Control unit and method for controlling a hybrid apparatus for driving a rotating device

Abstract

Control unit for controlling a hybrid apparatus for driving a rotating device comprising a driven element (4), designed to be connected to a rotating element of the device; a mechanical drive (20), designed to be connected to a drive shaft (2) for receiving a rotating movement, and an electromagnetic coupling (21), which rotationally engages / disengages the movement take-up element with / from the driven element; an electric drive (30), comprising a stator (32) and a rotor (31); wherein the control unit comprises an electronic component (54) for controlling the power supply to the electric drive, and a microprocessor (52), arranged between a power supply input line (51+, 51-) and a line for powering the electric drive, an electronic switch (55) arranged between the power supply input line (51+, 51), and the electronic component (54) for controlling the power supply of the electric drive; the opening / closing of the electronic switch (55) being determined by a control signal c(t) generated by the processor (53) on the basis of a signal ms (t) representing the speed of rotation of the rotor (31) of the electric drive.

Description

[0001] CONTROL UNIT AND METHOD FOR CONTROLLING A HYBRID APPARATUS FOR DRIVING A ROTATING DEVICE

[0002] DESCRIPTION

[0003] The present invention relates to a control unit for controlling hybrid apparatus for driving a rotating device and to an associated control method.

[0004] The hybrid apparatus to which reference is made, also known as dual drive apparatus, generally comprise:

[0005] a driven element, designed to be connected to a rotating device, for rotational operation thereof;

[0006] a mechanical drive, generally comprising a movement take-up element designed to be connected to a first movement source, and an electromagnet friction coupling, which engages / disengages the movement take-up element with / from the driven element;

[0007] an electric drive, comprising a stator and a rotor, which is controlled so as to drive the driven element independently of the mechanical drive;

[0008] an electronic control unit which controls and powers the electric motor and manages the transitions from mechanical drive to electric drive or, vice versa, from electric drive to mechanical drive.

[0009] A specific example of this dual drive system is for example present in the technical sector of cooling combustion engines for vehicles for which auxiliary cooling devices are known, such as in particular the pumps for recirculating a liquid and / or the fans for cooling the liquid contained inside a radiator; in these cases: the driven element consists of a rotor designed to be connected to the impeller of the water pump or to the fan of the auxiliary device so as to cause the rotation thereof;

[0010] the mechanical drive generally comprises a movement take-up element designed to be connected to a drive shaft in order to receive a rotating movement correlated to the revolutions of the engine itself, and an electromagnetic friction coupling which rotationally engages / disengages the movement take-up element with / from the driven element.

[0011] It is also known that the cooling must be performed with a flowrate corresponding to the real cooling requirement determined by the real conditions of use of the engine and by the external temperature, in order to avoid the constant and unnecessary operation at full speed of devices which draw useful power and thereby increase the wear of the various component parts and the fuel consumption of the vehicle.

[0012] For this purpose, the auxiliary hybrid devices may be operated by means of engagement of the electromagnetic friction coupling for transmission of a rotating movement depending on the revolutions of the drive shaft, or by means of the electric motor which instead is operated, when the friction coupling is disengaged, for rotation of the impeller or fan independently of the drive shaft and with a controlled number of revolutions.

[0013] Examples of auxiliary hybrid devices are for example known from WO2018229705 A1, WO2018229669 A1 and WO2020261077 A1 which describe hybrid drive apparatus in which a rotor of the electric drive is coupled to the driven element, and therefore made to rotate, even when the mechanical drive is engage.

[0014] In these conditions where the electric rotor is rotationally driven also during operation of the mechanical drive there is the generation of a counter-electromotive force (also known as BEMF -back electromotive force), namely a voltage which is generated at the terminals of a winding crossed by a variable magnetic field, causing a drop in voltage at the terminals of the electric rotor or stator when the rotor is driven by the mechanical drive.

[0015] Said force (BEMF) may be transmitted to all the devices connected to the upstream stages of the system, including the electronic control and the power supply source (battery) of the electric motor, resulting in significant problems if not suitably managed.

