CN113285651B - Device and method for converting multiphase power supply into single-phase power supply - Google Patents
Device and method for converting multiphase power supply into single-phase power supply Download PDFInfo
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- CN113285651B CN113285651B CN202110571183.2A CN202110571183A CN113285651B CN 113285651 B CN113285651 B CN 113285651B CN 202110571183 A CN202110571183 A CN 202110571183A CN 113285651 B CN113285651 B CN 113285651B
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P25/00—Arrangements or methods for the control of AC motors characterised by the kind of AC motor or by structural details
- H02P25/16—Arrangements or methods for the control of AC motors characterised by the kind of AC motor or by structural details characterised by the circuit arrangement or by the kind of wiring
- H02P25/18—Arrangements or methods for the control of AC motors characterised by the kind of AC motor or by structural details characterised by the circuit arrangement or by the kind of wiring with arrangements for switching the windings, e.g. with mechanical switches or relays
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P25/00—Arrangements or methods for the control of AC motors characterised by the kind of AC motor or by structural details
- H02P25/02—Arrangements or methods for the control of AC motors characterised by the kind of AC motor or by structural details characterised by the kind of motor
Abstract
The invention relates to a device and a method for converting a multiphase power supply into a single-phase power supply, comprising an input winding and a single-phase voltage output winding; the input winding is arranged on a stator of the multiphase alternating current motor; the input winding is at least a three-phase winding; the number of phases of the input winding is the same as that of the multiphase power supply; the single-phase voltage output winding comprises a stator output winding arranged on the stator and a rotor output winding arranged on the rotor; and the stator output winding is used for generating a composite rotating magnetic field when the input winding is connected with the multiphase power supply, and providing single-phase power supply for the load under the action of the composite rotating magnetic field. Therefore, in the invention, the input winding, the stator output winding and the rotor output winding are arranged on the alternating current motor, and the stator output winding generates single-phase voltage by utilizing the composite magnetic field generated by the three windings, so that the multi-phase power supply is converted into the single-phase power supply, and the reliability is high.
Description
Technical Field
The invention relates to the technical field of phase-number conversion of power supplies in electromagnetic equipment, in particular to a device and a method for converting a multiphase power supply into a single-phase power supply.
Background
The power supply system of the modern power system mainly comprises a three-phase system, and the power supply system which is most easily obtained by a user is a three-phase power supply or uses one phase of the three-phase power supply as a single-phase power supply. Therefore, the industrial power utilization equipment mainly uses three-phase or single-phase power utilization equipment, such as the alternating current electric transmission fields of industry, agricultural production and the like, the most widely used driving motor mainly uses a three-phase motor, the household appliances mainly use single-phase power sources due to household power utilization, and most of power supply lines provided by power supply enterprises for residents only provide single-phase power sources, so that the household appliances mainly use single-phase power sources for power supply.
It is common to use one phase in a three-phase utility power system as a single phase power source to balance the problem of asymmetry of the three-phase load by approximately equal power probabilities of the loads. However, by the method, complete symmetry of the three-phase load is difficult to ensure, even serious negative sequence components are caused in the three-phase public power system, safe operation of the system is affected, and larger negative sequence loss is generated in electric equipment. In addition, the conventional phase number conversion by the power electronics technology requires complex rectification and inversion processes, and a related filter device is also required to reduce the influence of harmonics. The basic principle of the technology is that the harmonic wave is easy to introduce into the system by carrying out area equivalent cutting combination on current or voltage, and meanwhile, the technology is based on a power electronic device, and the stability and overload capacity of the technology are limited. Therefore, the existing technology for converting the multiphase power supply into the single-phase power supply output has certain defects, so that the power supply reliability is low. In view of the above, the present invention provides a device and a method for converting a multiphase power supply into a single-phase power supply.
