereto.

The switching unit includes one or more switches connected in parallel to both ends of the DC output terminal of the rectifying unit. The one or more switches may be semiconductor switches. The semiconductor switch is not particularly limited, but is preferably an insulated gate bipolar transistor (IGBT), a field-effect transistor (FET), a gate turn-off thyristor (GTO), And a bipolar junction transistor (BJT) may be used.

The power storage unit may include a capacitor connected in parallel to both ends of the DC output terminal of the rectifying unit and connected to a rear end of the switching unit to store power induced by the rotor of the wound induction motor.

In addition, the speed control device of the winding type induction motor according to an embodiment of the present invention is further disposed between the power storage unit and the switching unit to prevent the reverse flow to prevent the electric power stored in the capacitor stored in the power storage unit to be discharged back It may include. The backflow prevention part includes one or more diodes, and the location of the backflow prevention diode is not particularly limited, and may be located at either of the DC terminals of the rectification part.

The reverse flow prevention unit prevents current from flowing in the reverse direction of the current transfer direction.

In one embodiment of the present invention, the power regenerative unit may be a system-linked regenerative inverter for converting power stored in the power storage unit into alternating current and supplying the alternating current to an external power supply system.

The grid-connected regenerative inverter is not particularly limited, but may preferably be selected from a pulse width modulation (PWM) inverter, a 120 degree energized inverter, and a thyristor converter.

In the present invention, the control unit includes a speed detector for detecting the rotational speed of the rotor of the wound induction motor. The apparatus may further include a speed controller configured to receive the current speed of the rotor and the required speed for the wound induction motor received from the user, and compare the current speed and the required speed, respectively.

The controller may include a signal generator configured to generate a switching control signal for controlling a switching operation of the switching unit by the control output.

In this case, the switching control signal may be a signal modulated by a pulse width modulation (PWM) scheme.

The controller may include a regenerative mode controller configured to activate the power regenerative unit to control the power regenerative operation mode or to determine a regenerative stop mode for stopping the operation of the power regenerative unit according to the amount of power stored in the power storage unit. Can be.

Speed control method of the winding induction motor according to an embodiment of the present invention for achieving the above object, the required speed or torque of the winding induction motor required by the user, and the current speed or torque of the winding induction motor Comparing; Generating and transmitting a switching control signal for controlling a switching operation of the switching unit connected to the wound induction motor such that the current speed or torque of the wound induction motor matches the required speed or torque of the wound induction motor required by the user. ; And changing the speed or torque of the wound induction motor by adjusting the amount of rotor current of the wound induction motor while the switching unit is turned on according to the turn on duty in response to the switching control signal.

The speed control method of the wound induction motor may include: receiving power derived from a rotor of the wound induction motor for a time other than a time when the switching unit is turned on and storing the power in a power storage unit; And supplying the stored power to the external power system as regenerative energy according to the amount of the stored power.

Here, the power stored in the power storage unit may be in a direct current form, and the method may further include converting the direct current power into an alternating current power before supplying the power stored in the power storage unit to the external power system as regenerative energy. .

The converting the DC-type power into the AC-type power may be performed by any one of the grid-associated regenerative inverters selected from a pulse width modulation (PWM) inverter, a 120-degree conduction inverter, and a thyristor converter.

Comparing the required speed or torque of the wound induction motor required by the user in the speed control method of the wound induction motor according to an embodiment of the present invention, and the current speed or torque of the wound induction motor, Detecting the rotational frequency of the power output from the rotor windings of the linear induction motor and the frequency of the power supply voltage applied to the stator of the wound induction motor; Calculating a slip of the wound induction motor by comparing the detected rotor frequency and a frequency of a power supply voltage; Calculating a current speed or torque of the wound induction motor using the slip; And comparing the current speed or torque and the required speed or torque with respect to the wound induction motor previously input from the user.

At this time, the slip is based on the electromagnetic rotational speed of the rotor winding calculated from the frequency of the three-phase AC power output from the winding of the rotor of the wound induction motor and the frequency of the power supply voltage applied to the stator of the wound induction motor. It may be a value calculated from the difference between the calculated electromagnetic rotational speeds of the stator windings.