[0016] The counter-electromotive force may moreover be propagated to the stages connected to the electric drive and cause malfunctioning or damage to the electronic components, including the electronic control unit connected to a power supply source, such as the battery itself, which provides the power supply for rotationally driving the driven element independently of the mechanical drive and the speed of rotation of the drive shaft.

[0017] A further critical condition may arise at the high speeds of rotation of the drive shaft, i. e. a condition where the counter-electromotive force generated could even subject the battery to a load in a manner similar to that of an alternator, resulting in a voltage higher than the charging capacity of the battery itself.

[0018] The technical problem which is posed, therefore, is to provide a method and apparatus for controlling the hybrid operation of rotating elements able to manage efficiently the counter-electromotive force and prevent damage to the electronic components and to the other devices connected thereto.

[0019] A particular object of the present invention is to provide a control method which is safer and more reliable, namely is able to prevent the counterelectromotive force from exceeding predefined safety values during the transition from electric drive to mechanical drive or vice versa from mechanical drive to electric drive.

[0020] During the transitions, in fact, increased risks arise since:

[0021] during the switch-over from electric to mechanical the mechanical rotor quickly adds its effects to the electric rotor generating the BEMF and exceeding the capacity of the battery; during the switch-over from mechanical to electric the reduction in the speed of the mechanical rotor is not instantaneous and it is therefore still necessary to protect the battery until a speed of the electric motor alone is reached.

[0022] In connection with this problem it is also required that the control method and the control unit should be simple and inexpensive to realize and do not give rise to further risks of breakages or malfunctions.

[0023] It is also required the control unit should be easy and inexpensive to produce and assemble and be able to be easily installed on existing devices without the need for special adaptation.

[0024] These results are obtained according to the present invention by a control unit for controlling hybrid apparatus for driving rotating elements according to Claim 1.

[0025] The present invention also relates to a method for controlling a control unit for hybrid apparatus for driving the rotating elements according to Claim 18.

[0026] Preferred embodiments are described in the dependent claims.

[0027] Further details may be obtained from the following description of a non-limiting example of embodiment of the subject-matter of the present invention relating, solely for clearer description, to the driving and control of auxiliary devices for cooling vehicle engines, provided with reference to the attached drawings in which:

[0028] - Figure 1 shows a schematic view of an example of embodiment of a hybrid apparatus for driving an auxiliary cooling device for a motor vehicle, controlled according to the present invention;

[0029] - Figure 2 shows a diagram illustrating a preferred example of embodiment of the control method according to the present invention;

[0030] - Figure 3a shows a block diagram of a further embodiment of the control method according to the invention for a closed electronic switch;

[0031] - Figure 3b shows a block diagram of a further embodiment of the control method according for an open electronic switch; and

[0032] - Figure 4 shows a diagram of the progression of the speed of rotation of the driven element determined by the control unit during operation of the mechanical drive or electric drive.

[0033] As shown in Fig. 1, the operating diagram of a hybrid drive apparatus for an auxiliary cooling device of a motor vehicle comprises: - a driven element 4 designed to be connected to a rotating element of the auxiliary device; in the specific example, the driven element 4 may be a drive shaft for the impeller of a pump or the support of a cooling fan hub;

[0034] - a mechanical drive 20 arranged between the driven element 4 and a drive shaft 2, which may be for example a shaft rotationally driven by means of an internal-combustion engine; the mechanical drive 20 comprises a movement take-up element, for example in the form of a pulley 5 connected to the drive shaft 2 by means of a drive belt 3 for receiving the rotational movement;

[0035] - an electromagnetic friction coupling 21 designed to engage / disengage rotationally the movement takeup element 5 with / from the driven element 4 in a mechanical drive mode so that, when the coupling is engaged, the driven element 4 is rotationally driven with a number of revolutions proportional to the rotational speed of the movement take-up element 5 and the drive shaft 2;

[0036] - an electric drive 30, comprising a stator 32 and a rotor 31 which is rotationally connected to the driven element 4; in particular, the rotor 31 may be integrally joined to a bell member in turn fastened to a driven shaft, as for example in the pump drive apparatus described in W02020261077A1. The electric drive 30 can be controlled so as to rotationally drive the driven element 4 independently of the mechanical drive and the rotational speed of the drive shaft and is for this purpose connected to an electronic control unit 50 which controls and powers the electric drive and manages the transitions between the mechanical drive mode 20 and an electric drive mode 30. The electronic control unit 50 comprises a processor 52, an electric power supply input line 51+, 51-, an electric power supply output 56 for supplying the stator 32, and an electronic component 54 for controlling the power supply of the electric drive, arranged between the power supply input line 51 +, 51- and the output line 56 for driving the stator.

