Motor-fan unit for a motor vehicle comprising a circuit board for controlling an electric motor

Abstract

The present invention relates to a motor-fan unit (GMV) for a motor vehicle (V), comprising an electric motor (MOT) and a control circuit board (CD) for controlling the electric motor (MOT), wherein the control circuit board (CD) comprises: an acquisition device (ADC) for acquiring at least one characteristic quantity (G) of the motor-fan unit (GMV); a driver device (MC) configured to drive the electric motor (MOT) via a primary pulse width modulation signal (PWM1); the driver device (MC) being further configured to send a trigger signal (S) for triggering the acquisition to the acquisition device (ADC), the trigger signal (S) being offset and synchronized with respect to the primary pulse width modulation signal (PWM1).

Description

Technical Field

[0001] The invention relates to a motor-fan unit for a motor vehicle comprising a control circuit board for controlling an electric motor.

[0002] The present invention is particularly applicable, but not limited to, motor vehicles. Background Art

[0003] A motor-fan unit for a motor vehicle known to a person skilled in the art comprises:

[0004] - electric motor;

[0005] - A control circuit board for controlling said electric motor.

[0006] The control circuit board comprises:

[0007] - a collection device for collecting at least one characteristic quantity of the motor-fan unit;

[0008] - a driver device configured to drive said electric motor via a primary pulse width modulation signal.

[0009] The at least one characteristic quantity is used to drive the electric motor. It is used as an input parameter of a feedback loop of the driving operation. The driver device includes a MOSFET switch configured to generate a primary pulse width modulation signal. The switching of the MOSFET switch generates a current peak, which interferes with the acquisition of the at least one characteristic quantity. Therefore, a low-pass filter with a determined cut-off frequency is used to attenuate the current peak.

[0010] One disadvantage of the prior art is that the low-pass filter is insufficient. The acquisition is still disturbed. In addition, the filter causes a delay in the acquisition, which leads to a slower response and unstable driving of the electric motor. The response time for driving the electric motor is not optimized relative to a given input characteristic quantity for driving the feedback loop.

[0011] Under such circumstances, the present invention aims to overcome the above-mentioned disadvantages. Summary of the invention

[0012] To this end, the present invention proposes a motor-fan unit for a motor vehicle, which comprises an electric motor and a control circuit board for controlling the electric motor, wherein the control circuit board comprises:

[0013] - a collection device for collecting at least one characteristic quantity of the motor-fan unit;

[0014] - a driver device configured to drive said electric motor via a primary pulse width modulated signal;

[0015] It is characterized in that the driver device is further configured to send a trigger signal for triggering the acquisition to the acquisition device, and the trigger signal is offset and synchronized with respect to the primary pulse width modulation signal.

[0016] Specifically, the triggering of acquisition is offset relative to the rising edge and the falling edge of the primary pulse width modulation signal. Therefore, the acquisition, also called measurement, is performed at a time offset relative to the rising edge and the falling edge of the primary pulse width modulation signal.

[0017] Thus, as will be seen in detail below, the acquisition of the at least one characteristic quantity is offset and synchronized with respect to the primary pulse width modulated signal, which makes it possible to prevent current peaks caused by the switching of the switches of the driver device from interfering with the acquisition. In this way, the distances of the rising and falling edges of the primary pulse width modulated signal corresponding to the switching are obtained. As a result, an acquisition without errors is obtained. This complements the effect of the low-pass filter. Thus, a low-pass filter with a lower cut-off frequency can be used, which makes it possible to no longer have delays in the acquisition and to reduce the size and cost of the low-pass filter.

[0018] According to some non-limiting embodiments, the motor-fan unit may further include one or more of the following additional features:

[0019] According to a non-limiting embodiment, the at least one characteristic quantity is a motor current, a motor voltage, a battery voltage or a circuit board temperature. These characteristic quantities affect the driving of the electric motor.

[0020] According to a non-limiting embodiment, the trigger signal is a secondary pulse width modulated signal. This makes it possible to control the triggering of the acquisition using an acquisition device which is an independent element from the driver device.

[0021] According to a non-limiting embodiment, the acquisition is performed on a rising edge or a falling edge of the secondary pulse width modulated signal.

[0022] According to a non-limiting embodiment, the acquisition is performed on a rising edge when the secondary pulse width modulated signal has bipolarity, or on a falling edge when the secondary pulse width modulated signal has unipolarity. This makes it possible to be at a distance from the rising and falling edges of the primary pulse width modulated signal so that the switching of the switches of the driver device affects the acquisition as little as possible.

[0023] According to a non-limiting embodiment, if the primary pulse width modulated signal comprises a primary duty cycle less than or equal to 50%, the triggering of the acquisition occurs at a time equal to the primary duty cycle divided by 2 plus 50%. Thus, each time the characteristic quantity is measured at a certain distance from the rising edge or the falling edge of the primary pulse width modulated signal. Thus, the measurement is not disturbed by the switching of the switch of the driver device, which is controlled by the primary pulse width modulated signal.

