RU72369U1 - CONTACTLESS TWO-STAGE COMPRESSION GENERATOR - Google Patents

Abstract

A non-contact two-stage compression generator containing a pulsed excitation source with a first commutator, an explicit pole ferromagnetic stator with a working winding located in open grooves between the poles, in parallel with which a load is connected via a second commutator, a monolithic rotor made of an electrically conductive material with teeth, between which magnetic circuits are fixed, the number of which is equal to the number of pole pairs (p) of the working winding, where p = 2, 3, 4, etc., characterized in that an additional winding is placed on the stator and excitations with the same number of pole pairs (p) in additional open grooves that are offset relative to the grooves of the working winding by an angle of 180 ° / r, while in parallel with the additional excitation winding, a pulse excitation source and through an additional switch the working winding are connected through the additional commutator with a second switch and load.

Description

The utility model relates to the field of parametric type electric machine generators with stator winding inductances periodically changing as the rotor rotates and can be used to frequency power electrophysical installations with powerful current pulses with an amplitude of up to 1 MA or more, for example, to power an inductive load, such as windings of an electric machine generator , inductive storage or accelerator electromagnet.

Known non-contact compression generator [Invited the compensated pulsed alternator program - a review / WLBird, WFWeldon, BMCarder, RJFoley - Proceedings of 3 rd IEEE International Pulsed Power Conference, Albuquerque, June 1981, p.134-141] containing a clearly polar ferromagnetic stator with one working winding, placed in open grooves between the poles, and a monolithic rotor of conductive material with teeth, the number of which is equal to the number of pairs of poles of the winding. When the rotor rotates, the inductance of the winding due to its screening by the teeth of the rotor periodically changes, and at the time of the minimum inductance (L _min ) the magnetic flux is displaced to the region of the winding, and at the time of the maximum inductance of the winding (L _max ) the magnetic flux passes a significant path through the air between the stator poles and to create it requires a lot of current.

The disadvantages of this generator are the significant power of the excitation source, which is associated with large currents, and the insignificant rate of change in the inductance of the winding (N = L _max / L _min <10), which limits the generated power.

The closest technical solution is a non-contact compression generator selected as a prototype [Patent RU No. 60807, IPC Н02K 57/00. - Publ. 01/27/2007. Bull. No. 3], containing an explicitly polar ferromagnetic stator with one working winding placed in open grooves between the poles, and a monolithic rotor made of conductive material with teeth, between which magnetic circuits are fixed, the number of which is equal to the number of pairs of winding poles. Parallel to the working

the winding is connected through the first switch to a pulsed excitation source and through the second switch the load. Due to the presence of magnetic circuits, the path of the magnetic flux through the air at the instant of maximum stator winding inductance (L _max ) is significantly reduced, which leads to a decrease in the current and power of the pulsed excitation source, as well as to an increase in the generated power of current pulses in the load due to an increase in the multiplicity of change in inductance (N )

The disadvantage of the prototype is insufficient for a number of loads generated power and the amplitude of the current pulses.

The objective of the utility model is to significantly increase the generated power and amplitude of the current pulses in the load while maintaining a small power of the pulsed excitation source.

This is achieved by the fact that the non-contact two-stage compression generator, as well as in the prototype, contains a pulsed excitation source with a first commutator, an explicit pole ferromagnetic stator with a working winding located in open grooves between the poles, in parallel with which a load is connected via a second commutator, a monolithic rotor from a conducting the electric current of the material with teeth between which the magnetic cores are fixed, the number of which is equal to the number of pole pairs (p) of the working winding. According to a utility model, an additional field winding with the same number of pole pairs (p = 2, 3, 4, etc.) is placed on the stator in additional open grooves that are offset relative to the grooves of the working winding by an angle of 180 ° / r. Parallel to the additional field winding, a pulse excitation source and a working winding with the second switch and the load are connected through the additional switch.

The achieved result will be explained with a pulsed power supply of the inductive load L _H without taking into account the active resistances of the generator windings and the load. We assume that when the first switch is closed at time t = 0, the pulse excitation source generates a pulse of the generator excitation current in the time interval 0≤t≤2t ₀ (Fig. 1, curve 1)

where I _m0 is the maximum value of the excitation current i ₀ (t).