[0037] The control component 54 is preferably an H-bridge, i. e. a circuit formed by a number of electronic switches, proportional to the number of phases of the electric motor, which control the load. The switches are controlled by the processor 52 by means of a power amplifier 53 (or gate driver) which amplifies the control signal (usually output by the processor) and controls the load with the correct voltage / current levels for switching on and off the phases of the motor for controlling the output 56 for driving the electric motor 30 so as to adjust, among other things, the direction of rotation and the speed of rotation of the electric rotor.

[0038] An electronic switch 55 is arranged between the power supply input line 51+, 51- and the electronic control component 54 and is controlled by the processor 52 so as to open or close the electric connection between the power supply input line 51+, 51- and the electronic control component 54, depending on a control signal c (t) generated by the processor 52.

[0039] The electronic switch 55 may for example consist of a bipolar junction transistor (BJT), MOSFET or a voltage and switching speed control device IGBT. Preferably, a power supply 52a for the processor 52 and the components of the control unit 50 is provided independently of the state of the electronic switch 55 and may be preferably derived from the power supply input line 51 +, upstream of the electronic switch, or derived from a dedicated power supply line, for example connected to the enable / key command device of the vehicle in order to keep the cooling active for a predetermined period of time, also when the engine is switched off in order to prevent dangerous heat surges.

[0040] With reference to Figs. 1 and 2, the electronic control unit 50 detects, by means of a measurement module 57, a feedback signal supplied by the electric drive 30, from which a signal ms (t) for measuring over time the speed of rotation of the rotor 31 of the electric motor is obtained. The speed of rotation ms (t) of the electric rotor is measured over time continuously, even when the electric motor is disabled by operation of the rotating element of the auxiliary device, with the control unit 50 being continuously informed of the position over time of the rotor 32, namely of the magnets which generate the magnetic field, allowing substantially continuous switching (i. e. without a high overshoot or undershoot ) between the mechanical drive and electric drive (so-called "catch-on-fly") in order to avoid the said problems during switch-over.

[0041] The detection modes for obtaining the measurement signal ms (t ) for the speed of rotation of the electric rotor may be many.

[0042] In the case of an electric motor 30 of the so-called "sensored" type, such as a BDLC (Brushless-DC), the position of the rotor is defined instant-by-instant by a position detector (resolver, encoder or Hall sensors ) present in the motor 30 itself, and the measurement signal ms (t) for the speed of rotation may be obtained by the processor 52 from the position signal detected.

[0043] In the case of so-called "sensorless" motors, namely motors without a rotor position sensor / detector, preferably a measurement ms (t) of the speed of rotation of the rotor 31 is estimated on the basis of a measurement or estimate of the counter-electromotive force BEMF (t ) present at each instant on the power supply inputs of the motor 30. In greater detail, in the case of trapezoidal control, for motors where only two phases out of three are simultaneously powered, it is possible to read at each instant the counter-electromotive force BEMF (t) on the phase which is not powered. As is known to the person skilled in the art, knowing the electric characteristics of the motor (resistance, inductance and concatenated flow) it is possible to solve the equations of a simplified model of the motor and estimate the speed of rotation of its rotor by means of mathematical operations.

[0044] In the example shown, the speed of rotation ms which is estimated (and therefore no longer measured over time) can be obtained from the frequency of the voltage signal BEMF (t ), for example using the formula:

[0045] ms = BEMF (f) / No. polar pairs

[0046] In the case of FOC (Field Oriented Control), as for example in PMSM motors, it is possible to estimate the BEMF (t) from the reading of the phase current and voltage of the motor.