Disclosure of Invention
The invention aims to provide a device and a method for converting a multiphase power supply into a single-phase power supply, which are characterized in that an input winding and a single-phase voltage output winding are arranged on a multiphase alternating current motor, a magnetic field is generated by the input winding and the single-phase voltage output winding, a single-phase voltage is generated by a stator output winding in the single-phase voltage output winding under the action of the magnetic field, the multiphase power supply is converted into the single-phase power supply, and the reliability of the conversion mode is high.
In order to achieve the above object, the present invention provides a device for converting a multiphase power supply into a single-phase power supply, comprising an input winding and a single-phase voltage output winding;
the input winding is arranged on a stator of the multiphase alternating current motor and is used for accessing electric energy of a multiphase power supply;
the input winding is at least a three-phase winding; the number of phases of the input winding is the same as the number of phases of the multiphase power supply;
the single-phase voltage output winding is arranged on a stator output winding of the stator;
and the stator output winding is used for generating a composite rotating magnetic field when the input winding is connected with the multiphase power supply, and providing single-phase power supply for a load under the action of the composite rotating magnetic field.
The invention also provides a method for converting the multiphase power supply into the single-phase power supply, which comprises the following steps:
generating a first rotating magnetic field using the input winding;
generating a second rotating magnetic field using the single-phase voltage output winding;
combining the first rotating magnetic field and the second rotating magnetic field to obtain a combined rotating magnetic field;
cutting a stator output winding of the single-phase voltage output winding by using the composite rotating magnetic field to generate single-phase output voltage; the single-phase output voltage is an output of the multi-phase power supply.
According to the specific embodiment provided by the invention, the invention discloses the following technical effects:
the invention relates to a device and a method for converting a multiphase power supply into a single-phase power supply, wherein the device comprises an input winding and a single-phase voltage output winding; the input winding is arranged on a stator of the multiphase alternating current motor; and the input winding is at least a three-phase winding; the number of phases of the input winding is the same as that of the multiphase power supply; the single-phase voltage output winding comprises a stator output winding arranged on the stator and a rotor output winding arranged on the rotor; and the stator output winding is used for generating a composite rotating magnetic field when the input winding is connected with the multiphase power supply, and providing the single-phase power supply for the load under the action of the composite rotating magnetic field. Therefore, in the invention, the input winding, the stator output winding and the rotor output winding are arranged on the multiphase alternating current motor, and the stator output winding generates single-phase voltage by utilizing corresponding magnetic fields generated by the input winding, the stator output winding and the rotor output winding. The device does not need complex rectifying, inverting devices, control algorithms and related filtering devices, has strong overload capacity, and ensures the reliability of the device for converting the multiphase power supply into the single-phase power supply. In addition, the conversion mode from the multiphase power supply to the single-phase power supply can provide a new scheme for symmetrical power supply arrangement of civil single-phase power distribution of the power system, and the symmetry of power supply loads is easier to ensure, so that the problem of negative sequence caused by asymmetrical loads in the system is reduced, the problem of asymmetrical loads (such as an electric locomotive traction power supply system) caused by supplying power to the single-phase load system by utilizing the multiphase power supply system is eliminated, the negative sequence current caused by asymmetrical loads is eliminated, and the reliability of the conversion mode from the multiphase symmetrical power supply to the single-phase power supply is further illustrated.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings can be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a schematic diagram of a device for converting a multiphase power supply into a single-phase power supply according to embodiment 1 of the present invention;
fig. 2 is a schematic Y-connection diagram of a three-phase winding when the input winding provided in embodiment 1 of the present invention is a three-phase winding;
fig. 3 is a schematic connection diagram of two-phase windings when the stator output winding provided in embodiment 1 of the present invention is a two-phase winding;
fig. 4 is a schematic connection diagram of a single-phase winding when the stator output winding provided in embodiment 1 of the present invention is a single-phase winding;
fig. 5 is a flowchart of a method for converting a multiphase power supply into a single-phase power supply according to embodiment 2 of the present invention;
fig. 6 is a schematic diagram of a magnetic field when the stator output winding provided in embodiment 2 of the present invention is a single-phase winding and the rotor output winding is a three-phase winding;
FIG. 7 is a graph showing the current flowing into the three-phase symmetrical winding of the rotor according to embodiment 2 of the present invention;
fig. 8 is a schematic diagram of induced electromotive force of a three-phase winding on a stator according to embodiment 2 of the present invention;
fig. 9 is a schematic diagram of induced electromotive force of a single-phase winding on a stator according to embodiment 2 of the present invention;
fig. 10 is a graph showing the current flowing in the three-phase windings on the stator according to embodiment 2 of the present invention;
fig. 11 is a graph showing the current flowing in the single-phase winding on the stator according to embodiment 2 of the present invention.
