Electrical refrigerating compressor

Claim 2

An electrical machine comprising a vibration type compressor including a mechanical vibration system having a drive coil with at least one spring resonant with the drive coil, an electrical vibration system having semiconductor switching elements of the type with a control electrode for switching-control according to variable factors of the electrical vibration system in relation to the vibration of the drive coil, and a control transformer of unsaturated core type for controlling the on and off of the semiconductor switching elements, the electrical vibration system being constructed and arranged to oPerate at the natural vibration cycle of the mechanical vibration system according to the movement of the mechanical vibration system, and at the same time, the electrical vibration system supplying the mechanical vibration system with electric power necessary to operate the mechanical vibration system.

Claim 3

An electrical machine as in claim 1 wherein the semiconductor switching element comprises at least one transistor, the mechanical vibration system includes a piston movable between a top dead point and a bottom dead point, the current flowing in the drive coil, which changes with change in the impedance dependent on the counter-electromotive force developed across the drive coil, is equaled to the output current of the transistor which performs switching control under the following condition: IC > or = hFE.IB where IC : the output collector current of a transistor used as the semiconductor element with a control electrode; IB : the base current of the transistor; hFE : the amplification factor of the transistor; at the maximum output current available at the minimum counterelectromotive force across the drive coil at the top dead point and the bottom dead point of the piston of the mechanical vibration system.

Claim 4

An electrical machine as in claim 1 wherein the semiconductor switching element comprises at least one rectifier element with a control electrode, such as thyristor, the current flowing in the drive coil, which changes with change in the impedance dependent on the counter-electromotive force developed across the drive coil, is equaled to the output current of the semiconductor switching element which performs switching control under the following condition: EO < or = K.IM where IM : the anode current of the rectifier element with a control electrode used as the semiconductor element having a control electrode; EO : the compared voltage in a voltage comparator circuit; K : the conversion ratio of secondary voltage to primary current of a current transformer; at the maximum output current available at the minimum counterelectromotive force across the drive coil.

Claim 5

An electrical machine as in claim 2 wherein at least one transistor is used as the semiconductor switching element with a control electrode included in the electrical vibration system, the electrical vibration system is coupled to the mechanical vibration system so that the change in the electrical characteristic of the drive coil, that is, the change in the impedance thereof, due to the vibration generated in the mechanical vibration system at its natural vibration cycle, causes the transistor to be on-off controlled through the control transformer of unsaturated core type, and even when the natural vibration cycle of the mechanical vibration system varies due to variation in the power source voltage and/or variation in the external condition, the change in the impedance across the drive coil is derived substantially proportionally to the change in the natural vibration cycle of the mechanical vibration system by utilizing the linear characteristic of the control transformer of unsaturated core type, and thus the switching of the transistor is controlled according to the perpetually changing natural vibration cycle of the mechanical vibration system.

Claim 6

An electric machine as in claim 3 wherein at least one rectifier element with a control electrode is used as the semiconductor switching element with a control electrode included in the electrical vibration system, a current transformer and a trigger circuit are provided, the current transformer being serial with the drive coil, and the trigger circuit being capable of generating a pulse according to the quantity of electrical change developed in the current transformer, so that the change in the electrical characteristic of the drive coil, that is, the change in the impedance tHereof, due to the vibration generated in the mechanical vibration system at its natural vibration cycle, causes the rectifier element with a control electrode to be on-off controlled through the control transformer of unsaturated core type, and even when the natural vibration cycle of the mechanical vibration system varies due to variation in the power source voltage and/or variation in the external condition, the change in the impedance across the drive coil is derived substantially proportionally to the change in the natural vibration cycle of the mechanical vibration system by utilizing the linear characteristic of the control transformer of unsaturated core type, and thus the rectifier element with a control electrode is on-off controlled by the pulse of the trigger circuit.

Claim 7

An electrical machine as in claim 1 wherein the vibration type compressor includes an electrical circuit driven either from a unidirectional power source or from an alternating current power source, and a means arranged to disconnect the control circuit of the compressor, which is normally connected to the unidirectional power circuit, from the control circuit comprising the switching elements when the alternating current power source is connected thereto.

