KR20140080439A - Method for detecting a compressor surge of an electrically driven compressor, and fuel cell system having an electrically driven compressor and a control device for performing the method - Google Patents

Abstract

The present invention relates to a method for detecting a compressor surge of an electrically driven compressor (18). The present invention also relates to a fuel cell system (10) including a fuel cell (12), a compressor (18), a turbo charger (34), a control device (36), and a driving device (26) for driving the compressor (18). The control device (36) performs the method for detecting a compressor surge. The compressor (18) includes the electrically driving device (26) for driving the compressor (18). The driving device (26) generates driving torque (MM).

Description

TECHNICAL FIELD [0001] The present invention relates to a method for detecting a compressor surge in an electric drive type compressor, and a fuel cell system including an electric drive type compressor and a control device for implementing the method. COMPRESSOR AND A CONTROL DEVICE FOR PERFORMING THE METHOD}

The present invention relates to a method for detecting a compressor surge of an electrically driven compressor, and to a fuel cell system including an electrically driven compressor and a control device for implementing the method.

Compressors are used in a variety of ways. In the case of fuel cell systems or internal combustion engines, for example in order to increase the output, the air filling of the combustion chamber of the internal combustion engine or fuel cell is increased by the use of a compressor such as a turbocharger. The pressure at which the air is compressed in the combustion chamber of the internal combustion engine or the fuel cell is also referred to as the air supply pressure and is generally measured by a pressure sensor near the combustion chamber. The pressure signal is supplied to the closed control circuit, which controls the turbocharger and sets the predetermined supply pressure accordingly.

The turbochargers have distinct time constants, that is to say they respond in a relatively time delayed manner to the modified control signals, which makes control of the supply air pressure difficult. Therefore, preferably, a direct state variable of the turbocharger to be controlled is detected. For this purpose, the rotational speed of the compressor of the turbocharger is particularly suitable. It is particularly important to know the compressor rotational speed, since a certain maximum rotational speed threshold must not be exceeded during operation of the turbocharger, otherwise an excess of the threshold voltage in the compressor impeller and a rotor in contact with the housing Because the deformation of the compressor impeller can damage the turbocharger.

The compressor rotational speed can be calculated using a known compressor map if certain variables, such as, for example, front and rear pressure of the compressor, air mass flow rate through the compressor, and temperature at the front of the compressor are known. Based on these variables, the position of the operating point in the compressor map and accordingly the rotational speed of the compressor are known, without the need to use a sensor for rotational speed measurement.

However, high compressor speeds can cause so-called compressor surges. The so-called compressor surge is a phenomenon that occurs when the pressure ratio is too high at a given rotational speed in the case of a turbo machine. In this case, flow separation occurs which causes vibration of the compressor blades, and this vibration causes destruction of the turbo machine. Therefore, operation in surge or above surge limit should be avoided in any case.

The surge limit detection for the compressor is generally accomplished through the detection of the pressure value and the air mass flow value and the comparison of the above values for the surge characteristic curve detected by the high resolution pressure sensor device at the test strips. As an alternative to this, the surge during operation is identified from the measured pressure fluctuations.

In the vehicle, the surge region is prevented through supply air pressure control. In the case of internal combustion engines, compressor surge is prevented, for example by using wastegate valves that limit the rotational speed of the turbocharger and hence the compressor pressure by guiding a portion of the exhaust gas past the turbine. If an excess of the surge limit is to be prevented by the characteristic curve pre-entered with the data, for example, a high altitude area running with reduced ambient pressure, interference of flow by the inhaled contaminants, an added air filter, undesirable operating points In order to prevent surges, it is necessary to adhere to the safety margin in all operating conditions such as, for example, and considering expansion of the temporary standard factory model. This limits the operating range of the compressor.

Also, the operation of the compressor near the surge limit may be important, depending on the application. Because the turbo compressor for fuel cell applications has its efficiency maximum near the surge limit, for example, optimal fuel consumption can only be achieved when operating near the surge limit.

