A kind of high frequency air-core transformer of magnetic coupling resonance
Technical field
The present invention relates to a kind of high frequency transformer, particularly a kind of high frequency air-core transformer based on magnetic coupling harmonic technology for electric power electric transformer.
Background technology
In order to adapt to following extensive direct current energy generating, storage, transmission, to use, especially towards the use of large-scale photovoltaic generating, extensive electrochemical cell storage and conversion, extensive direct current energy long-distance transmissions, extensive direct current network construction and high-capacity direct current electric energy, setting up and developing high-voltage direct current power grid becomes possibility.China is greatly developing the extensive DC power supply of various ways, and as photovoltaic generation power supply, electrochemical cell energy storage and fuel cell power source etc., the desirable access way of these extensive DC power supply should be directly to access high-voltage direct current power grid.In addition, the preferred access way of alongshore wind electric field is to be also connected with direct current network, compared with incoming transport electrical network, can save the power electronic device of half.Set up and develop the support that high-voltage direct current power grid needs a lot of key equipments, wherein high voltage DC breaker and high voltage DC power transformer are two kinds of critical equipment.High voltage DC breaker is for cutting off and isolated high-voltage DC Line Fault circuit or trouble unit.High voltage DC power transformer have with high-voltage alternating electric power transformer ' s type like function, realize the conversion of direct current energy in different direct voltage grades.Except electric power electric transformer, high-voltage switch gear DC power supply is also the power electronic equipment relevant to high voltage direct current transformer.Switch DC power supply is all widely used at industry, agricultural and civilian industry-by-industry, the industries such as such as electroplating industry, electrostatic precipitation, electrostatic sterilization.
Based on the great demand to direct current power transformer, researcher both domestic and external has done a large amount of research work, and the physics realization of electric power electric transformer is at present divided into two kinds of large technical schemes substantially.
The one, based on full power electronic technology, high and low pressure side is directly electrically connected, transless; As U.S.'s DianKeYuan is made the full electric power electric transformer experimental prototype of First in nineteen ninety-five, its main circuit topology adopts Buck main circuit structure.This circuit structure is simple, easily realizes voltage-regulation.But sort circuit also has a lot of shortcomings: circuit comprises series connection device, is difficult to control; Do not realize frequency conversion; There is no electrical isolation; Can not suppress current harmonics and the Modulating Power factor of input.
The 2nd, based on the magnetic-coupled power electronic technology of transformer, realize the electrical isolation of high and low pressure side inversion/rectification circuit by transformer magnetic coupling.Realize the electrical isolation of high and low pressure side circuit by transformer magnetic coupling, be conducive to ensure the safety of electric power system, and control program is simple.The electric power electric transformer topological structure that is applied to AC network is generally containing repeatedly power converter of the ac/dc/ac/dc of DC converting link/exchange.Utilize high-frequency iron core transformer to realize voltage transformation and the isolation of former and deputy limit circuit, be conducive to improve power converter efficiency, reduce commutator transformer cost and operating cost, raising direct current network safety in operation.But, owing to having adopted the permeability magnetic materials such as epoxy body as core body, along with improving constantly of demand capacity, volume of transformer constantly increases, though can reduce by improving the way of operating frequency the physical size of high frequency transformer body, but along with the raising of operating frequency, can reduce for the surface area of heat radiation thereupon, iron core and high-frequency loss also increase thereupon, cause delivery of electrical energy Efficiency Decreasing, and core material is the key factor that affects high frequency transformer performance.
Another kind of possible measure is to adopt air-core transformer, and the advantage of open-core type transformer is owing to there is no iron core, does not have iron loss problem, its frequency of utilization is not subject to the restriction of ferromagnetic material, meanwhile, air-core transformer overload capacity is strong, is the more promising Energy Transfer mode of one.But air-core transformer magnetic resistance is large, energy transmission efficiency is low.
