De-icing method using an electric motor

Abstract

The present application provides a de-icing method using an electric motor comprising a stator, a rotor, and a transmission shaft. The transmission shaft is mechanically connected to an output part, allowing the output part to be rotated by the electric motor. The de-icing method comprises the following steps: sensing the ambient temperature and the temperature of the electric motor's stator in response to a blockage of the electric motor; and, if the ambient temperature and the temperature of the electric motor's stator are below their respective limits, supplying an alternating current with a predefined current value and frequency to the electric motor, causing the electric motor to generate heat which is transferred to the output part via the transmission shaft for de-icing purposes.The present application further provides an electric motor suitable for carrying out the de-icing method according to the invention, as well as a computer program product capable of implementing the de-icing method according to the invention. By applying the de-icing method according to the invention, de-icing of the output part is made possible simply by controlling the electric motor. This reduces both the risk of electric motor failure and the manufacturing costs of the electric motor.

Description

Technical field The present invention relates to the electromechanical field, in particular a de-icing method using an electric motor, an electric motor and a computer program product. State of the art With the increasing global demand for climate neutrality, there is a growing trend towards using electric vehicles, which utilize electrical energy, instead of conventional motor vehicles, thereby reducing carbon emissions. Fuel cell systems are increasingly being used in some electric vehicles for power supply. These systems generate electrical energy through electrochemical reactions between fuel and oxidant, and the proton exchange membrane fuel cell (PEMFC) is a prime example. A PEMFC typically uses hydrogen as fuel and releases only water as a reaction product. During operation, the hydrogen fuel is fed to the anode of the PEMFC stack and adsorbed by the catalyst, ionizing it into hydrogen ions and electrons.The hydrogen ions are transported to the cathode via the proton exchange membrane, and the electrons flow to the cathode via an external circuit, thus generating an electric current. An excess of hydrogen is supplied to the anode stack to ensure the cell's electrochemical reaction is not interrupted. This excess hydrogen must be recovered and reused to increase fuel efficiency. A recirculation blower (ARB) is incorporated into the fuel subsystem of the PEMFC. The ARB includes a hydrogen recirculation pump that returns the excess hydrogen to the fuel circuit, allowing it to participate in the electrochemical reaction again. However, since water inevitably enters the anode side of the stack during the electrochemical reaction, the hydrogen entering the recirculation loop is also inevitably mixed with water (e.g., with gaseous water, i.e., the hydrogen is "wet"). In this case, icing frequently occurs in the recirculation loop during the cold start phase of electric vehicles at low winter temperatures, particularly between the impeller of the hydrogen circulation pump and its housing. Light icing leads to an increase in the instantaneous power consumption of the hydrogen circulation pump's electric motor and adversely affects its lifespan. Severe icing completely prevents the impeller from rotating, thus blocking the electric motor and ultimately destroying either the motor or the impeller. To address the problem of icing, the following solutions are proposed: using an additional heater that melts ice by heating it when the electric motor becomes blocked; providing an additional heating element inside the electric motor so that the electric motor generates heat; and circulating hot water through the housing (for example, via cooling pipes filled with hot water) to melt ice. While the above methods can solve the icing problem, they not only increase the manufacturing costs of the electric motor but may also be unsuitable for electric vehicle motors. This further increases the risk of malfunctions such as short circuits. Similarly, in other applications where electric motors are used, it is also necessary to introduce heat from the outside to de-ice the output parts if icing occurs. Therefore, it is necessary to propose a novel de-icing method that not only solves the problems with icing but also does so without changes to the existing hardware in order to reduce costs and increase the safety factor of the electric motor. Disclosure of the invention The present application aims to provide a de-icing method using an electric motor, an electric motor suitable for the application of this de-icing method, and a computer program product containing this de-icing method, in order to solve at least one of the problems existing in the prior art. According to one aspect of the present application, a de-icing method using an electric motor is proposed, wherein the electric motor comprises a stator, a rotor and a gear shaft, the gear shaft being mechanically connected to an output part so that the output part can be set in rotation by the electric motor, wherein the de-icing method comprises the following steps: detecting an ambient temperature and a temperature of the stator of the electric motor in response to a blockage of the electric motor; and when the ambient temperature and the temperature of the stator of the electric motor are below their respective limits, supplying an alternating current with a predefined current value and a predefined frequency to the electric motor so that the electric motor generates heat which is transferred to the output part via the gear shaft for the purpose of de-icing the output part. According to another aspect of the present application, an electric motor is proposed, wherein the electric motor comprises a stator, a rotor, a gear shaft and a control