[0047] Depending on the specific application and the design choice of the design engineer, the measurement module 57 may include hardware and / or software components of the unit 50; in some embodiments, the measurement module includes at least two, preferably three, current sensors designed to detect the phase current of the electric motor 30. The processing of the aforementioned signals in order to obtain the measurement signal ms (t) for the speed of the rotor 31 may be performed by the microprocessor 52 which may include, in order to speed up the calculations, a dedicated unit for the mathematical calculations or DSP.

[0048] With this arrangement, the electronic control unit 50 is configured to implement a method for controlling the hybrid drive apparatus according to a control logic which involves generating the control signal c (t) for opening or closing the electronic switch at least partly depending on a measured speed of rotation ms (t) of the rotor 31 of the electric drive 30.

[0049] In particular, as for example shown in Fig. 2, the control signal c (t) for the electronic switch 55 generated by the processor 52 is a feedback control signal based on a logic with one or more conditions for comparison of a parameter correlated to the measured speed of rotation ms (t) and a respective threshold value.

[0050] According to a first example of a condition which realizes instant-by-instant a comparison between the measured speed of rotation ms (t) of the rotor 31 and a predefined threshold value, for generation of a signal for controlling opening or closing of the electronic switch, the threshold value is preferably set so as to be proportional to a predefined maximum number of revolutions of the rotor (EMotor_max_speed) compatible with the electric drive.

[0051] In some embodiments the control signal may also be based on a signal indicating an engaged / disengaged condition of the electromagnetic coupling.

[0052] Preferred embodiments for generating a control signal are described below and involve keeping the electronic switch 55 closed so that, for protection against BEMF, the control signal c (t ) causes opening of the switch 55.

[0053] Once the microprocessor has acquired using conventional technology the closed switch condition 55, opening of the electronic switch, namely isolation of the electric drive from the upstream power supply source, is performed; the logic may be summarised as follows:

[0054] Proportional

[0055] If

[0056] Measured_Speed > EMotor_max_speed x kp wherein kp is a predefined arbitrary constant and

[0057] Measured_Speed represents the value of the signal ms (t) at the instant t of interest then the control unit generates a control signal for opening the electronic switch 55.

[0058] Derivative

[0059] As shown in Fig. 2, in preferred embodiments, the logic also includes a derivative control condition which comprises in particular a comparison between the value of a function derived over time of the measured speed of rotation ms (t)

[0060] ∂(Measured_Speed) / ∂t and a respective threshold value kd.

[0061] For the generation of a control signal for opening the electronic switch at a certain time instant, namely for isolation of the electric drive from the upstream power supply source said logic may be summarised as follows:

[0062] If

[0063] Measured_Speed > EMotor_max_speed x kp If

[0064] ∂(Measured_Speed) / ∂t > kd wherein the coefficients kp and kd are predefined arbitrary constants,

[0065] then a control signal for opening the switch 55 is generated.

[0066] Integrative

[0067] In even more preferable embodiments, the control logic is of the at least triple condition type and also comprises a condition which also considers a function

[0068] ∫(Measured_Speed)∂t integral over time of the measured speed of rotation ms(t);

[0069] by comparing the value of the integral function of the signal ms (t) within a certain time interval t2-tl, included between a current instant t2 of interest and a prior instant tl, with a respective threshold value the control unit is able to operate the electronic switch 55 in an intelligent and reliable manner, practically predicting the future BEMF values.

[0070] According to a further embodiment (not shown) the electronic switch 55 is operated on the basis of a logic with two proportional-integrative conditions, whereby:

[0071] If

[0072] Measured_Speed > EMotor_max_speed x kp wherein kp is a predefined arbitrary constant and

[0073] Measured_Speed represents the value of the signal ms (t) at the instant t of interest and

[0074] If

[0075] ∫(Measured_Speed)∂t > ki wherein the coefficients kp, ki are predefined arbitrary constants,

[0076] then a control signal for opening the switch 55 is generated.