Symbol description:
1: an input winding; 2: a stator output winding; 3: a rotor output winding; 4: a stator; 5: a rotor.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The invention aims to provide a device and a method for converting a multiphase power supply into a single-phase power supply, which are characterized in that an input winding and a single-phase voltage output winding are arranged on a multiphase alternating-current motor, a magnetic field is generated by the input winding and the single-phase voltage output winding, a single-phase voltage is generated by a stator output winding in the single-phase voltage output winding under the action of the magnetic field, the multiphase power supply is converted into the single-phase power supply, and the conversion mode is high in reliability.
In order that the above-recited objects, features and advantages of the present invention will become more readily apparent, a more particular description of the invention will be rendered by reference to the appended drawings and appended detailed description.
Example 1
Referring to fig. 1, a device for converting a multiphase power source into a single-phase power source includes an input winding 1 and a single-phase voltage output winding 2;
the input winding 1 is arranged on a stator 4 of the multiphase alternating current motor and is used for accessing electric energy of a multiphase power supply;
the input winding is at least a three-phase winding; the number of phases of the input winding and the number of phases of the multiphase alternating current motor are the same as the number of phases of the multiphase power supply; the number of phases may be three, four, five, six, seven, eight, nine, etc;
the input windings are uniformly and symmetrically distributed on the space of the motor stator 4, namely, the space included angle electric angle between the windings is 360/(phase number) degrees, and if the input windings are three-phase symmetrical windings, the mutual difference between winding axes is 120 degrees; if the four-phase windings are adopted, the mutual difference between the axes of the windings is 90 degrees; in the case of a five-phase motor, the winding axes are mutually offset by 72 degrees (the definition of the electrical angle is known from the Goubao et al, liang Yanping, tao Dajun and published by higher education publishers in the year 2020, "motor science", ISBN: 9787040535297).
As shown in fig. 2, taking the input winding 1 as a three-phase winding as an example, a Y-type (star connection) connection mode is adopted for the three-phase winding, and a triangle connection mode can be adopted for the three-phase winding. There is no limitation in this regard. In the view of figure 2,
induced electromotive forces in three-phase windings A1, B1 and C1 respectively; />
A power line voltage input to the three-phase winding for the three-phase power supply; r is (r) 1 、x 1σ The resistance and leakage reactance values of the three-phase windings are respectively;
the line currents of the three-phase windings, respectively.
The single-phase voltage output winding 2 comprises a stator output winding 2 arranged on a stator 4 and a rotor output winding 3 arranged on a rotor 5;
the stator output winding 2 is configured to generate a composite rotating magnetic field when the input winding 1 is connected to the multiphase power supply, and provide a single-phase power supply to a load under the action of the composite rotating magnetic field by the input winding 1 and the single-phase voltage output winding.
Two sets of windings are arranged on a stator 4 of the alternating current motor, one set is an input winding 1, is used as an input winding of a multiphase power supply and is similar to a primary side input winding of a transformer, the other set is a single-phase voltage output winding, is used as an output winding of the multiphase power supply and is similar to a secondary side output winding of the transformer, a single-phase equipment load is connected, and the single-phase voltage output winding comprises two parts, wherein one part is a stator output winding 2 arranged on the stator 4, and the other part is a rotor output winding 3 arranged on a rotor 5. For single-phase voltage output windings, two designs are presented in this embodiment.
