Heat pump, HVAC system, compressor device and method for monitoring a compressor device

Abstract

The invention relates to a heat pump, in particular for use in a HVAC system, comprising, as part of a working circuit of the heat pump, at least one compressor device (1) for compressing a working medium of the working circuit, wherein the compressor device (1) in turn comprises an electric motor (32) for providing a mechanical movement for compressing the working medium, an inverter (31) which supplies the electric motor (32) with alternating current, a rectifier (11) which supplies the inverter (31) with direct current, wherein the rectifier (11) can be connected to an alternating current source in order to supply power to the compressor device (1), and a monitoring device (12) for monitoring an operating state of the electric motor (32), which monitoring device comprises at least one measuring means (122, 123) for detecting an operating variable of the compressor device (1) and an evaluation means (121) for evaluating the detected operating variable, wherein the electric motor (32) and the inverter (31) supplying same with alternating current are jointly integrated in a DC compressor unit (30) of the compressor device (1), which is coupled via a DC interface (20) to an electronics unit (10) of the compressor device (1) which is separate from said DC compressor unit and in which, in turn, the rectifier (11) and the monitoring device (12) are jointly integrated.

Description

HEAT PUMP, HVAC SYSTEM, COMPRESSOR DEVICE AND METHOD FOR MONITORING A COMPRESSOR DEVICE DESCRIPTION Technical area

[0001] The present invention relates to a heat pump, in particular for use in an HVAC system, an HVAC system with a heat pump, a compressor device for use in a heat pump and a method for monitoring a compressor device. Background of the invention

[0002] State-of-the-art systems for heating, ventilation and air conditioning, so-called HVAC systems, are known, which are intended to implement, among other things, a targeted and as efficient as possible control of temperature, humidity or air flow within a building or parts of it.

[0003] In recent times, heat pumps have been increasingly used as a component of such HVAC systems, especially in private households, either as part of a heating system of the HVAC system to increase room temperatures, but also as part of an air conditioning system of the HVAC system to lower room temperatures.

[0004] Such heat pumps are thermodynamic devices that, via a connection to a heat source system, utilize various ambient energy sources, for example in the form of aerothermal energy, geothermal energy, or hydrothermal energy, for heating and / or air conditioning. For this purpose, the heat pump typically comprises a closed thermodynamic working circuit for a working medium, in which the working medium is compressed and expanded, as well as heated and cooled, according to generally known principles. Such that thermal energy can be transferred to the working medium at at least one point in the working circuit and thermal energy can be extracted from the working medium at at least one other point in the working circuit, thus converting a heat flow from or into a target system, e.g., a room in the building.

[0005] In cases where heat energy is to be extracted from the target system, for example in air conditioning, the heat pump is often also referred to as a refrigeration pump. In the following, however, the term "heat pump" is understood as a generic term that also includes the refrigeration pump version.

[0006] A key element in the heat pump's working circuit is the compressor, usually electrically operated, which compresses the working fluid to increase its pressure. A failure of the compressor will also result in the failure of the A complete heat pump, which can be particularly critical when used in an HVAC system. An example of this would be the failure of a heat pump installed as part of a heating system due to component damage during the cold winter months, which would cause the building to be heated to cool down and become uninhabitable. Depending on the type of damage, repair or replacement can take several days and should therefore be avoided at all costs.

[0007] Especially when using heat pumps as part of such HVAC systems, fail-safe operation over a long operating period of the heat pump, several years, if not decades, must be ensured, in which damage to individual components is excluded as far as possible.

[0008] One of the most critical components of the heat pump is the electrically operated compressor, which usually includes an electric motor that provides the mechanical movement required to compress the working medium. This electric motor is operated in different power ranges depending on the naturally varying performance requirements of the heat pump and is subjected to different thermal, electrical and mechanical loads.

[0009] In accordance with the safety standards stipulated in DIN EN 60335-1, the operating status of the electric motor, as an electrical device for household use, should be monitored to detect critical operating conditions and, if necessary, take countermeasures, e.g., by shutting down the compressor, to prevent unsafe operation and / or damage to the electric motor of the compressor. An example of such damage is thermal overload of the rotor and / or stator windings of the electric motor, which can, for example, damage the insulating layer applied to a conductor of a winding, leading to a short circuit and, under certain circumstances, permanent damage to the electric motor.

[0010] Damage to the compressor, which in this case naturally no longer compresses the working medium sufficiently, can affect the other components of the heat pump that work with the working medium, which may also be damaged. Summary

[0011] An object of the present invention is therefore to provide a possibility for compressing a working medium in a heat pump with an electrically operated compressor, which allows precise and reliable monitoring to implement safe operation, i.e. to avoid critical operating conditions, with the In particular, high safety standards can be maintained and damage to heat pump components can be reliably avoided.

[0012] To achieve this object, a heat pump according to claim 1, an HVAC system according to claim 12, a compressor device according to claim 13 and a method for monitoring a compressor device according to claim 14 are provided.

[0013] The respective dependent claims relate to preferred embodiments, which can be provided individually or in combination.

