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DESCRIPTION

The present invention relates to a device for managing the power supply voltage deriving from an electrical network.

Currently, the electrical networks in the various states provide the power supply electricity for industrial plants or domestic installations not at a standard value, but with a variation in the percentage of the standard value, for example 10 %.

This creates continuous variations of electricity absorption by machinery and devices of industrial plants calibrated to operate at a well- determined electricity value; said absorption peaks may therefore cause damage, sometimes even significant, to machinery and devices of industrial plants and additional management costs.

In consideration of the prior art, the object of the present invention is to provide a device for managing the power supply voltage deriving from an electrical network that reduces the additional consumption due to the excess of electrical network voltage variation of the national electrical network.

According to present invention, such an object is obtained by means of a device for managing the power supply voltage deriving from an electrical network, comprising means having at the input said supply voltage of the electrical network and configured to limit the peaks of the power supply voltage by providing at the output terminal an output voltage at a lower value with respect to the power supply voltage deriving from the electrical network, said means comprising at least one transformer with a primary winding and a secondary winding arranged in phase opposed, said secondary winding being connected between the input terminal and the output terminal of the device and said primary winding comprising at least two taps, said device comprising further means adapted to select one of the two taps of the primary winding as a function of the electric network supply voltage value, said supply voltage being arranged between said selected tap and the neutral, characterized in that said two taps comprise a first tap and a second tap respectively associated with a first output voltage and a second output voltage with said first output voltage greater than said second output voltage, said further means being configured to select said second tap in response to an electrical network power supply voltage higher than a reference voltage or said first tap in response to an electrical network power supply voltage lower than said reference voltage.

Thanks to the present invention it is possible to provide a device for managing the power supply voltage deriving from an electrical network that allows a considerable energy saving. Said management device does not stabilize the power supply voltage deriving from the electrical network, that is, it does not emit a regulated output voltage but reduces the additional consumption due to the excess of electrical network voltage variation of the national electrical network. Said management device lowers the value of the electrical network voltage in the presence of an excess of electrical network voltage variation of the national electrical network.

The management device lowers the value of the network output voltage in relation to the value of the network input voltage, regardless of what output load is connected.

The features and advantages of the present invention will become apparent from the following detailed description of an embodiment thereof, illustrated by way of non-limiting example in the accompanying drawings, in which:

Figure 1 is a block diagram of the device for managing the power supply voltage deriving from an electrical network according to the present invention;

Figure 2 is a more detailed electrical circuit scheme of the device for managing the power supply voltage deriving from an electrical network according to an embodiment of the present invention;

Figure 3 is a more detailed electrical circuit scheme of the device for managing the power supply voltage deriving from an electrical network according to a variant of the embodiment of the present invention;

Figure 4 shows a time diagram of the power supply voltage deriving from an electrical network and of the device output voltage according to the invention;

Figure 5 is a circuit scheme of a part of the device for managing the power supply voltage deriving from an electrical network according to another variant of the embodiment of the present invention.

Figure 1 shows a device 1 for managing the power supply voltage deriving from an electrical network according to the present invention.

The device 1 comprises an input IN for receiving the electrical energy Eal provided by the electrical network, detection means 2 adapted to detect the parameters of the electrical energy Eal at the input terminal IN, for example the voltage Val and the current lal of the electrical energy Eal, control means 3 adapted to analyze the voltage Val and the current lal detected by the means 2 and adapted to control the means 4 in relation to the detected parameters; the means 4 are adapted to limit the peaks of the power supply voltage Val at the input by providing at the output terminal OUT a more constant voltage Vout.

Preferably, the control means 3 are adapted to deactivate the means 4, by acting on the generic switch S of Figure 1 arranged between the input terminal IN and the output terminal OUT, and to send to the output terminal OUT the electrical power present at the input terminal IN, that is, to make the device 1 operate as by-pass, in the presence of overcurrent at the input, that is, if the current lal detected by the means 2 is higher than a given amount Ial-ref (for example, 63 A), or in the case wherein the device 1 has a failure or in the presence of an undervoltage, that is, a voltage Val lower than a given voltage Val-ref (for example, 218 V); thereby, a power supply voltage at the output is always ensured for the various electrical devices of the industrial plant or domestic installation where the device 1 is installed.

Preferably, the device 1 also comprises a mechanical self-latching system able to keep as by-pass the device 1 in case of absence of the electrical energy Eal.

Preferably, the device 1 comprises indicators 6, for example, LED diodes, adapted to indicate the operating status of the device 1 ; said indicators allow to inform the user if the device 1 operates as a voltage limiter or as by-pass of the input voltage. The indicators 6 are controlled by the control means 3.