DE 602 22 525 T2 describes, for example, a method for controlling the supply air pressure of a supercharged internal combustion engine, in which case the surge limit is recorded in the map, and the pressure ratio is based on representative parameters for the air flow rate through the compressor It can be determined whether or not the surge limit is exceeded.

Despite the numerous advantages of the methods known from the prior art for controlling the supply air pressure, the methods still have room for improvement.

Thus, in the last mentioned prior art, the creation of a map is complicated because of the detection of pressure values and air mass flow values and the comparison of the values for the surge characteristic curve detected by the high resolution pressure sensor device The creation of the map must be performed. In addition, the above-described surge detection from the measured pressure fluctuation is an indirect detection of the surge phenomenon. By reversing the air mass flow rate, the pressure in the volumes decreases. Since the intensity and speed of the reduction depends on the positioning of the corresponding system and pressure sensor, it must be reanalyzed and entered as data for each configuration. This again leads to a safety margin and additional data entry costs that can not be ignored for surge limits. Overall, the detection and prevention of compressor surges in electrically driven compressors is also expensive due to the additional sensor devices required.

It is an object of the present invention to enable direct detection of a compressor surge through a sensor device provided in an electronic output device of an electrically driven compressor and thus to provide a supply pressure control in connection with the prevention of compressor surges without additional sensors Thereby realizing improvement.

Accordingly, it is an object of the present invention to provide a compressor surge of an electrically driven compressor which can at least largely avoid the disadvantages of known methods and strategies for determining a compressor surge and which in particular can prevent or at least significantly reduce the aforementioned safety margin for the surge limit of the compressor. A fuel cell system including a method for detecting a fuel cell and a control device for implementing the method is presented. It is an object of the present invention to enable direct detection of a compressor surge through a sensor arrangement provided in an electronic output device of an electrically driven compressor and thus to provide a supply pressure control in connection with the prevention of compressor surges without additional sensors . Accordingly, the basic idea is to detect the compressor surge of an electrically driven compressor using sensors provided for operation of the compressor.

A method according to the invention for detecting a compressor surge of an electrically driven compressor, the compressor comprising an electric drive for driving a compressor, the control part of the drive device being configured to generate a drive torque, The method comprising the steps of: determining a drive torque of the drive based on a set rotational speed of the compressor; and determining the drive torque of the drive based on the set rotational speed of the compressor, A determining step of determining a current, a generating step of generating a voltage for driving the driving device based on the set current, a determining step of determining an actual current of the driving device and an actual rotating speed of the compressor, Based on the torque of the drive device, which is generated as a result of the drive torque and the load torque And a detecting step of detecting a compressor surge based on the set rotation speed and the set current based on the change in the resulting torque and the determining step.

The compressor surge can be detected when the set rotation speed and the set current change below the threshold value.

The threshold value of the change of the set rotation speed and the set current may be substantially zero.

In addition, in the case of the method of the present invention, a change with time of the set current per unit time and the set rotation speed can be determined.

The set current can be a set 3-phase alternating current.

By setting three-phase alternating current, phase voltages can be set. In addition, actual three-phase alternating currents can be detected.

The control unit may be configured to match the drive torque to the load torque of the shaft of the compressor.

The set rotational speed can be preset based on the external control parameter. The external control parameter may be, for example, a set fluid mass flow rate through the compressor.

A fuel cell system according to the present invention includes a fuel cell, a compressor, a drive device for electrically driving the compressor, and a control device. The control device is adapted to carry out the method according to the invention.

The fuel cell may be configured to drive a driving device of an automobile.

The control device can preset the set rotation speed of the compressor based on the set air mass flow rate.

The set air mass flow rate can be determined based on the output demand of the drive device of the vehicle.

The compressor can be connected to an exhaust gas turbine which can be driven by the exhaust gas mass flow rate of the fuel cell.

The fuel cell means, in the scope of the present invention, a galvanic cell that converts the chemical reaction energy of a fuel and an oxidant supplied thereto continuously or discontinuously into electrical energy. Fuel cells typically consist of electrodes separated from each other by a membrane or an electrolyte (ion conductor). The electrodes are usually made of metal or carbon nanotubes and coated with a catalyst such as platinum or palladium. As the electrolyte, for example, dissolved alkali or acid, alkali carbonate melt, ceramic or membrane may be used. The energy is supplied, for example, by the reaction of oxygen with fuel, which may be hydrogen or an organic compound such as, for example, methane or methanol. The two relative reactants are fed continuously through the electrodes.