unit, the control unit being suitable for carrying out the de-icing method described above. According to a further aspect of the present application, a computer program product is provided which comprises a computer program, wherein the computer program, when executed by a processor, is used to implement the de-icing procedure described above. By applying the method proposed in the present application, the use of additional components to support de-icing can be advantageously avoided by using only existing components, which significantly reduces the risk of component failures. At the same time, the overall cost of the electric motor is lower due to the absence of additional components, making it better suited for applications where retrofitting with additional components is not possible. Brief description of the characters The exemplary embodiments of the present application are described in detail below with reference to the accompanying drawings. It should be understood that the embodiments described below serve only to illustrate the present application and are not to be construed as limiting the scope of protection of the present application. Figure 1 shows a part of a fuel cell system comprising an electric motor in which a de-icing method according to an exemplary embodiment of the present application is used; Figure 2 shows a schematic representation of a hydrogen circulation pump in which a de-icing method according to an exemplary embodiment of the present application is used; Figure 3 shows a flowchart of a de-icing method according to an exemplary embodiment of the present application; Figure 4 shows the following:Figure 4 shows a circuit of an electric motor comprising a hydrogen circulation pump in which a de-icing method according to an exemplary embodiment of the present application is used; and Figure 5 shows a flow diagram of a de-icing method according to a further exemplary embodiment of the present application. Detailed descriptions Preferred embodiments of the present application are described in detail below by means of examples. In these embodiments, the present application is described using the example of an electric motor for a hydrogen circulation pump in a recirculation circuit of a hydrogen fuel cell system. However, a person skilled in the art should understand that these exemplary embodiments are not to be interpreted as limiting the present application. Furthermore, the features in the embodiments of the present application can be combined with one another, provided there are no conflicts. Identical elements are designated with the same reference numerals in different drawings. For the sake of clarity, other elements are omitted.However, this does not mean that the electric motor of the present application cannot include other components or that the method of the present application cannot include other steps. It should be understood that the dimensions, proportions, and number of individual components in the drawings are not considered limitations for the present application. It is further understood that terms such as "first", "second", etc., may be used in this document to describe different elements, but these elements should not be limited by these terms. These terms are used only to distinguish one element from another. For example, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element, without altering the scope of protection of the present application. The procedure is explained in detail below using an electric motor for a hydrogen circulation pump of a hydrogen fuel cell system as an example. The hydrogen fuel cell system can be used in vehicles for energy supply, either to power the vehicle's engine to provide propulsion or to activate the vehicle's onboard systems to perform various functions. Fig. 1 schematically shows a part of a hydrogen fuel cell system, including a recirculation circuit of an electric motor controlled according to the present method. The part of the hydrogen fuel cell system shown in Fig. 1 can comprise a fuel cell stack and a hydrogen supply system (as indicated by the dashed frame in Fig. 1). The fuel cell stack 100 comprises an anode 110 and a cathode 120. During operation of the hydrogen fuel cell system, as schematically indicated by arrow 11, hydrogen from a hydrogen source 200, such as a hydrogen tank, is supplied to the inlet side 111 of the anode 110 via a hydrogen supply device 310 (e.g., an ejector) of the hydrogen supply system. Air, on the other hand, is supplied to the cathode 120. The hydrogen atoms entering the anode 110 are adsorbed by a catalyst and ionized to hydrogen ions and electrons.Hydrogen ions migrate across a proton exchange membrane (not shown) to the cathode 120, while electrons flow to the cathode 120 via an external circuit (not shown) to generate an electric current. Oxygen from the air combines with the hydrogen ions and electrons at the cathode 120 to form water molecules. Typically, during operation of the hydrogen fuel cell system, an excess of hydrogen is supplied to the inlet side 111 of the anode 110 to ensure that all cells in the fuel cell stack 100 are adequately supplied with hydrogen. Reaction water, unused hydrogen, and non-reacting gases collect at the outlet side 112 of the anode 110. As used in this document, the term "non-reacting gases" refers to gases that do not participate in the reaction, primarily nitrogen. With further reference to Fig. 1, the recirculation circuit 300 is arranged between the outlet 112 of the anode 110 and a hydrogen supply device 310. It serves to receive a recirculation current 12 from the outlet 112 of the anode 110 of the fuel cell stack 100 during operation of the hydrogen fuel cell system and to supply this recirculation current 12 to the hydrogen supply device 310. As used in this document, the “recirculation current 12” refers to a fluid mixture comprising reaction water, unused hydrogen, and unreacted gases. The recirculation circuit 300 includes a hydrogen separator 320, which is designed to physically separate at least a portion of the hydrogen from the