WO1983001713A1

WO1983001713A1 - Parametric electric machine

Info

Publication number: WO1983001713A1
Application number: PCT/AT1982/000018
Authority: WO
Inventors: Österreichischer Industrieller ... Vereinigung
Original assignee: Cap, Ferdinand
Priority date: 1981-10-29
Filing date: 1982-06-07
Publication date: 1983-05-11
Also published as: BR8207847A; AT380358B; AR230903A1; ZA827384B; ES8308658A1; IL66842A0; NO823338L; EP0092549A1; EG14987A; GB2116802A; GB2116802B; GB8314101D0; AU8975982A; US4622510A; CA1181804A; IL66842A; IT8223981A0; DD208714A5; JPS58501852A; IT1191054B

Abstract

The parametric electric machine includes an oscillator loop comprising in series a capacity (C) (C1) which is varied by mechanical means, and inductance (L) (2, 3) and an ohmic resistance (R), for the load-free values (Co), (Lo), (Ro) for which the following oscillation relation is verified <IMAGE> At least one of the parameters (L, R, C) of the oscillating loop is a function of the current traversing the loop.

Description

Parametric electrical machine

The invention relates to a parametric electrical machine, consisting of at least one capacitor with time-variable capacitance in series with an inductor comprising at least one induction coil and an ohmic resistor.

Characteristic of the known prior art

It has already been proposed to convert mechanical energy into electrical energy by periodically changing the electrical quantities of an oscillating circuit. With such a "parametric generator" e.g. in a series resonant circuit consisting of a capacitor and an induction coil, the capacitance is changed periodically over time. If the capacitance of a capacitor is reduced, since the charge of the capacitor is limited, i.e. is squeezed to a smaller capacity, work is done. The energy source is the mechanism that reduces the capacity. If the capacity is increased, it is not necessary to supply the system with energy, since the charges of the same name repel themselves and occupy a larger space on the increased capacity. With periodic reduction and increase in capacity, therefore, there is only ever one flow of energy from the drive mechanism into the oscillation circuit (conversion of mechanical into electromagnetic energy).

A parametric generator can be expected to have some advantages over conventional generators based on the induction principle do not work with permanent magnets (e.g. bicycle dynamo) - the necessary magnetic field is generated by excitation coils, in the windings of which Joule'sehe losses naturally occur which are so great that direct water cooling is necessary from a certain generator output. However, considerable heat losses can also occur in the rotor windings. The parametric generator, however, is largely free of heat loss. Furthermore, relatively high voltages (in the kV range) can be generated directly with a parametric generator. Other advantages are the simple design and the low weight of a parametric generator.

However, previous attempts to build a parametric generator have failed. On the one hand, it was not possible to generate a stable periodic alternating current that was independent of changing loads from the consumers; on the contrary, there was either an exponentially increasing current strength and thus the induction coils burned out or the alternating current oscillation was damped quickly. On the other hand, it was also not possible to generate sinusoidal alternating current vibrations with a parametric generator. The reason for this arises from the consideration of the differential equation for the parametric resonant circuit, which is as follows for a periodically periodic capacitance

Here L _{o is} the (initially) assumed inductance, C _{o is} the mean value of the total capacitance defined by C _o = (Cmax + C _min ) / 2, where Cmax is the largest and Cmm. mean the smallest value of the capacity. The

The change in capacity is denoted by ΔC = (C _max - C _min ) / 2.

R _o is the (initially) constant ohmic resistance of the Inductance and Q (t) is the charge on the capacitor.

The differential equation (I) is a damped one

Mathieu's differential equation, which generally has unstable solutions, i.e. Voltage, charge and current either go exponentially towards infinity or towards zero. Only for very specific values of the parameters

R _o , L _o , C _o and ΔC result in a stable periodic oscillation, which does not change with time, however, after a sine function but after a math function. Hardly any supply network will be interested in electrical voltages that, according to Mathieu functions, function as a function of time.

To remedy this deficiency, it has been proposed (DE-PS 633 254) to force a parametric resonant circuit with variable capacitance or inductance by feeding in a sinusoidal AC voltage to amplify this external excitation by means of parametric effects ("power amplifier").

Object of the invention

The invention, however, is based on the object of providing a parametric electrical machine with which it is possible to generate stable sinusoidal alternating currents (generator) without the need for external excitation and which can also be used to convert electrical energy into mechanical energy (motor), and by connecting to a power supply network that supplies a sinusoidal alternating current.

State the nature of the invention

This is achieved according to the invention in that Resonant circuit, the machine the condition

applies, where C _o the (total) basic capacitance of the capacitor (or capacitors), ΔC the mechanical change in the (total) capacitance of the capacitor (or capacitors), L _o the (total) inductance of the induction coil ( n) and R _{o are} the (total) ohmic resistance of the induction coil (s) including any additional purely ohmic resistors in the no-load state, and that at least one parameter element (L, R, C) of the resonant circuit is one. Function of the current I flowing in the resonant circuit is.