Claim 8

An electrical machine as in claim 1 wherein the control transformer of unsaturated core type for controlling the switching elements of the electrical vibration system includes an AC power input winding.

Claim 9

An electrical machine as in claim 1 wherein an output transformer is connected between the mechanical vibration system of the compressor and the output terminal of a control circuit comprising the switching elements, and the output voltage of the output transformer is supplied to the terminals of the drive coil and, at the same time, the current changingly flowing in the drive coil is transferred through the output transformer to the control circuit which comprises switching elements.

Claim 10

An electrical machine as in claim 2 wherein the electrical vibration system is operated in such a manner that when transistors are used as the semiconductor switching elements for the electrical vibration system of the compressor, the transistors perform switching at an oscillating frequency which depends on the characteristic in a saturated range beyond the linear characteristic of the control transformer of unsaturated core type when the drive coil is disconnected from the electrical vibration system, or the transistors operate always at the natural vibration cycle of the mechanical vibration system of the compressor when the electrical vibration system is coupled to the drive coil of the compressor and supplied with power from the unidirectional power source.

Claim 11

An electrical machine as in claim 3 wherein the electrical vibration system is operated in such manner that when rectifier elements of the type with a control electrode are used as the switching elements for the electrical vibration system of the compressor, the rectifier elements perform switching at an oscillating frequency which depends on the characteristic in a saturated range beyond the linear characteristic of the control transformer of unsaturated core type or the electrical vibration system assumes a non-oscillating state, and the rectifier elements operate always at the natural vibration cycle of the mechanical vibration system of the vibration type compressor when the electrical vibration system is coupled to the drive coil of the compressor and supplied with power from the unidirectional power source.

Claim 12

An electrical machine as in claim 4 wherein a capacitor, a resistor, and a third winding of the control transformer are connected across between the positive and negative terminals of the unidirectional power source whereby a transient current is provided to compensate for the starting current of the vibration type compressor.

Claim 13

An electrical machine as in claim 4 comprising a bridge including four transistors, two opposite ones serially operable independent of thE other two opposite ones, the two opposite transistors having their emitter-collector circuits connected to the drive coil to allow a current to flow in the drive coil through the terminal of the compressor, and the other two opposite transistors having their emitter-collector circuits connected to a unidirectional power source to allow a current to be supplied to the drive coil, and wherein the primary winding of the control transformer using unsaturated core type is connected in parallel to the drive coil for detecting the current flowing through the drive coil, and the emitter-base circuits of the individual opposite transistors are connected to the secondary winding of the control transformer using unsaturated core type so that the emitter-base circuits of the transistors are controlled according to the on-off of the current flowing through the drive coil.

Claim 14

An electrical machine as in claim 4 including two transistors the collectors of which are connected across the control transformer using unsaturated core type in parallel with the drive coil of the vibration type compressor, the center tap of the control transformer using unsaturated core type and the emitters of the two transistors being connected to a unidirectional power source, and the bases of the transistors being connected across a second winding of the control transformer using unsaturated core type so that the transistors are controlled according to on and off of the current in the drive coil, a voltage about twice that of the unidirectional power source is applied to the drive coil.

Claim 15

An electrical machine as in claim 5 wherein the semiconductor switching elements comprise four rectifier elements with a control electrode such as thyristor, two of the rectifier elements with a control electrode having their anodes connected to the positive terminal of a unidirectional power source and the other two rectifier elements with a control electrode having their cathodes connected to the negative terminal of the unidirectional power source, the cathodes of the two rectifier elements with a control electrode being connected to one terminal of the windings of two commutation reactors, respectively, each having a center tap, the anodes of the latter pair of rectifier elements with a control electrode being connected to the other terminals of the two commutation reactors, a commutation capacitor connected between the power source and the center tap of each of the reactors, the primary winding of a current transformer in series with the drive coil being connected between the two center taps of the commutation reactors, the unidirectional power input primary winding of the control transformer using unsaturated core type being connected in parallel to the primary winding of the current transformer and drive coil connected series each other thereby forming a bridge circuit comprising the rectifier elements with a control electrode, a trigger circuit for generating trigger pulses to turn on and off alternately the two pairs of opposite rectifier elements with a control electrode, and the current transformer being selectively connected to the input terminals of the trigger circuit so that the timing of the trigger pulse is selectively taken out of the secondary winding of the current transformer.