The pressure ratio of the compressor means the share of the compressor outlet pressure with respect to the compressor inlet pressure in the scope of the present invention. In other words, the pressure of the air flowing in the direction from the compressor toward the combustion chamber Quot;

The critical pressure ratio means a pressure ratio at which the damage to the compressor can be caused through the surge in the range of the present invention. In this case, the limiting pressure ratio may be determined not only to correspond to the surge limit exactly, that is, to correspond to the limit at which the surge of the compressor will occur, but may also be determined by the safety margin for the surge limit.

The change with time of the set current and / or the set rotation speed means within the scope of the present invention, the absolute value of the change of the signals within a certain time, and the slope, that is, the derivative of the signal with time.

The reference pressure means, within the scope of the present invention, the air pressure associated with elevation above sea level. The reference pressure is generally about 1 bar.

The reference temperature means the ambient temperature of the fuel cell system within the scope of the present invention. The reference temperature is generally about 20 ° C.

This surge, also referred to as a surge of a compressor, or simply a compressor surge, means, within the scope of the present invention, an operational condition potentially dangerous to the structural integrity of the compressor. Within the compressor, the pressure of the incoming working medium, which may be air in the field of the present invention, is stepped up by a plurality of compressor stages. It can now be seen that the flow stalls and turbulence occurs in the compressor blades of the compressor. In this case, the compressor output is reduced. When the pressure formed at the downstream side of the compressor, or at the back thereof, exceeds the pressure generated by the compressor, the effect of reversing the flow of the air occurs. In this backwash, the pressure behind the compressor outlet is reduced, and the flow is again directed in the opposite direction, again flowing out of the compressor outlet in its original direction. The interaction of these air mass flows is called surge, which can result in significant periodic loading of the compressor and can cause compressor failure. Measures to reduce this behavior are called anti surge measures.

The driving torque means the torque generated by the driving device within the scope of the present invention. For example, the drive torque may be measured on the shaft of the drive. The driving device may be an electric motor such as an alternating-current motor in the sense of the present invention.

In the sense of the present invention, the load torque means a torque against a drive device generated by a compressor, and is also referred to as a counter torque.

The resulting torque is, within the scope of the present invention, the torque of the drive, such as, for example, at the shaft, corresponding to the difference between the drive torque and the load torque. Depending on the sign, the resulting torque causes acceleration or deceleration of the rotor or compressor of the electric drive.

According to the present invention, a compressor surge is detected using a sensor device provided in an electronic output device of an electrically driven compressor. Accordingly, in view of the prevention of the compressor surge, the supply air pressure control can be substantially improved without mounting additional sensors. The advantage is that the use of the operating range of the compressor is improved, without the risk of damage. The compressor whose rotational speed is controlled includes a cascaded control section, the external control circuit controls the rotational speed, and the internal control circuit controls the current and thus the torque. This type of compressor can be used, for example, in a fuel cell system. The compressor is configured to compress air or oxygen to be supplied to the fuel cell, for example.

In the case of this type of compressor, the current controller uses the phase voltages to set the phase currents, i. E., The actual phase currents. The current in the phases produces a torque at the shaft which inhibits the load torque produced by the compressor in this case. The resulting torque at the shaft corresponding to the difference between the motor torque and the load torque causes acceleration or braking of the rotor or compressor depending on the sign. The upper rotation speed control device attempts to control the predetermined rotation speed setting value by presetting the current and the torque corresponding thereto in the lower control section.

In the so-called compressor surge, there is a very strong change in the mass flow rate, which also affects the pressure. In addition, the change directly affects the load torque. The load torque fluctuates particularly strongly in the surge region despite a constant rotational speed. This is the direct impact of the compressor bibliography.

