EP3647553A1 - Supply of an electromechanical power converter with electrical energy from a thermodynamic cyclical process - Google Patents

Abstract

The invention discloses a device for operating an electromechanical energy converter, for example a fan or a pump; the device comprising: a thermodynamic cycle device; an electric generator connected to a shaft of an expansion machine of the thermodynamic cycle device and rotatable together with the shaft; wherein the generator is electrically connected to a first voltage converter, the first voltage converter is electrically connected to a DC voltage intermediate circuit and the DC voltage intermediate circuit for operating the electromechanical energy converter can be electrically connected to the latter; wherein the first voltage converter is designed to convert a first AC voltage of the electrical generator into a DC voltage; and wherein the DC voltage intermediate circuit can be connected to an additional electrical power supply, in particular a public power grid. The device further comprises a regulating device (60) for regulating the electrical energy supplied to the electromechanical energy converter, so that the electromechanical energy converter can be operated at a predetermined speed, the regulating device for regulating the electrical energy supplied to the electromechanical energy converter from the generator and, if that Electrical energy provided by the generator is not sufficient to regulate the electrical energy supplied to the electromechanical energy converter from the additional energy supply. The invention further discloses a corresponding method for operating an electromechanical energy converter.

Description

Field of the Invention

The invention relates to a device for operating an electromechanical energy converter and a method for operating an electromechanical energy converter.

State of the art

A thermodynamic cycle device for the production of electrical energy from thermal energy comprises the following main components: a feed pump, which conveys liquid working medium to an evaporator while increasing the pressure, the evaporator itself, in which the working medium is preheated, evaporated and optionally additionally overheated, with the addition of heat Expansion machine in which the vaporized working medium under high pressure is expanded and thereby generates mechanical energy, which can be converted into electrical energy, for example, via a generator, and a condenser in which the low-pressure steam (relaxed working medium) from the expansion machine is heated and liquefied . The liquid working medium returns from the condenser to the system feed pump, which closes the thermodynamic cycle. In the event that the working medium is an organic working medium, it is an Organic Rankine Cycle as a thermodynamic cycle (ORC process).

The prior art includes so-called dry coolers (for example, recoolers in combined heat and power plants, CHPs) through which air flows through electrically driven fans. In order to minimize energy consumption, according to the applicant's internal state of the art, these fans should be supplied with electrical energy via a thermodynamic cycle (for example an ORC process). At the same time, the heat dissipation of the cycle should be realized by the fans of the dry cooler (normally the cycle contains or ORC process a separate fan to provide cooling of the condenser via an air flow). The cycle process converts heat (eg unused exhaust gas heat from an internal combustion engine or part of the heat of the fluid to be cooled in the cooler) into electrical energy. It is problematic here to ensure a stable supply of the fan with electrical energy in order not to impair the cooling function. Another disadvantage is that excess energy from the ORC process is fed back into the public power grid. Feeding energy into the power grid is linked to other requirements, such as compliance with the feed-in guidelines, system certification, registration with the network operator, and payment of the EEG surcharge in accordance with the Renewable Energy Sources Act (Renewable Energies Act, EEG) .

Description of the invention

The object of the invention is to avoid or at least alleviate the disadvantages mentioned.

The cycle or ORC process should always deliver as much power as possible as the fan consumes (quasi-island operation). Due to the joint use of the fan for the cooling process and the cycle, the speed of the fan and thus its power consumed is only dependent on the cooling requirement of the cooling process. The recooler of the ORC process cannot be influenced in terms of control technology. In order to ensure a high level of operational safety, additional power must be able to be drawn from the public power grid if the ORC process (e.g. due to high outside temperature or insufficient process energy (waste heat)) cannot provide enough power to operate the fan.

So a way must be found to cover the fluctuating power requirement of the fan as accurately as possible with the ORC generator. If the cycle does not provide enough energy, there must be a way to supply the fan with energy from the public grid or another source and at the same time to avoid feeding it into the grid.

The invention describes the solution to at least part of the problems mentioned above.

The solution according to the invention is defined by a device with the features according to claim 1.