In addition, in the method according to another embodiment of the present invention, comparing the required speed or torque of the wound induction motor, and the current speed or torque of the wound induction motor, the rotation of the wound induction motor Calculating a current speed or torque of the wound induction motor by detecting a mechanical speed of self-rotation; And comparing the current speed with a required speed for the winding type induction motor previously input by the user.

The present invention is an improvement of the secondary resistance method in the conventional technology for controlling the winding type induction motor, and does not use the secondary resistance in controlling the speed and torque of the winding type induction motor, therefore, the use of the secondary resistance There is an effect to improve the problems caused by.

In particular, since the control device of the wound induction motor is simplified, the manufacturing cost can be reduced.

As the discontinuous and smooth operation characteristics generated when controlling the speed of the wound induction motor by using the secondary resistance are improved, speed control of linear acceleration or deceleration is possible.

In addition, power consumption is reduced by returning the power consumed by the secondary resistor to the grid power supply side.

1 is a block diagram showing the configuration of a speed control apparatus of a wound induction motor according to an embodiment of the present invention.

2 is a circuit diagram illustrating a speed control device of a wound induction motor according to an exemplary embodiment of the present invention.

3 is a block diagram showing the configuration of the control unit shown in FIG. 1.

Fig. 4 is a graph showing the relationship between the magnitude of the secondary resistance and the amount of generated torque connected to the rotor of the wound induction motor.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

In addition, in the various embodiments, components having the same configuration will be representatively described in the first embodiment using the same reference numerals, and in other embodiments, only the configuration different from the first embodiment will be described.

In order to clearly describe the present invention, parts irrelevant to the description are omitted, and like reference numerals designate like elements throughout the specification.

Throughout the specification, when a part is "connected" to another part, this includes not only "directly connected" but also "electrically connected" with another element in between. . In addition, when a part is said to "include" a certain component, which means that it may further include other components, except to exclude other components unless otherwise stated.

1 is a block diagram showing a configuration of a speed control device 100 of a wound induction motor according to an embodiment of the present invention.

In the embodiment of FIG. 1, the speed control device 100 of the wound induction motor is connected to the rotor winding of the wound induction motor 200 to control the speed and torque of the wound induction motor 200.

The speed control device 100 of the wound induction motor includes a rectifier 101, a switching unit 103, a power storage unit 105, a backflow prevention unit 107, a power regeneration unit 109, and a control unit 111. do.

The rectifier 101 receives the alternating current output from the rotor of the wound induction motor 200 and rectifies the DC. The rectifier 101 is not particularly limited, but may be configured as a three-phase full-wave rectifier circuit. The rectifier 101 including the three-phase full-wave rectifier circuit is illustrated in detail in the circuit diagram of FIG. 2.

Referring to FIG. 2, the rectifier 101 includes six three-phase full-wave rectifying bridge diodes connected to each of the three-phase current output terminals of the rotor winding of the wound induction motor 200. The number of bridge diodes is not particularly limited, and may be adjusted according to the number of output terminals of the rotor windings of the wound induction motor 200.

The current output from the output end of the rotor winding of the wound induction motor 200 is an alternating current corresponding to the voltage induced in the wound induction motor 200, and the operating principle of the three-phase full-wave rectification circuit shown in FIG. Since it is well-known fact, detailed description is abbreviate | omitted. The switching unit 103 is connected to both ends of the DC output terminal of the rectifying unit 101 to control the amount of current flowing through the rotor winding of the wound induction motor 200.

The switching unit 103 may be configured by connecting at least one semiconductor switch in parallel, preferably an insulated gate bipolar transistor (IGBT), a field-effect transistor (FET), a gate Semiconductor switches, such as gate turn-off thyristors (GTOs) and bipolar junction transistors (BJTs), may be used.

The switching unit 103 receives the switching control signal generated for the speed control of the winding type induction motor 200 by the control unit 111 to control the operation.

