CN111564862B - Rotating frequency conversion and voltage transformation method based on double-fed motor - Google Patents
Rotating frequency conversion and voltage transformation method based on double-fed motor Download PDFInfo
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- CN111564862B CN111564862B CN202010437728.6A CN202010437728A CN111564862B CN 111564862 B CN111564862 B CN 111564862B CN 202010437728 A CN202010437728 A CN 202010437728A CN 111564862 B CN111564862 B CN 111564862B
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/34—Arrangements for transfer of electric power between networks of substantially different frequency
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- H—ELECTRICITY
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- H02K—DYNAMO-ELECTRIC MACHINES
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Abstract
The invention disclosesA rotating frequency conversion and voltage transformation method based on a double-fed motor solves the problems of large equipment size, high manufacturing cost and low conversion efficiency of the traditional frequency conversion equipment of a motor-generator set. The rotating speed of the magnetic field in the air gap when the wound double-fed asynchronous generator is supplied with 50Hz and the rotating speed of the magnetic field in the air gap when the wound double-fed asynchronous generator is supplied with 60Hz, namely n = n s2 ‑n s1 (ii) a As the rated rotation speed of the asynchronous motor; coaxially connecting an asynchronous motor (2) and a wound-rotor type double-fed asynchronous generator (1) together; connecting a three-phase rotor winding on the wound double-fed asynchronous generator with a 50Hz power grid through a collecting ring, and connecting a three-phase stator winding on the wound double-fed asynchronous generator with a 60Hz power grid; the invention realizes the superposition of the rotating speed provided by the asynchronous motor and the air gap rotating magnetic field provided by the 50Hz power grid in the wound double-fed asynchronous generator, and realizes the conversion of two electric systems.
Description
Technical Field
The invention relates to a voltage frequency conversion device based on a double-fed motor, in particular to a device and a method for converting different power frequency electric systems by adopting the device.
Background
With the increasing of the environmental protection, many countries have come out of more stringent environmental protection policies, such as: in shipping, traffic management departments and environmental protection departments in many countries require that shore power is used during the berthing of ships at ports and docks, and diesel generator sets on the ships are not allowed to be started, so that the purpose of protecting the ecological environment of the ports and docks is achieved; however, different countries use different power frequency electric systems, some use 50Hz power frequency electric system, some use 60Hz power frequency electric system, the electric systems used by ships of different countries are different, and the wharf shore power also has two different electric systems; when the electric system frequency used by a ship berthed at a port wharf is different from the electric system frequency of berthed wharf shore power, the problem that the ship cannot be directly connected to the shore power exists; therefore, the quay shore power is required to be provided with two shore power supplies with different frequencies, or a device which can convert the two shore power supplies into each other is arranged on a ship; at present, the scheme of equipping a device capable of mutually converting two frequency power supplies on a ship is common, the existing conversion device adopts a motor-generator set to carry out two frequency conversions, namely a 50Hz 10-pole synchronous motor and a 60Hz 12-pole synchronous motor, the rotating speeds are both 600rpm, the two synchronous motors form a set of motor-generator set, and the mutual conversion of 50Hz-60Hz power supplies can be carried out; however, the main problems with this solution are: the equipment has large volume, higher manufacturing cost, low efficiency and large operation noise; with the development of power electronic technology, the frequency conversion equipment of the motor-generator set is gradually replaced by a static power electronic frequency converter, and although the frequency converter based on the power electronic technology overcomes the defects of large volume, low efficiency and high noise of the scheme of the motor-generator set, the frequency converter has the problem of high price, and the reliability, electromagnetic compatibility and power supply quality are inferior to those of the frequency conversion equipment of the traditional motor-generator set.
Disclosure of Invention
The invention provides a rotary frequency conversion and transformation device based on a double-fed motor, which solves the problems of high price, low electromagnetic compatibility and low power supply quality of a power electronic frequency converter and also solves the problems of large equipment volume, high manufacturing cost and low conversion efficiency of the frequency conversion equipment of the traditional motor-generator set.