[0014] According to a first aspect of the invention, a heat pump is provided, in particular for use in an HVAC system, which comprises, as part of a working circuit of the heat pump, at least one compressor device for compressing a working medium of the working circuit, wherein the compressor device in turn comprises an electric motor for providing a mechanical movement for compressing the working medium, an inverter that supplies the electric motor with alternating current, a rectifier that supplies the inverter with direct current, wherein the rectifier can be connected to an alternating current source to supply energy to the compressor device, and a monitoring device for monitoring an operating state of the electric motor, which monitoring device comprises at least one measuring means for detecting an operating variable of the compressor device and an evaluation means for evaluating the detected operating variable.wherein the electric motor and the inverter supplying it with alternating current are jointly integrated in a DC compressor unit of the compressor device, which is coupled via a DC interface to an electronic unit of the compressor device which is separate from the latter and in which, in turn, the rectifier and the monitoring device are jointly integrated.

[0015] The construction of the compressor device provided by the invention has particularly good electromagnetic compatibility, since the components operating with alternating current, namely the inverter and the electric motor, are separated from the other electrical components and are integrated together in a separate component, namely the DC compressor unit.

[0016] Electromagnetic compatibility should be understood as a measure of the ability of a technical component not to interfere with other components through unwanted electrical or electromagnetic effects, or to be interfered with by other components. Electromagnetic compatibility can be defined both at the component level of a device and at the device level itself.

[0017] In the case of the compressor device according to the invention, the components operating with alternating current are the main cause of electromagnetic fields, which may affect other electrical or electronic components and may cause them to malfunction or behave incorrectly.

[0018] The design according to the invention, in which the inverter and electric motor as well as the rectifier and monitoring device are each arranged "close" to one another, thus achieves particularly good electromagnetic compatibility, in which, above all, the monitoring device designed as part of the separate electronics unit is protected from negative influences by the inverter and / or the electric motor.

[0019] The inventors have discovered that the inventive design leads to significantly improved electromagnetic compatibility, since the joint integration in the DC compressor unit means the spatial distance between the inverter and the electric motor is very small, in contrast to the "classic" design known from the prior art with separate inverter and electric motor. This allows the electrical connection between the inverter and electric motor, which is very critical in terms of electromagnetic compatibility, to be made comparatively short and, in turn, emits less electromagnetic interference, which would sometimes require complex design measures to suppress.

[0020] By arranging it in the separate electronics unit, the monitoring device is additionally shielded from the interference source described above

[0021] In this way, not only the electromagnetic compatibility of the entire compressor device but also of its components is improved, so that interference with the safety-relevant monitoring device in particular is reduced.

[0022] This not only allows reliable operation of the compressor device, but also reliable monitoring with regard to critical operating states of the compressor device, which in turn increases operational safety (for example by minimizing the risk of electric shock) and reduces the risk of damage to the compressor device. Such damage may not only lead to a loss of function, but also to damage to other components of the heat pump.

[0023] These critical operating conditions include, among others, overheating of the electric motor's windings, which can, for example, damage the insulating layer applied to the conductor of a winding, leading to a short circuit and thus to a permanent loss of function of the electric motor or even to an unsafe condition of the entire electrical system from a regulatory perspective, for example, due to the risk of electric shock. Likewise, the electric motor can also be inhibited or even blocked, so that the mechanical movement for compaction does not occur as desired or, in some cases, does not occur at all.

[0024] The separate arrangement of the two units (electronics unit and DC compressor unit) should be understood as meaning that these are separate units or components, as parts of which or in which the respective components (inverter, electric motor, rectifier, etc.) are implemented or housed. The two units can be arranged at a distance from each other (apart from the electrical connection via the DC interface). An air gap or an intermediate layer can be present between the units.

[0025] The evaluation means of the monitoring device is preferably electronic and, in particular, processor-based, and itself comprises means for signal transmission (sending and receiving). The evaluation means can, for example, be a control device of the compressor device or a part of such a control device. Alternatively, the evaluation means can also be coupled to a control device of the compressor device or directly to a control device of the heat pump.

[0026] In a preferred embodiment, the DC compressor unit and the electronics unit each comprise a housing, which can be spaced apart from one another, wherein at least a part of the electric motor, in particular its stator- and / or rotor-side windings which are supplied with current, and the inverter are arranged within the housing of the DC compressor unit and the rectifier and the monitoring device are arranged within the housing of the electronics unit.

[0027] Preferably, all electrical components of the electric motor are arranged within the housing of the DC compressor unit

[0028] The housings may be made of plastic or a metallic material, but are not limited to this.

[0029] In a preferred embodiment, at least the housing of the DC compressor unit comprises an electromagnetic shielding means, preferably in the form of metallic components of the housing or a metal foil or a metal mesh.

[0030] The shielding agent additionally shields the part of the electric motor and the inverter in the housing of the DC compressor unit from the other electrical components of the compressor device.

[0031] In a preferred embodiment, an electromagnetic shielding means can also be arranged between the DC compressor unit and the electronics unit, for example between the respective housings of said units.

[0032] In a preferred embodiment, the evaluation means is configured to determine at least one operating characteristic value describing the operating state of the electric motor as a function of the detected operating variable.

[0033] The operating parameters offer a particularly easy-to-implement option for identifying critical operating conditions, for example by detecting a limit value being exceeded.

[0034] For example, one, two, three or more operating parameters can be determined, which may include, among other things, values ​​of electrical or mechanical quantities of the electric motor.

[0035] In a preferred embodiment, the at least one measuring means is configured to detect a current and / or a voltage at the DC interface.

[0036] Values ​​of the aforementioned quantities are preferably recorded at regular intervals, thereby capturing temporal profiles of the aforementioned operating variables. The recorded current and / or voltage can subsequently refer to either a single value or a temporal profile.