[0024] According to a non-limiting embodiment, if the primary pulse width modulated signal comprises a primary duty cycle higher than 50%, the triggering of the acquisition occurs at a time equal to the primary duty cycle divided by 2. Therefore, each time the characteristic quantity is measured at a certain distance from the rising edge or the falling edge of the primary pulse width modulated signal. Therefore, the switching of the switches of the driver device does not disturb the measurement result.

[0025] According to a non-limiting embodiment, the acquisition device does not form part of the driver device. It is independent of the driver device.

[0026] According to a non-limiting embodiment, the trigger signal is an interrupt. This makes it possible to control the triggering of the acquisition using an acquisition device forming part of the driver device.

[0027] According to a non-limiting embodiment, the interrupt signal is sent at the following times:

[0028] - if the primary pulse width modulated signal comprises a primary duty cycle less than or equal to 50%, at a time equal to the primary duty cycle of the primary pulse width modulated signal divided by 2 plus 50%; or

[0029] - if said primary pulse width modulated signal comprises a primary duty cycle greater than 50%, at a time when the primary duty cycle of said primary pulse width modulated signal is divided by 2.

[0030] Therefore, the characteristic quantity is measured at a certain distance from the rising edge or the falling edge of the primary pulse width modulation signal each time. Therefore, the switching of the switch of the driver device will not interfere with the measurement result.

[0031] According to a non-limiting embodiment, the acquisition device forms part of the driver device.

[0032] The present invention also proposes a control method for controlling an electric motor of a motor-fan unit of a motor vehicle, the control method comprising:

[0033] - collecting at least one characteristic quantity of the motor-fan unit by means of a collecting device;

[0034] - driving the electric motor by means of a driver device via a primary pulse width modulated signal;

[0035] Characterized in that the control method further comprises: the driver device sends a trigger signal for triggering the acquisition to the acquisition device, and the trigger signal is offset and synchronized with respect to the primary pulse width modulation signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The present invention and its various applications will be better understood by reading the following description and referring to the accompanying drawings, in which:

[0037] Figure 1 shows a schematic diagram of a motor-fan unit for a motor vehicle comprising an electric motor and a control circuit board including an acquisition device and a driver device according to a first non-limiting embodiment;

[0038] Figure 2 shows a schematic diagram of a motor-fan unit for a motor vehicle comprising an electric motor and a control circuit board according to a second non-limiting embodiment, the control circuit board comprising an acquisition device and a driver device;

[0039] Figure 3a Shown by Figure 1 Schematic diagram of a secondary pulse width modulated signal and a primary pulse width modulated signal with bipolarity sent by a driver device, the primary pulse width modulated signal and the secondary pulse width modulated signal including a duty cycle according to a first non-limiting variant embodiment;

[0040] Figure 3b Shown by Figure 1 Schematic diagram of a secondary pulse width modulated signal and a primary pulse width modulated signal with bipolarity sent by a driver device, the primary pulse width modulated signal and the secondary pulse width modulated signal including a duty cycle according to a second non-limiting variant embodiment;

[0041] Figure 4a Shown by Figure 1 Schematic diagram of a secondary pulse width modulated signal and a primary pulse width modulated signal with a single polarity sent by a driver device, the primary pulse width modulated signal and the secondary pulse width modulated signal including a duty cycle according to a first non-limiting variant embodiment;

[0042] Figure 4b Shown by Figure 1Schematic diagram of a secondary pulse width modulated signal and a primary pulse width modulated signal with a single polarity sent by a driver device, the primary pulse width modulated signal and the secondary pulse width modulated signal including a duty cycle according to a second non-limiting variant embodiment;

[0043] Figure 5a According to a first non-limiting variant embodiment, Figure 2 A diagram of a primary pulse width modulation signal and an interrupt signal sent by a driver device;

[0044] Figure 5b According to a second non-limiting variant embodiment, Figure 2 A diagram of a primary pulse width modulation signal and an interrupt signal sent by a driver device;

[0045] Figure 6 A flow chart of a control method implemented by a motor-fan unit for controlling an electric motor according to a non-limiting embodiment is shown. DETAILED DESCRIPTION

[0046] Unless otherwise indicated, elements that are identical in structure or function and appear in the various figures are given the same reference numerals.

[0047] Reference Figures 1 to 5b , a motor-fan unit GMV for a motor vehicle V according to the invention is described on the basis of a non-limiting embodiment.

[0048] The term "motor vehicle" is understood to mean any type of motor vehicle.