The invention solves the technical problems through the following technical scheme:
the general concept of the invention is: firstly, a wound-rotor type double-fed asynchronous generator is taken, when the motor is supplied with power at 50Hz, the magnetic field rotating speed in an air gap, namely the synchronous rotating speed is n S1 The magnetic field rotating speed in the air gap when the motor is powered at 60Hz, namely the synchronous rotating speed is n S2 Obtaining the rotating speed difference n of the motor under two frequency electric systems, namely n = n s2 -n s1 (ii) a And then, taking an asynchronous motor, wherein the rated rotating speed of the motor when the motor is connected with 50Hz three-phase alternating current is equal to the rotating speed difference n of the double-fed asynchronous generator under the two frequency electric systems, so that the motor is called as a slip motor, namely the rotating speed of the motor is as follows: n = n s2 -n s1 (ii) a Coaxially connecting a double-fed asynchronous generator and an asynchronous motor together; finally, connecting a three-phase rotor winding on the winding type double-fed asynchronous generator with a 50Hz power grid through a collecting ring, and connecting a three-phase stator winding on the winding type double-fed asynchronous generator with a 60Hz power grid; the invention realizes the superposition of the rotating speed provided by the slip motor and the air gap rotating magnetic field provided by the 50Hz power grid in the winding type double-fed asynchronous generator, and realizes the conversion between the 50Hz power system and the 60Hz power system.
A rotating frequency conversion and transformation device based on a double-fed motor comprises a winding double-fed asynchronous generator, a slip motor, a 50Hz power grid access end and a 60Hz power grid access end, wherein a rotor central shaft of the winding double-fed asynchronous generator and a rotor central shaft of the slip motor are coaxially connected together through a coupler, the 50Hz power grid access end is respectively and electrically connected with a stator three-phase winding of the slip motor and an electric brush on a rotor collecting ring of the winding double-fed asynchronous generator through a first knife switch, and the stator three-phase winding of the winding double-fed asynchronous generator is connected with the 60Hz power grid access end through a second knife switch; the rotating speed n of the slip motor is equal to the difference value of the following two rotating speeds, namely the synchronous rotating speed n of the wound double-fed asynchronous generator when the 60Hz power grid supplies power S2 Synchronous speed n with wound double-fed asynchronous generator in 50Hz power supply S1 Is formulated as: n = n s2 -n s1 。
The slip motor is an alternating current asynchronous motor, or a permanent magnet synchronous motor started asynchronously, or a brushless direct current motor, or a reluctance motor.
The slip motor and the wound double-fed asynchronous generator are integrated together; or a unit consisting of two separate motors.
When the power frequency electricity connected with the 50Hz power grid access end is a 50Hz power grid, the power frequency electricity connected with the 60Hz power grid access end is a 60Hz power grid; when the power frequency electricity connected with the 50Hz power grid access end is a 60Hz power grid, the power frequency electricity connected with the 60Hz power grid access end is a 50Hz power grid; that is to say, the 50Hz power frequency electric system and the 50Hz power frequency electric system respectively connected to the two power grid connection ends can be connected in an interchangeable way, and under the condition of interchange, the rotating speed of the slip motor still needs to be equal to the synchronous rotating speed n of the wound double-fed asynchronous generator when the 60Hz power grid supplies power S2 Synchronous speed n with wound double-fed asynchronous generator in 50Hz power supply S1 The difference of (c).
A rotating frequency conversion and voltage transformation device based on a double-fed motor comprises a winding type double-fed asynchronous generator, a slip motor, a 50Hz power grid access end and a 60Hz power grid access end, wherein a rotor central shaft of the winding type double-fed asynchronous generator and a rotor central shaft of the slip motor are coaxially connected together through a coupler, the 50Hz power grid access end is respectively and electrically connected with a stator three-phase winding of the slip motor and a stator three-phase winding of the winding type double-fed asynchronous generator through a first knife switch, and an electric brush on a rotor collecting ring of the winding type double-fed asynchronous generator is connected with the 60Hz power grid access end through a second knife switch; the rotating speed n of the slip motor is equal to the difference value of the following two rotating speeds, namely the synchronous rotating speed n of the wound double-fed asynchronous generator when the 60Hz power grid supplies power S2 Synchronous speed n with wound double-fed asynchronous generator in 50Hz power supply S1 Is formulated as: n = n s2 -n s1 (ii) a That is to say, the 50Hz grid access end in the above technical scheme can be connected with the stator winding of the wound-rotor type doubly-fed asynchronous generator, and the 60Hz grid access end can be connected with the rotor winding of the wound-rotor type doubly-fed asynchronous generator, at this time, it is only necessary to connect the relevant phase sequence of the slip motor in reverse.