The first way is to set the stator output winding 2 to be a two-phase winding, and for the rotor output winding 3, a cage rotor of an induction motor or a permanent magnet rotor of a synchronous motor or an excitation winding structure of an electrically excited rotor can be adopted. When the rotor 5 adopts the direct current excitation winding of the synchronous motor, the control of the synthetic magnetic field can be realized, thereby achieving the effect of controlling the reactive power of the system. Therefore, the device of the embodiment not only can realize the conversion from a multi-phase power supply to a single-phase power supply, but also can realize the function of adjusting the reactive power of the power supply by controlling the exciting current of the rotor output winding 3. As shown in fig. 3, the stator output winding 2 is a connection schematic diagram of two-phase windings; in the figure
Induced electromotive forces in the A2 and B2 two-phase windings respectively; />
Is the output single-phase power supply voltage; r is (r) 2 、x 2σ The resistance and leakage reactance values of the two-phase windings are respectively; x is x C A capacitor connected in series with the B2 phase winding;
the currents of the two parallel windings are respectively.
In the first mode, the rotor 5 may be free to rotate, and the rotor 5 may or may not be connected to a mechanical load or a mechanical prime mover. It is also possible to have the function of an electric motor and the function of an electric generator if a prime mover or a mechanical load is put on the rotor shaft. The number of poles of the rotor 5 may be 2 poles, 4 poles, 6 poles, etc., and may be set as required.
In the two-phase windings, one of the two-phase windings is required to be connected in series with one capacitor and then connected in parallel with the other phase winding, so that the axes of the two-phase windings can be spatially mutually different by 90 degrees in electrical angle. In addition, the number of turns of the two-phase winding is also required to be the same.
The second is to set the stator output winding 2 to a single-phase winding and the rotor output winding 3 to a three-phase winding, and in this way, it is necessary to put the rotor 5 of the ac motor in a stationary state. As shown in fig. 4, the stator output winding 2 is a connection schematic diagram of a single-phase winding; in the figure
Is the induced electromotive force in the A3 single-phase winding; />
Is the output single-phase power supply voltage; r is (r) 3 、x 3σ The resistance and leakage reactance values of the single-phase winding are obtained; />
Is the current of the single phase output winding.
It should be noted that the schematic diagram shown in fig. 1 is merely an arrangement schematic diagram of the input winding 1 (three-phase winding) and the stator output winding 2 (two-phase winding) taking the three-phase power supply converted into the single-phase power supply as an example. When the multiphase power supply is other phase number power supply, the three-phase winding is directly replaced by a winding with the corresponding phase number. The relative spatial positions of the axes of the input winding 1 and the stator output winding 2 may be arranged according to actual needs.
In the embodiment, the conversion from a multiphase power supply to a single-phase power supply is realized by arranging two sets of windings on the alternating current motor by utilizing the law of electromagnetic induction and the construction theory of a rotating magnetic field. The transformation from the multiphase power supply to the single-phase power supply based on the device is relatively based on the power electronic technology, the overload and impact resistance of the device are limited only by the insulation thermal effect of the motor winding, the overload and impact resistance of the device are stronger, the device has advantages for some strong impact load application occasions, and the transformed power waveform has high sine property.
In particular, the device of the embodiment can realize the conversion from the single-phase power supply to the multi-phase power supply in addition to the conversion from the multi-phase power supply to the single-phase power supply. The method is characterized in that a single-phase voltage output winding is used as an input winding, and the input winding is used as the single-phase voltage output winding.
Example 2
As shown in fig. 5, the present embodiment provides a method for converting a multiphase power source into a single phase power source, including:
step S1: generating a first rotating magnetic field with the input winding 1;
the step S1 specifically includes:
the input winding 1 is connected to a multiphase power supply, the input winding 1 and the multiphase power supply form a loop, multiphase symmetrical current is generated in the input winding 1, and the first rotating magnetic field is formed according to a rotating magnetic field theory.
Step S2: generating a second rotating magnetic field using the single-phase voltage output winding;
considering that there are two ways of generating the second rotating magnetic field in the single-phase voltage output winding, the two ways can be selected according to actual requirements, and will be described separately below.