Referring to the circuit diagram of FIG. 2, it can be seen that the semiconductor switch M1 uses IGBT. The IGBT semiconductor switch M1 controls the flow of the DC current rectified from the rectifying unit 101.

Specifically, when the switching control signal for controlling the switching operation of the semiconductor switch M1 is transmitted to the gate electrode of the semiconductor switch M1, the semiconductor switch M1 is turned on or turned off in response to the switching control signal. When the switching control signal having the gate-on voltage level is transmitted to the gate electrode of the semiconductor switch M1, the semiconductor switch M1 is turned on. The DC current rectified from the rectifying unit 101 is turned on via the semiconductor switch M1 while being turned on. Then, the current amount of the rotor is gradually increased by the inductance component induced in the rotor winding of the wound induction motor 200.

The switching control signal is generated by a command generated by a control program of the control unit 111 operating according to the speed control instruction of the user and is transmitted to the semiconductor switch M1. Preferably, the switching control signal may be transmitted in a pulse width modulated (PWM) form for switching control of the semiconductor switch M1.

When the switching control signal having the gate-off voltage level is transmitted to the gate electrode of the semiconductor switch M1, the semiconductor switch M1 is turned off. At this time, the DC current rectified from the rectifying unit 101 is not transmitted to the switching unit 103. And is transmitted to the power storage unit 105 via the backflow prevention unit 107.

The power storage unit 105 may be composed of at least one capacitor C1.

The backflow prevention unit 107 may be configured as a backflow prevention diode M2.

Referring to the circuit diagram of FIG. 2, it can be seen that the backflow prevention diode M2 is connected to the connection point of the DC terminal of the switching unit 103 and the rectifying unit 101 in the direction of current flow. At this time, the installation position of the backflow prevention diode M2 is not particularly limited, and may be installed at any one of the DC terminals through which the DC current flows from the rectifying unit 101. As can be seen in the circuit diagram of FIG. 2, the reverse flow prevention diode M2 may be installed at any one of the positions of M2 ′, M2 ″, and M2 ′ ″ shown by dotted lines to form the reverse flow prevention unit 107. This has the same effect regardless of location. The reverse flow prevention diode M2 is installed for the purpose of preventing the reverse flow of the electric energy stored in the capacitor when the semiconductor switch M1 is turned on.

The other end of the backflow prevention diode M2 is connected to a capacitor C1 that stores power output from the rotor winding of the wound induction motor 200.

Referring to the circuit diagram of FIG. 2, the power regeneration unit 109 is connected to one end and the other end of the capacitor C1 serving as the power storage unit 105, respectively, and corresponds to the control command received from the control unit 111. The power stored in the power storage unit 105 is supplied to the commercial power of the external system.

In addition, the power regeneration unit 109 converts the electric energy stored in the direct current form in the capacitor (C1) to the power of the alternating current type to supply to the commercial power supply side of the external system.

The grid-connected inverter constituting the power regenerative unit 109 is not particularly limited, but a pulse width modulation (PWM) inverter, a 120-degree conduction inverter, a thyristor converter, or the like can be used.

The control unit 111 performs a function of controlling each component in the speed control device 100 of the wound induction motor.

That is, referring to FIG. 1, the control unit 111 is connected to the switching unit 103 and the power regenerative unit 109, respectively, and at least one output end and the winding type of the rotor winding output end of the wound induction motor 200. It is connected to any one or more input terminals of a power input terminal connected to the stator of the induction motor 200. However, typically, since the power input terminal connected to the stator of the wound induction motor 200 is a commercial power source having a frequency of 60 Hz, the power input terminal connected to the stator may be omitted from connecting to the control unit 111.

The control unit 111 controls the speed of the wound induction motor 200 by comparing the speed control command of the winding induction motor 200 with the rotor rotational speed of the wound induction motor detected in real time. That is, the control unit 111 may control the speed of the winding type induction motor 200 by adjusting the ratio of the switching turn on time and the turn off time of the switching unit 103. The switching control signal required for the speed control of 200 is generated.

