CN1061684A

CN1061684A - Efficient inductive ac frequency convertor

Info

Publication number: CN1061684A
Application number: CN 90102983
Authority: CN
Inventors: 於岳亮; 於宙
Original assignee: Individual
Current assignee: Individual
Priority date: 1990-11-15
Filing date: 1990-11-15
Publication date: 1992-06-03
Anticipated expiration: 2005-11-15
Also published as: CN1031440C

Abstract

A kind of induction frequency conventer is made main frame by induction type line winding motor, and subsidiary engine made by interchange or direct current machine and mechanical connector constitutes.This machine has fundamentally been reformed the electromechanical energy conversion mechanism of synchronous frequency changer, make part or big portion electric energy directly become the electric energy of another frequency without this link of mechanical energy, therefore its energy conversion efficiency (being about 93%) is than synchronous frequency changer height, and volume, consumptive material, cost all decrease.This organizational security has stayed many advantages of motor, and is therefore big than electronic reverse converter power capacity, overload capacity is strong, waveform good, and reactive power can be provided, absorb inverse probability.It is the utility unit of the formation capacity conversion of electricity system, VVVF power supply from several kilowatts to ten thousand kilowatts.

Description

Efficient inductive ac frequency convertor

A kind of rotation AC frequency conversion machine belongs to electricity frequency transform techniques field.

Existing synchronous frequency changer generally is made up of the synchronous motor and each one in the synchronous generator of coaxial connection, and the former is with f ₁The AC energy of frequency fully is transformed to mechanical energy, and the latter fully is transformed to f with this mechanical energy ₂The AC energy of frequency is because through secondary energy converting between mechanical in full, so loss is bigger, the energy conversion gross efficiency of unit reduces, and unit volume is big, consumptive material is many, rotating speed is high, cost is expensive; With state type electronic inverter conversion frequency, though energy loss is little, its overload capacity is low, power capacity is little, the waveform difference of alternating current, provide the reactive current difficulty.

The objective of the invention is to design and a kind ofly make main frame, be equipped with that energy conversion efficiency height, power capacity that auxilliary () machine and mechanical connector constitute are big, waveform good, rotary frequency converter simple in structure by induction machine.

Principle of the present invention is to make frequency conversion main frame 1 with the wire wound induction machine, and it and another motor (being called for short subsidiary engine 2) drive through mechanical connector 3 shaft couplings and constitute the frequency convertor main body, finish frequency conversion function.In conversion process, the f of input main frame 1 primary side ₁The f of frequency electric energy and the output of its secondary side ₂Conversion between the frequency electric energy is directly to form by induction rather than via this circulation of energy converting between mechanical, only account for a fraction of in total frequency conversion energy, via the energy of the conversion of subsidiary engine 2 via electromechanical energy conversion, so the gross energy conversion efficiency of device obviously improves.Ignore loss, following relation arranged between its switching energy and frequency translation:

f ₂＝f ₁±np ₁/60

P _Ⅱ＝P _Ⅰ±P _m

(P _I)/(f ₁) = (P _Ⅱ)/(f ₂)

In the formula: f ₁Be device input supply frequency (hertz)

f ₂Be device output AC frequency (hertz),

N be main frame 1 rotating speed (rev/min),

p ₁Be the number of pole-pairs of main frame 1,

P _IFor the electric energy of input main frame primary side (watt),

P _IIFor the electric energy of main frame secondary side output (watt),

P _mFor the mechanical energy of advancing/go out subsidiary engine (watt).

Narrate embodiments of the invention below with reference to accompanying drawing:

Fig. 1 induction frequency conventer block diagram;

Fig. 2 makes the induction frequency conventer block diagram of subsidiary engine with direct current machine.

Among Fig. 1,1 is main frame, is wire wound induction motor, W ₁, W ₂Be respectively its primary side and secondary side, p ₁It is the main frame number of pole-pairs.2 is subsidiary engine, and it can be to exchange or direct current machine, and Fig. 1 is alternating current machine (comprising squirrel-cage motor and synchronous machine).The 3rd, main and auxiliaries connects the mechanical connector of usefulness, can be shaft coupling, also can be speed changer.2 armature is by input power supply f ₁Power supply if 2 be synchronous machine, also need increase rectifier 4,4 also by f ₁One phase or heterogeneous power supply of power supply exported direct current then and supplied with 2 excitation electric energy.If f ₂＜f ₁, when immediate shipment was changed to the frequency reducing machine, no matter be that squirrel-cage motor or synchronous machine 2 all work in the generator state, the armature of this moment 2 can meet input power supply f ₁, the mechanical energy by 1 output is changed into electric energy return power supply source, also can connect 1 output, with the common outwards power supply of the secondary side of main frame 1, this mechanical energy is changed into f ₂As long as the electric energy of frequency is 1 W ₂Winding has identical structure and parameter with 2 armature, and the two can power to the load in parallel connection.