The internal rotation speed control section of the electrically driven turbo compressor tries to control the predetermined rotation speed by matching the motor torque to the load torque. Due to the small time constant of the current, this takes only a few milliseconds. Conversely, surge phenomena have much slower dynamics. Finally, from the information of the set rotational speed and the set current in the electronic output apparatus, the validity of whether or not strong fluctuations of the torque are based on the rotational speed fluctuation or on the compressor surge can be checked. Finally, countermeasures such as the opening of the system bypass, for example, can be made through the corresponding message supply to higher level control devices.

Thus, a substantial advantage of the present invention is that utilization of the operating range of the compressor is improved without risk of damage, for example.

Other optional details and features of the present invention are set forth in the following description of the preferred embodiments, which are schematically illustrated in the drawings.
1 is a schematic view of the configuration of a fuel cell system.
2 is a schematic diagram of a control unit according to the present invention.
3 is a schematic graph of mass flow during compressor surge;
4 is a schematic graph of pressure front and rear of the compressor during compressor surge;
5 is a schematic graph of the compressor output during compressor surge;
6 is a schematic graph of the load torque during compressor surge;

1, a fuel cell system 10 according to the present invention is shown. The fuel cell system 10 includes a fuel cell 12, an air supply line 14, an exhaust gas line 16, a compressor 18, an exhaust gas turbine 20, Pass valve 22 and a feed line not shown in detail for the fuel to the fuel cell 12. The bypass valve 22 may be, for example, a butterfly valve. As the bypass valve 22, for example, a waste gate valve may be used. The fuel cell 12 has a chemical reaction energy of the fuel supplied through the fuel supply line not shown and the oxidant, which is the intake air supplied to the fuel cell 12 through the air supply line 14 in the case of the illustrated embodiment, It is a galvanic cell that converts into electric energy. The fuel can be hydrogen, methane or methanol. Correspondingly, steam is generated as exhaust gas, or steam and carbon dioxide are generated. The fuel cell 12 is configured, for example, to drive a drive device of an automobile. For example, the electric energy generated through the fuel cell 12 drives the electric motor of the automobile.

The compressor 18 is disposed in the air supply line 14. An exhaust gas turbine (20) is disposed in the exhaust gas line (16). The compressor (18) and the exhaust gas turbine (20) are mechanically connected via a shaft (24). The shaft 24 may be electrically driven by a drive device 26. [ The exhaust gas turbine 20 is used to support a drive device 26 for driving the compressor 18. Further, in the air supply line 14, an air mass sensor 28 and / or a pressure sensor 30 are disposed upstream of the compressor 18, and / or a pressure sensor 32 is disposed in the compressor 18, As shown in FIG. The air mass sensor 28 and the pressure sensor 30 are purely optional so that the method described in detail below can be implemented without the air mass sensor and the pressure sensor. The compressor 18, the shaft 24 and the exhaust gas turbine 20 together form a turbocharger 34. In addition, the fuel cell system 10 also includes a control device 36, or simply, The control device 36 is configured to implement the method according to the invention for detecting the compressor surge of the compressor 18, which is described in detail below.

2, the basic principle of the control unit according to the present invention of the mass flow rate in the fuel cell of the fuel cell system 10 is shown. Based on the external control parameter, the set rotational speed n * of the compressor 18 is preset. For example, the external control parameter is the set fluid mass flow rate through the compressor 18. For the illustrated embodiment using the fuel cell system 10 in the vehicle, the control device 36 can preset the set rotational speed n * of the compressor 18 based on the set air mass flow rate. The set air mass flow rate can be determined based on the required output of the fuel cell 12. If the car is to be accelerated, for example, the output demand will increase. In order for the fuel cell 12 to be able to supply the elevated electrical output, the fuel cell 12 requires a higher air mass flow rate. The higher air mass flow rate can be supplied, for example, through the higher rotational speed of the compressor 18. [