More specifically, the configuration of the control unit 111 is shown in FIG. 3.

Referring to FIG. 3, the controller 111 includes a speed detector 301, a speed controller 305, a signal generator 307, and a regenerative mode controller 309.

The speed detector 301 detects the rotational speed of the rotor. Preferably, the speed detector 301 compares the frequency of the alternating current voltage induced in the rotor windings with the frequency of the power supply voltage applied to the stator windings. By calculating the slip, the rotational speed of the rotor can be detected. In addition, it is possible to detect the mechanical rotational speed of the rotor by using a rotary encoder or taco generator that directly detects the mechanical rotational speed of the rotor.

Naturally, the embodiment of the speed detector 301 is not limited to the slip detection method, the rotary encoder, or the detection method using a taco generator. The slip calculation method, which is often used as a method of detecting the rotational speed of the induction motor 200, is well known and thus will not be described.

The speed controller 305 compares the rotor speed of the rotor of the wound induction motor 200 with the speed required by the user and calculates the difference in real time.

In addition, the speed controller 305 may increase or decrease the rotor current of the wound induction motor 200 in response to the turn-on time of the switching unit 103, and the rotor speed required by the user. The control unit determines whether the signals match, and if there is a difference, manages the signal generation method of the signal generator 307 necessary for following the user's required speed.

4 is a graph showing a relationship between the resistance, the speed, and the amount of generated torque of a rotor winding of a conventional wound induction motor.

In the graph of FIG. 4, the X axis represents the speed of the wound induction motor 200, and the Y axis represents the torque. As the X-axis increases, the speed of the wound induction motor 200 increases. According to Equation 1, slip is reduced.

Slip is defined as the ratio of the electrical angular speed of the rotor of the wound induction motor 200 to the electrical angular speed applied to the stator winding. Specifically, Equation 1 is as follows.

Equation 1

Ws: Electric angle speed applied to the stator

Wm: electric angle speed induced on the rotor

Therefore, when the electric angular speed of the power applied to the stator of the wound induction motor 200 is constant, the slip is reduced as the electric angular speed of the rotor increases (that is, as the speed of the wound induction motor increases). .

The resistance of the rotor increases as the graphs T1, T2, and T3 increase, and the tendency of speed, slip, and torque according to the resistance can be determined. That is, as the resistance of the rotor increases, it can be seen that the speed at each point where the maximum torque is generated is low, and the slip corresponding to the speed at which the maximum torque is generated is high.

This relationship can be summarized as the following equation (2).

Equation 2

S: slip (Equation 1) Ws: applied voltage frequency of the stator

Rs: resistance of stator Rr: winding resistance inside rotor

Rx: secondary resistance value Vs: applied voltage

Xs: stator reactance Xr: rotor reactance

In the control of the speed or torque of the conventional winding type induction motor 200, it was controlled by adjusting the secondary resistance value (Rx) connected to the output of the rotor. That is, by changing the rotor equivalent resistance (Rr + Rx), the torque amount was adjusted and the speed was controlled in the same relationship as in equation (2). For this purpose, the speed control device of the conventional winding type induction motor has connected a secondary resistor composed of a plurality of stages to the winding of the rotor. By changing the secondary resistance, the amount of current flowing through the rotor winding is changed, and as a result, the equivalent resistance (Rr + Rx) of the rotor winding viewed from the stator side is changed, so that the speed or torque characteristics of the wound induction motor 200 are improved. Changed.

However, in one embodiment of the present invention, the speed control unit 305 of the control unit 111 changes the amount of current flowing through the rotor winding in controlling the torque or speed of the wound induction motor 200. By controlling the on time adjustment, the result is that the equivalent resistance (Rr, eq) of the rotor winding is adjusted without the secondary resistance.

Then, the speed control method of the wound induction motor 200 according to an embodiment of the present invention has a relationship of the equation (3).