[0037] In a preferred embodiment, the at least one measuring means is configured to detect a current intensity at the direct current interface and the monitoring device comprises a further measuring means configured to detect a voltage at the direct current interface, wherein the evaluation means is also configured to evaluate the voltage detected by the further measuring means

[0038] By recording several operating variables, the operating status of the Compressor device monitored even better.

[0039] In a preferred embodiment, the evaluation means of the Monitoring device configured to determine, based on the detected current intensity and / or the detected voltage at the DC interface, at least one effective value of a current flowing through a winding of the electric motor as an operating characteristic of the electric motor, in particular an effective value of the voltage, the current intensity or the electrical power of the current flowing through the winding of the electric motor, wherein each of the variables can preferably be handled as a separate operating characteristic.

[0040] The description of the alternating current flowing in the winding using the determined effective values ​​is kept simple and yet representative in order to describe the complex, time-variant processes in the winding and to implement monitoring based on this.

[0041] In a preferred embodiment, the evaluation means of the monitoring device is configured to determine a temperature of the winding of the electric motor as an operating characteristic of the electric motor based on the at least one determined effective value of the current flowing through the winding of the electric motor.

[0042] In this way, temperature monitoring is implemented without having to install a temperature sensor in the compressor device, in order to detect, in particular, an operating condition that is critical for the insulating layer of the windings.

[0043] The temperature is determined by a predetermined or self-learning algorithm that receives the said effective values ​​and / or the measured current and / or the measured voltage as input variables. The algorithm preferably incorporates design parameters and / or electrical parameters of the electric motor and / or the inverter. Alternatively, the algorithm can also receive spectra of the respective operating parameters determined from temporal profiles of the measured operating parameters as input variables. Non-exhaustive examples of such spectra are transformations of the temporal profiles into a frequency domain, for example, using an FFT or the like.

[0044] Preferably, the temperature is determined by the algorithm based on two or all three effective values ​​of voltage, current or electrical power of the current flowing through the winding.

[0045] Alternatively, the evaluation means of the monitoring device is configured to determine a temperature of a winding of the electric motor as an operating characteristic of the electric motor based on the detected current intensity and / or the detected voltage at the DC interface.

[0046] In this case, the algorithm worked directly with the measured current and / or the measured voltage (or their time courses) without first determining effective values.

[0047] In a preferred embodiment, the evaluation means is configured to determine a rotational speed of the electric motor as an operating characteristic of the electric motor based on the detected current intensity and / or the detected voltage at the DC interface.

[0048] In this way, it can be concluded that the electric motor is inhibited or even blocked and is no longer compressing the working medium insufficiently or not at all.

[0049] In a preferred embodiment, the compressor device further comprises a switch unit coupled to the monitoring device for interrupting a power supply to the electric motor by the alternating current source, wherein the compressor device, in particular the evaluation means, is configured to interrupt the power supply to the electric motor via the switch unit based on at least one operating characteristic of the electric motor determined by the evaluation means, in particular if this is outside a predetermined target range.

[0050] In this way, a critical operating condition can be prevented and / or terminated by immediately cutting off the power supply, so that an unsafe operating condition and / or damage to the compressor device is avoided.

[0051] The said operating parameters may be (but are not limited to) the effective values ​​of the current described above, the temperature of the winding or the speed of the electric motor, or spectra in a frequency range derived from the temporal characteristics of these parameters.

[0052] Preferably, the evaluation means is configured to interrupt the power supply via the switch unit for each determined operating characteristic value, in particular if one of the determined operating characteristic values ​​lies outside a respective predetermined target range

[0053] In this way, monitoring is extended to several operating parameters.

[0054] Preferably, the switch unit is connected between the AC power source and the rectifier so that the current flow between the AC power source and the rectifier can be interrupted, thereby ensuring the electrical safety of the heat pump and, among other things, protecting the entire electronics of the compressor device from damage.

[0055] Alternatively, the switch unit can also be arranged downstream of the rectifier, in particular between the rectifier and the inverter, with respect to the electrical energy flow.

[0056] Preferably, an interruption occurs if the determined operating characteristic value is outside an associated target range. In particular, this can be implemented by a limit value monitoring with continuous or repeated recording of the operating variable and determination of the operating value or the operating value by the monitoring device, in which it is monitored whether the determined operating characteristic value exceeds an upper and / or lower limit of its associated target range.

[0057] The target ranges can be predetermined externally by an operator, for example, based on test bench measurements, by a simulation program, or by a self-learning algorithm during a learning phase. Preferably, the target ranges are adaptable; in particular, the evaluation means is configured to adapt the target ranges depending on the operating variables recorded by the measuring units of the monitoring device.

[0058] Preferably, the compressor device further comprises at least one sensor coupled to the monitoring device for detecting a state variable of the Working medium in the working circuit, in particular a pressure sensor, so that the state variable is a pressure of the working medium, wherein the evaluation means is configured to interrupt the energy supply to the electric motor via the switch unit based on a value of the state variable detected by the at least one sensor.

[0059] In this way, the monitoring is supplemented by thermodynamic operating variables of the compressor device, which allows it to be implemented even more reliably and accurately.

[0060] Preferably, an interruption occurs if the detected value of the state variable lies outside a predetermined second target range. In particular, this can be implemented by a limit value monitoring with temporally continuous or repeated detection by the monitoring device, in which it is monitored whether the detected value of the state variable exceeds a limit of the second target range.