In the first mode, step S2 specifically includes:
setting the stator output winding 2 to be a two-phase winding parallel connection mode, wherein one phase winding is connected with a capacitor in series and then connected with the other phase winding in parallel;
forming a loop by the stator output winding 2 and a load, generating two currents with 90-degree electric angles of phase difference in the stator output winding 2, and forming a first stator rotating magnetic field according to the rotating magnetic field theory;
the rotor output winding 3 in the single-phase voltage output winding is arranged to be a cage rotor of an induction motor or a permanent magnet rotor or an excitation winding structure of an electric excitation rotor of a synchronous motor;
forming a first rotor rotating magnetic field by using an excitation mode of the excitation winding; the second rotating magnetic field includes the first stator rotating magnetic field and the first rotor rotating magnetic field.
In the second mode, step S2 specifically includes:
setting the stator output winding 2 as a single-phase winding;
forming a loop between the stator output winding 2 and a load, generating current in the stator output winding 2, and forming a second stator rotating magnetic field according to the rotating magnetic field theory;
setting a rotor output winding 3 in the single-phase voltage output winding to be a three-phase winding;
maintaining the rotor 5 in a static state, and connecting symmetrical currents with opposite phase sequences of the input winding 1 to the rotor output winding 3, wherein the rotor output winding 3 generates a second rotor rotating magnetic field according to the rotating magnetic field theory;
and counteracting the negative sequence rotating magnetic field in the second stator rotating magnetic field by using the second rotor rotating magnetic field to obtain a positive sequence rotating magnetic field of the second stator rotating magnetic field, namely a second rotating magnetic field. As shown in fig. 6, the distribution of the magnetic field generated when the stator output winding 2 is a single-phase winding and the rotor output winding 3 is a three-phase winding is shown; in the figure, fr is the magnetomotive force amplitude of a counter-rotating magnetic field formed in a three-phase winding of a rotor in a stationary state, F Single- Is a reverse rotation negative sequence magnetic field generated in a single-phase winding of the stator, F Singly+ Is a positive sequence rotating magnetic field in a single-phase winding.
Step S3: combining the first rotating magnetic field and the second rotating magnetic field to obtain a combined rotating magnetic field;
step S4: cutting the stator output winding 2 of the single-phase voltage output winding by using the composite rotating magnetic field to generate single-phase output voltage; the single-phase output voltage is an output of the multi-phase power supply.
In order to enable those skilled in the art to clearly understand the scheme of the present invention, the three-phase power supply is converted into the single-phase power supply by way of example for explanation:
a set of three-phase windings for power input and a set of windings for power output are arranged on the three-phase alternating current motor. The arrangement mode of the three-phase input winding 1 is consistent with that of the three-phase winding of the industrial motor, and the single-phase voltage output winding can have two modes, which are respectively described as follows:
the specific implementation phase number transformation process of the mode one is as follows:
1) The input winding 1 is a three-phase symmetrical winding, a three-phase symmetrical power supply is connected to the three-phase symmetrical winding, the three-phase symmetrical winding and the power supply form a loop, and three-phase symmetrical current flows in the three-phase symmetrical winding, so that a rotating magnetic field F is formed 3-in (first rotating magnetic field) whose amplitude can be determined by the formula (1), wherein F φ1 Is the amplitude of magnetomotive force of a single-phase winding, theta s For the electromechanical angle of the motor space, ω is the power frequency, t is the power conversion time;
2) The stator output winding 2 is composed of two phase windings, the two phase windings have the same turns arrangement mode, the axes of the two phase windings are in 90 degrees of electrical angle with each other in space, wherein after a capacitor is connected in series in one phase winding, the two phase windings and the load form a loop, current flows in the two phase windings and passes through the capacitor x C To shift the phase of (a) to
And->
Equal in magnitude and 90-degree in phase difference to form a resultant magnetic field F 2-up (a first stator rotating magnetic field) whose magnitude can be determined by formula (2);
F 2-up ＝F φ1 cos(θ s -ωt) (2)
3) Two rotating magnetic fields in the stator 4 of the motor, plus the rotating magnetic field of the rotor 5 (second stator rotating magnetic field), form a composite magnetic field, which cuts the three-phase windings (input windings) on the stator 4 and the two-phase windings (output windings) on the stator 4, respectively, to generate induced electromotive force in the three-phase windings on the stator 4
Induced electromotive force +.>
The induced electromotive force in the three-phase winding is used as a load of the three-phase power supply to be balanced with the three-phase power supply, and the three-phase power supply is absorbed to realize the connection of the three-phase power supply; the two induced electromotive forces generated by the two-phase windings are connected in parallel and then used as an output power supply to balance with a load, and a single-phase power supply is provided for the load, so that the power supply is converted from three phases to single-phase power supply.