recirculation stream 12 when the recirculation stream 12 flows through it. This allows the separated hydrogen to flow to the hydrogen supply device 310 (as schematically represented by arrow 12a) and the remaining components of the recirculation stream 12, apart from the separated hydrogen, to be discharged from the hydrogen fuel cell system (as schematically represented by arrow 12b).As used in this document, the phrase “physically separating at least some of the hydrogen from the recirculated stream” refers to the physical separation of at least some of the hydrogen from the recirculated stream by means of a physical process using different physical properties of hydrogen and the other components in the recirculated stream, without any chemical reactions taking place. A hydrogen circulation pump 330 is typically provided for supplying the separated hydrogen to the hydrogen supply device in order to pressurize the separated hydrogen and pump it to the hydrogen supply device 310. Fig. 2 shows a schematic representation of the hydrogen circulation pump 330. As shown in Fig. 2, the hydrogen circulation pump 330 comprises at least one impeller 331, a gear shaft 332 mechanically connected to the impeller 331, and an electric motor 333 (not shown in detail) that drives the gear shaft to rotate, with the impeller 331 being housed in a circulation pump casing 334. As indicated by the arrows, the separated hydrogen enters the hydrogen circulation pump 330 in the direction of the arrows, is pressurized at the impeller 331, and then flows to the hydrogen supply device 310. It can be seen that there is a gap between the impeller 331 and the circulation pump casing 334, where icing is most likely to occur at low temperatures. The electric motor can be a conventional permanent magnet three-phase motor having a stator and a rotor (not shown).The rotor is connected to the transmission shaft 332 to generate torque and drive the output part (in this example, the impeller 331) to rotation. If ice forms in the aforementioned gap, the impeller 331 can no longer rotate, leading to a blockage of the electric motor 333 and damage to the hydrogen circulation pump 330. In this case, the method according to the invention can be advantageously used to utilize the blocked electric motor for de-icing. Fig. 3 shows a flowchart of a de-icing process according to a schematic embodiment of the present application. The de-icing procedure comprises step S1: receiving a start request from the electric motor. Typically, this start request originates from the vehicle control system's start request to the individual subsystems when the electric vehicle is started. Alternatively, a dedicated icing monitoring system could be used, which detects the icing condition of the driven component connected to the electric motor by starting the motor. After receiving the start request from the electric motor, the de-icing procedure enters step S2, in which it is determined whether the electric motor is blocked. As explained above, an iced-up output shaft leads to the electric motor being blocked. Therefore, if the electric motor is not blocked, de-icing is obviously not necessary, and de-icing is only performed in the event of a blockage. Whether the electric motor is blocked can be determined by changes in the output power. In response to a blockage of the electric motor 333, the method, according to an exemplary embodiment of the present application, enters step S3. In step S3, the ambient temperature and the temperature of the electric motor's stator are recorded. The ambient temperature can be provided by a temperature sensor of the hydrogen fuel cell system or, alternatively, by a temperature sensor of the electric vehicle. This means that the ambient temperature does not necessarily have to be measured near the electric motor or the output stage, but can also be a temperature measured by the system containing the electric motor or the output stage. However, it is understandable that the ambient temperature should preferably be measured near the output stage or the electric motor 333.Similarly, the temperature of the electric motor's stator is measured by a temperature sensor of the electric motor, without the need to install other temperature sensors. After measuring the ambient temperature and the temperature of the electric motor's stator, these two temperatures are evaluated. For example, it is conceivable that if the ambient temperature exceeds a certain value (this value depends, for instance, on the operating environment of the output component or the area to be defrosted), icing is unlikely under almost all circumstances. Therefore, the procedure only proceeds to the following steps if the ambient temperature is below a certain value (limit). This evaluation logic also applies to the temperature of the electric motor's stator. Due to the stalling of the electric motor 333, all of its power is dissipated as heat energy. Therefore, if the stator temperature is too high, there is a risk that the surrounding coils will burn out.Consequently, the subsequent steps of the procedure cannot be carried out if the temperature of the electric motor's stator is too high. If both the ambient temperature and the temperature of the electric motor's stator are below their respective limits, the de-icing process in step S4 is initiated: an alternating current with a predefined current value and frequency is supplied to the electric motor 333. Preferably, the same current supply method as during normal operation of the electric motor is used to avoid the need for additional components. However, other current supply methods are also conceivable, as explained below with reference to Fig. 4. The generated heat is then transferred via the transmission shaft 332 to the output shaft to defrost it. After the heat has been generated in the coils, their temperature rise leads to a heating of the entire stator, which in turn heats the electric motor 333 and the transmission shaft 332, thus increasing the temperature of the transmission shaft 332. The heated transmission shaft 