Patent Description:
Generally speaking, an electric energy generating plant, for supplying electric energy to an electric power network, comprises an electric machine assembly comprising a rotary electric machine; an electric energy converter arranged between the rotary electric machine and an electric power network; and a control device coupled to the converter and to the electric machine assembly.

In use, the control device is configured to control the energy converter and thus the rotary electric machine so as to regulate the torque and make it work in certain conditions.

Machines with a control device are disclosed in <CIT> and <CIT>.

However, in some cases the operating conditions may be such as to damage the rotary electric machine.

The purpose of the present invention is therefore to provide an electric machine assembly that reduces the inconveniences of the prior art.

According to the present invention, there is provided an electric machine assembly according to the claim <NUM>.

Thanks to the present invention the magnetic induction values in the electric machine, in particular the axial component of the magnetic induction, can be measured directly and the electric machine assembly can be controlled according to the magnetic induction and temperature values measured.

The magnetic probe and the temperature probe are housed at the same detection point in the stator.

According to another embodiment of the present invention, the electric machine extends along the axis and comprises two axial end portions; the detecting device being housed in one of the axial end portions to detect an axial component of the magnetic induction.

According to another embodiment of the present invention, the electric machine assembly comprises a plurality of detecting devices arranged in the stator and radially to the axis at different distances from the axis, preferably the detecting devices are housed on a plane perpendicular to the axis.

According to another embodiment of the present invention, the stator comprises a plurality of windings that are associated with a plurality of phases; the detecting device being arranged between two windings each of which associated with different phases.

According to another embodiment of the present invention, the stator comprises a plurality of packs of ferromagnetic plates and the detecting device is glued to the plate preferably by means of a silicone resin.

According to another embodiment of the present invention, the detecting device is made according to any one of the claims from <NUM> to <NUM>.

A further purpose of the present invention is to provide an electric energy generating plant that reduces the inconveniences of the prior art.

According to the present invention there is provided an energy generating plant comprising an electric machine assembly according to any one of the claims from <NUM> to <NUM>; a measuring device coupled to the electric machine for detecting electric quantities of the electric machine; an electric energy converter coupled to the electric machine assembly; and a control unit coupled to the at least one detecting device for receiving the temperature and the magnetic induction values, to the measuring device for receiving the electric quantities of the electric machine, and to the converter; the control unit being configured to:.

According to another embodiment of the present invention, the control unit is configured to compare the temperature values detected with threshold temperature values and the magnetic induction values detected with magnetic induction threshold values and control the reactive power so as to decrease its absolute value if at least one of the two values exceeds the threshold.

According to another embodiment of the present invention, the plant comprises at least one further temperature sensor housed at least on the inside diameter of the electric machine or on a stack pressing device of the electric machine; the control unit being in communication with the further temperature sensor to receive the further temperature measurement and act to control the reactive power so as to decrease its absolute value if at least the further temperature measurement exceeds a further temperature threshold value.

A further purpose of the present invention is to provide a detecting device for detecting parameters of a rotary electric machine.

According to the present invention there is provided a detecting device for detecting parameters of a electric machine assembly of any one of the claims <NUM> to <NUM>; the detecting device comprising a support which extends predominantly along an axis; a magnetic probe configured to detect a magnetic induction value and housed along the support; a thermal probe configured to detect a temperature value and housed along the support; and a casing which surrounds the thermal probe, the magnetic probe and the support; wherein the coupling element is coupled to one end of a stator of the electric machine; the coupling element is L-shaped to be coupled to one end of the stator.

According to a preferred embodiment of the present invention, the magnetic probe is of the Hall effect type and preferably the thermal probe is a thermistor.

According to another preferred embodiment of the present invention, the support is made of an insulating material, preferably fibreglass.

According to another preferred embodiment of the present invention, the casing is made of an insulating material, preferably fibreglass.

According to another preferred embodiment of the present invention, the device comprises a coupling element configured to be coupled to the electric machine, and a seat formed in the support for housing the magnetic probe and the thermal probe; the seat being arranged at a given distance from the coupling element to arrange the magnetic probe and the thermal probe inside the electric machine in a predetermined detecting point.

A further purpose of the present invention is to provide a method for controlling an electric machine assembly that reduces the inconveniences of the prior art.

According to the present invention there is provided a control method for controlling the electric machine assembly of any one of the claims <NUM> to <NUM>; the electric machine assembly comprising a rotary electric machine; the method comprising: detecting a magnetic induction value of the electric machine, preferably an axial component value of the magnetic induction; detecting a temperature value of the electric machine; detecting electric quantities of the electric machine and calculating a reactive power value of the electric machine; adjusting the reactive power of the electric machine if the reactive power is negative and on the basis of the detected magnetic induction and/or temperature values.