The design of the non-contact two-stage compression generator is such that at the time of the maximum inductance value (L _max1 ) of the additional field winding, the inductance of the working winding takes the minimum value (L _min2 ) and vice versa, i.e. the inductance of the windings during rotation of the rotor periodically change and are shifted in time one relative to another by an angle equal to 180 electrical degrees. Therefore, the inductances of the additional field winding L ₁ (t) and the working winding L ₂ (t) of the generator during rotation of the rotor change in time t with a period T = 2π / ω and taking into account the constant component and the first harmonic,

L ₁ (t) = L ₀₁ [1 + m ₁ cosω (tt ₀ )];

L ₂ (t) = L ₀₂ [1-m ₂ cosω (tt ₀ )],

Where ; - modulation coefficients of the inductances of the windings;

L ₀₁ = (L _max1 + L _min1 ) / 2; L ₀₂ = (L _max2 + L _min2 ) / 2 - the average values of the inductances of the windings;

N ₁ = L _max1 / L _min1 ; N ₂ = L _max2 / L _min2 - the _rate of change of the inductances of the windings;

ω = 2πpf is the angular frequency determined by the rotor speed f and the number of pole pairs p of the windings.

1. Consider the first time interval 0≤t≤t ₀ , when at the moment t = 0 the first switch closes with the second and additional switches open. At this time interval, the current in the additional excitation winding of the generator i ₁ (t) will be equal to the excitation current i ₀ (t), i.e. i ₁ (t) = i ₀ (t) (Fig. 1, curve 2 in the interval 0≤t / T≤0.1). At time t = t ₀ , when the inductance of the additional winding and the excitation current are maximum, the initial energy stored in the magnetic field of the additional winding will be equal to

2. Consider the second time interval t ₀ ≤t≤2t ₀ , when at the moment t = t ₀ an additional switch closes when the first and open second switches are closed. Joint solution of equations

under known initial conditions

i ₀ (t ₀ ) = I _m0 ; i ₁ (t ₀ ) = I _m0 ; i ₂ (t ₀ ) = 0

allows you to determine the current in the additional field winding (Fig. 1, curve 2 in the interval 0.1≤t / T≤0.2)

and current in the working winding of the generator (Fig. 1, curve 3 in the interval 0.1≤t / T≤0.2)

3. Consider the third time interval 2t ₀ ≤t≤t ₀ + π / ω, when at time t = 2t ₀ for i ₀ (2t ₀ ) = 0, the first switch opens and disconnects the excitation source, with the additional switch closed and the second switch For i ₁ (t) = i ₂ (t) from the solution of equation (1) under known initial conditions

determine the currents in the windings of the generator (figure 1, curves 2 and 3 in the interval 0.2≤t / T≤0.6)

At time t = t ₀ + π / ω, when the inductance of the additional field winding is minimal (L _min1 ) and the working winding is maximum (L _max2 ), we find the current values

and energy stored in the magnetic field of the working winding

which will be the largest at L _max2 = L _min1 and equal to

4. Consider the fourth time interval t ₀ + π / ω≤t≤t ₀ + 3π / ω, when at the moment t = t ₀ + π / ω the second switch closes, and the additional switch is closed and the first switch is open. equations (1) and equations

under known initial conditions

i ₁ (t ₀ + π / ω) = I _m1 ; i ₂ (t ₀ + π / ω) = I _m1 ; i ₃ (t ₀ + π / ω) = 0

determine the current in the inductive load L _H (Fig. 1, curve 4 in the interval 0.6≤t / T≤1.6)

and also the current in the additional field winding (Fig. 1, curve 2 in the interval 0.6≤t / T≤1.6)

and the current in the working winding (Fig. 1, curve 3 in the interval 0.6≤t / T≤1.6)

At time t = t ₀ + 2π / ω, when the inductance of the additional field winding is maximum (L _max1 ), and the working winding is minimum (L _min2 ), we find the amplitude value of the current in the load

as well as the maximum energy stored in the magnetic field of the load

which will be greatest at load inductance

and will be at L _max2 = L _min1 and L _max1 ≫ L _min2

moreover

L _H ≈L _min2 ;

In turn, the prototype when feeding an inductive load L _H = L _min2 and with the same values of the initial energy W ₀ and the maximum excitation current I _m0 has

;

Thus, we obtain

; ,

those. claimed contactless two-stage compression generator has N _1/4 times greater energy and N to _1/2 times the amplitude of the current pulse in the load and, consequently, high power pulses compared with the prior art with the same drive power. The number of turns of the windings is chosen so that the minimum inductance of the additional field winding (L _min1 ) is equal to the maximum inductance of the working winding (L _max2 ).