The phase number conversion process is specifically realized in the second mode:
1) The input winding 1 is a three-phase symmetrical winding, and the process of generating the first rotating magnetic field is the same as 1) in the first mode, and is not described herein.
2) The stator output winding 2 is composed of a single-phase winding, the single-phase winding and the load form a loop, and current flows in the winding to form a pulse vibration magnetic field F Single sheet (a second stator rotating magnetic field) whose magnitude can be determined by formula (3);
F single sheet ＝F Singly+ +F Single- (3)
F in formula (3) Singly+ Is a positive sequence rotating magnetic field in a single-phase winding, F Single- Is a reverse rotation negative sequence magnetic field generated in a single-phase winding of a stator, and comprises the following steps:
the rotor output winding 3 is configured as a three-phase symmetrical winding, while the rotor 5 is in a stationary state, and symmetrical currents having opposite phase sequences to those of the three-phase windings on the stator 4 are input to the three-phase symmetrical winding on the rotor 5, as shown in fig. 7, I RA : a current curve of the phase A in the three-phase symmetrical winding on the rotor 5 is introduced; i RB : a current curve of a B phase in a three-phase symmetrical winding on the rotor 5 is introduced; i RC : a current curve of a C phase in a three-phase symmetrical winding on the rotor 5 is introduced; the abscissa in the figure represents time, and the ordinate represents current value, so that a counter-rotating magnetic field F is generated in the three-phase windings on the rotor 5 r And let F r ＝-F Singly+ Counteracting the counter-rotating negative-sequence magnetic field F generated in the single-phase winding on the stator 4 Single- (second rotor rotating magnetic field), (as shown in fig. 6), so that only the positive-order rotating magnetic field F is present in the single-phase winding Singly+ (second rotating magnetic field).
3) Combining the first rotating magnetic field and the second rotating magnetic field to obtain a combined magnetic field, wherein the combined magnetic field cuts the three-phase winding on the stator 4 and the single-phase winding on the stator 4 respectively, and induced electromotive force is generated in the three-phase winding on the stator 4
As shown in FIG. 8, E WA : induced electromotive force of an A-phase winding in the three-phase windings on the stator 4; e (E) WB : induced electromotive force of a B-phase winding in the three-phase windings on the stator 4; e (E) WC : induced electromotive force of a C-phase winding among three-phase windings on the stator 4. Induced electromotive force +.>
As shown in FIG. 9, E WS : induced electromotive force in the single-phase winding on the stator 4. The load of the three-phase winding which is used as the input power source balances with the input power source, absorbs the power of the power source, and is shown as I in figure 10 WA : a current curve flowing in an A-phase winding in the three-phase windings on the stator 4; i WB : a current curve flowing in a B phase winding in the three-phase windings on the stator 4; i WC : and a current curve flowing in a C-phase winding in the three-phase windings on the stator 4. The induced electromotive force generated by the single-phase winding is used as an output power source and is balanced with a load, and the power source is output to the load, as shown in FIG. 11, I WS : the stator 4 is provided with a single-phase winding for supplying current to convert the power from three-phase to single-phaseAnd a phase power supply.