In addition, also have one often to adopt Tesla transformer at pulse power source domain, this transformer is an air-core transformer with special construction, to ensure that it does not under high pressure discharge; Transformer frequency response is a capacitor, and transformer load is the pulse forming line of a capacitive; When work, former limit winding forms line capacitance resonance with capacitor resonance, secondary winding and load pulse to winding electric discharge, and has identical resonance frequency.The purpose of design of this transformer is to obtain the high output voltage of trying one's best, and for the attainment of one's purpose, coupling coefficient k can only get some fixing value.As above-mentioned, the special construction of Telsa transformer, just in order not discharge under high voltage, can not ensure stable energy output, and former and deputy limit coupling coefficient needs strict control simultaneously, and this is not easy to realize aborning.
Also having at present a kind of technology is the wireless energy transmission technology of magnetic coupling resonance, this technology has the seminar of masschusetts, u.s.a Polytechnics to find the earliest, can realize the transmission of medium and long distance (being that transmission range is several times of transmitting coil size), and still can obtain higher efficiency and larger power, but its main target is to realize remote, high efficiency Energy Transfer.
In patent CN201210301956.6, CN201310035764.x and CN201310061424.4, all mention and adopt magnetic coupling harmonic technology to carry out the equipment of medium and long distance Energy Transfer, but wherein main purpose is to realize higher transmission efficiency, longer-distance Energy Transfer, can not realize change in voltage.
Summary of the invention
The object of the invention is to overcome above-mentioned existing air-core transformer magnetic resistance large, inefficient shortcoming, proposes a kind of high frequency transformer that adopts hollow-core construction.It is large that the present invention not only can overcome air-core transformer magnetic resistance, inefficient shortcoming, and also because of relatively loose to the span of coupling coefficient k, and can stable transfer energy.
To achieve these goals, the present invention is by the following technical solutions:
Described high frequency air-core transformer comprises former limit winding, secondary winding, winding skeleton, former limit matching capacitance and 5 parts of secondary matching capacitance.
The former limit of described high frequency air-core transformer winding, secondary winding, former limit matching capacitance, secondary matching capacitance can be one of four kinds of structures of the following stated:
Described former limit winding and former limit matching capacitance are connected in series, and the series circuit generation series resonance that when work, former limit winding and former limit matching capacitance form, described secondary winding and secondary matching capacitance are connected in series, the series circuit generation series resonance that secondary winding and secondary matching capacitance form.
Described former limit winding and former limit matching capacitance are connected in series, and the series circuit generation series resonance that when work, former limit winding and former limit matching capacitance form, described secondary winding and secondary matching capacitance are connected in parallel, the parallel circuits generation parallel resonance that secondary winding and secondary matching capacitance form.
Described former limit winding and former limit matching capacitance are connected in parallel, and the parallel circuits generation parallel resonance that when work, former limit winding and former limit matching capacitance form, described secondary winding and secondary matching capacitance are connected in series, and secondary winding and secondary matching capacitance form series circuit generation series resonance.
Described former limit winding and former limit matching capacitance are connected in parallel, and the parallel circuits generation parallel resonance that when work, former limit winding and former limit matching capacitance form, described secondary winding and secondary matching capacitance are connected in parallel, secondary winding and secondary matching capacitance forming circuit generation parallel resonance.
Described former limit resonance frequency is identical with secondary resonance frequency.
Described winding skeleton adopts annular, the various structures such as square, former limit winding, secondary winding technique are on winding skeleton, and coiling is that inner ring is that former limit, outer ring are secondary with one heart, also can decentraction coiling, but need the coupling coefficient that keeps higher, reduce the consumption of wire rod.The material of winding skeleton is non-magnet material, preferred epoxy material.
Described secondary winding and secondary matching capacitance can be two or more.Multiple to can be connected in series or in parallel between secondary winding and multiple secondary matching capacitance, the circuit that multipair secondary winding and multiple secondary matching capacitance form can be series resonant circuit or antiresonant circuit.