Claim 16

An electrical machine as in claim 5 wherein the semiconductor switching elements comprise two rectifier elements with a control electrode such as thyristor, the two rectifier elements with a control electrode having their cathodes commonly connected to one terminal of a commutation reactor, the other terminal of the commutation reactor being connected to the negative terminal of a unidirectional power source, the anodes of the two rectifier elements with a control electrode being connected to each other through a commutation capacitor, the commutation capacitor being connected in parallel to the unidirectional power input primary winding of the control transformer using unsaturated core type, a tap installed at nearLy the center of the primary winding of the control transformer using unsaturated core type, the tap being connected to the positive terminal of the unidirectional power source, the drive coil being connected to the anodes of the rectifier elements with a control electrode through the primary winding of a current transformer, a trigger circuits for generating trigger pulses to turn on and off alternatively the two rectifier elements with a control electrode, and the current transformer being connected to the input terminal of the trigger circuits whereby the timing of the trigger pulse is selectively determined on the secondary winding of the current transformer.

Claim 17

An electrical machine as defined in claim 4 wherein the switching elements comprise one transistor element, a series connection between a unidirectional power source, the primary winding of the control transformer using unsaturated core type, a limiting resistor and the emitter-collector circuit of the transistor element, the drive coil of the compressor being connected in parallel to the winding of the control transformer using unsaturated core type and the limiting resistor so that the collector current of the transistor serves directly as the current supplied to the drive coil, the secondary winding of the control transformer using unsaturated core type being connected to the base of the transistor so that the current flowing through the drive coil is controlled according to the on and off of the transistor, and a starting transient current compensating resistor connected between the base and the collector of the transistor.

Claim 18

An electrical machine as in claim 4 wherein four transistors are used as the switching elements connected in a bridge form, of which a pair of serial transistors make up each bridge arm, and the two pairs of them are connected in parallel to the two ends of the drive coil, one pair of serial transistors are of the same structure type such as PNP type (or NPN type) and the other pair of serial transistors are also of the same structure type such as NPN type (or PNP type), the two pair of serial transistors whose are connected in parallel to the two ends of the unidirectional power source are different structure type from each other (such as PNP and NPN type), and the switching control output winding of the control transformer of unsaturated core type is connected between the emitter and the base of each transistor.

Claim 19

An electrical machine as in claim 17 wherein four transistors are used as the semiconductor switching elements, connected in a bridge form, of which one PNP type transistor and one NPN type transistor make up a pair, each pair of transistors have their emitter in common, as well as their bases in common, the two pairs of common emitters are connected respectively to the two ends of the drive coil, the collectors of the two PNP type transistors are connected to the negative terminal of the unidirectional power source, and the collectors of the two NPN type transistors are connected to the positive terminal thereof, the control output winding of the control transformer of unsaturated core type is common to each pair of PNP and NPN type transistors and connected between the base and the emitter of each transistor.

Claim 20

An electrical machine as in claim 17 wherein four transistors are used as the semiconductor switching elements, connected in a bridge form, of which one PNP type transistor and one NPN type transistor make up a pair, each pair of transistors have their collectors in common, the two pairs of common collectors are connected respectively to the two ends of the drive coil, the emitters of the two PNP type transistors are connected to the negative terminal of the unidirectional power source, and the emitters of the two NPN type transistors are connected to the positive terminal thereof, the control output winding of the control transformer of unsaturated core type is common to each pair of transistors whose structure types are tHe same and is connected between the base and the emitter of each transistor, and a diode is inversely connected between the emitter and the base of each transistor, thus forming a bridge-like feedback circuit mechanism together with the base circuit.