[0061] Preferably, the compressor device comprises such a sensor both at a compressor inlet for the working medium and at a compressor outlet, wherein the evaluation means is configured to interrupt the power supply of the electric motor via the switch unit based on the two values ​​of the state variable of the working medium at the compressor inlet and at the compressor outlet detected by the two sensors.

[0062] In this way, the degree of compression of the working fluid can be determined, which can be used to detect any compression malfunction. For example, a sudden drop in the degree of compression with the heat pump's settings unchanged usually indicates a jammed or blocked electric motor.

[0063] In a preferred embodiment, the heat pump is designed as part of a heating system of an HVAC system that is designed to heat a building.

[0064] Heat pumps have recently been used as alternatives to oil- and gas-based systems, as heating systems in HVAC systems. Safe and reliable operation must be ensured here, especially during the cold winter months, which is ensured by the heat pump according to the invention.

[0065] According to a second aspect of the invention, an HVAC system is provided which comprises a heat pump at least according to the first aspect or one of its preferred embodiments

[0066] In this way, the previously described advantages of the heat pump according to the invention can be transferred to the entire HVAC system, which, among other things, ensures its reliable and energy-efficient operation.

[0067] The term HVAC system refers to any combination of one or more of the subsystems summarized therein, i.e. a heating system, a ventilation system and an air conditioning system, as an HVAC system within the meaning of the invention does not have to include all of the above subsystems.

[0068] For example, the heat pump can be used in a heating system and / or in an air conditioning system of the HVAC system.

[0069] According to a third aspect of the invention, a compressor device is provided which is particularly suitable for use in a heat pump, preferably in a heat pump according to the first aspect of the invention. The compressor device comprises an electric motor for providing a mechanical movement for compressing a working medium, an inverter that supplies the electric motor with alternating current, a rectifier that supplies the inverter with direct current, wherein the rectifier is connectable to an alternating current source for supplying power to the compressor device, and a monitoring device for monitoring an operating state of the electric motor.which comprises at least one measuring means for detecting an operating variable of the compressor device and an evaluation means for evaluating the detected operating variable. The electric motor and the inverter supplying it with alternating current are jointly integrated in a DC compressor unit of the compressor device, which is coupled via a DC interface to an electronic unit of the compressor device which is separated from the latter and in which the rectifier and the monitoring device are jointly integrated,

[0070] In this way, any heat pump can be retrofitted with the compressor device according to the invention in order to obtain a heat pump according to the first aspect of the invention with all its advantages.

[0071] However, the use of the compressor device is not limited to a heat pump in an HVAC system, but can also be used in other heat pumps, such as a heat pump in a refrigerator / freezer, a tumble dryer and other household appliances.

[0072] According to a fourth aspect of the invention, a method for monitoring the compressor device is provided at least according to the third aspect or one of its preferred embodiments. The method comprises at least operating the compressor device by supplying the rectifier of the compressor device with alternating current from an alternating current source, detecting at least one operating variable of the compressor device by means of the at least one measuring means of the monitoring device, and determining an operating characteristic value describing an operating state of the electric motor of the compressor device as a function of the detected operating variable by means of the Evaluation means of the monitoring device, in particular in order to detect a dangerous condition and to enable the safety-related interruption of the power supply to the compressor device.

[0073] In a preferred embodiment, the at least one measuring means is configured to detect a current and / or a voltage at the DC interface of the compressor device, wherein the detection of the operating variable of the compressor device further comprises detecting a current and / or a voltage at the DC interface of the compressor device

[0074] Preferably, the determination of the operating characteristic value describing the operating state of the electric motor of the compressor device further comprises determining an effective value of a current flowing through a winding of the electric motor, in particular an effective value of the voltage, the current intensity or the electrical power, as a function of the detected current intensity and / or the detected voltage at the DC interface, and outputting the determined effective value as an operating characteristic value of the electric motor.

[0075] Alternatively, determining the operating characteristic value describing the operating state of the electric motor of the compressor device further comprises determining an effective value of a current flowing through a winding of the electric motor, in particular an effective value of the voltage, the current intensity or the electrical power, as a function of the detected current intensity and / or the detected voltage at the DC interface, and determining a temperature of the winding of the electric motor as a function of the determined effective value of the current flowing through the winding of the electric motor, and outputting the determined temperature as an operating characteristic value of the electric motor.

[0076] Further alternatively, determining the operating characteristic value describing the operating state of the electric motor of the compressor device further comprises determining an effective value of a current flowing through a winding of the electric motor, in particular an effective value of the voltage, the current intensity or the electrical power, as a function of the detected current intensity and / or the detected voltage at the DC interface, and determining a temperature of the winding of the electric motor as a function of the detected current intensity and / or the detected voltage at the DC interface, and outputting the determined temperature as an operating characteristic value of the electric motor.

[0077] The method preferably comprises shutting down the compressor device, in particular by interrupting the power supply to the electric motor, if at least one or more of the determined operating parameters lie outside a respective predetermined target range. The interruption is preferably carried out by interrupting an electrical connection between the rectifier and the AC power source.

[0078] Further aspects and their advantages as well as more specific embodiments of the aforementioned aspects and embodiments are described below with the aid of the drawings shown in the attached figures.

[0079] Fig. 1 shows schematically an embodiment of the heat pump according to the invention.

[0080] Fig. 2 shows schematically a first embodiment of the compressor device according to the invention.

[0081] Fig. 3 shows schematically a second embodiment of the compressor device according to the invention.