332 then transfers the heat to the connected impeller 331, heating it and ultimately causing the ice between the impeller 331 and the circulation pump housing 334 to melt. Since the heat is transferred from the electric motor 333 to the impeller 331 by simple thermal conduction, some of the heat remains in the conduction path during this process.This "lost" heat can effectively warm the ambient temperature around the output element (impeller 331), thereby not only preventing potential icing within the output element but also significantly reducing icing in its vicinity. This means that the self-heating of the electric motor can defrost not only the output element directly mechanically connected to it, but also components near the electric motor or connected to the output element. In this way, by applying the defrosting method according to the invention, the defrosting of the output element and its adjacent components is simply carried out by controlling the electric motor, without the need to add any other components.At the same time, the output part can be put back into operation immediately after the icing has been removed, under the drive of the electric motor, whereby the electric motor power is now switched from heat generation to torque provision, thus avoiding possible damage to coils or stator due to overheating. According to some exemplary embodiments in the present application, the de-icing method further comprises step S5: measuring the temperature of the electric motor's rotor. Similar to the stator of the electric motor, damage to the rotor components due to overheating should also be avoided. Although the rotor itself does not generate heat, the heat radiated by the stator can be sufficient to raise the rotor's temperature. Therefore, the rotor's temperature must also be monitored in the method of the present application. The rotor's temperature can be measured directly via the electric motor's own temperature monitoring system or via additional temperature measuring devices, or it can be calculated indirectly from the internal electric motor temperature. After measuring the rotor temperature of the electric motor, the predefined current values ​​and frequencies of the supplied alternating current, as well as the defrosting duration, are determined in step S6 based on the rotor and stator temperatures. Due to the properties of alternating current, the coils can be considered equivalent resistances (inductances). Therefore, the heat generated in the coils can be simplified to being proportional to the current value and frequency of the current flowing through them. Consequently, if the stator or rotor temperature is too high, a lower current value and frequency can be supplied, or a shorter defrosting duration can be set to prevent overheating and damage to the components.At lower stator and rotor temperatures, a higher current with a higher frequency can be applied to complete the de-icing steps as quickly as possible, or a longer de-icing duration can be set to perform de-icing under extreme conditions. Preferably, the ambient temperature can also be taken into account to make an initial assessment of the de-icing duration. Based on the specific electric motor type and the aforementioned stator and rotor temperatures, the predefined current value and frequency of the alternating current can be determined. For example, in the case of the hydrogen circulation pump 330 in the present application, the current value of the alternating current can be from 30 A to 60 A, for example, 30 A or 60 A or an intermediate value, and the frequency of the alternating current can be from 500 Hz to 1500 Hz, for example, 500 Hz or 1500 Hz or an intermediate value.The selection of the specific current value and the specific frequency of the current is preferably based on simulation and experimental data. Furthermore, the limit values ​​for the aforementioned ambient temperature and the aforementioned temperature of the electric motor's stator can also be determined using simulation and experimental data. Icing typically does not occur at ambient temperatures above 0 °C. However, due to varying air pressures, the icing temperature may exceed 0 °C. Therefore, the limit value for the ambient temperature is preferably set at 5 °C. This means that no icing is assumed at ambient temperatures above 5 °C, while below this temperature, icing is possible and the de-icing method according to the invention should be used. The temperature of the electric motor's stator should preferably not exceed 165 °C, as otherwise there is a risk of burnout.However, the de-icing method according to the invention is not suitable for starting or continuing in all cases. Besides the aforementioned cases of excessive stator or rotor temperature, as well as ambient temperatures above the limit, whether the electric motor 333 is blocked is, as previously described, also an important factor in determining whether the de-icing method according to the invention should be started or continued. With an electric motor that is not blocked, it is obviously unlikely that icing will form on the associated output part. Alternatively, after a certain period of time during the de-icing process, the output part may begin to run as the icing on the output part decreases, so that the electric motor 333 is no longer blocked. In these cases, the de-icing method according to the invention enters step S8: termination of the de-icing process.At the same time, the electric motor 333 is supplied with power based on the entered control parameters in order to put the electric motor 333 into normal operating condition. The above described de-icing of the output section connected to the electric motor 333 by means of self-heating of the electric motor 333 using a normal power supply. In the aforementioned embodiments, the current and frequency of the alternating current supplied to the electric motor 333 can be determined based on the measured ambient temperature and the temperature of the electric motor's stator; however, this power supply method is still capable of