As in equation (I) above, C _o and Δ C relate to the highest value of the (total) capacitance C _max and to the lowest value of the (total) capacitance C _{min of} the capacitor (s) in the following relationship:

In the simplest case, the "capacitance" of the resonant circuit consists of a single capacitor with variable capacitance and the "inductance" consists of a single induction coil with a core made of ferromagnetic material. The "capacity" can, however, also from parallel or. Series connections of several capacitors (at least one of which is a variable over time

Has capacity) and the "inductor" consist of several induction coils connected in parallel or in series (at least one of which has a stationary core made of ferromagnetic material). The invention is based on the knowledge that it is possible to convert the differential equation (I) into an oscillation equation which has sine functions as solutions, namely when the oscillation equation is given a non-linear term. The invention is also based on the knowledge that such a non-linear element of the oscillation equation can be technically realized in that at least one parameter element (L, R, C) of the oscillating circuit is a function of the current I = Q '= flowing in the oscillating circuit

is. For example, suppose that inductance obeys the following law

L = L _o (1 + g (Q '))

this gives the following homogeneous nonlinear differential equation for the parametric resonant circuit

With a suitable and also technically feasible choice of g (Q '), the differential equation (II) has a stable sinusoidal solution (after a few periodic non-sinusoidal settling processes), provided that the threshold condition according to the invention applies

as well as one of the possible resonance conditions. One of them is:

Although the threshold condition contains the values C _o , R _o , L _o , i.e. the parameter elements of the load-free oscillating circuit, it is considered an inequality even in the loaded state.

In the case of the generator, compliance with the threshold condition means that at least as much mechanical energy is supplied to the generator as there are losses in the ohmic resistors. With the motor, compliance with the threshold condition guarantees that the electrical energy supplied is equal to the losses in the ohmic resistances.

The feature according to the invention, according to which at least one parameter element (L, R, C) is a function of the current flowing in the resonant circuit (which leads to non-linearity of the oscillation equation and to sinusoidal solutions) means that an induction coil and / or a resistor is present in the resonant circuit of the machine and / or there must be a capacitor whose inductance or resistance or capacitance changes depending on the current strength. There are various technical options.

One possibility according to the invention is that at least one induction coil of the inductance of the resonant circuit contains a stationary core made of magnetic material. In order to keep the "iron losses" caused by the core made of ferro-magnetic material as low as possible, it is advisable to use a low-loss ferro-magnetic material for the core of the induction coil, the hysteresis loop of which therefore includes the smallest possible area. The

Iron losses should suitably be in the order of 1 to 3 W / kg (loss figure V ₁₀ at 50 Hz and 1 T = 10 kG maximum reduction). In addition, the Hysteresis curve should be as steep as possible, so that the dependency

is very large.

Another technical possibility of non-linearization of the vibration equation is e.g. in a circuit of a thermal resistor in series with the inductance of the resonant circuit, i.e. a resistor that changes depending on the current (and temperature), or in the use of a capacitor, the capacitance, e.g. due to its special properties, its dielectric depends on the current flowing through it.

With the help of the features according to the invention, it is possible to create a real parametric generator which, even with strong stochastically variable values for the ohmic resistance, the inductance and the capacitance of the consumers connected to the generator, delivers a frequency-stable and amplitude-stable, sinusoidal alternating current, in contrast to the usual frequency-sensitive alternators.

Furthermore, with the help of the features according to the invention it is possible to create a parametric motor which can be fed from a normal AC network and which is also of light construction and (depending on the choice of parameters) by the possibility of generating high speeds and direct connection high voltages (in the kV range).

Description of the drawing figures

The invention is explained below with reference to the drawings by an embodiment.

1 shows the circuit diagram of a parametric generator according to the invention,

Fig. 2 shows in section an embodiment of a capacitor with time-varying capacitance and an induction coil with an iron core connected in series.

FIG. 3 shows a rotor plate in view and FIG. 4 shows a stator plate of the capacitor according to FIG. 2. FIGS. 5 and 6 show further circuit diagrams of the parametric generator according to the invention.

Description of preferred embodiments

1, the parametric generator consists of a capacitor 1 with a periodically changing capacitance and an induction coil 2 with a core 3 made of ferromagnetic material. 4 with a consumer is designated, which in this case is connected in parallel to the induction coil 2.

The capacitor 1 consists, as can be seen in FIG. 2, of stator plates 5 and rotor plates 6. The rotor plates 6 sit in an electrically conductive connection on the shaft 7, which is driven by a symbolically represented mechanical drive 8, e.g. an engine or a turbine. The stator plates 5 are held by electrically conductive rods 9. The stator plates 5 and rotor plates 6 are constructed essentially the same and consist, as can be seen from FIGS. 3 (rotor plate) and 4 (stator plate), alternately from sectors 10 made of electrically conductive material, e.g. Copper, and sectors 11 of electrically insulating material, e.g. Plastic. Due to the rotation of the rotor plates 6, the capacitance C of the capacitor changes periodically with time.