[0082] Fig. 4 shows a flowchart of a first embodiment of the method according to the invention for monitoring a compressor device.

[0083] It is emphasized that the present invention is in no way limited to the exemplary embodiments described below and their embodiment features. The invention further comprises modifications of the aforementioned exemplary embodiments, in particular those which result from modifications and / or combinations of individual or multiple features of the described exemplary embodiments within the scope of protection of the independent claims. Detailed character description

[0084] Fig. 1 shows schematically an embodiment of the heat pump according to the invention.

[0085] The heat pump comprises a compressor device 1, a condenser 2, an expansion valve 3 and an evaporator 4 arranged in a working circuit for a working medium.

[0086] The illustrated heat pump 1 is configured for heating operation, in which heat energy is transferred from the heat source system 6 to the heat receiver 7 through the thermodynamic cycle, for example to a hot water circuit of a heating system or to a water heater for domestic water.

[0087] For this purpose, the condenser 2 is thermally coupled to a heat receiver 7 in order to supply the heat energy extracted from the working medium in the condenser 2. The evaporator 3 is thermally coupled to a heat source system 6 in order to transfer the heat energy from this source to the working medium.

[0088] The compressor device 1 serves to compress the heated and thus usually gaseous working medium and for this purpose comprises an electric motor 32 for providing a mechanical movement for compressing the working medium.

[0089] The electric motor 32 is supplied with alternating current. For this purpose, an inverter 31 is connected upstream of the electric motor, which in turn is supplied with direct current via a rectifier 11 connected upstream. The rectifier 11 is in turn supplied with alternating current via an alternating current source (~).

[0090] To monitor an operating state of the compressor device 1, in particular of its electric motor 32, the latter comprises a monitoring device 12, which comprises at least one measuring means for detecting an operating variable of the compressor device 1 and an evaluation means for evaluating the detected operating variable

[0091] The electric motor 32 and the inverter 31 supplying it with alternating current are integrated together in a DC compressor unit 30 (DC for direct current) of the compressor device 1.

[0092] The rectifier 11 and the monitoring device 12 are integrated together in a separate electronics unit 10, wherein the electronics unit 10 and the DC compressor unit 30 are coupled to one another via a DC interface 20.

[0093] The monitoring device 12 preferably uses the The operating variable or variables to be recorded by the compressor device 1 are measured via measuring devices at the DC interface 20.

[0094] The structure of the compressor device 1 provided by the invention has particularly good electromagnetic compatibility, since the components operating with alternating current, namely the inverter 31 and the electric motor 32, are separated from the other electrical components and are integrated together in a separate component, namely the DC compressor unit 30.

[0095] Components that operate with alternating current are the main sources of electromagnetic fields that can affect other electrical or electronic components and, under certain circumstances, lead to malfunctions and faulty behavior.

[0096] The compressor device further comprises pressure sensors 501, 502, which are each arranged on the side of the compressor inlet 511 and the compressor outlet 512 for the working medium and are each configured to detect a pressure of the working medium.

[0097] The pressure sensors 501, 502 are coupled to the monitoring device 12 and are available to it, in particular to the evaluation means, as additional variables for the purpose of monitoring the electric motor 32.

[0098] For example, the recorded pressure values ​​at the compressor inlet 511 and the compressor outlet 512 can be used to determine whether compression is insufficient or not occurring at all.

[0099] The heat pump 1 described above should not be understood as being limited to heating operation, but can also be used as a cooling pump.

[0100] Fig. 2 shows schematically a first embodiment of the compressor device 1 according to the invention.

[0101] The compressor device 1 serves to compress a working medium which enters the compressor device 1 through the compressor inlet 511 and exits again in a compressed state from the compressor outlet 512.

[0102] To compress the working medium, the compressor device 1 comprises an electric motor 32 designed as a three-phase motor, whose rotor and / or stator-side windings 321 are supplied with three-phase alternating current (three-phase current) in this case to provide mechanical movement for compressing the working medium. The electric motor 32 is not intended to be limited to a three-phase motor; electric motors operated with any other type of alternating current can also be used.

[0103] The electric motor 32 is supplied with alternating current, as described. For this purpose, an inverter 31 is connected upstream of the electric motor 32, which in turn is supplied with direct current via a rectifier 11 connected upstream. The rectifier 11, in turn, is supplied with alternating current via an alternating current source (~).

[0104] Rectifier 11 and inverter 31 can be configured according to designs commonly used in the prior art. Thus, in this case, rectifier 11 comprises a plurality of diodes 111 connected according to the circuit diagram shown in Fig. 2, and inverter 31 comprises a plurality of IGBTs connected according to the circuit diagram shown in Fig. 2.

[0105] To monitor an operating state of the compressor device 1, in particular of its electric motor 32, the latter comprises a monitoring device 12, which in the present exemplary embodiment comprises two measuring means, namely a voltmeter 122 and an ammeter 123, and an evaluation means 121 coupled thereto is configured to evaluate the detected amperage and / or the detected voltage.

[0106] The electric motor 32 and the inverter 31 supplying it with alternating current are integrated together in a DC compressor unit 30 (DC for direct current) of the compressor device 1

[0107] The rectifier 11 and the monitoring device 12 are integrated together in a separate electronic unit 10, wherein the electronic unit 10 and the DC compressor unit are coupled to one another via a DC interface 20.