The invention thus discloses a device for operating an electromechanical energy converter, for example a fan or a pump; the device comprising: a thermodynamic cycle device; an electric generator connected to a shaft of an expansion machine of the thermodynamic cycle device and rotatable together with the shaft; wherein the generator is electrically connected to a first voltage converter, the first voltage converter is electrically connected to a DC voltage intermediate circuit and the DC voltage intermediate circuit for operating the electromechanical energy converter can be electrically connected to the latter; wherein the first voltage converter is designed to convert a first AC voltage of the electrical generator into a DC voltage; and wherein the DC voltage intermediate circuit can be connected to an additional electrical power supply, in particular a public power grid. The device further comprises a regulating device (60) for regulating the electrical energy supplied to the electromechanical energy converter, so that the electromechanical energy converter can be operated at a predetermined speed, the regulating device for regulating the electrical energy supplied to the electromechanical energy converter from the generator and, if that Electrical energy provided by the generator is not sufficient to regulate the electrical energy supplied to the electromechanical energy converter from the additional energy supply.

The device according to the invention has the advantages that energy is saved by supplying an electromechanical energy converter (for example fan or pump) via a circuit or ORC process using waste heat, and that for example a separate circuit process or ORC fan is not required. that the operation of the fan is independent of the ORC process and thus a high level of system reliability is achieved, and that grid feed-in is avoided and the supply of feed-in requirements is thereby avoided.

The device according to the invention can be further developed such that a second voltage converter for converting a DC voltage in the DC voltage intermediate circuit into a second AC voltage for operating an electromechanical energy converter without its own voltage converter is further provided, the second voltage converter being electrically connected to the DC voltage intermediate circuit.

Another further development is that the additional energy supply is a public electricity network, which is connected to the DC voltage intermediate circuit via a rectifier circuit or via a power factor correction stage, and the control device in particular is further designed to reduce the energy provided by the generator in order to feed electrical energy into it To avoid energy in the public power grid, in particular by reducing the heat flow introduced into the thermodynamic cycle device and / or by reducing the efficiency of the thermodynamic cycle device.

Alternatively, the public power grid can be connected to the direct voltage intermediate circuit via a bidirectional converter circuit in order to feed excess energy from the generator into the public power grid.

According to another development, the DC voltage intermediate circuit can comprise a first partial DC voltage intermediate circuit connected to the first voltage converter, a second partial DC voltage intermediate circuit which can be connected to the electromechanical energy converter or connected to the second voltage converter, and a step-up converter arranged between the two partial circuits.

This can be developed in such a way that a further electromechanical energy converter can be operated via a parallel connection on the second partial DC voltage intermediate circuit, a third voltage converter for converting the direct voltage in the second partial DC voltage intermediate circuit into a third AC voltage for operating the further electromechanical energy converter being optionally provided, wherein the further electromechanical energy converter is, for example, a further pump, in particular a feed pump for pumping a working medium in the thermodynamic cycle device or a further fan.

The electromechanical energy converter can comprise an intermediate circuit with an AC voltage connection and the AC voltage connection can be connected directly to the second partial DC voltage intermediate circuit.

According to another development, a battery can be connected via a parallel connection to the second partial DC voltage intermediate circuit and a bidirectional DC voltage converter.

The invention further provides a system comprising: a heat generating device with a cooling fluid for dissipating heat from the heat generating device and a cooling device with an electrically operated fan for cooling the cooling fluid, in particular the speed of the fan and thus in particular its intake Power is predetermined by the cooling requirement of the cooling device; and a thermodynamic cycle device, in particular an organic Rankine cycle device, which comprises an evaporator for evaporating a working medium, an expansion machine which can be operated by expanding the evaporated working medium with the evaporated working medium, an electric generator which can be operated with the expansion machine and a capacitor for condensing the expanded Working medium includes; wherein the fan is further provided for cooling the working medium in the condenser; and wherein the system further comprises a device according to the invention for operating the fan as an electromechanical energy converter or one of the developments described above.

The system can be developed in such a way that the speed of the fan is predetermined by a temperature of the cooling fluid to be achieved with the cooling device.