When described secondary winding and secondary matching capacitance form parallel circuits, the secondary winding inductance Ls of high frequency air-core transformer, the mutual inductance M of former limit winding and secondary winding, resonance frequency omega, the equivalent resistance Rp of former limit winding, the equivalent resistance Rs of secondary winding, load resistance R meets following relation:
Described high frequency air-core transformer also needs to meet following condition:
(ω·L
s)
2>>R·R
s
And now described high frequency air-core transformer no-load voltage ratio K is maximum, as described below:
The former limit winding of described high frequency air-core transformer, secondary winding preferably adopt litz wire coiling, can effectively reduce the impact of skin effect, proximity effect, while making to obtain same inductance value, the equivalent resistance Rs of the equivalent resistance Rp of former limit winding, secondary winding is lower.Meanwhile, the distributed capacitance of litz wire can be used as matching capacitance.
When the secondary winding of described high frequency air-core transformer and secondary matching capacitance form series circuit, the no-load voltage ratio K of described transformer, the mutual inductance M of former limit winding and secondary winding, resonance frequency omega, the equivalent resistance Rp of former limit winding, the equivalent resistance Rs of secondary winding, load resistance R meets following relation:
And
The former limit of described high frequency air-core transformer winding, secondary winding preferably adopt litz wire coiling, can effectively reduce the impact of skin effect, proximity effect, while making to obtain same inductance value, the equivalent resistance Rs of the equivalent resistance Rp of former limit winding, secondary winding is lower.
Adopt the high frequency air-core transformer of aforesaid way, owing to not using iron core, avoided the ferromagnetic loss that produces under high frequency, transmitting energy efficiently, can substitute high-frequency iron core transformer in occasion necessarily; Owing to having adopted harmonic technology, overcome the large problem of air-core transformer magnetic resistance, coupling coefficient k span is large simultaneously, is convenient to design and produce simultaneously.
Brief description of the drawings
Fig. 1 a is the structure diagram of one embodiment of the present invention;
Fig. 1 b is described execution mode winding skeleton circular cross-section figure;
Fig. 1 c is described execution mode winding skeleton square-section figure;
Fig. 2 is string-string structure magnetic coupling resonance high frequency air-core transformer principle schematic of the present invention;
Fig. 3 is that string-string structure magnetic coupling resonance high frequency air-core transformer no-load voltage ratio K and efficiency change schematic diagram with load resistance R described in Fig. 2;
Fig. 4 is string of the present invention-and structure magnetic coupling resonance high frequency air-core transformer principle schematic;
Fig. 5 be string described in Fig. 4-and structure magnetic coupling resonance high frequency air-core transformer no-load voltage ratio K change schematic diagram with load resistance R;
Fig. 6 be the present invention also-string structure magnetic coupling resonance high frequency air-core transformer principle schematic;
Fig. 7 be the present invention also-and structure magnetic coupling resonance high frequency air-core transformer principle schematic;
Fig. 8 is that the present invention contains two secondary winding magnetic coupling resonance high frequency air-core transformer principle schematic.
Embodiment
Further illustrate the present invention below in conjunction with the drawings and specific embodiments.
Fig. 1 a is the structure diagram of one embodiment of the present invention.As shown in Figure 1a, string of the present invention-and structure magnetic coupling resonance air-core transformer comprise winding skeleton 1, former limit winding 4, former limit matching capacitance 5, secondary winding 2 and secondary matching capacitance 3.The insulating material such as described winding skeleton 1 is a cirque structure, and material is epoxy resin.Former limit winding 4 and secondary winding 2 are wound on winding skeleton 1 in nonconcentric(al) mode, and coiling direction makes Same Name of Ends in same direction, the cross section of described winding skeleton 1 can be the circle as shown in Fig. 1 b cross section 10, can be also square as shown in Fig. 1 c cross section 11.One end ground connection of described former limit winding 4, the other end and former limit matching capacitance 5 are connected in series; One end ground connection of described secondary winding 2, the other end is connected with the high-pressure side of secondary matching capacitance 3, the low-pressure end ground connection of secondary matching capacitance 3, secondary winding 2 is connected in parallel with secondary matching capacitance 3; Described former limit matching capacitance 5 and secondary matching capacitance 3 are placed in the middle position of winding skeleton 1, and three's mutual insulating.