According to a preferred embodiment of the present invention, the method comprises comparing the magnetic induction value with a magnetic induction threshold value and acting on the reactive power of the electric machine if the magnetic induction value exceeds the threshold value.

According to a preferred embodiment of the present invention, the method comprises comparing the temperature value with a temperature threshold value and acting on the reactive power of the electric machine if the temperature value exceeds the threshold value.

According to a preferred embodiment of the present invention, the magnetic induction value is detected between two windings of a stator of the electric machine associated with two different phases of the stator.

According to a preferred embodiment of the present invention, the method comprises the step of detecting a plurality of temperature and magnetic induction values in a plurality of detecting points of a stator of the electric machine located radially to a rotation axis of the electric machine and spaced radially one with respect to the other.

A further purpose of the present invention is to provide a method for installing a detecting device in a rotary electric machine that reduces the inconveniences of the prior art.

According to the present invention there is provided a method for installing a detecting device in the rotary electric machine assembly of any one of the claims <NUM> to <NUM>;; the detecting device comprising a thermal probe, a magnetic probe, a support and a casing: the method comprising the steps of: creating a seat in the support and housing the thermal probe and the magnetic probe in the seat; covering the support, the thermal probe and the magnetic probe with the casing; wherein the electric machine comprises a stator and a rotor; and the stator comprises a plurality of packs of ferromagnetic plates; the method comprising inserting the support in a channel radial to the axis of rotation of the electric machine and formed between two packs of plates.

The present invention will now be described with reference to the accompanying drawings, illustrating some non-limiting embodiments thereof, in which:.

In <FIG>, denoted as a whole by reference numeral <NUM> is an electric energy generating plant. The electric plant <NUM> exchanges electric energy with an electric power network <NUM> at a point of exchange <NUM>.

The electric plant <NUM> comprises an electric machine assembly <NUM> comprising a rotary electric machine <NUM> and a plurality of detecting devices <NUM> coupled to the electric machine <NUM>; an electric energy converter <NUM> coupled to the electric machine assembly <NUM>; a control device <NUM> coupled to the electric energy converter <NUM> and to the electric machine assembly <NUM>.

With reference to <FIG> and <FIG>, the rotary electric machine <NUM> comprises a stator <NUM>, and a rotor <NUM> coaxial with respect to one another about the axis A. In more detail, the electric machine <NUM> is a two-pole machine. In another embodiment, the electric machine <NUM> has more than two poles. With reference to <FIG>, the stator <NUM> extends along the axis A and between two axial end portions 9a.

With reference to <FIG> and <FIG>, the stator <NUM> is hollow and comprises a plurality of packs of stator plates <NUM>. The stator <NUM> has a plurality of stator slots <NUM> and a plurality of stator teeth <NUM> spaced at intervals and formed along an inside surface <NUM> of the stator <NUM>. In more detail, the packs of plates <NUM> are shaped so as to form the plurality of slots <NUM> and the plurality of teeth <NUM> which are arranged between two adjacent slots <NUM>. Moreover, the stator <NUM> comprises a plurality of windings <NUM> housed in the plurality of slots <NUM> around the packs of stator plates <NUM>. Each pack of plates <NUM> extends radially with respect to the axis A. The packs of stator plates <NUM> are arranged radially about the axis A. Furthermore, the packs of stator plates <NUM> are aligned with one another parallel to the axis A and are held together by means of two stack pressing devices <NUM> arranged at two axial ends <NUM> of the electric machine <NUM>. The stack pressing devices <NUM> are, for example, stack pressing flanges. The stator <NUM> is provided with channels <NUM> obtained between adjacent packs of plates <NUM>, which extend radially to the axis A. In other words, the stator <NUM> has one channel <NUM> for each pair of adjacent packs of plates <NUM>. Thus, the packs of plates <NUM> are aligned parallel to the axis A without coming into contact with one another. The channels <NUM> define cavities between adjacent packs of plates <NUM> which act as cooling channels through which a cooling fluid, preferably air, can flow.

The rotor <NUM> defines a magnetic field and comprises a plurality of rotor slots <NUM> obtained along an outside surface <NUM> of the rotor <NUM>. In particular, the plurality of slots <NUM> are grouped in two groups 18a of slots <NUM> so as to define two poles of the rotor <NUM>.