The above-mentioned problems are at least partially solved by the inventive method according to claim 10.

The invention thus discloses a method for operating an electromechanical energy converter, for example a pump or a fan at a predetermined speed, comprising the steps: converting a first alternating voltage of a generator into a direct voltage in a direct current intermediate circuit between the generator and the electromechanical energy converter, the electrical Generator is connected to a shaft of an expansion machine of a thermodynamic cycle device, rotates together with the shaft and is driven by the shaft; Applying the DC voltage in the DC voltage intermediate circuit to the electromechanical energy converter; Applying a DC voltage to the DC voltage intermediate circuit from an additional electrical energy supply, in particular with electrical energy from a public electricity network; Regulating the electrical energy supplied to the electromechanical energy converter from the generator in order to operate the electromechanical energy converter at the predetermined speed, and regulating the electrical energy supplied to the electromechanical energy converter from the additional energy supply if the electrical energy provided by the generator for operating the electromechanical energy converter with the predetermined speed is not sufficient.

Optionally, a second AC voltage can be generated from the DC voltage intermediate circuit, and this (instead of the DC voltage in the DC voltage intermediate circuit) can be applied to the electromechanical energy converter (for example to a fan motor).

The advantages of the method according to the invention or its developments correspond to those of the device according to the invention or its developments and are therefore not repeated here.

The method according to the invention can be further developed in such a way that the additional energy supply is a public electricity network, which is connected to the DC voltage intermediate circuit via a rectifier circuit, and the method further comprises the following step: avoiding feeding electrical energy into the public electricity network by reducing the amount generated by the generator provided energy, in particular by reducing the heat flow introduced into the thermodynamic cycle device and / or by reducing the efficiency of the thermodynamic cycle device.

As an alternative to this, the method according to the invention can be further developed such that the additional energy supply is a public electricity network that is connected to the direct voltage intermediate circuit via a bidirectional converter circuit, the method further comprises the following step: feeding excess energy from the generator into the public electricity network.

Another development is that the DC voltage intermediate circuit comprises a first partial DC voltage intermediate circuit connected to the generator and a second partial DC voltage intermediate circuit connected to the electromechanical energy converter, the method comprising the following further step: converting the first DC voltage in the first partial DC voltage intermediate circuit to a higher second direct voltage introduced into the second partial direct voltage intermediate circuit.

This can be developed in such a way that the method comprises the further step: setting the second DC voltage below a third DC voltage provided by the additional energy supply in the second partial DC voltage intermediate circuit if the electrical energy provided by the generator for operating the electromechanical energy converter at the predetermined speed is not is sufficient.

According to another development, the method can include the following further step: converting the DC voltage in the DC voltage intermediate circuit into a third AC voltage for operating a further electromechanical energy converter, in particular a pump, for example a feed pump for pumping a working medium in the thermodynamic cycle device or for operating a further fan .

The further developments mentioned can be used individually or, as claimed, suitably combined with one another.

Further features and exemplary embodiments and advantages of the present invention are explained in more detail below with reference to the drawings. It is to be understood that the embodiments are not exhaustive of the scope of the present invention. It goes without saying that some or all of the features described below can also be combined with one another in other ways.

drawings

Fig. 1A

shows a first embodiment of the device according to the invention.

Figure 1B

shows an inventive system with the first embodiment of the device according to the invention.

Fig. 2

shows operating states of the fan or fans in the first embodiment of the device according to the invention.

Fig. 3

shows a second embodiment of the device according to the invention.

Fig. 4

shows a third embodiment of the device according to the invention.

Fig. 5

shows a fourth embodiment of the device according to the invention.

Fig. 6

shows a fifth embodiment of the device according to the invention.

Fig. 7

shows a sixth embodiment of the device according to the invention.

Fig. 8

shows a seventh embodiment of the device according to the invention.

Fig. 9

shows an eighth embodiment of the device according to the invention.

Fig. 10

shows a ninth embodiment of the device according to the invention.

Fig. 11

shows a tenth embodiment of the device according to the invention.