Preferably, an electrical power counter 7 is present, controlled by the control means for measuring the electrical power that passes through the device 1. In a screen 71 it is possible to display the electrical energy detected by the counter 7. Preferably, the counter 7, in the case wherein also the input terminal IN is connected, acts as detection means 2 as it is able to detect the parameters of the electrical energy Eal at the input terminal IN.

The means 4, according to the embodiment of the present invention, comprise at least one transformer 41 of the multiple taps S1-S3 type with a primary winding LI and a secondary winding L2 (Figure 2). The primary winding LI and the secondary winding L2 are in phase opposed, as the voltage across the secondary winding L2 is placed so as to subtract voltage from the voltage across the primary winding LI . The multiple taps SI -S3 belong to the primary winding LI and only the taps SI, S2 are selectable. At the selected tap SI, S2 the power supply voltage Val is present, while the secondary winding L2 is arranged between the input terminal IN and the output terminal OUT.

Each tap SI, S2 allows to obtain a partition of the input voltage Val; thereby, the output voltage Vout of the device 1 will only be a part of the voltage Val.

The selection of one of the two taps SI and S2 is defined by a switch K2, preferably a remote controller switch, controlled by means of the signal T2 by the control device 3.

The device 1 comprises another switch K3, preferably a remote controller switch, controlled by means of the signal T3 by the control means or control device 3 and a further switch Kl, preferably a remote controller switch; the remote controller switch Kl is typically open to allow the power supply of the primary winding LI and the secondary winding L2 and the remote controller switch K3 is typically arranged so as to allow the power supply of the remote controller switch K2.

The taps S I and S2 refer to two different partitions of the primary winding LI ; thereby, it is possible to externally manage the required amount of output voltage Vout as a percentage of the power supply voltage Val deriving from the electrical network. In particular, the taps SI and S2 identify a smaller (SI) or greater (S2) partition of the primary winding LI which corresponds to a lower or greater output voltage Vout at the output terminal OUT. If the voltage Val keeps being higher than a reference voltage Val-th (Val>Val-th wherein for example Val-th=228 V), initially, the control device 3 selects the tap S 1 to have a lower output voltage Vout; in case the voltage Val falls below the reference value Val-th (Val<Val-th), the control device 3 in response selects by means of the control T2 the tap S2 to increase the output voltage Vout.

The presence of the currents circulating in phase opposed through the respective primary winding LI and secondary winding L2 allows a current with a lower value than the current Ial to circulate on the transformer core 41 ; this allows a low heating of the ferromagnetic core of the transformer 41 and low losses.

Preferably, in case the electrical energy Eal provided by the electrical network is of the three-phase type according to a variant of the embodiment of the present invention (Figure 3), the components Iall, Ial2, Ial3 of the current Ial are at the inputs on the respective terminals INI , ΓΝ2 and ΓΝ3 and the transformer 41 comprises three primary windings LI a, Lib and Lie and three secondary windings L2a, L2b and L2c in phase opposed, as the voltage across the three secondary windings L2a, L2b and L2c is placed so as to subtract voltage from the voltage across the three primary windings LI a, Lib and Lie. Each primary winding LI a, Lib and Lie has the multiple taps SI -S3 and only the taps SI, S2 are selectable; on the selected tap SI, S2 of the three primary windings LI a, Lib and Lie the power supply voltage Val is present, given by the respective components Vail, Val2, Val3, while the three secondary windings L2a, L2b and L2c are arranged between the input terminals ΓΝ1, IN2 and Γ 3 and the output terminals OUT1, OUT2 and OUT3.

Each tap SI, S2 allows to obtain a partition of the input voltage Val; thereby, the output voltage Vout of the device 1 will only be a part of the voltage Val.

The selection of one of the two taps S 1 and S2 is defined by a switch K2, preferably a remote controller switch, controlled by means of the signal T2 by the control device 3.

The device 1 comprises another switch K3, preferably a remote controller switch, controlled by means of the signal T3 by the control device 3 and a further switch Kl, preferably a remote controller switch, arranged in parallel to the transformer 41 ; the remote controller switch Kl is typically open to allow the power supply of the primary windings LI a, Lib and Lie and the secondary windings L2a, L2b and L2c and the remote controller switch K3 is controlled so as to allow the power supply of the remote controller switch K2.

The taps SI and S2 refer to two different partitions of the primary windings LI a, Lib and Lie; thereby, it is possible to manage the required amount of output voltage Vout as a percentage of the power supply voltage Val deriving from the electrical network. In particular, the taps SI and S2 identify a smaller (SI) or greater (S2) partition of the primary windings LI a, Lib and Lie, which corresponds to a lower or greater output voltage Voutl, Vout2 and Vout3. If the voltage Val keeps being greater than a reference voltage Val-th (Val>Val-th), initially, the control device 3 selects the tap SI to have a lower output voltage Voutl, Vout2 and Vout3; in case the voltage Val falls below the reference rate of Val-th (Val<Val-th), the control device 3 in response selects by means of the control T2 the tap S2 to increase the output voltage Voutl, Vout2 and Vout3.