Figure 1 shows the calculated current curves of a non-contact two-stage compression generator. Figure 2 schematically shows a non-contact two-stage compression generator with four pairs of poles (p = 4) with the rotor position, when the inductance of the additional field winding is maximum, the working winding is minimal. Figure 3 shows the electrical diagram of a non-contact two-stage compression generator.

The non-contact two-stage compression generator (Fig. 2) contains a housing 1, an explicitly polar ferromagnetic stator 2 with an additional field winding 3 and a working winding 4, a monolithic rotor 5 made of conductive material with teeth, between which magnetic circuits 6 are fixed, and also shaft 7. Additional the field winding 3 and the working winding 4 have the same number of pole pairs (p = 2, 3, 4, etc.) and are placed in the open grooves of the stator, and the grooves of the additional field winding 3 are offset relative to the grooves of the working winding 4 at an angle of 180 ° / r. In order to reduce the energy losses due to eddy currents, the explicit pole ferromagnetic stator 2 and the magnetic circuits 6 of the rotor 5 are manufactured in batch mode, i.e. recruited from separate insulated sheets of electrical steel.

The electrical circuit of a non-contact two-stage compression generator (Fig. 3) contains an additional field winding 3 and a working winding 4, a pulsed field source 8 (I), a first switch 9, an additional switch 10, a second switch 11, and a load 12 (N). and parallel to the additional field winding

3 are connected via a first switch 9, a pulse excitation source 8 (I) and through an additional switch 10 a working winding 4, in parallel with which a second switch 11 is connected with a load of 12 (N). A capacitor bank charged from an external source can be selected as a pulse excitation source 8 (I), and, for example, an inductive energy storage device (inductor) can be selected as a load 12 (N).

Non-contact two-stage compression generator operates as follows. An external drive motor rotor 5 of the generator spins up to a certain speed. Switches 9, 10, and 11 are open. At a moment close to the maximum inductance of the additional field winding 3, the first switch 9 is closed and the pulse excitation source 8 (I) generates an excitation current pulse i ₀ in the additional field winding 3. Further, at the moment of maximum inductance of the additional field winding 3, the additional switch 10 closes and the working winding 4 is connected in parallel with the additional field winding 3. Due to the changing inductances of the windings 3 and 4, the currents in these windings i ₁ and i ₂ begin to increase, and at the moment when the current excitation i ₀ becomes equal to zero, the first switch 9 is opened, and the pulse source 8 (I) is turned off. Further, at the instant of maximum inductance of the working winding 4, when the currents i ₁ = i _{2 are} maximum, the second switch 11 is closed, which connects the load 12 (N) in parallel to the working winding 4. Due to the changing inductance of the working winding 4 in the load 12 (N), a current pulse i _{3 is} generated. At the moment when the current i ₃ becomes equal to zero, the second switch 11 is opened and disconnects the load 12 (N). Further, when the currents i ₁ = i _{2 of the} windings 3 and 4 of the generator become close to zero, the additional switch 10 opens. The generator circuit (Fig. 3) returns to its initial state and the generator is ready to generate the next current pulse i ₃ in the load 12 (H )

The utility model, in comparison with the prototype, based on calculations and experimental studies conducted by the author, has at the same power of a pulsed excitation source approximately three times more energy and power of current pulses generated in a load.

This utility model is implemented as a non-contact two-stage compression generator weighing 500 kg (N ₁ = 30; N ₂ = 10) with thyristor switches for pulse-frequency power supply of inductive load. This generator has

pulse power of 58 MW with an amplitude of current pulses in a load of up to 300 kA and a pulse repetition rate of up to 100 Hz.

Claims (1)

A non-contact two-stage compression generator containing a pulsed excitation source with a first commutator, an explicit pole ferromagnetic stator with a working winding located in open grooves between the poles, in parallel with which a load is connected via a second commutator, a monolithic rotor made of conductive material with teeth, between which magnetic circuits are fixed, the number of which is equal to the number of pole pairs (p) of the working winding, where p = 2, 3, 4, etc., characterized in that an additional winding is placed on the stator and excitations with the same number of pole pairs (p) in additional open grooves that are offset relative to the grooves of the working winding by an angle of 180 ° / r, while in parallel with the additional excitation winding, a pulse excitation source and through an additional switch the working winding are connected through the additional commutator with a second switch and load.