The same reference symbols in the drawings refer to identical or corresponding components. In some cases, in order to simplify the illustration in the drawings, only additional components are provided with reference numerals compared to the previously described embodiments.

Embodiments

As electromechanical energy converters, the embodiments show, by way of example only, one or more fans and / or one or more pumps, in particular, for example, a feed pump in the thermodynamic cycle device. Electromechanical energy converters convert electrical energy into mechanical kinetic energy, whereby the movement can be linear or rotating. Accordingly, a distinction is made between linear machines and rotating electrical machines. The embodiments relate to rotating electrical machines, but linear machines can also be used for the electromechanical energy converters in the embodiments in which speed control is not essential.

Furthermore, the electromechanical energy converters in the embodiments are predominantly constructed in such a way that the electromechanical energy converter itself Has intermediate circuit with an AC voltage connection. These embodiments can each be modified such that a corresponding voltage converter is provided on the DC link for connection to the electromechanical energy converter.

Fig. 1A shows a first embodiment 100 of the device according to the invention for operating a fan.

The device 100 comprises an electrically operable fan 80 with a motor 10 and a DC / AC voltage converter 44, an electrical generator 20 which is connected to a shaft 35 of an expansion machine 30 of a thermodynamic cycle device, here an ORC device, and together with the Shaft 35 is rotatable. A first voltage converter 42 (input converter 42) and a DC voltage intermediate circuit 40 are provided between the generator 20 and the fan 80. The first voltage converter 42 is designed to convert a first AC voltage of the electrical generator 20 into a DC voltage. The DC / AC voltage converter 44 (or output converter 44) is designed to convert a DC voltage in the DC voltage intermediate circuit 40 into a second AC voltage for operating the fan motor 10. The DC voltage intermediate circuit 40 is connected to an additional electrical energy supply 50, here a public power grid 51. The device 100 further comprises a control device 60 for controlling the electrical energy supplied to the fan 80, so that the fan can be operated at a predetermined speed, the control device 60 being designed such that it controls the electrical energy supplied to the fan 80 from the generator 20 and, if the electrical energy provided by the generator 20 is not sufficient for this, regulates the electrical energy supplied to the fan 80 from the additional energy supply 50.

The DC voltage intermediate circuit 40 includes a capacitor 41. The AC voltage from the public power grid 51 is rectified by a rectifier circuit 52 and applied to the DC voltage intermediate circuit 40. The control device 60 is also designed to reduce the energy provided by the generator 20 in order to meet the energy requirements of the To meet consumer (s), in particular by reducing the heat flow introduced into the thermodynamic cycle device and / or by reducing the efficiency of the thermodynamic cycle device.

The ORC device for the generation of electrical energy from thermal energy (for example waste heat) comprises: a feed pump which conveys liquid working medium to an evaporator while increasing the pressure, the evaporator itself, in which the working medium is preheated, evaporated and optionally additionally overheated by supplying heat , the expansion machine 30, in which the vaporized working medium under high pressure is expanded and thereby generates mechanical energy, which can be converted into electrical energy via the generator 20, and a condenser in which the low-pressure steam (expanded working medium) from the expansion machine 30 is heated and liquefied. The liquid working medium returns from the condenser to the system feed pump, which closes the thermodynamic cycle.

Figure 1B shows a system according to the invention in combination with the first embodiment of the device according to the invention Fig. 1A .

The system comprises a heat-generating device 110, an outlet 111 of the heat-generating device, the outlet 111 being provided for removing process fluid to be cooled from the heat-generating device 110; an input 112 of the heat generating device 110, the input 112 being provided for supplying cooled process fluid to the heat generating device 110; and a thermodynamic cycle device, in particular an ORC device, the thermodynamic cycle device comprising: an evaporator 120 with an inlet 121 for supplying the process fluid to be cooled from the outlet 111 of the heat-generating device 110 and with an outlet 122 for discharging the cooled process fluid to the inlet 112 the heat-generating device 110, the evaporator 120 being designed to evaporate a working medium of the thermodynamic cycle device by means of heat from the process fluid; the expansion machine 30 for expanding the evaporated working medium and for generating electrical energy electric generator 20; an air-cooled condenser 150 for liquefying the expanded working medium; and a pump 160 for pumping the liquefied working medium to the evaporator.