[0108] Fig. 2 shows the advantageous structure of the compressor device 1 already described in the context of Fig. 1 with a particularly good electromagnetic compatibility

[0109] Preferably, the inverter 31 and the electric motor 32, or at least its winding(s) 321, are housed together in a housing 33 of the DC compressor unit 30. To further improve electromagnetic compatibility within the compressor device 1, the housing 33 can comprise an electromagnetic shielding means (not shown here). The shielding means can be (not limited to) a metal foil or a metal mesh, or can be implemented by partially or completely providing the housing 333 as a metallic housing.

[0110] Preferably, the rectifier 11 and the monitoring device 12 are housed together in a housing 13 of the electronics unit 10. To further improve the electromagnetic compatibility within the compressor device 1, the housing 13 can comprise an electromagnetic shielding means (not shown here). The shielding means can be (non-limiting) a metal foil or a metal mesh.

[0111] The two housings 13, 33 can be arranged at a distance from each other. This can be understood as meaning that the housings 13, 33 do not have direct contact, but rather at least an air gap or an intermediate layer is present between them. The intermediate layer can optionally be an electrically insulating material. Alternatively, the housings 13, 33 can also be adjacent to each other.

[0112] Said intermediate layer between the two housings 13, 33 may preferably be an electromagnetic shielding means, whereby the electromagnetic compatibility within the compressor device 1 is further improved.

[0113] The evaluation means 121 is preferably electronic and in particular processor-based, and itself comprises means for signal transmission (sending and receiving). The evaluation means 1 can be, for example, a control device of the compressor device 1 or a part of such a control device. Alternatively, the evaluation means 121 can be coupled to a control device of the compressor device 1 or directly to a control device of a heat pump in which the shown compressor device 1 is used.

[0114] The evaluation means 121 is configured to receive and evaluate the values ​​detected by the voltmeter 122 and the ammeter 123. During this process, the evaluation means 121 is configured to determine at least one operating characteristic value describing the operating state of the electric motor 32 based on the detected values. One or more operating characteristic values ​​can be determined.

[0115] The operating characteristic value(s) determined can be used for control by a control device of the compressor device 1, displayed to an operator via a display (not shown here), or transmitted to an external monitoring system (not shown here).

[0116] Preferably, an operating characteristic value to be determined by the evaluation means 121 is one or more effective values, in particular an effective value of the voltage, the current and / or the electrical power, of a current flowing through the winding 321 of the electric motor 32, which is or are determined on the basis of the values ​​detected by the voltmeter 122 and / or the ammeter 123.

[0117] Based on the determined effective value(s) as operating parameters of the electric motor 32, the operating state of the compressor device can be monitored such that a critical operating state, for example, in the form of overheating of the winding 321 of the electric motor 32, can be detected in a timely manner, thereby preventing damage or unsafe operation. Said monitoring is particularly reliable due to the inventive design with improved electromagnetic compatibility.

[0118] Preferably, a temperature of the winding 321 can be determined as an operating characteristic value alternatively or additionally from the values ​​recorded by the voltmeter 122 and / or the ammeter 123 or from effective values ​​of the current determined as described above.

[0119] The structure shown in Fig. 2 is by no means limited to the continuous use of three-phase current (three-phase alternating current). Thus, any other alternating current, for example with one or two phases, can be used both as the output of the alternating current source and / or as the input for the electric motor 32, whereby the number of phases of the alternating current source can also differ from that of the electric motor 32. The changes to the rectifier 11 and / or the inverter 31 and / or the electric motor 32 necessary for conversion to a different type of alternating current are known to the person skilled in the art.

[0120] The compressor device 1 in the embodiment described above for Fig. 2 can also be used in the heat pump shown in Fig. 1.

[0121] Fig. 3 shows schematically a section of a second embodiment of the compressor device 1 according to the invention.

[0122] The second embodiment corresponds in large parts to the first embodiment of Fig. 2 and differs from it by the switch unit 40 arranged between the alternating current source and the electronic unit 10, which is coupled to the evaluation means 121 of the monitoring device 12.

[0123] The switch unit 40 is controllable and at least configured to interrupt a current flow between the alternating current source and the rectifier 11 and thus to interrupt the energy supply to the electric motor 32.

[0124] The evaluation means 121 is designed to control the switch unit 40 and to interrupt an electrical connection between the rectifier 11 and the alternating current source via the switch unit 40.

[0125] The interruption by actuating the switch unit 40 preferably takes place on the basis of an operating characteristic value determined by the evaluation means 121, in particular a determined effective value of the current flowing through the winding 321 or a temperature of the winding 321. If at least one of the determined operating characteristic values ​​lies outside a predetermined target range, this is evaluated as a critical operating state and the evaluation means 121 sends a signal to the switch unit 40, as a result of which the switch unit 40 interrupts the current flow in order to avoid an unsafe operating state and to protect the compressor device 1 from damage.

[0126] Optionally, the switch unit 40 can also be designed as part of the electronic unit 10 and, in particular, can be integrated together with the rectifier 11 and the monitoring device 12 in the same housing 13.

[0127] As an alternative to the arrangement shown in Fig. 3, the switch unit 40 according to a third embodiment of the compressor device 1 can also be arranged, with reference to Fig. 2, between the rectifier 11 and the inverter 31.

[0128] The compressor device 1 in the embodiment described above for Fig. 3 can also be used in the heat pump shown in Fig. 1.

[0129] Fig. 4 shows a flowchart of a first embodiment of the method according to the invention for monitoring a compressor device.