operating the electric motor 333, meaning that limited output power (electric motor stalling) can lead to the electric motor 333 burning out. At the same time, the current used in this power supply method is significantly higher compared to the current used in a normally operated electric motor, which also increases the risk of the electric motor 333 or the battery powering the electric motor 333 burning out.The following describes another type of power supply in which different coils of the stator are periodically used to heat the stator in order to minimize the probability of the coils burning out. Fig. 4 shows a power supply circuit for the electric motor. Typically, in an electric vehicle system, the electric motor, which is connected to the hydrogen circulation pump, is powered by a battery Ud. The battery Ud supplies direct current (DC), which is converted by an inverter into alternating current (AC) usable by the electric motor. The inverter is simplified in Fig. 4 as an array of six switching transistors, with each pair of switching transistors arranged in a bridge branch (i.e., the first bridge branch comprises a first switching transistor Q1 and a second switching transistor Q2, the second bridge branch comprises a third switching transistor Q3 and a fourth switching transistor Q4, and the third bridge branch comprises a fifth switching transistor Q5 and a sixth switching transistor Q6).Each bridge branch is connected to one of the three phase windings of the electric motor (first winding U, second winding V, third winding W), and all are connected to the battery Ud. The switching transistors can be, for example, insulated-gate bipolar transistors (IGBTs) or metal-oxide-semiconductor field-effect transistors (MOSFETs). It is evident that the circuit consists of the existing electric motor drive circuit and components, without requiring any additional components or wiring. Although not shown in the figure, the circuit configuration of the electric motor windings does not affect the implementation of the method of the present application. During heating, the de-icing method according to the invention periodically switches the electric motor between a first sub-step, a second sub-step, and a third sub-step at predefined time intervals. The predefined time interval can be, for example, 10 seconds. In the first sub-step, the circuit is operated such that it switches at a predefined frequency between a state in which the first switching transistor Q1 and the fourth switching transistor Q4 are switched on and the second switching transistor Q2 and the third switching transistor Q3 are switched off, and a state in which the second switching transistor Q2 and the third switching transistor Q3 are switched on and the first switching transistor Q1 and the fourth switching transistor Q4 are switched off, while the fifth switching transistor Q5 and the sixth switching transistor Q6 remain switched off (i.e.,It is switched at a predefined frequency between a state in which only the first switching transistor Q1 and the fourth switching transistor Q4 are switched on, and a state in which only the second switching transistor Q2 and the third switching transistor Q3 are switched on. Thus, the first winding U and the second winding V of the electric motor 333 are used and generate heat, while the third winding W remains without current.In the second step, the circuit is operated in such a way that it switches at a predefined frequency between a state in which the first switching transistor Q1 and the sixth switching transistor Q6 are switched on and the second switching transistor Q2 and the fifth switching transistor Q5 are switched off, and a state in which the second switching transistor Q2 and the fifth switching transistor Q5 are switched on and the first switching transistor Q1 and the sixth switching transistor Q6 are switched off, while the third switching transistor Q3 and the fourth switching transistor Q4 remain switched off (i.e., it switches at a predefined frequency between a state in which only the first switching transistor Q1 and the sixth switching transistor Q6 are switched on, and a state in which only the second switching transistor Q2 and the fifth switching transistor Q5 are switched on).The first winding U and the third winding W of the electric motor are thus used and generate heat, while the second winding V remains without current. In the third step, the circuit is operated so that it switches at a predefined frequency between a state in which the third switching transistor Q3 and the sixth switching transistor Q6 are switched on and the fourth switching transistor Q4 and the fifth switching transistor Q5 are switched off, and a state in which the fourth switching transistor Q4 and the fifth switching transistor Q5 are switched on and the third switching transistor Q3 and the sixth switching transistor Q6 are switched off, while the first switching transistor Q1 and the second switching transistor Q2 remain switched off (i.e.,It is switched at a predefined frequency between a state in which only the third switching transistor Q3 and the sixth switching transistor Q6 are switched on, and a state in which only the fourth switching transistor Q4 and the fifth switching transistor Q5 are switched on. In this way, the second winding V and the third winding W of the electric motor are used and generate heat, while the first winding U remains de-energized. In this manner, the windings (and consequently the stator of the electric motor) can be heated with a lower current and a lower frequency of alternating current, without the use of additional components or wires. At the same time, in each step, there is always one phase winding that is not conducting current (the current through this phase winding is 0), and the period of de-energization is significantly longer than the period of de-energization in the normal operating state.This prevents the temperature of each phase winding from becoming excessive, thus avoiding the windings burning out. In other exemplary embodiments of the present application, only