In addition, an air cooler 170 is provided for cooling at least part of the process fluid to be cooled. The system includes a branch 171, which is provided, for example with respect to a flow direction of the process fluid downstream of the outlet 111 and upstream of the inlet 121, for dividing the process fluid to be cooled into a first and a second partial flow of the process fluid. The system further includes a junction 172 that is provided with respect to a flow direction of the process fluid downstream of the outlet 122 and upstream of the inlet 112 for merging the second partial flow of the process fluid cooled by the cooler 170 and the first partial flow of the process fluid cooled by the evaporator 120 ; the branch 171 is designed to supply the first partial flow to the evaporator 120 and to supply the second partial flow to the cooler 170. The flow of ambient air is sequentially first through the cooler 170 and then through the condenser 150.

The specific design of the system is only an example.

Fig. 2 shows the operating states of the fan or fans in the first embodiment 100 of the device according to the invention in a diagram of power versus outside temperature, which are described in more detail below.

The fan 80 is connected to the generator 20 via the DC intermediate circuit 40 (or via a plurality of DC intermediate circuits). The speed of the fan 80 is regulated depending on a target flow temperature of a cooling system and is independent of the generator speed and energy supply from the ORC process.

If the ORC process generates less energy than is required at the intermediate circuit 40 (U_DC), the missing energy is obtained from the public network 51 via the rectifier 52. Rectifier 52 also provides operation of fan 80 independent of the thermodynamic cycle (e.g. in the event of failure, errors). In the event of an error or failure of the cycle, the entire required power is drawn from the network 51. The cooler, which is operated by this fan 80, can therefore consistently and independently provide sufficient cooling capacity.

If the ORC process generates more energy than is required at the DC link 40 (U_DC) (the system is designed for this under normal operating conditions below a certain outside temperature), suitable measures must be taken.

The speed of the generator 20 is first aligned to the optimal operating point of the ORC process and regulated by means of input converter 42 (regulated operation). At this operating point, the amount of heat Q transferred _{to the ORC is converted} into electrical energy P _el with an optimum efficiency η _ORC .

• Reduktion der zugeführten Wärme Q_zu durch Reduktion der Speisepumpendrehzahl
• Reduktion des Wirkungsgrads η_ORC=η_th•η_Gen•η_EW durch Verschlechterung von einzelnen Wirkungsgraden in der Wirkungsgradkette wie z.B. des thermischen Wirkungsgrads η_th, des Generatorwirkungsgrads η_Gen oder des Wirkungsgrads des Eingangswandlers η_EW

In principle, there are two different ways of reducing the converted electrical energy:

• Reduction of the heat supplied Q _to by reducing the feed pump speed
• Reduction of the efficiency η _ORC = η _{th •} η _{Gen •} η _EW due to deterioration of individual efficiencies in the efficiency chain such as the thermal efficiency η _th , the generator efficiency η _Gen or the efficiency of the input converter η _EW

In the real implementation, the measures will influence each other slightly, e.g. the reduction of the feed pump speed leads to different steam parameters and thus also to a changed thermal efficiency.

In contrast to previous ORC regulations, the voltage U_DC is now used as a control variable for the generator speed and / or the feed pump speed and the speed is reduced or increased again until it increases establishes a stable balance between ORC power generation and energy consumption. With a constant decrease by the fan, the voltage U_DC behaves in such a way that it also increases with increasing ORC output. The voltage U_DC thus serves as a controlled variable.

According to the prior art, a brake chopper would be provided on the intermediate circuit 40, which limits the intermediate circuit voltage to a value that is not critical for the components. However, this has the disadvantage that sufficient heat dissipation of the braking resistor must be ensured and the material costs increase due to the additional component. This can be omitted here. Instead, according to the invention, more losses are generated in the generator 20 by rapidly regulating the input converter 42 and activating the generator 20 in the suboptimal range, thereby limiting the intermediate circuit voltage. That is, the input converter 42 is intentionally operated with poorer efficiency.