[0049] In a non-limiting embodiment, the motor-fan unit GMV forms part of a blower.In a non-limiting embodiment, the blower forms part of an air conditioning, ventilation and / or heating device (not shown) known as HVAC (Heating, Ventilation and Air Conditioning) for a motor vehicle.

[0050] The air conditioning, ventilation and / or heating HVAC device also comprises a housing and an air duct (not shown) in which one or more heat exchangers are arranged which will allow the air flow passing through them to be thermally conditioned (i.e. heated or cooled). The air flow is intended to enter the vehicle interior of the motor vehicle V via at least one air outlet of the housing. The heating, ventilation and / or air conditioning HVAC device for a motor vehicle is usually arranged under the dashboard of the motor vehicle.

[0051] like Figure 1 and Figure 2 As shown, the motor-fan unit GMV comprises:

[0052] - Electric motor MOT;

[0053] - a control circuit board CD for controlling the electric motor MOT, the control circuit board CD comprising:

[0054] - a collection device ADC for collecting at least one characteristic quantity G of the motor-fan unit GMV;

[0055] - a driver device MC for driving said electric motor MOT.

[0056] The electric motor MOT is a brushed motor or a brushless motor.

[0057] It is known to those skilled in the art that the motor-fan unit GMV further comprises: a motor bracket (not shown) accommodating the electric motor; and a centrifugal wheel (not shown) mounted on the drive shaft of the electric motor. In addition, the motor-fan unit is mounted on a heating, ventilation and / or air conditioning HVAC system at the height of the blower housing. The blower housing is defined, for example, by the wall of the housing of the heating, ventilation and / or air conditioning system. Therefore, the blower housing is an air duct with a variable cross-section for guiding the air flow. The wheel arranged in the blower housing allows air to be sucked in axially (that is, along an axis substantially parallel to the axis of rotation of the wheel) and discharged radially (that is, for example, along an axis substantially perpendicular to the axis of rotation of the wheel) via the air inlet of the blower housing, and the air is sucked in via the air outlet of the blower housing.

[0058] The "motor-fan unit and blower housing" assembly is often referred to as the "blower".

[0059] In a non-limiting embodiment, the control circuit board DC is a printed circuit board called PCBA (printed circuit board assembly).

[0060] The components of the control circuit board DC are described in detail below.

[0061] ADC of acquisition equipment

[0062] In a non-limiting embodiment, the acquisition device ADC is an analog-to-digital converter.

[0063] It is configured to collect at least one characteristic quantity G( Figure 1 and Figure 2 The function ACQ(ADC,G) shown is the measured physical quantity G.

[0064] In a non-limiting embodiment, the acquisition device ADC is configured to acquire a plurality of feature quantities G.

[0065] exist Figure 1In a non-limiting embodiment shown, the acquisition device ADC is external to said driver device MC.

[0066] exist Figure 2 In another non-limiting embodiment shown, the acquisition device ADC forms a part of said driver device MC.

[0067] In some non-limiting embodiments, the at least one characteristic quantity G is a motor current i, a motor voltage Uv, a battery voltage Vbat, or a circuit board temperature tp, etc.

[0068] These physical quantities G influence the control of the electric motor MOT. They are therefore input parameters of a feedback loop for driving the electric motor MOT.

[0069] The physical quantity G includes a feedback value and a protection value.

[0070] In some non-limiting examples, the motor current i and the motor voltage Uv are used as feedback values. Therefore, the motor voltage Uv is feedback-controlled according to the setpoint motor voltage, and the motor current i is feedback-controlled according to the set motor current. It is known to those skilled in the art that the motor speed Vit depends on the motor voltage Uv, and the motor voltage Uv is obtained from the battery voltage Vbat. Specifically, the battery voltage Vbat is used to define the primary duty cycle α1 described below so that the set motor voltage can be achieved. Specifically, the set motor voltage is equal to Vbat*α1. Therefore, in order to obtain a 6-volt motor voltage Uv using a 12-volt battery voltage, α1=50%.

[0071] In some non-limiting examples, the protection value is the battery voltage Vbat or the circuit board temperature tp. Thus, if the circuit board temperature tp exceeds a threshold temperature, the electric motor MOT can be turned off. Thus, if the battery voltage Vbat exceeds a threshold battery voltage, the electric motor MOT can be turned off.

[0072] The feature quantity G is collected in an analog form.

[0073] The acquisition device ADC is also configured to convert the feature quantity G acquired in analog form into a digital value ( Figure 1 and Figure 2 The function CONV(ADC,G) is shown.

[0074] In a non-limiting embodiment, the acquisition device ADC is configured to acquire a plurality of measurement samples having the same characteristic quantity G.

[0075] Therefore, the acquisition device ADC is configured to acquire at least twice the feature quantity G. Therefore, it measures the feature quantity G at least twice so as to have at least two measurement samples.