The set rotation speed n * is used as a basis for determining the set current I * for the drive device 26 of the compressor 18 within the speed control section 38 of the control device 36. [ In this case, the set current I * can be given as a set three-phase alternating current. The set three-phase alternating current may comprise, for example, set phase currents I _a *, I _b *, I _c *. The set phase currents I _a *, I _b * and I _c * are applied to a drive device 26 for driving the shaft 24 of the compressor 18, in the current control section 40 of the control device 36. To the corresponding phase voltages U _a , U _b , and U _c that are applied to the first and second input terminals. In the electric drive 26, actual phase currents I _a , I _b , I _c are detected in the drive section 42 of the control device 36, Is supplied to the section (40). In other words, the current control section 40 sets the actual phase currents I _a , I _b , I _c using the phase voltages U _a , U _b , and U _c . Thus, based on the set rotation speed n *, the set torque that the drive device 26 supplies on the shaft 24 is determined. The currents in the phases of the phase voltages U _a , U _b and U _c produce a drive torque M _M supplied onto the shaft 24 of the drive 26. The shaft 24 provides a load torque M _{L L} for the required drive torque M _M. The control unit is configured to match the drive torque M _M to the load torque M _L acting on the drive unit 26. In particular, the control unit is configured to match the drive torque M _M to the load torque M _L of the shaft 24 of the compressor 18. [ The matching means that the drive sets the drive torque M _M corresponding to the load note M _L so as to maintain the set rotation speed n *. The drive torque M _M as well as the load torque M _L are then considered to generate the torque M _R resulting from rotating the shaft 24. The resulting torque M _R arises from the difference between the drive torque M _M and the load torque M _L. Acceleration or braking of the rotor of the drive unit 26 is performed in accordance with the sign of the resulting torque M _R. The resulting torque M _R thus rotates the shaft 24 at a specific actual rotational speed n . Thereby, since the compressor 18 is connected to the shaft 24, the compressor 18 also rotates at the actual rotational speed n . The actual rotation speed n is again detected in the speed detection section 44 of the control device 36. [ Then, the detected actual rotation speed n is supplied again to the speed control section 38 of the control device 36. [ In the case of the method according to the invention for controlling the mass flow rate of the fuel cell 12 of the fuel cell system 10, the compressor surge is based on a change in the resulting torque M _R , , The set rotation speed ( n *), and the set current ( I *). First, however, within the scope of the present invention, the reason why the compressor surge can be detected only by the sensors used during the operation of the electrically driven compressor 18, without requiring additional sensors, is explained. First of all, the phenomenon of the compressor surge acting on the signals of the various sensors is illustrated illustratively. It should be emphasized that the curves shown in Figs. 3-6 are exemplary and only the compressor surge is described as such, but it need not necessarily be a component of the method according to the invention.

In Fig. 3, as an example, a flow signal indicative of an air mass flow rate, such as that detected by an air mass sensor 28, is shown. 3, the time in seconds is indicated on the X-axis 46 and the calibrated air mass flow rate W * in g / s on the Y-axis 48. The air mass flow rate W can be corrected in relation to the reference temperature T _REF and the reference pressure P _REF to form the corrected air mass flow rate W *. This can be performed, for example, by the following equation.

The parameters T _IN and P _IN represent the temperature and pressure of the air at the inlet of the compressor 18, respectively. The reference temperature (T _REF ) is in the range of the normal ambient temperature, as mentioned above, and the reference pressure (P _REF ) is the air pressure associated with the elevation. In the graph of Fig. 3, the calibrated air mass flow rate (W *) is expressed in g / s.

As shown in Fig. 3, very strong fluctuations of the air mass flow W during the compressor surge can occur. During the operation of the surgeon compressor 18, the flow signal of the air mass sensor 26 is immediately abruptly dropped due to a change in the direction of the intake air, as can be seen, for example, at the position indicated by 50 in Fig. 3, Air mass flow rate (W *).

For example, in a pressure signal detected by pressure sensors 30 or 32, this type of compressor surge appears, as described below with reference to Fig. In FIG. 4, the time in seconds is displayed on the X-axis 52 and the pressure in Pascal is displayed on the Y-axis. In this case the curve 56 represents the pressure detected upstream of the compressor 18 by the pressure sensor 30 and the curve 58 represents the pressure detected by the pressure sensor 32 downstream of the compressor 18 . Examples of surges can be found at locations marked 60 respectively.