In this embodiment, two rotating magnetic fields in the motor stator 4, plus the rotating magnetic field of the rotor 5, form a resultant magnetic field, which cuts the stator multiphase input winding 1 and the stator output winding 2, respectively, and generates induced electromotive forces in both the multiphase winding and the single-phase voltage output winding. The induced electromotive force in the multiphase winding is used as a load of an input power supply and connected with the multiphase power supply, the induced electromotive force of the stator output winding 2 is used as an output power supply, and single-phase power supply is output to the load, so that the power supply is converted from the multiphase power supply to the single-phase power supply, and the conversion function from the multiphase power supply to the single-phase power supply is realized. The rotating magnetic field based on the electromagnetic induction principle is subjected to phase number conversion by a winding cutting theory, and is different from the rectification and inversion technology principle utilizing the power electronic technology. The method only realizes the conversion from the multiphase power supply to the single-phase power supply, and does not change the power frequency.
The principles and embodiments of the present invention have been described herein with reference to specific examples, the description of which is intended only to assist in understanding the methods of the present invention and the core ideas thereof; also, it is within the scope of the present invention to be modified by those of ordinary skill in the art in light of the present teachings. In view of the foregoing, this description should not be construed as limiting the invention.
Claims (7)
1. A method for converting a multiphase power supply into a single-phase power supply, characterized in that the method is implemented based on a device for converting a multiphase power supply into a single-phase power supply, the device for converting a multiphase power supply into a single-phase power supply comprising an input winding and a single-phase voltage output winding; the input winding is arranged on a stator of the multiphase alternating current motor and is used for accessing electric energy of a multiphase power supply; the input winding is at least a three-phase winding, and the number of phases of the input winding is the same as that of the multiphase power supply; the single-phase voltage output winding comprises a stator output winding arranged on the stator and a rotor output winding arranged on the rotor; the stator output winding is used for generating a composite rotating magnetic field when the input winding is connected with the multiphase power supply, and providing single-phase power supply for a load under the action of the composite rotating magnetic field;
the method comprises the following steps:
generating a first rotating magnetic field using the input winding;
the first rotating magnetic field generated by the input winding specifically comprises:
the input winding is connected to a multiphase power supply, the input winding and the multiphase power supply form a loop, multiphase symmetrical current is generated in the input winding, and the first rotating magnetic field is formed according to a rotating magnetic field theory;
generating a second rotating magnetic field using the single-phase voltage output winding;
the generating a second rotating magnetic field by using the single-phase voltage output winding specifically comprises:
setting the stator output winding to be a two-phase winding parallel connection mode, wherein one phase winding is connected with a capacitor in series and then connected with the other phase winding in parallel;
forming a loop by the stator output winding and a load, generating two currents with 90-degree electric angles of phase difference in the stator output winding, and forming a first stator rotating magnetic field according to the rotating magnetic field theory;
the rotor output winding in the single-phase voltage output winding is arranged to be a cage rotor of an induction motor or a permanent magnet rotor or an excitation winding structure of an electric excitation rotor of a synchronous motor;
forming a first rotor rotating magnetic field by using an excitation mode of the excitation winding; the second rotating magnetic field includes the first stator rotating magnetic field and the first rotor rotating magnetic field;
combining the first rotating magnetic field and the second rotating magnetic field to obtain a combined rotating magnetic field;
cutting a stator output winding of the single-phase voltage output winding by using the composite rotating magnetic field to generate single-phase output voltage; the single-phase output voltage is an output of the multi-phase power supply.