Fig. 3 shows a second embodiment 200 of the device according to the invention for operating a fan.

Compared to the first embodiment 100 according to Fig. 1A The DC voltage intermediate circuit 40 comprises a first partial DC voltage link 46 connected to the input converter 42, a second partial DC voltage link 48 connected to the output converter 44 and a step-up converter 45 arranged between the two step circuits. The step-up converter 45 also becomes synonymous as a step-up converter or step-up converter designated.

In order to obtain generators with a nominal voltage significantly below the required output voltage for the fans, the step-up converter 45 is interposed. The mains connection consists of a passive B6 rectifier 52 which is connected in three phases.

Fig. 4 shows a third embodiment 300 of the device according to the invention for operating a fan.

As an alternative to the second embodiment 200 according to FIG Fig. 3 the network coupling can also take place on the input side of the step-up converter 45. In addition, an active network coupling via power factor correction stage 54 (active PFC, Power Factor Correction) is used, which always draws low power from the network and thus provides scope for regulating the power balance between the ORC generator and the consumer (fan). In contrast to the second embodiment, a 1-phase mains connection is sufficient. In contrast to the second embodiment, the active PFC makes the current consumption almost sinusoidal (avoiding harmonics).

Fig. 5 shows a fourth embodiment 400 of the device according to the invention.

In the fourth embodiment 400, in comparison to the second embodiment 200, a parallel connection is provided on the second partial DC voltage intermediate circuit 48. In this way, a pump 81 can via a further output converter 49 for converting the direct voltage in the second partial direct voltage intermediate circuit 48 into a third alternating voltage for operating a motor 11 of the pump 81, for example a water pump and / or a feed pump for pumping a working medium in the thermodynamic Cyclic device are driven.

In addition to the fan 80, the pump 81 is also supplied from the second intermediate circuit 48 (U_DC2). The advantage is a further increase in efficiency, since in normal operation the energy of the pump 81 also comes from the ORC process and does not have to be obtained from the network 51. For the start of the ORC process, the energy is drawn from the network 51 via the B6 bridge 52. In the same way, an auxiliary voltage supply (for example 24 VDC, not shown) can also be taken from the intermediate circuit 48.

Fig. 6 shows a fifth embodiment 500 of the device according to the invention.

Compared to the fourth embodiment 400, a further fan 82 is driven instead of the pump 81.

The fifth embodiment 500 shows a parallel connection of several fans 80, 82 on the common DC link. Depending on the performance of the fans, any number of fans can be connected in parallel here. In practice, multiple fans and larger coolers are often used to improve smoothness and efficiency through reduced air speeds.

Fig. 7 shows a sixth embodiment 600 of the device according to the invention.

The sixth embodiment 600 includes the supply of a plurality of fans 80, 82 via a common converter, namely the output converter 44. The parallel connection therefore takes place on the AC side. A sine filter 13 connected downstream of the common converter 44 is required for this. This delivers a sinusoidal output current of variable frequency. The advantage over the fifth embodiment 500 results from simpler cabling (dielectric strength, no shielded cable) and better EMC properties (electromagnetic compatibility). The cabling between converter 44 and fan motor can become 10 m and longer, for example.

Fig. 8 shows a seventh embodiment 700 of the device according to the invention.

The seventh embodiment 700 shows the connection of a three-phase AC input of a fan 80 directly to the DC intermediate circuit 48. The converter 44 generally has input rectifier diodes (body diodes) which enable a direct connection to a DC circuit. The intermediate circuit 48 (U_DC2) is thus connected directly to the intermediate circuit of the fan converter (converter 44). For example, commercially available regulated EC fans (Electronically Commutated Motor) can be used. Any phase failure or AC voltage monitoring must be deactivated for this. This embodiment also allows a plurality of fans to be connected in parallel in a modification.

Fig. 9 shows an eighth embodiment 800 of the device according to the invention.