A rotating frequency conversion and voltage transformation method based on a double-fed motor is characterized by comprising the following steps:
the method for converting the 50Hz power frequency electric system into the 60Hz power frequency electric system comprises the following steps:
closing a first knife switch, and simultaneously connecting a rotor winding of the wound double-fed asynchronous generator and a slip motor to a 50Hz power grid access end; the unit rotating shafts which are coaxially connected together are started under the drive of a slip motor and reach a rated rotating speed n, namely the synchronous rotating speed n of the wound double-fed asynchronous generator when the power grid of 60Hz supplies power S2 Synchronous speed n with wound double-fed asynchronous generator in 50Hz power supply S1 When the difference value of (a) is greater than (b), a difference value is formed in the stator-rotor air gap of the wound double-fed asynchronous generator: synchronous speed n of wound double-fed asynchronous generator in 50Hz power grid power supply S1 A rotating magnetic field with a speed n superposed with the rated speed n of the slip machine S2 And, is formulated as: n is a radical of an alkyl radical s2 =n s1 + n; when the second knife switch is closed, the three-phase winding of the stator of the wound double-fed asynchronous generator outputs 60Hz power frequency electric system voltage to the 60Hz power grid access end, so that the 50Hz power frequency electric system is converted into the 60Hz power frequency electric system;
the method for converting the 60Hz power frequency electric system into the 50Hz power frequency electric system comprises the following steps:
closing the second knife switch, inducing the starting voltage of the slip motor under the power supply of a 60Hz alternating current power grid in a rotor coil of the wound type double-fed asynchronous generator, starting the slip motor, and when the rotating speed of the slip motor reaches the rated rotating speed n, namely, the synchronous rotating speed n of the wound type double-fed asynchronous generator under the power supply of the 60Hz power grid S2 Synchronous speed n with wound double-fed asynchronous generator in 50Hz power supply S1 Is formulated as: n = n s2 -n s1 When the first knife switch is closed, the three-phase winding of the rotor of the wound double-fed asynchronous generator outputs 50Hz power frequency electric system voltage to the 50Hz power grid access end, and the purpose of converting the 60Hz power frequency electric system into the 50Hz power frequency electric system is achieved.
In the technical scheme of the invention, a 50Hz power grid can be connected to a stator of the doubly-fed asynchronous generator, at the moment, the phase sequence of the slip motor is reversely connected, and the rotation direction of the slip motor is opposite to the rotation direction of an air gap magnetic field in the doubly-fed asynchronous generator, and the specific scheme is as follows: a rotating frequency conversion and voltage transformation method based on a double-fed motor is characterized by comprising the following steps:
the method for converting the 50Hz power frequency electric system into the 60Hz power frequency electric system comprises the following steps:
closing a first knife switch, and simultaneously connecting a stator winding of the wound double-fed asynchronous generator and a slip motor to a 50Hz power grid access end; the unit rotating shafts which are coaxially connected together are started under the drive of a slip motor and reach a rated rotating speed n, namely the synchronous rotating speed n of the wound double-fed asynchronous generator when the power grid of 60Hz supplies power S2 Synchronous speed n with wound double-fed asynchronous generator in 50Hz power supply S1 The difference value of (a) is formed in the air gap between the stator and the rotor of the wound double-fed asynchronous generator: synchronous speed n of wound double-fed asynchronous generator in 50Hz power grid power supply S1 A rotating magnetic field with a rotating speed n superposed with the rated rotating speed n of the slip motor S2 And is formulated as: n is s2 =n s1 + n; when the second knife switch is closed, the three-phase winding of the rotor of the wound double-fed asynchronous generator outputs 60Hz power frequency electric system voltage to the 60Hz power grid access end, so that the 50Hz power frequency electric system is converted into the 60Hz power frequency electric system;
the method for converting the 60Hz power frequency electric system into the 50Hz power frequency electric system comprises the following steps:
closing the second knife switch, inducing the starting voltage of the slip motor under the power supply of a 60Hz alternating current power grid in the stator coil of the wound type double-fed asynchronous generator, starting the slip motor, and when the rotating speed of the slip motor reaches the rated rotating speed n, namely the synchronous rotating speed n of the wound type double-fed asynchronous generator under the power supply of the 60Hz power grid S2 Synchronous speed n with wound double-fed asynchronous generator in 50Hz power supply S1 Is formulated as: n = n s2 -n s1 When the first knife switch is closed, the three-phase winding of the rotor of the wound double-fed asynchronous generator outputs 50Hz power frequency electric system voltage to the 50Hz power grid access end, and the purpose of converting the 60Hz power frequency electric system into the 50Hz power frequency electric system is achieved.