Fig. 2 is string-string structure magnetic coupling resonance high frequency air-core transformer principle schematic of the present invention.In Fig. 2, dotted line frame 20 comprises part and is string-string structure magnetic coupling resonance high frequency air-core transformer.Described transformer primary side winding L p and former limit matching capacitance Cp are connected in series, and secondary winding L s and secondary matching capacitance Cs are connected in series.When work, power supply Up provides frequency and former limit winding, alternating current that secondary winding resonance frequency is identical to transformer, and former limit winding L p and former limit matching capacitance Cp, under power supply excitation, series resonance occurs, and produces high frequency magnetic field; High frequency magnetic field and secondary winding L s coupling induce electric current in secondary winding L s, and secondary winding L s and secondary matching capacitance Cs also produce series resonance, and to responsible R output energy, the R of load simultaneously voltage U s is required voltage.
Fig. 3 is that string-string structure magnetic coupling resonance high frequency air-core transformer no-load voltage ratio K and efficiency change schematic diagram with load resistance R described in Fig. 2.According to the magnetic coupling resonance air-core transformer of described formula (2), (3) design, transformer nominal transformation ratio K is 2, nominal load resistance R is 1 ohm, and load resistance increases to 2 ohm by 0.2 ohm, and the situation of change of no-load voltage ratio K and efficiency as shown in Figure 3.The transformer of this structure, load resistance R changes, and no-load voltage ratio K and efficiency change change thereupon, and therefore load resistance R need meet design condition operation.
Fig. 4 is string of the present invention-and structure magnetic coupling resonance high frequency air-core transformer principle schematic.In Fig. 4, dotted line frame 40 comprises part and is string-and structure magnetic coupling resonance high frequency air-core transformer.Described transformer primary side winding L p and former limit matching capacitance Cp are connected in series, and secondary winding L s and secondary matching capacitance Cs are connected in parallel.
Fig. 5 be shown in Fig. 4 string-and structure magnetic coupling resonance high frequency air-core transformer no-load voltage ratio K with load resistance R change schematic diagram., according to the magnetic coupling resonance air-core transformer of described formula (1) design, transformer nominal transformation ratio K is 2, and nominal load resistance R is 10 ohm, and load resistance increases to 20 ohm by 2 ohm, and the situation of change of no-load voltage ratio K and efficiency is as shown in Figure 5.Visible at load resistance R in the scope of (50%~200%), no-load voltage ratio K and efficiency change are little.
Fig. 6 be the present invention also-string structure magnetic coupling resonance high frequency air-core transformer principle schematic.In Fig. 6, dotted line frame 60 comprises be also-string structure of part magnetic coupling resonance high frequency air-core transformer.Described transformer primary side winding L p and former limit matching capacitance Cp are connected in parallel, and secondary winding L s and secondary matching capacitance Cs are connected in series.
Fig. 7 be the present invention also-and structure magnetic coupling resonance high frequency air-core transformer principle schematic.In Fig. 7, dotted line frame 70 comprises part and is also-and the circuit of structure magnetic coupling resonance air-core transformer.Described transformer primary side winding L p and former limit matching capacitance Cp are connected in parallel, and secondary winding L s and secondary matching capacitance Cs are connected in parallel.
Fig. 8 is that the present invention contains two secondary winding magnetic coupling resonance high frequency air-core transformer principle schematic.As shown in Figure 8, dotted line frame 80 comprises part and is two secondary winding magnetic coupling resonance air-core transformers.Described transformer primary side winding L p and former limit matching capacitance Cp are connected in series, and secondary winding L s and secondary matching capacitance Cs are connected in series, and secondary winding L s1 and secondary matching capacitance Cs1 are connected in series.