The rotor <NUM> comprises windings <NUM> housed in the slots <NUM> to define a magnetic field. In another embodiment of the present invention not illustrated in the accompanying figures, the rotor <NUM> comprises permanent magnets housed in the rotor slots to define a magnetic field. In another embodiment of the present invention not illustrated in the accompanying figures, the electric machine is an asynchronous electric machine and the rotor comprises a squirrel cage to define an induced magnetic field.

With reference to <FIG>, the detecting devices <NUM> are arranged in the channels <NUM> close to the axial end portions 9a of the electric machine <NUM>. In more detail, the detecting devices <NUM> are arranged at respective detection points 6a of the electric machine <NUM>, the axial distance of which from the axial end <NUM> is less than <NUM>% of the total length of the electric machine <NUM>.

In another embodiment of the present invention, the detecting devices <NUM> are arranged in one of the first ten channels <NUM>, preferably one of the first five channels <NUM> moving axially from the axial end <NUM> towards the centre of the electric machine <NUM>.

The detecting devices <NUM> are configured to detect an axial component of the magnetic induction B of the electric machine <NUM> at the respective detection point 6a. Furthermore, the detecting devices <NUM> are configured to measure a temperature at the respective detection point 6a.

With reference to <FIG>, the detecting device <NUM> comprises a support <NUM> which extends predominantly along an axis B; a magnetic probe <NUM> configured to detect a magnetic induction value and housed along the support <NUM>; a thermal probe <NUM> configured to detect a temperature value and housed along the support <NUM>; a connector (not illustrated in the accompanying figures); a connection cable <NUM> configured to connect the thermal probe <NUM> and the magnetic probe <NUM> to the connector and comprising a portion of cable 44a rigidly fixed to the support <NUM>; and a casing <NUM> which surrounds the magnetic probe <NUM>, the thermal probe <NUM>, the support <NUM> and the portion of cable 44a.

In more detail, the magnetic probe <NUM> is of the Hall effect type and the thermal probe <NUM> is a thermistor. The scope of protection of the present invention also covers the case in which the magnetic probe <NUM> and the thermal probe <NUM> are provided in the form of a single sensing element incorporating the two functions and which provides a measurement of a magnetic induction B value and a temperature T value.

The casing <NUM> is made of an insulating material, preferably fibreglass.

The support <NUM> is made of an insulating material, preferably fibreglass, and comprises a cantilevered portion <NUM> extending radially with respect to the axis B that defines a coupling element <NUM> with the electric machine <NUM>. In other words, the portion <NUM> is L-shaped to couple with the stator <NUM> of the electric machine <NUM>.

Furthermore, the detecting device <NUM> comprises a seat <NUM> obtained in the support <NUM> to house the magnetic probe <NUM> and the thermal probe <NUM>. The seat <NUM> is arranged along the support <NUM> at a given distance D from the coupling element <NUM> so that the magnetic probe <NUM> and the thermal probe <NUM> are arranged inside the electric machine <NUM> at the predetermined detection point 6a.

During the installation step, the detecting device <NUM> is glued to the electric machine <NUM>, in particular to the stator <NUM> of the electric machine <NUM>. In more detail, the detecting device <NUM> is inserted in one of the channels <NUM> as described previously and the coupling element <NUM> is coupled to one of the packs of plates <NUM> of the stator <NUM>. With reference to <FIG> and <FIG>, during the installation step, the support <NUM> is inserted in the channel <NUM> and glued by means of a silicone resin to one of the two packs of plates <NUM> that form said channel <NUM>. The insertion is performed by inserting the detecting device <NUM> from the inside of the stator <NUM>, that is to say, from the stator cavity towards the outside of the stator <NUM>. In other words, the support <NUM> is inserted from the inside surface <NUM> towards an outside surface of the stator <NUM>. As a consequence, the support <NUM> is inserted from the air gap towards the outside of the electric machine <NUM>.

With reference to <FIG>, the coupling element <NUM> abuts against a side surface <NUM> of the pack of plates <NUM>. The side surface <NUM> of the pack of plates <NUM> faces the air gap. In other words, the portion <NUM> of the support <NUM> is coupled to a corner <NUM> of the plate <NUM> formed by a side surface <NUM> adjacent to the channel <NUM> and by the side surface <NUM>.

The detecting device <NUM> is housed in the channel <NUM> so as to measure an axial component of the magnetic induction B. In particular, the axial component of the magnetic induction B relative to the axial end portion 9a of the electric machine <NUM>.

With reference to <FIG>, <FIG>, the detecting devices <NUM> of the plurality of detecting devices <NUM> differ from one another in that their supports differ in length and the seats <NUM> are arranged at different distances from the coupling element <NUM>. As a consequence, when the plurality of detecting devices <NUM> have been inserted in the channel <NUM>, they house the thermal probes <NUM> and the magnetic probes <NUM> at different distances from the axis A along the channel <NUM> so as to obtain in this way a map of the different temperature T and magnetic induction B values inside the channel <NUM>.