The technical scheme of the invention does not use any power electronic device, not only keeps the characteristics of high reliability and excellent power supply quality of the motor-generator set, but also achieves the same high efficiency as a power electronic frequency converter, and simultaneously has lower price and small volume and weight; the operation and maintenance are very simple and easy; the device can be used for shore power, shipborne and all occasions requiring two frequency power systems for conversion.
Drawings
FIG. 1 is a schematic diagram of the structure of a 50Hz power grid connected to a rotor winding of a wound double-fed asynchronous generator (1);
fig. 2 is a schematic diagram of the structure of the 50Hz grid of the invention connected to the stator winding of a wound double-fed asynchronous generator (1).
Detailed Description
The invention is described in detail below with reference to the accompanying drawings:
a rotating frequency conversion and transformation device based on a double-fed motor comprises a winding type double-fed asynchronous generator 1, a slip motor 2, a 50Hz power grid access end 7 and a 60Hz power grid access end 8, wherein a rotor central shaft of the winding type double-fed asynchronous generator 1 and a rotor central shaft of the slip motor 2 are coaxially connected together through a coupler 3, the 50Hz power grid access end 7 is respectively and electrically connected with a stator three-phase winding of the slip motor 2 and a brush on a rotor collecting ring 4 of the winding type double-fed asynchronous generator 1 through a first knife switch 5, and the stator three-phase winding of the winding type double-fed asynchronous generator 1 is connected with the 60Hz power grid access end 8 through a second knife switch 6; the rotating speed n of the slip motor 2 is equal to the difference value of the following two rotating speeds, namely the synchronous rotating speed n of the wound double-fed asynchronous generator 1 when the 60Hz power grid supplies power S2 Synchronous speed n of wound double-fed asynchronous generator 1 in 50Hz power supply S1 Is formulated as: n = n s2 -n s1 。
The slip motor 2 is an alternating current asynchronous motor, or a permanent magnet synchronous motor started asynchronously, or a brushless direct current motor, or a reluctance motor.
The slip motor 2 and the wound double-fed asynchronous generator 1 are integrated into a motor; or a unit consisting of two separate motors.