The eighth embodiment 800 shows an energy store, for example a battery 70 on the intermediate circuit 48. This is a step in the direction of a completely de-energized fan (all consumers such as pumps, fans, auxiliary voltage supply are connected to the intermediate circuit, at least there is no permanent connection to the electrical supply network required, and with appropriate dimensioning of the battery 70, the mains connection can be dispensed with entirely) and also allows more freedom in the design of the control loop of the ORC power.

Fig. 10 shows a ninth embodiment 900 of the device according to the invention.

In the ninth embodiment 900, a topology with a regenerative power converter 53 (bidirectional converter circuit) is shown. Excess energy thus flows back into the network 51 without limiting the performance of the ORC generator. The infeed converter 53 must comply with the infeed guidelines applicable in the respective country. The elimination of the increased effort for the fulfillment of all technical and regulatory feed-in guidelines is the advantage of all previous embodiments.

Fig. 11 shows a tenth embodiment 1000 of the device according to the invention.

The tenth embodiment 1000 represents the supply of a pump 83, for example a hot water pump of a heating circuit from the DC intermediate circuit 48. However, instead of the pump 83, a compressor or any other electrical consumer can also be connected.

In this application pumps often have a higher power requirement than the fans. If the required pump power is permanently higher than the ORC power, a direct connection of the DC output of the ORC generator converter to the voltage intermediate circuit of a regulated pump is possible. The ORC will then generate maximum energy at its optimal operating point, which is used to operate the pump. Additional energy is permanently drawn from the grid.

The illustrated embodiments are only examples. The full scope of the present invention is defined by the claims.

Claims (15)