[0130] The monitored compressor device comprises at least one electric motor for providing a mechanical movement for compressing a working medium, an inverter that supplies the electric motor with alternating current, a rectifier that supplies the inverter with direct current, wherein the rectifier can be connected to an alternating current source to supply energy to the compressor device, and a monitoring device that comprises at least one measuring means for detecting an operating variable of the compressor device and an evaluation means for evaluating the detected operating variable. The electric motor and the inverter that supplies it with alternating current are jointly integrated in a DC compressor unit of the compressor device, which is coupled via a DC interface to an electronics unit of the compressor device that is separate from the latter and in which the rectifier and the monitoring device are jointly integrated.

[0131] In step S1, the compressor device is operated by supplying the rectifier of the compressor device with alternating current from an alternating current source. The alternating current of the alternating current source can be, for example, a two-phase or a three-phase alternating current.

[0132] In step S2, a first operating variable of the compressor device is detected by means of the at least one measuring means of the monitoring device, wherein the at least one measuring means is configured to detect a current intensity at the direct current interface, for example in the form of an ammeter, and thus the first operating variable is a current intensity.

[0133] In step S3, a second operating variable of the compressor device is detected by means of a further measuring means of the monitoring device, wherein the further measuring means for detecting an electrical voltage at the direct current interface, for example in the form of a voltmeter, and thus the second operating variable is a voltage.

[0134] In step S4, an operating characteristic value describing the operating state of the electric motor of the compressor device is determined as a function of the detected current intensity and the detected voltage from steps S2 and S3 by means of the evaluation means of the monitoring device, wherein the operating characteristic value is preferably an effective value of a current flowing through a winding of the electric motor, preferably an effective current intensity, but optionally also effective values ​​of the voltage or the electrical power of the current flowing through the winding.

[0135] Optionally, the determined operating characteristic value can be output to an operator of the compressor device so that he or she can be informed about the current operating status.

[0136] In step S5, the determined effective current (as the determined operating characteristic) is evaluated by comparing the effective current with a predetermined first limit value, which can be understood as the boundary of a predetermined first target range. Depending on whether the effective current, voltage, or electrical power is selected as the operating characteristic for the method, the first limit value or the first target range will naturally vary, and the first limit value can be an upper or lower limit of the target range. In the present case, for example, the first limit value is selected as the upper limit of a target range.

[0137] If the effective current is below the predetermined first limit value for the current, there is no critical operating state of the electric motor and the method is repeated after a pause of a predetermined duration in step S6 starting from step S2.

[0138] If, however, the effective current is above the predetermined first limit value, a critical operating state of the electric motor exists and the method proceeds to step S7.

[0139] In step S7, the compressor device is shut down, in particular by disconnecting the power supply to the electric motor. This is preferably done by disconnecting the electrical connection between the rectifier and the external AC power source.

[0140] In this way, safe operation is ensured and the compressor device can be protected, among other things, from damage that could result from the critical operating condition.

[0141] Embodiments of the present invention and their advantages have been described in detail above with reference to the attached figures.

[0142] It is emphasized again that the present invention is in no way limited to the embodiments and their features described above. The invention further encompasses modifications of the above-mentioned embodiments, in particular those resulting from modifications and / or combinations of individual or multiple features of the described embodiments within the scope of protection of the independent claims. List of reference symbols 1 compressor device 2 condensers 3 Relief valve 4 evaporators 5 Pipe system for working medium 6 Heat source system 7 heat receivers 10 Electronic unit 11 rectifiers 12 Monitoring device 13 Housing of the electronics unit 20 DC interface 30 DC compressor unit 31 inverters 32 electric motor 33 Housing of the DC compressor unit 40 switch unit 111 Diode 121 evaluation tools 122 voltmeters Current meter IGBT Electric motor winding First pressure gauge Second pressure gauge Compressor inlet for working medium Compressor outlet for working medium

Claims

CLAIMS 1. A heat pump, in particular for use in an HVAC system, which comprises, as part of a working circuit of the heat pump, at least one compressor device (1) for compressing a working medium of the working circuit, wherein the compressor device (1) in turn comprises: an electric motor (32) for providing a mechanical movement for compressing the working medium; an inverter (31) which supplies the electric motor (32) with alternating current; a rectifier (11) which supplies the inverter (31) with direct current, wherein the rectifier (11) is connectable to an alternating current source to supply power to the compressor device (1); and a monitoring device (12) for monitoring an operating state of the electric motor (32), which comprises at least one measuring means (122, 123) for detecting an operating variable of the compressor device (1) and an evaluation means (121) for evaluating the detected operating variable;wherein the electric motor (32) and the inverter (31) supplying it with alternating current are jointly integrated in a DC compressor unit (30) of the compressor device [1], which is coupled via a DC interface (20) to an electronic unit (10) of the compressor device (1) separated therefrom, in which in turn the rectifier (11) and the monitoring device (12) are jointly integrated; 2. Heat pump according to claim 1, wherein the DC compressor unit (30) and the electronics unit (10) each comprise a housing (13, 33) which are preferably spaced apart from one another, wherein at least a part of the electric motor (32) and the inverter (31) are arranged within the housing (33) of the DC compressor unit (30) and the rectifier (11) and the monitoring device (12) are arranged within the housing (13) of the electronics unit (10).

3. Heat pump according to claim 2, wherein at least the housing (33] of the DC compressor unit (30] comprises an electromagnetic shielding means, preferably in the form of metallic components of the housing (33] or in the form of a metal foil or a metal mesh.