If 2 is direct current machine, and f ₂＞f ₁(when device is the raising frequency machine), its connection and 2 is close when being synchronous motor, and the output that promptly must increase rectifier 4,4 is powered to 2 armature and excitation winding respectively.If f ₂＜f ₁, then 2 become generator, at this moment also need increase straight/hand over inverter 5, so that be f with the direct current energy inversion ₂AC energy output, see Fig. 2.

If subsidiary engine 2 is an adjustable speed motor, perhaps,, increase corresponding speed setting controller to change the value of engine speed n by carrying out speed governing with 3 of speed governing speed changer formation, this frequency convertor device just becomes a kind of by fixed frequency f so ₁The variable voltage variable frequency supply unit (VVVF power supply) of power supply power supply.

The input of apparatus of the present invention can manufacture and design by the input power supply of any number of phases, and the output number of phases can be identical with input, also can be different with input, as long as can in main frame, form common unified rotating magnetic field.Main frame 1 can be installed in the same casing with subsidiary engine 2, also can be made of each individual motor to be installed on the same support.

The advantage of apparatus of the present invention is energy conversion efficiency height, this is because in frequency conversion process, one one or big section electric energy directly by induction effect become another frequency electric energy and needn't be through mechanical energy link in the middle of this, so energy loss is very little, its energy conversion efficiency is far above the synchronous frequency conversion machine. Because main frame is induction machine, its cost is than low with the synchronous generator of power, because subsidiary engine is only born one one or little section in total transform power, so its power, volume, cost are all much lower than the synchronous motor in the synchronous frequency conversion machine. Apparatus of the present invention have kept the advantage of motor, so compare with electronic inverter, have that power capacity is big, overload capacity is strong, waveform solid and reliable, alternating current is good, and reactive power can be provided, and absorb the plurality of advantages such as inverse probability.

Claims

1, a kind of inductive ac frequency convertor device, it is characterized in that it by a wound induction motor make main frame 1, another motor is made subsidiary engine 2, mechanical connector 3 is formed and is installed on the same support primary side W of main frame 1 ₁Winding and subsidiary engine 2 and f ₁The heterogeneous input power sourced electric of frequency connects 1 secondary side winding W ₂As the exportable f of main output winding ₂The heterogeneous electric energy of frequency.

2, by the described frequency convertor device of claim 1, it is characterized in that being the mouse cage AC induction machine when subsidiary engine 2, when installing to the frequency reducing machine, subsidiary engine 2 can be connected to the input supply terminal of device, also can be connected to the output of device, with the common outwards power supply of the secondary side of main frame 1.

3, by the described frequency convertor device of claim 1, it is characterized in that when subsidiary engine 2 is ac synchronous motor, increase the direct and f of armature of rectifier 4,2 ₁The heterogeneous input power sourced electric of frequency connects, and 2 excitation winding connects 4 dc output end, and 4 ac input end connects a phase or heterogeneous of input power supply, and when device was the frequency reducing machine, 2 armature also can be hinged with the output of putting.

4, by the described frequency convertor device of claim 1, it is characterized in that when subsidiary engine 2 is direct current machine, rectifier 4 is arranged, when device was the raising frequency machine, the armature of direct current machine and excitation winding were received 4 dc output end respectively, and 4 ac input end connects a phase or heterogeneous of input power supply, when device is the frequency reducing machine, the armature that also need increase DC/AC inverter 5,2 connects 5 direct-flow input end, and 5 ac output end meets f ₂The frequency AC power.

5, by the described frequency convertor device of claim 1, it is characterized in that subsidiary engine 2 is adjustable speed motor, perhaps mechanical connector 3 is the speed governing speed changer, also has the both to each have corresponding speed setting controller to have the function of VVVF power supply in addition.

6, by claim 2,3,4,5 described frequency convertor devices, it is characterized in that the subsidiary engine 2 and the mechanical connector of main frame 1 can be shaft couplings, also can be speed changer, main frame 1 and subsidiary engine 2 can be installed on the public frame, also can be installed in the same housing.