A method for converting a rotating double-fed motor frequency converter into different power frequency electric systems comprises the following steps:
closing the first knife switch 5, and simultaneously connecting a rotor winding of the wound double-fed asynchronous generator 1 and the slip motor 2 to a 50Hz power grid access end 7; the unit rotating shafts which are coaxially connected together are started under the drive of the slip motor 2 and reach a rated rotating speed n, namely, the synchronous rotating speed n of the wound double-fed asynchronous generator 1 when the power is supplied by a 60Hz power grid S2 Synchronous speed n of wound double-fed asynchronous generator 1 in 50Hz power supply S1 The difference between the two values, then, a difference is formed in the stator-rotor air gap of the wound double-fed asynchronous generator 1: synchronous speed n of wound double-fed asynchronous generator 1 in 50Hz power supply of power grid S1 A rotating magnetic field having a rotational speed n superimposed on the rated rotational speed n of the slip motor 2 S2 And, is formulated as: n is s2 =n s1 + n; when the second knife switch 6 is closed, the three-phase winding of the stator of the wound double-fed asynchronous generator 1 outputs 60Hz power frequency electric system voltage to the 60Hz power grid access end 8, so that the 50Hz power frequency electric system is converted into the 60Hz power frequency electric system; the power flow direction of the system is that electric power P is obtained from a 50Hz power grid 1 The power is respectively input to a rotor of a winding type double-fed asynchronous generator 1 through slip rings of a slip motor 2 and the winding type double-fed asynchronous generator 1, the power is transmitted to a stator of the winding type double-fed asynchronous generator 1 through electromechanical energy conversion of an air gap of the winding type double-fed asynchronous generator 1, the slip motor 2 operates as a motor, and the power P input through the slip motor 2 M1 Power P input through slip ring of wound double-fed asynchronous generator 1 M2 The sum of which is P 1 ，P 1 =P M1 +P M2 The ratio of the two P M1 /P M2 =n/n s1 The 60Hz electric power P output from the stator of the wound double-fed asynchronous generator 1 is obtained by neglecting various losses 2 Is equal to P 1 。
The method for converting the 60Hz power frequency electric system into the 50Hz power frequency electric system comprises the following steps:
closing the second knife switch 6 atThe rotor coil of the wound double-fed asynchronous generator 1 induces the starting voltage of the slip motor 2 under the power supply of a 60Hz alternating current power grid, the slip motor 2 starts to start, and when the rotating speed of the slip motor 2 reaches the rated rotating speed n, namely, the synchronous rotating speed n of the wound double-fed asynchronous generator 1 under the power supply of the 60Hz power grid S2 Synchronous speed n of wound double-fed asynchronous generator 1 in 50Hz power supply S1 Is formulated as: n = n s2 -n s1 When the first knife switch 5 is closed, the three-phase winding of the rotor of the wound-rotor type double-fed asynchronous generator 1 outputs 50Hz power frequency electric system voltage to the 50Hz power grid access end 7, the 60Hz power frequency electric system is converted into the 50Hz power frequency electric system, and the wound-rotor type double-fed asynchronous generator 1 operates as a generator at the moment.
The working principle of the invention is that the double-fed motor is used as a rotary transformer, 5/6 of power is converted by the wound double-fed asynchronous generator 1, and only 1/6 of slip power is transmitted and converted by the slip motor 2; because the conversion power born by the slip motor 2 only accounts for about 1/6 of the total conversion power, the rated power of the slip motor 2 is very small, thereby greatly reducing the manufacturing cost of the whole unit, and because most of the power is directly converted by the wound double-fed asynchronous generator 1 relying on the principle of a transformer, the conversion efficiency is very high, thereby realizing the high efficiency of the whole unit device.
The slip motor can also be supplied by a 60Hz power grid as long as the rotating speed of the slip motor under the 60Hz power grid is the difference between the synchronous rotating speeds under two power frequencies of 50Hz and 60Hz, namely n = n s2 -n s1 And (4) finishing.
In the technical scheme of the invention, a 50Hz power grid can be connected to a stator of the doubly-fed asynchronous generator 1, at the moment, the phase sequence of the slip motor 2 is reversely connected, and the rotation direction of the slip motor is opposite to the rotation direction of an air gap magnetic field in the doubly-fed asynchronous generator 1, and the specific scheme is as follows: a rotating frequency conversion and voltage transformation method based on a double-fed motor is characterized by comprising the following steps:
the method for converting the 50Hz power frequency electric system into the 60Hz power frequency electric system comprises the following steps:
closing the first knife switch 5 to wind the wireA stator winding of the double-fed asynchronous generator 1 and the slip motor 2 are simultaneously connected to a 50Hz power grid access end 7; the unit rotating shafts which are coaxially connected together are started under the drive of the slip motor 2 and reach a rated rotating speed n, namely the synchronous rotating speed n of the wound double-fed asynchronous generator 1 when the power grid of 60Hz supplies power S2 Synchronous speed n of wound-rotor type double-fed asynchronous generator 1 in 50Hz power supply of power grid S1 The difference between (a) and (b) is formed in the stator-rotor air gap of the wound double-fed asynchronous generator 1: synchronous speed n of wound double-fed asynchronous generator 1 in 50Hz power grid power supply S1 A rotating magnetic field having a rotational speed n superimposed on the rated rotational speed n of the slip motor 2 S2 And is formulated as: n is a radical of an alkyl radical s2 =n s1 + n; when the second knife switch 6 is closed, the three-phase winding of the rotor of the wound double-fed asynchronous generator 1 outputs 60Hz power frequency electric system voltage to the 60Hz power grid access end 8, so that the 50Hz power frequency electric system is converted into the 60Hz power frequency electric system;
the method for converting the 60Hz power frequency electric system into the 50Hz power frequency electric system comprises the following steps:
when the second knife switch 6 is closed, the starting voltage of the slip motor 2 under the power supply of the 60Hz alternating current power grid is induced in the stator coil of the wound double-fed asynchronous generator 1, the slip motor 2 starts to start, and when the rotating speed of the slip motor 2 reaches the rated rotating speed n, namely the synchronous rotating speed n of the wound double-fed asynchronous generator 1 under the power supply of the 60Hz power grid S2 Synchronous speed n of wound-rotor type double-fed asynchronous generator 1 in 50Hz power supply of power grid S1 Is formulated as: n = n s2 -n s1 When the first knife switch 5 is closed, the three-phase winding of the rotor of the wound-rotor type double-fed asynchronous generator 1 outputs 50Hz power frequency electric system voltage to the 50Hz power grid access end 7, and the purpose of converting the 60Hz power frequency electric system into the 50Hz power frequency electric system is achieved.
Claims (2)
1. A rotating frequency conversion and voltage transformation method based on a double-fed motor comprises a winding type double-fed asynchronous generator (1), a slip motor (2), a 50Hz power grid access end (7) and a 60Hz power grid access end (8), wherein a rotor central shaft of the winding type double-fed asynchronous generator (1) is coaxially connected with a rotor central shaft of the slip motor (2) through a coupler (3), the 50Hz power grid access end (7) is respectively and electrically connected with a stator three-phase winding of the slip motor (2) and an electric brush on a rotor double-fed ring (4) of the winding type double-fed asynchronous generator (1) through a first knife switch (5), and the stator three-phase winding of the winding type asynchronous generator (1) is connected with the 60Hz power grid access end (8) through a second knife switch (6); the method is characterized by comprising the following steps:
the method for converting the 50Hz power frequency electric system into the 60Hz power frequency electric system comprises the following steps:
closing a first knife switch (5), and simultaneously connecting a rotor winding of the wound double-fed asynchronous generator (1) and a slip motor (2) to a 50Hz power grid access end (7); the unit rotating shafts which are coaxially connected together are started under the drive of the slip motor (2) and reach a rated rotating speed n, namely, the synchronous rotating speed n of the wound double-fed asynchronous generator (1) when the 60Hz power grid supplies power S2 Synchronous speed n of wound double-fed asynchronous generator (1) in 50Hz power grid power supply S1 When a difference value is formed in a stator-rotor air gap of the wound double-fed asynchronous generator (1): synchronous speed n of wound double-fed asynchronous generator (1) during power supply of 50Hz power grid S1 A rotating magnetic field which is superposed with the rated rotating speed n of the slip motor (2), wherein the rotating speed n of the rotating magnetic field S2 And, is formulated as: n is s2 =n s1 + n; when the second knife switch (6) is turned on, the three-phase winding of the stator of the wound double-fed asynchronous generator (1) outputs 60Hz power frequency electric system voltage to the 60Hz power grid access end (8), so that the 50Hz power frequency electric system is converted into the 60Hz power frequency electric system;
the method for converting the 60Hz power frequency electric system into the 50Hz power frequency electric system comprises the following steps:
closing the second knife switch (6), inducing the starting voltage of the slip motor (2) under the power supply of a 60Hz alternating current power grid in a rotor coil of the wound type double-fed asynchronous generator (1), starting the slip motor (2), and when the rotating speed of the slip motor (2) reaches the rated rotating speed n, namely, the wound type double-fed asynchronous generator (1) supplies power to the 60Hz power gridSynchronous speed n of electricity S2 Synchronous speed n with wound-rotor double-fed asynchronous generator (1) when power is supplied by 50Hz power grid S1 Is formulated as: n = n s2 -n s1 When the first knife switch (5) is closed, the three-phase winding of the rotor of the wound double-fed asynchronous generator (1) outputs 50Hz power frequency electric system voltage to the 50Hz power grid access end (7), and the purpose of converting the 60Hz power frequency electric system into the 50Hz power frequency electric system is achieved.