2. A method for converting a multiphase power supply into a single-phase power supply, characterized in that the method is implemented based on a device for converting a multiphase power supply into a single-phase power supply, the device for converting a multiphase power supply into a single-phase power supply comprising an input winding and a single-phase voltage output winding; the input winding is arranged on a stator of the multiphase alternating current motor and is used for accessing electric energy of a multiphase power supply; the input winding is at least a three-phase winding, and the number of phases of the input winding is the same as that of the multiphase power supply; the single-phase voltage output winding comprises a stator output winding arranged on the stator and a rotor output winding arranged on the rotor; the stator output winding is used for generating a composite rotating magnetic field when the input winding is connected with the multiphase power supply, and providing single-phase power supply for a load under the action of the composite rotating magnetic field;
the method comprises the following steps:
generating a first rotating magnetic field using the input winding;
the first rotating magnetic field generated by the input winding specifically comprises:
the input winding is connected to a multiphase power supply, the input winding and the multiphase power supply form a loop, multiphase symmetrical current is generated in the input winding, and the first rotating magnetic field is formed according to a rotating magnetic field theory;
generating a second rotating magnetic field using the single-phase voltage output winding;
the generating a second rotating magnetic field by using the single-phase voltage output winding specifically comprises:
setting the stator output winding as a single-phase winding;
forming a loop by the stator output winding and a load, generating current in the stator output winding, and forming a second stator rotating magnetic field according to the rotating magnetic field theory;
setting a rotor output winding in the single-phase voltage output windings to be a three-phase winding;
maintaining a rotor stationary state, and connecting symmetrical currents with opposite phase sequences of the input windings to the rotor output windings, wherein the rotor output windings generate a second rotor rotating magnetic field according to the rotating magnetic field theory;
the negative sequence rotating magnetic field in the second stator rotating magnetic field is counteracted by the second rotor rotating magnetic field, so that a positive sequence rotating magnetic field of the second stator rotating magnetic field, namely a second rotating magnetic field, is obtained;
combining the first rotating magnetic field and the second rotating magnetic field to obtain a combined rotating magnetic field;
cutting a stator output winding of the single-phase voltage output winding by using the composite rotating magnetic field to generate single-phase output voltage; the single-phase output voltage is the output of the multiphase power supply;
the positive sequence rotating magnetic field of the second stator rotating magnetic field is the second rotating magnetic field.
3. The method according to claim 1 or 2, wherein the stator output winding is a two-phase winding, and the rotor output winding adopts a cage rotor of an induction motor or a permanent magnet rotor of a synchronous motor or an excitation structure of an electrically excited rotor.
4. A method according to claim 3, wherein one of the two phase windings is connected in parallel with the other phase winding after the capacitor is connected in series.
5. The method of claim 4, wherein the number of turns of the two-phase winding is the same.
6. A method according to claim 3, wherein the stator output winding is a single phase winding and the rotor output winding is a three phase winding.
7. The method of claim 6, wherein the rotor remains stationary while the rotor output winding is the three-phase winding.
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2286337Y (en) * | 1996-12-04 | 1998-07-15 | 朱彦鸣 | Three-phase input single-phase output voltage transformer |
| CN206040409U (en) * | 2016-07-06 | 2017-03-22 | 蒋光祖 | Covert transformer of balance of three -phase input two -phase output |
| CN208353222U (en) * | 2018-07-05 | 2019-01-08 | 西南交通大学 | A kind of Universal flexible Energy Management System based on Modular multilevel converter |
| CN109450205A (en) * | 2019-01-08 | 2019-03-08 | 中铁电气化局集团有限公司第二工程分公司 | A kind of three-phase symmetrical alternating current becomes the alternating current generator of single-phase alternating current |
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2021
- 2021-05-25 CN CN202110571183.2A patent/CN113285651B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2286337Y (en) * | 1996-12-04 | 1998-07-15 | 朱彦鸣 | Three-phase input single-phase output voltage transformer |
| CN206040409U (en) * | 2016-07-06 | 2017-03-22 | 蒋光祖 | Covert transformer of balance of three -phase input two -phase output |
| CN208353222U (en) * | 2018-07-05 | 2019-01-08 | 西南交通大学 | A kind of Universal flexible Energy Management System based on Modular multilevel converter |
| CN109450205A (en) * | 2019-01-08 | 2019-03-08 | 中铁电气化局集团有限公司第二工程分公司 | A kind of three-phase symmetrical alternating current becomes the alternating current generator of single-phase alternating current |
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