It will now be appreciated that, in accordance with the present invention, the air mass sensor 28 and / or the pressure sensors 30, 32 need not be used for the detection of the compressor surge, i.e. they are omitted without replacement, The compressor surge can be clearly identified by the control section. Therefore, how the compressor surge works on the control unit is explained.

Also at the compressor output P, a compressor surge of this type appears, as described below with reference to Fig. 5, the time in seconds is displayed on the X-axis 62, and the compressor output P in watts is displayed on the Y-axis. In Figure 5, the isentropic compressor output (P) is shown more accurately.

As an example, a lossless path is shown here, without taking into account the efficiency that occurs. From the measurement data, the isotropic compressor output (P) can be calculated by the following equation.

And wherein, c _p is the specific heat capacity of air at constant pressure (constant pressure), T _in is the temperature of the air at the compressor inlet, p _out is the pressure at the downstream of the compressor (18), p _in the compressor ( 18, where W is also the air mass flow rate, k is the isentropic coefficient of air, i. E., The share of c _p and c _v , where c _v is the specific heat capacity of air at a constant temperature to be. For air, k = 1.4. 5 shows, by way of example, the position 66 indicating the compressor surge in the curve of the compressor output. During the compressor surge, the air mass flow (W) fluctuates, as described above with reference to Fig. 3 as an example. Therefore, in the case of a compressor surge, the output P of the electric drive device 26 also fluctuates.

Using the angular frequency ω of the rotor of the drive 26, the lossless load torque M _L of the compressor 18 is given by the following equation:

Where n is the actual rotational speed of the compressor 18 and this actual rotational speed is equal to the rotational speed of the rotor of the drive 26 because the compressor and drive are connected via the shaft 24 It is because.

With reference to the curve of the load torque M _L of the compressor 18, the compressor surge can be ascertained, as will be explained with reference to Fig. 6, the time in seconds is displayed on the X-axis 68 and the load torque M _L of the compressor 18 is displayed on the Y-axis 70 in units of Nm. 6 shows, as an example, the position 72 indicating the compressor surge in the curve of the load torque M _L of the compressor 18. As shown in Fig.

From the above equations, it can be concluded that a strong fluctuation of the load torque M _L can occur as a result of a change in the set rotational speed n *, or as a result of a compressor surge. This conclusion is determined according to the compressor output P which can be varied by two variables, that is, the air mass flow rate W, and the rotational speed n which can vary due to the control unit as well. Finally, from the information of the set rotation speed n * and the set current I * in the electronic output device, whether or not the strong fluctuation of the load torque M _L is based on the rotation speed change or on the compressor surge Can be performed. Therefore, a change in the load torque M _L causes a change in the resulting torque M _R. Now, in the case of the method according to the present invention, the compressor surge is detected when the set rotation speed n * and the threshold value of the change in the set current I * fall short of each other. For example, a change with time of the set current I * and the set rotation speed n * per unit time is determined. The threshold value of the change of the set rotation speed n * and the set current I * is, for example, substantially zero. Here, substantially 0 means that the set rotation speed n * and the set current I * are substantially constant and only technically inevitable changes or variations are experienced. A change of 0 means that a fixed operating point is set. Now, when a change in the resulting torque M _R occurs, this change can be clearly assigned to the compressor surge because the set rotation speed n * and the set current I * are unchanged, Is not considered as an influence variable for the change in the resulting torque ( M _R ) according to the control unit. In other words, the load torque M _L and the resulting torque M _R vary strongly despite a constant set rotational speed n * and hence a constant set current I *. Accordingly, as an influence variable on the fluctuating load torque M _L , only the output P that varies depending on the fluctuating air mass flow rate W caused by the compressor surge is considered. When the compressor surge is detected according to the above method, a lower set rotational speed n * is preset by the control device 36. [ In addition, the bypass valve 22 can be opened.