[0077] In the embodiment of Fig. 2, the diagram of a method is schematically shown whereby, for opening of the electronic switch, a triple condition logic also comprising an integrative check is applied:

[0078] If

[0079] Measured_Speed > (EMotor_max_speed x kp) or fixed threshold

[0080] If

[0081] ∂(Measured_Speed) / ∂t > kd

[0082] If

[0083] J"(Measured_Speed) d t > ki

[0084] wherein the coefficients kp, ki and kd are predefined arbitrary constants,

[0085] then a control signal for opening the switch 55 is generated.

[0086] In general, the coefficients kp, ki and kd are to be regarded as arbitrary constants and may be calibrated by the person skilled in the art in accordance with the specific application and the operating conditions of the system (mainly inertia and load torque). Said calibration, even if it requires calculations or measurements which are time-consuming and resource-intensive, falls within the normal design capabilities of the technical expert.

[0087] The integration range t2-tl may also be chosen by the technical expert depending on the operating conditions and characteristics of the electric drive and device. The wider the range, the more the system has a greater historical memory and is less sensitive to the derivative component, avoiding undesirable responses in the event of an increase in the signal ms (t) due to noise / disturbance. The widening of the integration range results, however, in a slowing down of the reaction speed of the control unit 50.

[0088] Basically, measuring the speed of the motor also during the generator phase and analysing it mathematically using the derivative and / or integral function allows the direction and rate of change of the aforementioned parameter to be understood.

[0089] In particular, if the derivative of the speed of rotation is positive, the speed is also increasing rapidly and becoming greater than a certain threshold.

[0090] Moreover, by also resolving the integral within a certain prior time interval, the control unit is able to evaluate also the value of the energy of the aforementioned signal, obtaining a historical memory which allows it to determine whether the increase detected is a temporary spike or a real increase.

[0091] The preferred embodiments described above avoid delays in the control dynamics of the switch-over between mechanical drive and electric drive, and vice versa.

[0092] The control method is however similarly applicable by setting the control unit so as to keep the electronic switch open and therefore the electric connection closed (negated logic).

[0093] The control signal c (t ) generated will therefore be a signal for closing the electronic switch 55, which restores the continuity of the electrical connection between the power supply source and the electric drive 30 if current for powering the electric motor is required.

[0094] Both the preferred solutions achieve control of the opening / closing of the switch in order to prevent no enabling or delayed enabling of the protection against BEMF, minimizing any imperfections in the control dynamics of switching between the mechanical drive and the electric drive, while allowing insertion of the control signal only if necessary.

[0095] For simplicity, only an example of the triple condition logic of this type is described, being applicable to the case where the switch 55 is open, it being understood that the prior teachings, relating to the different conditions for generating the control signal, i. e. proportional, double proportional-derivative condition or proportional-integrative respectively, can be effectively realized also in this context by means of suitable reversal of the comparison conditions.

[0096] In detail, in the case of the triple integrative condition:

[0097] If

[0098] Measured_Speed < EMotor_max_speed x kp (or a fixed threshold)

[0099] If

[0100] d (Measured_Speed) / d t < kd

[0101] If

[0102] (Measured_Speed) d t < ki

[0103] then the control unit 52 generates a control signal for closing the electrical connection.

[0104] Figures 3a, 3b show two further embodiments of the method according to the invention, for each of which the reference parameters correlated to the measured speed of rotation are assumed, making reference to equivalent parameters such as the frequency f and the voltage V discharged in the upstream circuit.

[0105] In this case, bearing in mind that:

[0106] the speed of rotation of the rotor is defined by the ratio f / n = f requency / number of poles of the motor

[0107] and that

[0108] the voltage V is linked to the product VMAX x kv, i. e. the maximum speed of rotation of the rotor of a motor multiplied by the constant universal speed of the motors

[0109] it is possible to implement the BEMF control by means of an AND logic unit which generates a signal c (t) which, in the case where:

[0110] the switch ( 55) is closed, causes the opening thereof only if

[0111] the measured frequency Fmeasured>= the maximum permissible frequency fw x and

[0112] the measured voltage Vmeasured>= the maximum permissible voltage Vmax;

[0113] while in the where:

[0114] the switch (55) is open, it causes the closing thereof with negated logic in order to obtain which the addition of a NOT downstream of the AND is sufficient.