Claim 21

An electrical machine as in claim 5 wherein the semiconductor switching elements comprise at least one rectifier element with a control electrode, such as thyristor, which has its anode connected to the positive terminal of a unidirectional power source and its cathode connected to one terminal of the drive coil by way of a control transformer of unsaturated core type operated as a commutation reactor, the negative terminal of the unidirectional power source being connected to the other terminal of the drive coil, a current transformer for detecting the value of the current flowing in the drive coil connected in series between one terminal of the unidirectional power source and one terminal of the drive coil, and a trigger circuit and a turn-off circuit having a thyristor capable of causing the rectifier element to repeat turn-on and turn-off, and such switching operation being selectively performed at both extreme amplitude positions of the drive coil.

Claim 22

An electrical machine as in claim 5 wherein a trigger circuit is provided, which receives a current input signal from the secondary winding of a current transformer connected in series between a unidirectional power source and one terminal of the drive coil, a resistor for converting the current input signal into a voltage signal is provided in the trigger circuit in parallel with the secondary winding of the current transformer, a pair of voltage comparator circuits operated alternately due to compare with predetermined value and the value of the voltage signals produced across the resistor is provided in the trigger circuit, the resistor being connected between the two input terminals of the individual voltage comparator circuits, and the voltage comparator circuits generate trigger pulses alternately and selectively according to the direction and value of the current flowing in the drive coil.

Claim 23

An electrical machine as in claim 21 comprising a trigger circuit wherein a pulse shaping circuit is provided, which shapes the output signal of a set of voltage comparator circuits driven according to the value of the current input signal and supplies the shaped pulses to a pulse amplifier circuit, and this circuits capable of amplifying the pulse signal from the pulse shaping circuit and thus generating a pulse output are provided respectively for a set of the voltage comparator circuits.

Claim 24

An electrical machine as in claim 4 wherein at least two transistors are used as the semiconductor switching elements, the emitters of a pair of the transistors being connected commonly to one terminal of a unidirectional power source, the collectors of the pair of transistors being connected to the both terminals of said drive coil respectively, diodes connected between the bases and the emitters of the individual transistors so that the currents of the transistors are inverted from each other, and the base-emitter circuits of the pair of transistors and the diodes constituting a bridge rectifier circuit.

Claim 25

An electrical machine as in claim 5 wherein at least one set of initial oscillation compensating circuits is provided, which comprises a series circuit of at least one resistor and one capacitor, thyristors are used as the semiconductor switching elements, the series circuit is connected between the positive terminal of a unidirectional power source and the gate of the thyristor, and thus the initial oscillation is compensated.

Claim 26

An electrical machine as in claim 20 wherein a resistor for converting the current signal from the secondary winding of a current transformer connected in series between the unidirectional power source and one terminal of the drive coil, into a voltage signal is connected in parallel with the secondary winding thereof, a turn-off cirCuit is constituted of a series circuit comprising a comparator circuit due to compare with predetermined value and the value of the voltage signals produced across the resistor and thereby generating a pulse voltage, a shaping circuit for shaping the waveform of the pulse voltage from the comparator circuit, and an amplifier circuit for amplifying the output signal of the shaping circuit, while, a turn-on circuit is constituted of a series circuit comprising the shaping circuit, the amplifier circuit and a zero-cross circuit for generating a pulse signal at the moment the terminal voltage of the drive coil changes its polarity, and a trigger circuit is constituted of a pair of the turn-off and turn-on circuits.

Claim 27

An electrical machine as in claim 20 comprising a primary winding operated as a commutation reactor when a unidirectional power source is connected to the control circuit, and a relay operated so that when an alternating power source is connected to the circuit an alternating voltage is induced across the primary winding of the control transformer using unsaturated core type having an alternating power input winding wound on the core on which the primary winding is wound thus supplying alternating power to the drive coil.

Claim 28

An electrical machine as in claim 1 wherein the drive coil is inserted in the magnetic field produced in a magnetic circuit comprising a york, a permanent magnet, and a pole piece, which constitute the magnetic circuit of the vibration type compressor, the polarity of a unidirectional power source is selectively connected to the electrical vibration system so that the electromagnetic force produced by the unidirectional interrupted drive current flowing in the drive coil is exerted always in the direction along which the permanent magnet is magnetized, and thus the permanent magnet operates always with a magnetic intensity above a value corresponding to the no-load performance point when the permanent magnet undergoes initial magnetization.