The communication of the compressor 18 with the control device 36 may be performed by an interface useful in the vehicle, for example, a Controller Area Network (CAN) in the above embodiment. The data provided by the electronic output device can be recorded and evaluated during compressor surge. For example, through comparison with data of other sensors such as air mass sensor 28 and / or pressure sensors 30, 32, the information of the compressor surge can be more accurately identified.

It is emphasized that the method according to the present invention is not limited to the application to the electrically driven compressor 18 of the fuel cell system 10. For example, the electrically driven compressor 18 may be used in an internal combustion engine as well. The above-described control is not limited to the control of the air mass flow rate. Alternatively, it is contemplated that pressure control, pure control using characteristic curves of air mass flow / pressure at the inlet of compressor 18, or discrete load level presets.

10 Fuel cell system
12 Fuel cell
18 Compressor
20 Exhaust gas turbine
26 drive
34 Turbocharger
36 Control unit, control unit
I actual current
I * Setting current
M _L Load torque
M _M Drive torque
M _{R The} resulting torque
n Actual rotational speed
n * Set rotation speed
U voltage

Claims (14)

A method for detecting a compressor surge of an electrically driven compressor (18), the compressor (18) comprising an electric drive (26) for driving the compressor (18) And to generate a torque M _M ,
Control unit 36 is the drive torque (M _M) of the load torque, the drive torque is configured to match the (M _M), the drive means 26 to the (M _L) acting on the drive means 26 is a set current (I *) of the compressor 18 is determined to be set based on the rotational speed (n *), of the drive system 26 is in the set based on the rotational speed (n *) of the compressor (18) And a voltage U for driving the driving device 26 is generated based on the set current I * so that the actual current I of the driving device 26 and the actual current I of the compressor 18 the actual rotational speed (n) is detected, and the actual rotational speed (n) of the compressor 18 is the drive assembly 26, it occurred as a result of the drive torque (M _M) and the load torque (M _L) the torque is determined based on the (M _R), wherein the compressor surge based on the change in the torque (M _R) generated as the result, and the settings The rotation speed ( n *) and the set current ( I *). The compressor surge detection method according to claim 1, wherein the compressor surge is detected when the set rotation speed ( n *) and the set current ( I *) fall below a threshold value. The compressor surge detection method according to claim 2, wherein the threshold value of the change in the set rotation speed ( n *) and the set current ( I *) is substantially zero. The compressor surge detection method according to any one of claims 1 to 3, wherein the change in the set current ( I *) and the set rotation speed ( n *) with respect to time is determined per unit time. The compressor surge detection method according to any one of claims 1 to 4, wherein the set current ( I *) is a set three-phase alternating current ( I _a *, I _b *, I _c *). The method of claim 5, wherein the set three-phase alternating-current _{(I a *, I b *} , I c *) of the phase voltage by a (U _a, U _b, U _c) and is set, the actual three-phase alternating-current (I _a *, I _b *, I _c *) are detected. 7. The control system according to any one of claims 1 to 6, wherein the controller (36) is arranged to match the drive torque ( M _M ) to the load torque ( M _L ) of the shaft (24) Wherein the compressor surge detection method comprises: The compressor surge detection method according to any one of claims 1 to 7, wherein the set rotation speed ( n *) is preset based on an external control parameter. The compressor surge detection method according to claim 8, wherein said external control parameter is a set fluid mass flow rate passing through said compressor (18). In a fuel cell system 10 including a fuel cell 12, a compressor 18, a drive device 26 for electrically driving the compressor 18, and a control device 36,
The control device (36) is configured to implement the compressor surge detection method according to any one of claims 1 to 9. 11. The fuel cell system according to claim 10, wherein the fuel cell (12) is configured to drive a drive device (26) of an automobile. 12. The fuel cell system according to claim 11, wherein the control device pre-sets the set rotational speed ( n *) of the compressor (18) based on the set air mass flow rate. 13. The fuel cell system according to claim 12, wherein the set air mass flow rate is determined based on an output requirement of a drive device of a vehicle. 14. The fuel cell system according to any one of claims 10 to 13, wherein the compressor (18) is connected to an exhaust gas turbine (20) which can be driven with an exhaust gas mass flow rate of the fuel cell (12).

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