[0115] It is therefore clear how the solution according to the present invention is at the same time low-cost, but reliable in ensuring protection against the counter-electromotive force (BEMF) generated in a hybrid system for driving rotating elements.

[0116] With the method according to the invention it is also possible to reduce the number of electronic components used, reducing the costs and increasing the reliability of the system which is less dependent on the reliability of the components themselves.

[0117] Control, by means of the processor, of the electronic switch based on the speed of rotation measured is rapid and reliable as well as being able to be easily adapted to different conditions of use and types of device.

Claims

CLAIMS1) Control unit for controlling a hybrid apparatus for driving a rotating device comprising:- a driven element (4 ), designed to be connected to a rotating element of the device;- a mechanical drive (20 ), comprising a movement take-up element designed to be connected to a drive shaft (2 ) for receiving a rotating movement, and an electromagnetic coupling (21 ) which rotationally engages / disengages the movement take-up element with / from the driven element for rotational driving thereof;- an electric drive ( 30 ), comprising a stator (32 ) and a rotor (31 ), the electric drive being able to be controlled so as to rotationally drive the driven element independently of the mechanical drive;characterized in that the control unit comprises: - an electric power supply input line (51+, 51-) and a line ( 56) for supplying power to the electric drive (30 ),- an electronic component (54 ) for controlling the power supply to the electric drive;- a microprocessor (52 ), arranged between the electric power supply input line (51+, 51-) and the line for supplying power to the electric drive, configured to manage both the normal operation thereof and the transitions between a mechanical drive mode and an electric drive mode;and in thatan electronic switch ( 55 ) is arranged between the power supply input line (51+, 51-) and the electronic component (54 ) for controlling the power supply to the electric drive;the electronic switch ( 55) status being determined by a control signal c (t) generated by the processor (53) on the basis of a signal ms (t) representing the speed of rotation of the rotor (31 ) of the electric drive.2) Control unit according to Claim 1, characterized in that the control signal c (t ) for opening the electronic switch ( 55 ) is generated on the basis of the comparison between the value of a signal ms (t) representing a speed of rotation of the rotor (31 ) of the electric drive ( 30 ), measured instant by instant, and a predefined threshold value (kp).3) Control unit according to Claim 1, characterized in that the electronic switch is closed and the control signal c (t ) is a signal for opening the switch for electrical isolation of the electric drive (30 ) from the energy source.4) Control unit according to the preceding claim, characterized in that the comparison between the signal ms (t ) and a predefined threshold value (kp) is of the proportional type defined by the relation:Measured Speed > EMotor max speed x kp whereinMeasured- Speedis the value of the signal ms (t) at the instant t of interest andEMotor_max_speedis the maximum permissible number of revolutions, andkpis a predefined arbitrary constant.5) Control unit according to Claim 3, characterized in that the comparison between the signal ms (t) anda predefined threshold value (kd) is of the derivative type defined by the double condition:Measured_Speed > EMotor_max_speed x kp d(Measured_Speed) / dt > kd wherein∂(Measured_Speed) / ∂tis a function derived over time of the speed of rotation ms (t ), and kp and kd are predefined arbitrary constants.6) Control unit according to Claim 3, characterized in that the comparison between the signal ms (t ) and a predefined threshold value (ki) is of the integrative type defined by the double condition:Measured_Speed > EMotor max speed x kp wherein kp is a predefined arbitrary constant and Measured_Speed represents the value of the signal ms (t) at the instant t of interestand∫(Measured_Speed)∂t > kiwherein the coefficients kp,ki are predefined arbitrary constants.7) Control unit according to Claim 3, characterized in that the comparison between the signal ms (t) and a predefined threshold value (ki) is of the integrative type defined by the triple condition:Measured_Speed > (EMotor_max_speed x kp) d(Measured_Speed) / dt > kd∫(Measured_Speed)∂t > kiwherein∫(Measured_Speed) / ∂tis an integral function over time of the speed of rotation ms (t); and kp, ki and kd are predefined arbitrary constants.8) Control unit according to Claim 