The induction coil 2 connected in series with the capacitor 1 consists of the coil winding 12 and the iron core 3, which in the present case is an EI core, made up of technical dynamo sheets IV of 0.35 mm Thickness and a loss figure (V ₁₀ ) of 1.3 W / kg. The consumer, not shown, is connected, for example, to the terminals 13 of the induction coil 2.

Since the temporal periodicity of the capacitance of the capacitor 1 must correspond to the frequency of the resonant circuit in the sense of the "resonance condition", it is expedient if the parametric generator has setting options in this regard. The length of the period of the time change of the capacitance 'of the capacitor 1 depends on the speed of the motor or the turbine, and in the case of the exemplary embodiment shown. - From the number of sectors 10, 11 of the rotor plates 6 or 5 stator plates. To meet the resonance conditions, one can e.g. the speed of the drive 8, for example with the help of a continuously variable transmission, vary. Instead, the electromagnetic variables of the resonant circuit can also be designed to be adjustable, for example the inductance of the induction coil 2 by adjusting the air gap between the yoke (I-piece) 3 'and the

E-piece of the iron core 3, or change the total capacity by connecting an additional small variable capacity in series.

With a parametric generator according to the invention with L _o = 80 H, Co = 2.13.10 ^"9 F, ΔC = 0.22 C _o , R _o = 10 kΩ and an iron core made of dynamo sheet IV of 0.35 mm thickness and an iron loss ( V ₁₀ ) of 1.3 W / kg, a stable alternating voltage of 1050 V at a frequency of 300 Hz could be achieved. For lower frequencies and higher voltages, the speed of the capacitor and / or the parameters L _o , C _o , To vary ΔC accordingly. 1, the load 4 is connected in parallel to the induction coil 2. However, there is also the possibility - as can be seen in FIG. 5 - to connect the consumer 4 'in series with the capacitor 1 and the induction coil 2. In practice, however, it will be cheapest according to FIG. 2 to connect the consumer 4 "to the resonant circuit of the parametric generator via a transformer, the coil winding 12 of the inductance of the resonant circuit forming the primary winding of the transformer and the iron core 3 of the inductance of the resonant circuit is designed so that it magnetically couples the primary winding 12 and secondary winding 14. The entire coil winding 12 of the inductance of the resonant circuit does not necessarily have to be the primary winding of the transformer at the same time part of the induction coils form the primary winding of the transformer.

The time-periodically changing capacitance can also be solved in a technically different manner than in the exemplary embodiment described, for example by forming the dielectric of the capacitor as a gearwheel and the like, driven by a motor, a water turbine or the like. can rotate between the capacitor plates. Furthermore, the use of a cylindrical capacitor is possible, which consists of two mutually rotatable, alternately divided into sections of conductive and dielectric material, coaxially pushed cylindrical rollers. The capacitor shown in the drawings can (according to general thermodynamic principles) also be used as a motor if one applies an alternating voltage to the terminals 13 in FIG. 2 and gives the rotor plates 6 of the capacitor 1 or the capacitor shaft 7 an initial torque in order to "Resonance condition" to meet. This then results in positive and negative charging of the sectors 10 and in electrostatic repulsive forces or torques.

Claims

Patent claims:

1. Parametric electrical machine, consisting of at least one capacitor with time-varying capacitance in series with an inductor comprising at least one induction coil and an ohmic resistor, ¹ characterized in that the condition in the resonant circuit of the machine

applies, where C _o the (total) basic capacitance of the capacitor (1) (or the capacitors), ΔC the mechanical change in the (total) capacitance of the capacitor. (1) (or the capacitors), L _o the (total) inductance of the induction coil (s) (2) 'and R _o the (total) ohmic resistance of the induction coil (s) including any additional pure ohms' shear resistors are in the no-load state, and that at least one parameter element (L, R, C) of the resonant circuit is a function of the current I flowing in the resonant circuit.

2. Parametric machine according to claim 1, characterized in that at least one induction coil (2) of the inductor contains a stationary core (3) made of a ferromagnetic material.

3. Parametric machine according to claim 2, characterized in that the core (3) of the induction coil (2) consists of a low-loss ferromagnetic material.

4. Parametric machine according to claim 3, characterized in that the core (3) of the induction coil (2)

Has a loss figure (V _1o ) of about 1 to 3 W / kg.

5. Parametric machine according to one of claims 2 to 4, characterized in that the core (3) of the induction coil (2) consists of a package of dynamo sheets IV of 0.35 mm thickness.

6. Parametric machine according to claim 1, characterized in that the capacitor (1) with time-variable capacitance from mutually rotatable, alternating in sectors (10, 11) made of conductive and dielectric material, axially normal disks (5,6).

7. Parametric machine according to claim 1, characterized in that the capacitor with time-varying capacitance consists of mutually rotatable, alternately divided into sections of conductive and dielectric material, coaxially pushed cylindrical rollers.

8. Parametric machine according to one of claims 1 to 7, characterized in that the consumer (4 ") is connected via a transformer to the resonant circuit, the primary winding of the transformer and the coil winding (s) (12) of the inductor (2) of the resonant circuit are at least partially identical.