The presence of the currents circulating in phase opposed through the respective primary windings LI a, Lib and Lie and secondary windings L2a, L2b and L2c allows a current with a lower value than the current lal to circulate on the transformer core 41 ; this allows a low heating of the ferromagnetic core of the transformer 41 and low losses.

The remote controller switch Kl is closed when a control T3 is sent by the device 3 to the remote controller switch K3, which interrupts the power supply of the remote controller switch K2 and allows the closing of the remote controller switch Kl supplying power to it. The remote controller switch Kl is closed in case the device 1 is in by-pass phase. In particular, when the control device 3, after the detection of an overcurrent at the input, that is, an input current lal higher than a predetermined current lal-ref, or in the presence of a failure of the device 1 or in the presence of an undervoltage, that is, a voltage Val lower than a given voltage Val-ref, controls the bringing about of the by-pass status, the control device 3 itself controls the remote controller switch K3 for interrupting the power supply of the remote controller switch K2 and allowing the closing of the remote controller switch Kl ; thereby, a voltage is always present on the output terminal OUT1, OUT2, OUT3 of the device 1. The set of remote controller switchs Kl - K3 represents the generic switch S of Figure 1.

A failure of an element of the device 1 is detected by the control device 3 monitoring the state of the remote controller switchs Kl- K3 by means of the signals SK1-SK3 and monitoring the state of the thermal magnetic circuit-breaking device 50, arranged between the terminals of the secondary windings L2a, L2b and L2c and the input terminals INI, ΓΝ2 and ΓΝ3 of the device 1 , by means of the signal S50.

Preferably, the control device 3 is equipped with an electromechanical system called mechanical self-latching for the remote controller switch l which allows to make the by-pass remain active in case of absence of electrical energy Eal from the electrical network.

To exit the by-pass status, the control device 3, after the detection of an input current Ial lower than the predetermined current Ial-ref or a supply voltage Val higher than the reference voltage Val-ref or after the resolution of the failure of the device 1, controls at first the opening of the remote controller switch Kl by means of a control signal Tl and then the interruption of the power supply of the remote controller switch Kl with a control signal T3 to the remote controller switch K3 with a resulting control of the power supply of the remote controller switch K2.

Preferably, the by-pass status may be forced by the user; by means of an external control M activatable by means of a button, the user may control the control device 3 to bring the device 1 in a by-pass status.

Preferably, the control device 3 comprises a programmable logic controller or PLC which processes the input signals Ial, M, SK1-SK3 and S50 and sends the signals T1-T3 for the control of the remote controller switchs K1-K3. The PLC is also able to detect an overcurrent (Ial>Ial-ref) at the input terminal IN and, if the power supply voltage Val is higher or lower than the voltage Val-th, to control the remote controller switch K2 to respectively select the tap S2 or the tap SI .

The PLC also sends the control signals L and C respectively to the LED diodes 6 and the counter 7.

Preferably, the control device 3 may be controlled remotely, in particular by means of a TCP/IP data line.

The LED diodes 6 indicate the normal operating status of the device 1 , the presence of a failure in the device 1 and if the device 1 itself is in bypass status.

The counter 7 activated by the control C allows to detect the electrical power which transits in the device 1. As it is possible to make the device 1 operate in by-pass status, the counter allows to detect the electrical power that transits in the device 1 also when the latter is in by-pass status; the screen 71 allows to display the electrical power that transits both when the device 1 is in operation status, and when the device 1 is in by-pass status. Preferably, the counter 7 comprises means for the remote transmission of data.

Protective devices are provided for the various elements of the device 1 which comprise thermal magnetic circuit-breaking devices for some elements and fuses for other elements of the device 1. For example, the thermal magnetic circuit-breaking device 50 is provided for, arranged between the terminal 43 of the transformer 41 and the input terminal IN of the device 1.

The chart in Figure 4 shows the time diagrams of the power supply voltage Val and of the output voltage Vout; the output voltage Vout is lower than the voltage Val if no input overcurrent is detected, while in the presence of an overcurrent at the input, the device goes in by-pass mode by bringing the output voltage Vout equal to the voltage Val.

According to another variant of the embodiment of the present invention, the transformer 41 of the device 1 comprises a core 80, and the device is contained in a metal box 81 or case which acts as a heatsink of the heat produced by the core 80, as schematically shown in Figure 5. Between the core 80 and the case 81 a plurality of thermocouples 82 is arranged, for example Peltier cells, preferably connected in series one with the other and adapted to transform the heat difference between core and case into electrical power and to supply it to the device 1 , preferably to the control means 3, to meet part of the self-consumption of the device 1, increasing the performance thereof.