Furthermore, the detecting devices <NUM> may also be inserted in different channels <NUM>, preferably the channels <NUM> that are chosen must all be at the same axial distance from the end <NUM>. In other words, the detecting devices <NUM> must all be housed on a plane P that is perpendicular to the axis A, that is to say, the plane P is perpendicular to a plane on which the axis A lies. In <FIG>, the detecting devices <NUM> are aligned radially to the axis A.

Furthermore, the detecting devices <NUM> are inserted in one of the channels <NUM> of the teeth <NUM> and in particular of one of the teeth <NUM> which is arranged between two different phases of the electric machine <NUM>. In more detail, the windings <NUM> are housed in the slots <NUM> and grouped in phases, some adjacent windings <NUM> belong to the same phase, while other adjacent windings <NUM> belong to different phases. The channel <NUM> in which the detecting device <NUM> is inserted is chosen in one of the teeth <NUM> arranged between two windings <NUM> with different phases, so that the magnetic induction B and the temperature T are measured between two different phases.

The control device <NUM> comprises a measuring device <NUM> coupled to the electric machine <NUM> to detect electric quantities of the electric machine <NUM>; a control unit <NUM> coupled to the detecting devices <NUM> for receiving the temperature T and magnetic induction B values and to the measuring device <NUM> for receiving the electric quantities of the electric machine. In more detail, the measuring device <NUM> is coupled to the windings <NUM> of the stator <NUM> and is arranged between the stator <NUM> and the converter <NUM> to detect voltages or currents of the windings <NUM> of the electric machine <NUM>. According to one embodiment, the measuring device <NUM> is connected to the windings of the rotor <NUM> to measure the excitation currents.

The electric machine assembly <NUM> comprises further end temperature sensors <NUM> arranged on the stack pressing devices <NUM>. The control unit <NUM> is connected to end temperature sensors <NUM> to receive the temperature T of the ends <NUM> of the electric machine <NUM>.

The control unit <NUM> thus receives the temperature T and magnetic induction B values from the plurality of detecting devices <NUM>, the temperature T values from the temperature sensors <NUM> and the electric quantities of the electric machine <NUM> from the measuring devices <NUM>.

The control unit <NUM> calculates the reactive power of the electric machine <NUM> according to the electric quantities detected.

When the control unit <NUM> detects a negative reactive power, it is configured to act on the converter <NUM> to adjust the value of the reactive power on the basis of the detected magnetic induction B and temperature T values. In more detail, the control unit <NUM> is coupled to the converter <NUM> and sends a command signal ST to the converter <NUM>. The control unit <NUM> compares the temperature T values of the detecting devices <NUM> and of the end temperature sensors <NUM> detected with temperature threshold values. The control unit <NUM> compares the magnetic induction B values detected with magnetic induction threshold values. If the reactive power is negative, and at least one of the values detected exceeds the threshold value, the control unit <NUM> acts on the command signal ST in order to control the reactive power and decrease its absolute value. In other words, the control unit <NUM> controls the converter <NUM> by means of a command signal ST which is defined on the basis of the temperature T and magnetic induction B values, in particular the axial component of the magnetic induction B of the electric machine <NUM>.

In a further embodiment, the electric machine assembly comprises a further temperature sensor housed on the inside diameter of the electric machine, in particular along the air gap and the control unit is in communication with the further temperature sensor and acts on the command signal sent to the converter also on the basis of the temperature values of the further temperature sensor.

Claim 1:
An electric machine assembly comprising an electric machine (<NUM>) having a stator (<NUM>) and a rotor (<NUM>) rotatable about an axis (A); and at least one detecting device (<NUM>) housed inside the stator (<NUM>) and comprising a magnetic probe (<NUM>) for measuring a magnetic induction (B) value of the electric machine (<NUM>), and a thermal probe (<NUM>) for measuring a temperature (T) value of the electric machine (<NUM>), a support (<NUM>) and a casing (<NUM>); wherein the magnetic probe (<NUM>) and the thermal probe (<NUM>) are housed at the same detection point (6a) in the stator (<NUM>);
characterized in that
the stator (<NUM>) comprises a plurality of packs of ferromagnetic plates (<NUM>); wherein the support (<NUM>) is inserted in a channel (<NUM>) radial to the axis of rotation of the electric machine (<NUM>) and formed between two packs of plates (<NUM>).