2. A rotating frequency conversion and voltage transformation method based on a double-fed motor comprises a winding type double-fed asynchronous generator (1), a slip motor (2), a 50Hz power grid access end (7) and a 60Hz power grid access end (8), wherein a rotor central shaft of the winding type double-fed asynchronous generator (1) is coaxially connected with a rotor central shaft of the slip motor (2) through a coupler (3), the 50Hz power grid access end (7) is respectively and electrically connected with a stator three-phase winding of the slip motor (2) and a stator three-phase winding of the winding type double-fed asynchronous generator (1) through a first knife switch (5), and an electric brush on a rotor collecting ring (4) of the winding type double-fed asynchronous generator (1) is connected with the 60Hz power grid access end (8) through a second knife switch (6); the method is characterized by comprising the following steps:
the method for converting the 50Hz power frequency electric system into the 60Hz power frequency electric system comprises the following steps:
closing a first knife switch (5), and simultaneously connecting a stator winding of the wound double-fed asynchronous generator (1) and a slip motor (2) to a 50Hz power grid access end (7); the unit rotating shafts which are coaxially connected together are started under the drive of the slip motor (2) and reach a rated rotating speed n, namely, the synchronous rotating speed n of the wound double-fed asynchronous generator (1) when the 60Hz power grid supplies power S2 Synchronous speed n of wound double-fed asynchronous generator (1) in 50Hz power grid power supply S1 When a difference value is formed in a stator-rotor air gap of the wound double-fed asynchronous generator (1): synchronous speed n of wound double-fed asynchronous generator (1) during power supply of 50Hz power grid S1 A rotating magnetic field superposed with the rated rotating speed n of the slip motor (2) and rotatingSpeed is n S2 And, is formulated as: n is s2 =n s1 + n; when the second knife switch (6) is closed, the three-phase winding of the rotor of the wound double-fed asynchronous generator (1) outputs 60Hz power frequency electric system voltage to the 60Hz power grid access end (8), so that the 50Hz power frequency electric system is converted into the 60Hz power frequency electric system;
the method for converting the 60Hz power frequency electric system into the 50Hz power frequency electric system comprises the following steps:
the second knife switch (6) is closed, the starting voltage of the slip motor (2) under the power supply of a 60Hz alternating current power grid is induced in the stator coil of the wound double-fed asynchronous generator (1), the slip motor (2) starts to start, and when the rotating speed of the slip motor (2) reaches the rated rotating speed n, namely, the synchronous rotating speed n of the wound double-fed asynchronous generator (1) under the power supply of the 60Hz power grid S2 Synchronous speed n of wound double-fed asynchronous generator (1) in 50Hz power grid power supply S1 Is formulated as: n = n s2 -n s1 When the first knife switch (5) is closed, the three-phase winding of the rotor of the wound double-fed asynchronous generator (1) outputs 50Hz power frequency electric system voltage to the 50Hz power grid access end (7), and the purpose of converting the 60Hz power frequency electric system into the 50Hz power frequency electric system is achieved.
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| CN102332830A (en) * | 2011-07-13 | 2012-01-25 | 国电南京自动化股份有限公司 | Double-frequency power supply device for ship shore power system |
| CN103036307A (en) * | 2012-11-28 | 2013-04-10 | 广州供电局有限公司 | Mains supply fault detection circuit and mains supply fault detection method and protective power supply emergency power supply system |
| WO2019062398A1 (en) * | 2017-09-27 | 2019-04-04 | 广州航海学院 | Method and apparatus for seamlessly switching 50hz-60hz and 50hz-50hz dual-frequency shore power to ship power |
| CN207573087U (en) * | 2017-12-21 | 2018-07-03 | 国网上海市电力公司 | A kind of harbour bank electricity monitoring system |
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