Device (100-1000) for operating an electromechanical energy converter (80, 81, 82, 83), for example a fan or a pump; full: a thermodynamic cycle device (30, 120, 150, 160); an electric generator (20) connected to a shaft (35) of an expansion machine (30) of the thermodynamic cycle device and rotatable together with the shaft; wherein the generator (20) is electrically connected to a first voltage converter (42), the first voltage converter (42) is electrically connected to a DC voltage intermediate circuit (40) and the DC voltage intermediate circuit (40) for operating the electromechanical energy converter (80, 81, 82, 83) can be electrically connected to it; wherein the first voltage converter (42) is designed to convert a first AC voltage of the electrical generator (20) into a DC voltage; and wherein the DC voltage intermediate circuit (40) can be connected to an additional electrical energy supply (50), in particular a public electricity network; and a regulating device (60) for regulating the electrical energy supplied to the electromechanical energy converter (80, 81, 82, 83) so that the electromechanical energy converter can be operated at a predetermined speed, the regulating device for regulating the electrical energy supplied to the electromechanical energy converter from the generator and, if the electrical energy provided by the generator is not sufficient for this, to regulate the electromechanical Energy converter supplied electrical energy from the additional energy supply, is formed. The apparatus of claim 1, further comprising a second voltage converter (44) for converting a DC voltage in the DC voltage intermediate circuit into a second AC voltage for operating the electromechanical energy converter, the second voltage converter being electrically connected to the DC voltage intermediate circuit. Apparatus according to claim 1 or 2, wherein the additional energy supply is a public electricity network (51) which can be connected to the DC voltage intermediate circuit via a rectifier circuit (52) or via a power factor correction stage (54), and the control device is optionally further designed to be provided by the generator reduce the energy provided in order to avoid feeding electrical energy into the public power grid, in particular by reducing the heat flow introduced into the thermodynamic cycle device and / or by reducing the efficiency of the thermodynamic cycle device; or
wherein the additional energy supply is a public electricity network (51) which can be connected to the DC voltage intermediate circuit via a bidirectional converter circuit (53), and excess energy can be fed into the public electricity network from the generator. Apparatus according to one of claims 1 to 3, wherein the direct voltage intermediate circuit (40) comprises a first partial direct voltage intermediate circuit (46) connected to the first voltage converter (42), a second one which can be connected to the electromechanical energy converter or, in combination with claim 2, is connected to the second voltage converter Partial DC voltage intermediate circuit (48) and a step-up converter (45) arranged between the two partial circuits. Apparatus according to claim 4, wherein a further electromechanical energy converter can be operated via a parallel circuit on the second partial direct voltage intermediate circuit, optionally in combination with claim 2 a third voltage converter for converting the direct voltage in the second partial direct voltage intermediate circuit into a third alternating voltage for operating the further electromechanical energy converter is provided, the further electromechanical energy converter being, for example, a further pump, in particular a feed pump for pumping a working medium in the thermodynamic cycle device or a further fan. Device according to one of claims 4 or 5 in combination with claim 2, wherein the electromechanical energy converter comprises an intermediate circuit with an AC voltage connection and the AC voltage connection is connected directly to the second partial DC voltage intermediate circuit. Device according to one of claims 3 to 6, wherein a battery is connected via a parallel connection to the second partial direct voltage intermediate circuit and a bidirectional direct voltage converter. System comprising: a heat generating device (110) having a cooling fluid for removing heat from the heat generating device and a cooling device (150) having an electrically operated fan (80) for cooling the cooling fluid; wherein the thermodynamic cycle device is in particular an organic Rankine cycle device and wherein the thermodynamic A cycle process device includes an evaporator (120) for evaporating a working medium, the expansion machine (30) operable by expanding the evaporated working medium with the evaporated working medium, and a condenser for condensing the expanded working medium; the fan (80) is further provided for cooling the working medium in the condenser (150); and wherein the system further comprises a device according to one of claims 1 to 7 for operating the fan as an electromechanical energy converter. The system of claim 8, wherein the speed of the fan is predetermined by a temperature of the cooling fluid to be achieved with the cooling device. Method for operating an electromechanical energy converter, for example a pump or a fan at a predetermined speed, comprising the steps: Converting a first alternating voltage of a generator into a direct voltage which is supplied to a direct current intermediate circuit between the generator and the electromechanical energy converter, the electrical generator being connected to a shaft of an expansion machine of a thermodynamic cycle device, rotating together with the shaft and being driven by the shaft ; optionally converting a DC voltage in the DC voltage intermediate circuit into a second AC voltage; Applying the DC voltage in the DC voltage intermediate circuit or the second AC voltage to the electromechanical energy converter; Applying a DC voltage to the DC voltage intermediate circuit from an additional electrical energy supply, in particular with electrical energy from a public electricity network; Regulating the electrical energy supplied to the electromechanical energy converter from the generator to operate the electromechanical energy converter at the predetermined speed, and Regulating the electrical energy supplied to the electromechanical energy converter from the additional energy supply if the electrical energy provided by the generator is not sufficient for operating the electromechanical energy converter at the predetermined speed. The method of claim 10, wherein the additional power supply is a public power grid, which is connected to the DC voltage intermediate circuit via a rectifier circuit, and the method further comprises the following step:
Avoid feeding electrical energy into the public power grid by reducing the energy provided by the generator, in particular by reducing the heat flow introduced into the thermodynamic cycle device and / or by reducing the efficiency of the thermodynamic cycle device. The method of claim 10, wherein the auxiliary power supply is a public power grid connected to the DC link via a bidirectional converter circuit, the method further comprising the step of:
Feeding surplus energy from the generator into the public power grid. Method according to one of claims 10 to 12, wherein the direct voltage intermediate circuit comprises a first partial direct voltage intermediate circuit connected to the generator and a second partial direct voltage intermediate circuit connected to the electromechanical energy converter, the method comprising the following further step:
Converting the first direct voltage in the first partial direct voltage intermediate circuit into a higher second direct voltage introduced in the second partial direct voltage intermediate circuit. The method of claim 13, further comprising the step of:
Setting the second DC voltage below a third DC voltage provided by the additional energy supply in the second partial DC voltage intermediate circuit if the electrical energy provided by the generator is not sufficient to operate the electromechanical energy converter at the predetermined speed. Method according to one of claims 10 to 14, with the further step:
Converting the DC voltage in the DC voltage intermediate circuit into a third AC voltage for operating a further electromechanical energy converter, in particular a pump, for example a feed pump for pumping a working medium in the thermodynamic cycle device or for operating a further fan.

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