1 or 2, characterized in that the electronic switch ( 55 ) isopen and the control signal c (t ) is a signal for closing the switch for electrical connection of the electric drive ( 30 ) to the energy source.9) Control unit according to the preceding claim, characterized in that the comparison between the signal ms (t ) and a predefined threshold value (kp) is of the proportional type defined by the relation Measured_Speed < EMotor_max_speed x kp whereinMeasured- Speedis the value of the signal ms (t) at the instant t of interest andEMotor_max_speedis the maximum permissible number of revolutions and kp is an arbitrary predefined constant.10) Control unit according to Claim 8, characterized in that the comparison between the signal ms (t) and a predefined threshold value (kd) is of the derivative type defined by double condition:Measured_Speed < EMotor_max_speed x kp d(Measured_Speed) / dt < kd wherein∂(Measured_Speed) / ∂tis a function derived over time of the speed of rotation ms (t), and kp and kd are predefined arbitrary constants.11) Control unit according to Claim 8, characterized in that the comparison between the signal ms (t) and a predefined threshold value (ki) is of the integrative type defined by the double condition:Measured_Speed < EMotor_max_speed x kp wherein kp is a predefined arbitrary constant and Measured Speed represents the value of the signal ms (t) at the instant t of interestand\(Measured_Speed)dt < ki wherein the coefficients kp, ki are predefined arbitrary constants.12) Control unit according to Claim 8, characterized in that the comparison between the signal ms (t ) and a predefined threshold value (ki) is of the integrative type defined by the triple condition:Measured_Speed < (EMotor_max_speed x kp) d(Measured_Speed) / dt < kd\(Measured_Speed)dt < ki whereinJ ( Measured- Speed) / dtis a function derived over time of the speed of rotation ms (t) and kp, ki and kd are predefined arbitrary constants.13) Control unit according to any one of the preceding claims, characterized in that a signal for measuring the speed of rotation of the rotor is obtained from:a signal representing the position of the rotor (31 ) over time, generated by a position indicator of the electric drive; oran estimate (ms) of the measurement of the speed of rotation of the rotor, obtained from a measurement or estimate of the counterelectromotive voltage BEMF (t) present at each instant on one or more of the power supply inputs of the electric drive (30 ).14) Control unit according to one of the preceding claims, wherein at least the processor (52 ) is electrically supplied with power independently of the power supply source for driving the electric drive (30 ).15) Control unit for controlling driving of a rotating device according to any one of the preceding claims, characterized in that the rotating element is an auxiliary cooling device for a motor vehicle.16) Control unit according to Claim 10, characterized in that the rotating element is the impeller of a recirculating pump of a motor vehicle.17) D rive control unit according to Claim 10, characterized in that the rotating element is a fan for cooling the coolant of the engine.18) Method for controlling a hybrid apparatus for driving a rotating device comprising:- a mechanical drive, comprising a movement take-up element designed to be connected to a drive shaft for receiving a rotating movement, and an electromagnetic coupling which rotationally engages / disengages the movement take-up element with / from the driven element for rotational driving thereof;- an electric drive, comprising a stator and a rotor, the electric drive being able to be controlled so as to rotationally drive the driven element independently of the mechanical drive; - a control unit for controlling the electric drive;- an electronic switch arranged between the control unit and the electric drive and controlled by the control unit.the method comprising the steps of:- generating a control signal c (t) for opening / closing the electronic switch;- the control signal c (t) being generated on the basis of the comparison between a signal ms (t)representing a speed of rotation of the rotor of the electric drive, measured instant by instant and a predefined threshold value (kp; kd; ki).19) Method according to the preceding claim, characterized in that the electronic switch is closed and the control signal c (t) is a signal for opening the switch for electrical connection of the electric drive to the energy source.20) Method according to the preceding claim, characterized in that the comparison between the signal ms (t) and a predefined threshold value (kp) is of the proportional type defined by the relation:Measured_Speed > EMotor_max_speed x kp whereinMeasured- Speedis