the first, second, or third step of the de-icing process can be carried out to protect a specific phase winding and prevent excessive use in a faulty condition (for example, in the case of local corrosion). Now back to Fig. 3. In some cases, the degree of icing of the drive element may be so high that the ice cannot be completely melted by a single de-icing operation (i.e., a de-icing cycle comprising at least steps S1 to S4), and the drive element remains iced over (the drive element cannot rotate). Therefore, after a de-icing operation has been performed for a predetermined time, the de-icing procedure further includes reassessing whether the drive element needs to be de-iced. This assessment is carried out in the same way as the assessment described previously: taking measurements of the ambient temperature and the temperature of the electric motor stator and comparing the ambient temperature with the temperature of the electric motor stator.If both the ambient temperature and the temperature of the electric motor's stator are below their respective limits and the electric motor remains blocked, it is determined that icing is still present and the output shaft requires further de-icing. In this case, a suitable method is again applied in the de-icing procedure to heat the electric motor, thereby achieving de-icing of the output shaft. This means that after de-icing is complete, steps S1 to S3 are repeated. If the assessment still requires de-icing, step S4 is repeated; otherwise, the de-icing procedure is terminated by initiating step S8: Terminating the de-icing procedure (i.e., the electric motor 333 (hydrogen circulation pump 330) is started normally). It should be noted that in the cases described above, the blockage of the electric motor 333 is assumed to be due to icing. In other cases, however, the blockage of the electric motor 333 may be due to mechanical malfunctions, such as the seizing of the gear shaft 332 or the breakage of the impeller 331, which lead to a rotational obstruction. In these cases, it is desirable to detect these malfunctions as early as possible, rather than allowing the electric motor to rotate and thereby causing further damage. Therefore, the de-icing process is not carried out indefinitely (i.e., the repetition of steps S1 to S4). Experimental data show that after three cycles of the de-icing procedure, virtually no icing remains on the output part. Therefore, it can be assumed that if the electric motor continues to block after three cycles, this blockage is not due to icing.Therefore, according to a further embodiment of the present application, as shown in Fig. 5, the de-icing procedure preferably includes, after step S4, step S7: assessing whether the de-icing cycle (steps S1 to S4) has been performed three times. If the de-icing process has already been performed three times, it can be determined whether another mechanical fault requiring maintenance has occurred in the electric motor 333 or its associated components, or whether the icing has been eliminated. Step S8 is then initiated: terminating the de-icing procedure. Otherwise, if the de-icing cycle has not yet been performed three times, steps S1 to S4 are repeated. Based on different operating environments and electric motor types, the maximum number of de-icing operations can also vary and can be determined according to the specific circumstances. In summary, the embodiments described above in the present application provide a de-icing method using an electric motor. According to the technical solution of the present application, the electric motor is heated by measuring the ambient temperature, the temperature of the stator, and the stalled state of the electric motor, and the heat generated is used to melt ice on the drive element, thus performing a de-icing process. By applying the present de-icing method, the use of additional components to support de-icing can be advantageously avoided by utilizing only existing components, which significantly reduces the risk of component failure.At the same time, due to the lack of additional introduced components, the overall cost of the electric motor is lower, making it better suited for applications where retrofitting with additional components is not possible. According to another aspect of the present application, an electric motor is provided, the electric motor comprising a stator, a rotor, a gear shaft, and a control unit, the control unit being suitable for performing the de-icing method described above, whereby icing on the components connected to the electric motor can be easily removed by heating the electric motor without the addition of other components. For example, the electric motor could be the electric motor 333 for the hydrogen circulation pump 330, as illustrated in the embodiments described above. Alternatively, the electric motor could be an electric motor connected to the cooling fan of an electric vehicle or any other electric motor connected to an output part that may exhibit icing. According to a further aspect of the present application, a computer program product is also provided which comprises a computer program, wherein the computer program can be executed by a processor to implement the de-icing procedure described above. By using the electric motor or computer program product according to the invention, de-icing of the output part can be easily achieved by controlling the electric motor, without adding other components. This reduces both the risk of electric motor failure and the manufacturing costs of the electric motor. The present application has been described in detail above with reference to specific embodiments. It is obvious that the above description and the embodiments shown in the drawings are to be understood as exemplary and do not constitute a limitation of the present application. A person skilled in the art can make various modifications and changes without departing from the spirit of the present application, and all such modifications and changes remain within the scope of protection of the present application.