4. Heat pump according to at least one of the preceding claims, wherein the evaluation means (121) is configured to determine at least one operating characteristic value describing the operating state of the electric motor (32) as a function of the detected operating variable.

5. Heat pump at least according to claim 4, wherein the at least one measuring means (122, 123) is arranged to detect a current and / or a voltage at the direct current interface (20) 6. Heat pump at least according to claim 5, wherein the at least one measuring means (123) is configured to detect a current intensity at the direct current interface (20), and the monitoring device (12) comprises a further measuring means (122) which is configured to detect a voltage at the direct current interface (20), wherein the evaluation means (121) is also configured to evaluate the voltage detected by the further measuring means (122).

7. Heat pump at least according to one of claims 5 or 6, wherein the evaluation means (121) of the monitoring device (12) is set up to determine, based on the detected current intensity and / or the detected voltage at the DC interface (20), at least one effective value of a current flowing through a winding (321) of the electric motor (32) as an operating characteristic of the electric motor (32), in particular an effective value of the voltage, the current intensity or the electrical power of the current flowing through the winding (321) of the electric motor (32).

8. Heat pump at least according to claim 7, wherein the evaluation means (121) of the monitoring device (12) is configured to determine a temperature of the winding (321) of the electric motor (32) as an operating characteristic of the electric motor (32) based on the at least one determined effective value of the current flowing through the winding (321) of the electric motor (32).

9. Heat pump according to at least one of claims 5 to 7, wherein the evaluation means (121) of the monitoring device (12) is configured to determine a temperature of a winding (321) of the electric motor (32) as an operating characteristic of the electric motor (32) based on the detected current intensity and / or the detected voltage at the DC interface (20).

10. Heat pump according to at least one of claims 5 to 9, wherein the evaluation means (121) is configured to determine a rotational speed of the electric motor (32) as an operating characteristic of the electric motor (32) based on the detected current intensity and / or the detected voltage at the direct current interface (20).

11. Heat pump according to at least one of claims 4 to 10, wherein the compressor device (1) further comprises a switch unit (40) coupled to the monitoring device (12) for interrupting a power supply to the electric motor (32), which switch unit is connected in particular between the rectifier (11) and the AC power source or between the rectifier (11) and the inverter (31), wherein the compressor device, in particular the evaluation means (121), is configured to interrupt the power supply to the electric motor (32) via the switch unit (40) based on at least one operating characteristic of the electric motor (32) determined by the evaluation means (121), in particular if this operating characteristic lies outside a predetermined target range.

12. HVAC system for use in a building, comprising a heat pump according to at least one of claims 1 to 11.

13. A compressor device (1), particularly suitable for use in a heat pump according to one of claims 1 to 11, comprising: an electric motor (32) for providing a mechanical movement for compressing a working medium; an inverter (31) that supplies the electric motor (32) with alternating current; a rectifier (11) that supplies the inverter (31) with direct current, wherein the rectifier (11) is connectable to an alternating current source to supply power to the compressor device (1); and a monitoring device (12) for monitoring an operating state of the electric motor (32), which comprises at least one measuring means (122, 123) for detecting an operating variable of the compressor device (1) and an evaluation means (121) for evaluating the detected operating variable;wherein the electric motor (32) and the inverter (31) supplying it with alternating current are jointly integrated in a DC compressor unit (30) of the compressor device (1), which is connected to an electronics unit (10) separated therefrom; Compressor device (1), in which the rectifier [11] and the monitoring device (12) are integrated together, is coupled via a DC interface (20) 14. A method for monitoring a compressor device (1) at least according to claim 13, comprising the steps: Operating the compressor device (1) by supplying the rectifier (11) of the compressor device (1) with alternating current from an alternating current source; Detecting at least one operating variable of the compressor device (1) by means of the at least one measuring means (122, 123) of the monitoring device (12); and Determining at least one operating characteristic value describing an operating state of the electric motor (32) of the compressor device (1) as a function of the detected operating variable by means of the evaluation means (121) of the monitoring device (12).

15. The method according to claim 14, wherein the at least one measuring means (122, 123) is configured to detect a current intensity and / or a voltage at the DC interface (20) of the compressor device (1), wherein the detection of the operating variable of the compressor device (1) further comprises: Detecting a current intensity and / or a voltage at the DC interface (20) of the compressor device (1); and wherein the determination of the at least one operating characteristic value describing the operating state of the electric motor (32) of the compressor device (1) in turn comprises: Determining an effective value of a current flowing through a winding (321) of the electric motor (32), in particular an effective value of the voltage, the current intensity or the electrical power, as a function of the detected current intensity and / or the detected voltage at the DC interface (20); and Outputting the determined effective value as an operating characteristic value of the electric motor (32); and / or wherein the determination of the at least one operating characteristic value describing the operating state of the electric motor (32) of the compressor device (1) in turn comprises: Determining an effective value of a current flowing through a winding (321) of the electric motor (32), in particular an effective value of the voltage, the current intensity or the electrical power, as a function of the detected current intensity and / or the detected voltage at the DC interface (20), and Determining a temperature of the winding (321) of the electric motor (32) as a function of the determined effective value of the current flowing through the winding (321) of the electric motor (32); or - Determining a temperature of the winding (321) of the electric motor (32) in Dependence of the detected current and / or the detected voltage at the DC interface (20); and Outputting the determined temperature as an operating characteristic of the electric motor (32).

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