the value of the signal ms (t) at the instant t of interest andEMotor max speedis the maximum permissible number of revolutions, and kp is an arbitrary predefined constant.21) Method according to Claim 19, characterized in that the comparison between the signal ms (t) and a predefined threshold value (kd) is of the derivative type defined by double condition:Measured_Speed > EMotor_max_speed x kp d(Measured_Speed) / dt > kd whereind(Measured_Speed) / dtis a function derived over time of the speed of rotation ms (t), and kp and kd are predefined arbitrary constants.22) Method according to Claim 19, characterized in that the comparison between the signal ms (t) and a predefined threshold value (kd) is of the derivative type defined by double condition:Measured_Speed > EMotor max speed x kp wherein kp is a predefined arbitrary constant and Measured_Speed represents the value of the signal ms (t) at the instant t of interestand∫(Measured_Speed)∂t > kiwherein the coefficients kp,ki are predefined arbitrary constants.23) Method according to Claim 19, characterized in that the comparison between the signal ms (t) and a predefined threshold value (ki) is of the integrative type defined by the triple condition:Measured_Speed > (EMotor_max_speed x kp) ∂(Measured_Speed) / ∂t > kd∫(Measured_Speed)∂t > kiwhereinf ( easured- Speed) / dtis an integral function over time of the speed of rotation ms (t), and kp, ki and kd are predefined arbitrary constants.24) Method according to Claim 18, characterized in that the electronic switch ( 55 ) is open and the control signal c (t ) is a signal for closing the switch for electrical connection of the electric drive (30 ) to the energy source.25) Method according to the preceding claim, characterized in that the comparison between the signal ms (t ) and a predefined threshold value (kp) is of the proportional type defined by the relation:Measured_Speed < EMotor_max_speed x kp whereinMeasured- Speedis the value of the signal ms (t) at the instant t of interest andEMotor_max_speedis the maximum permissible number of revolutions, and kp is an arbitrary predefined constant.26) Method according to Claim 24, characterized in that the comparison between the signal ms (t) and a predefined threshold value (kd) is of the derivative type defined by double condition:Measured_Speed < EMotor_max_speed x kp d(Measured_Speed) / dt < kd whereind(Measured_Speed) / dtis a function derived over time of the speed of rotation ms (t), and kp and kd are predefined arbitrary constants.27) Method according to Claim 24, characterized in that the comparison between the signal ms (t) and a predefined threshold value (ki) is of the derivative type defined by double condition:Measured_Speed < EMotor_max_speed x kp wherein kp is a predefined arbitrary constant and Measured_Speed represents the value of the signal ms (t) at the instant t of interest and \(Measured_Speed)dt < ki wherein the coefficients kp,ki are predefined arbitrary constants.28) Method according to Claim 24, characterized in that the comparison between the signal ms (t) and a predefined threshold value (ki) is of the derivative type defined by triple condition:Measured_Speed < (EMotor_max_speed x kp) d(Measured_Speed) / dt< kd\(Measured_Speed)dt < ki whereinf ( Measured- Speed) / dtis an integral function over time of the speed of rotation ms (t), and kp, ki and kd are predefined arbitrary constants.29) Method according to any one of the preceding claims, characterized in that the control is performed by means of a logic unit on the basis of respectively measured and maximum permissible frequency (f) and voltage (V).30) Method according to the preceding claim 29, characterized in that the logic unit is an AND logic unit.31) Method according to Claim 29 or 30, characterized in that opening of the closed switch (55) occurs if both the following relations are satisfied:measured frequency Fmeasured>= maximum permissible frequency fMAXmeasured voltage Vmeasured>= maximum permissible voltage Vmax32) Method according to Claim 29 or 30, characterized in that closing of the open switch (55) occurs if the outcome of both of the following relations is negative:measured frequency Fmeasured>= maximum permissible frequency fMAXmeasured voltage Vmeasured>= maximum permissible voltage Vmax33) Method according to any one of the preceding claims, characterized in that the rotating element is an auxiliary cooling device for a motor vehicle.34) Method according to the preceding claim, characterized in that the rotating element is the impeller of a recirculating pump of a motor vehicle.35) Method according to any one of the preceding claims, characterized in that the rotating element is a cooling fan of a motor vehicle.

Images