Claims

A de-icing method using an electric motor, wherein the electric motor (333) comprises a stator, a rotor and a gear shaft (332), the gear shaft being mechanically connected to an output part so that the output part can be set in rotation by the electric motor, characterized in that the de-icing method comprises the following steps: detecting an ambient temperature and a temperature of the stator of the electric motor in response to a blockage of the electric motor; and when the ambient temperature and the temperature of the stator of the electric motor are below their respective limit values, supplying an alternating current with a predefined current value and a predefined frequency to the electric motor so that the electric motor generates heat which is transferred to the output part via the gear shaft for the purpose of de-icing the output part. De-icing method according to claim 1, characterized in that the de-icing method further comprises: detecting the temperature of the rotor of the electric motor before supplying the alternating current to the electric motor; and determining the current value and frequency of the alternating current as well as a de-icing duration based on the temperature of the rotor of the electric motor and the temperature of the stator of the electric motor. De-icing method according to claim 2, characterized in that the current value of the alternating current is in the range of 30 A to 60 A and the frequency of the alternating current is in the range of 500 Hz to 1500 Hz. De-icing method according to one of claims 1 to 3, characterized in that the limit value of the ambient temperature is 5 °C and the limit value of the temperature of the stator of the electric motor is 165 °C. De-icing method according to claim 1, characterized in that the de-icing method ends when the ambient temperature or the temperature of the stator of the electric motor is not below their respective limit values ​​or the electric motor is not blocked. De-icing method according to claim 1, characterized in that a circuit of the electric motor comprises a first bridge branch connected to a first winding (U), a second bridge branch connected to a second winding (V), and a third bridge branch connected to a third winding (W), wherein the first bridge branch comprises a first switching transistor (Q1) and a second switching transistor (Q2), wherein the second bridge branch comprises a third switching transistor (Q3) and a fourth switching transistor (Q4), wherein the third bridge branch comprises a fifth switching transistor (Q5) and a sixth switching transistor (Q6), and wherein, for the generation of heat by the electric motor, the electric motor is further controlled such that the coils are heated in the following periodic sub-steps: in a first sub-step: switching the circuit at a predefined frequency between a state,in which only the first and fourth switching transistors are switched on, and a state in which only the second and third switching transistors are switched on; in a second sub-step: switching the circuit at a predefined frequency between a state in which only the first and sixth switching transistors are switched on, and a state in which only the second and fifth switching transistors are switched on; and in a third sub-step: switching the circuit at a predefined frequency between a state in which only the third and sixth switching transistors are switched on, and a state in which only the fourth and fifth switching transistors are switched on. De-icing method according to claim 1, characterized in that the de-icing method further comprises terminating the de-icing method after a maximum of three de-icing cycles. De-icing method according to claim 1, characterized in that the output part is an impeller (331) connected to the transmission shaft, and the de-icing method is suitable for removing the ice formed between the impeller and a circulating pump housing (334) surrounding the impeller. Electric motor, characterized in that the electric motor comprises a stator, a rotor, a gear shaft and a control unit, wherein the control unit is suitable for carrying out the de-icing method according to one of claims 1 to 8. Computer program product comprising a computer program, characterized in that the computer program, when executed by a processor, is used to implement the de-icing method according to one of claims 1 to 8.

Images