Equation 3

S: slip (Equation 1) Ws: applied voltage frequency of the stator

Rs: resistance of stator Rr, eq: equivalent resistance of rotor winding

Vs: applied voltage Xs: stator reactance

Xr: rotor reactance

In the relationship between FIG. 4 and Equation 3, when the current rotational speed of the rotor of the wound induction motor 200 does not reach the required speed of the user, the speed of the rotor should be accelerated to follow the required speed. In order to accelerate the rotational speed of the rotor, the equivalent resistance (Rr, eq) of the rotor winding should be changed in the state that the maximum torque occurs at a faster rotational speed than present. This means that the equivalent resistance (Rr, eq) of the rotor winding should be lowered, as can be seen in the relationship of FIG. 4. Therefore, in order to lower the equivalent resistances Rr and eq of the rotor windings, the switching method of the switching unit 103 is controlled in the direction of increasing the current flowing through the rotor.

The signal generator 307 of FIG. 3 provides a switching control signal for controlling the switching operation of the switching unit 103 such that the amount of rotor current required for the speed control of the wound induction motor 200 flows through the switching unit 103. Create and deliver.

In the above example, in order to follow the required speed or torque of the user, the signal generator 307 may generate and supply a switching control signal applied at an on voltage level so that the switching unit 103 is turned on in response to the amount of current to increase. . Specifically, when the pulse width of the pulse width modulated switching control signal is increased, the turn-on time of the switching unit 103 is increased, so that the rotor current amount of the wound induction motor 200 is gradually increased. On the contrary, when the pulse width of the pulse width modulated switching control signal is reduced, the turn-on time of the switching unit 103 is decreased, so that the rotor current amount of the wound induction motor 200 is gradually reduced.

According to an embodiment of the present invention to control the turn-on time of the switching unit 103 composed of at least one semiconductor switch, rather than controlling the speed or torque by directly changing the rotor resistance of the wound induction motor 200 By controlling the amount of current flowing through the rotor winding, thereby changing the equivalent resistance (Rr) of the rotor winding to obtain the effect of indirectly controlling the speed and torque of the wound induction motor 200. This allows linear speed control and smooth and stable operation due to the control device without the secondary resistor.

The controller 111 of FIG. 3 includes a regenerative mode controller 309 that controls the power regenerative unit 109. The regenerative mode controller 309 supplies the power stored in the power storage unit 105 to the commercial power system during the turn off time of the switching unit 103. When the supply of such regenerative energy is continued and the amount of power stored in the power storage unit 105 falls below a predetermined amount of power, the regenerative mode controller 309 may temporarily stop the regenerative operation as necessary.

By such a method, the device according to the present invention can regenerate power induced in the rotor of the wound induction motor 200 to a commercial power source, thereby reducing power consumption.

Claims

Rectifying unit for receiving the AC power output from the rotor winding of the wound induction motor to rectify the DC voltage;

A switching unit connected to an output terminal of the rectifying unit and adjusting a turn-on time in response to a switching control signal;

A power storage unit configured to receive and store electric power induced by the rotor of the wound induction motor during the time when the switching unit is turned off;

A power regenerative unit supplying power stored in the power storage unit to an external power system; And

Winding induction including a control unit for controlling the switching operation of the switching unit, and the operation state of the power regenerative unit so that the speed or torque of the winding induction motor to match the speed or torque of the winding induction motor required by the user Speed control device of the electric motor.
The method of claim 1,

And the rectifier is a three-phase full-wave rectifier circuit for rectifying the three-phase AC power output from the winding of the rotor of the wound induction motor into direct current.
The method of claim 1,

The switching unit is a speed control device for a wound type flow motor of at least one switch connected in parallel to both ends of the DC output terminal of the rectifier.
The method of claim 3, wherein

The switching unit is a speed control device of a wound induction motor including at least one semiconductor switch.
The method of claim 1,

The power storage unit,

And a capacitor connected in parallel to both ends of the DC output terminal of the rectifying unit and connected to a rear end of the switching unit to store power induced by the rotor of the wound induction motor.
The method of claim 1,

And a backflow prevention unit disposed between the power storage unit and the switching unit to prevent backflow and discharge of power stored in the capacitor of the power storage unit.
The method of claim 6,

The reverse flow prevention unit is a speed control device of the wound induction motor, characterized in that it comprises one or more diodes.
The method of claim 1,

The power regenerative unit,

The speed control device of the wound induction motor which is a grid-connected regenerative inverter for converting the power stored in the power storage unit into an alternating current to supply to an external power supply system.
The method of claim 8,

The grid-connected regenerative inverter is any one selected from a pulse width modulated (PWM) inverter, a 120-degree conduction inverter, and a thyristor converter.
The method of claim 1,

The control unit,

And a speed detector for detecting a rotational speed of the rotor of the wound induction motor.
The method of claim 10,

The controller may further include a speed controller configured to receive a current rotational speed of the rotor and a required speed for a wound induction motor received from a user, and compare the current speed and the required speed, respectively. Speed control device.
The method of claim 1,

The control unit,

And a signal generator for generating a switching control signal for controlling a switching operation of the switching unit.
The method of claim 12,

And the switching control signal is a signal modulated by a pulse width modulation (PWM) scheme.
The method of claim 1,

The control unit,

According to the magnitude of the amount of power stored in the power storage unit of the winding type induction motor including a regenerative mode control unit to activate the power regenerative unit to control the power regenerative operation mode or to determine the regenerative stop mode to stop the operation of the power regenerative unit. Speed control device.
Comparing a required speed or torque of the winding induction motor requested by a user, and a current speed or torque of the winding induction motor;

Generating and transmitting a switching control signal for controlling a switching operation of the switching unit connected to the wound induction motor such that the current speed or torque of the wound induction motor matches the required speed or torque of the wound induction motor required by the user. ; And

A speed control of the wound induction motor including changing the speed or torque of the wound induction motor by adjusting the amount of rotor current of the wound induction motor according to the switching control signal in response to the switching control signal. Way.
The method of claim 15,

Speed control method of the wound induction motor,

Receiving power derived from the rotor of the wound induction motor during a time other than the time when the switching unit is turned on and storing the power in the power storage unit; And

And supplying the stored power to the external power system as regenerative energy according to the magnitude of the stored amount of power.
The method of claim 16,

The power stored in the power storage unit is a direct current form,

And converting the DC power into AC power before supplying the power stored in the power storage unit to the external power system as regenerative energy.
The method of claim 17,

The step of converting the electric power of the direct current form into the electric power of the alternating current type, the winding type induction motor performed in any one of the grid-associated regenerative inverter selected from a pulse width modulation (PWM) inverter, a 120-degree conduction inverter, and a thyristor converter Speed control method.
The method of claim 15,

Comparing the required speed or torque of the winding induction motor required by the user, and the current speed or torque of the winding induction motor,

Detecting a rotation frequency of electric power output from the rotor winding of the wound induction motor and a frequency of a power supply voltage applied to the stator of the wound induction motor;

Calculating a slip of the wound induction motor by comparing the detected rotor frequency and a frequency of a power supply voltage;

Calculating a current speed or torque of the wound induction motor using the slip; And

Comparing the current speed or torque, and the required speed or torque for the winding induction motor previously input from the user, the speed control method of the wound induction motor.
The method of claim 19,

The slip is calculated from the electromagnetic rotational speed of the rotor winding calculated from the frequency of the three-phase AC power output from the winding of the rotor of the wound induction motor and the frequency of the power supply voltage applied to the stator of the wound induction motor. A method for speed control of a wound induction motor, the value calculated from the difference between the electromagnetic rotational speeds of the stator windings.
The method of claim 15,

Comparing the required speed or torque of the winding induction motor required by the user, and the current speed or torque of the winding induction motor,

Calculating a current speed or torque of the wound induction motor by detecting a mechanical speed at which the rotor of the wound induction motor rotates; And

Comparing the current speed and the required speed for the winding induction motor previously input from the user, the speed control method of the winding induction motor.
The method of claim 15,

And the switching control signal is a signal modulated by a pulse width modulation (PWM) scheme.