[0076] The acquisition device ADC is further configured to receive a trigger signal S( Figure 1 and Figure 2 The trigger signal S makes it known when the characteristic quantity G must be acquired, ie when the characteristic quantity G must be measured.

[0077] Driver device MC

[0078] The driver device MC is also called a driver.

[0079] The driver device MC is configured as:

[0080] - Drive the electric motor MOT via the primary pulse width modulation signal PWM1 ( Figure 1 and Figure 2 The function shown is DRIV(MC,MOT,PWM1,G));

[0081] - Sending a trigger signal S (for triggering the acquisition) to the acquisition device ADC Figure 1 and Figure 2 As shown in the function TX(MC, ADC, S), the trigger signal S is offset and synchronized with respect to the primary pulse width modulation signal PWM1.

[0082] In the rest of this description, the primary pulse width modulation signal PWM1 will also be referred to as signal PWM1 .

[0083] Driving is performed according to the collected at least one characteristic quantity G. Therefore, the driver device MC is configured to drive the electric motor MOT according to the at least one characteristic quantity G.

[0084] In a non-limiting embodiment, known to a person skilled in the art, the driver device MC comprises a switch Swi configured to drive the electric motor MOT according to the primary pulse width modulated signal PWM1. The signal PWM1 is thus sent to the switch Swi. Figure 1 and Figure 2 In a non-limiting example shown, the switches Swi are MOSFETs. The switches Swi are switched according to the rising and falling edges of the primary pulse width modulation signal PWM1.

[0085] In a non-limiting embodiment, the driver device MC further comprises a microcontroller Mic. The microcontroller Mic is configured to send said primary pulse width modulation signal PWM1.

[0086] The primary pulse width modulation signal PWM1 includes a duty cycle α1 and a frequency f1. In a non-limiting example, the frequency f1 is equal to 20kHz, which corresponds to a period T1 of 50 microseconds. It should be understood that the duty cycle α is the ratio of the duration of the high time of the PWM signal (i.e., the switching time of the switch) divided by the period.

[0087] The acquisition of the characteristic quantity G, also referred to as the measurement of the physical quantity G, is the measurement of an analog value. As described below, the acquisition is performed at a time different from the switching of the switch Swi of the driver device MC so as not to be disturbed by the noise generated by the switching. In addition, the acquisition is performed at a time sufficiently far away from the switching operation so as not to be disturbed by the noise generated by the switching.

[0088] As mentioned above, in a non-limiting embodiment, the driver device MC may or may not include the acquisition device ADC. To this end, the driver device MC triggers the acquisition of characteristic quantities G performed by the acquisition device ADC according to two non-limiting embodiments described below.

[0089] oFirst non-limiting embodiment

[0090] like Figure 1 As shown, according to this first non-limiting embodiment, the acquisition device ADC is independent of said driver device MC, ie it is an electronic component external to said driver device MC and therefore does not constitute a part of said driver device MC.

[0091] like Figure 3a and Figure 3b As shown, according to this first non-limiting embodiment, the trigger signal S for triggering the acquisition is a secondary pulse width modulation signal PWM2 sent by the driver device MC, and the secondary pulse width modulation signal PWM2 is synchronized and offset relative to the primary pulse width modulation signal PWM1.

[0092] In the rest of this description, the secondary pulse width modulated signal PWM2 will also be referred to as signal PWM2.

[0093] Thus, in a non-limiting embodiment, the driver device MC comprises a copy of the signal PWM1 stored in a memory, said copy being the signal PWM2.

[0094] In a non-limiting embodiment, the signal PWM2 has an even polarity P1 (eg Figure 3a and Figure 3b ) or odd polarity P2 (as shown) Figure 4a and Figure 4bAs shown in the figure, the rising edge of the signal PWM2 of the unipolar P2 corresponds to the falling edge of the signal PWM2 of the bipolar P1, and the falling edge of the signal PWM2 of the unipolar P2 corresponds to the rising edge of the signal PWM2 of the bipolar P1. Therefore, the signal PWM2 of the unipolar P2 is complementary to the signal PWM2 of the bipolar P1.

[0095] As can be seen from the figure, the signal PWM2 includes a frequency f2 equal to the frequency f1 of the signal PWM1, that is, a period T2 equal to the period T1 of the signal PWM1, and a secondary duty cycle α2 equal to the primary duty cycle α1 of the signal PWM1. Therefore, in a non-limiting example, the acquisition of the same feature quantity G is performed every 50 microseconds.

[0096] It can be seen that there is an offset between the primary pulse width modulation signal PWM1 and the secondary PWM2. Therefore, the rising edge and the falling edge of the signal PWM2 are offset in time relative to the rising edge and the falling edge of the signal PWM1. They do not occur at the same time.

[0097] In a non-limiting embodiment, the triggering of the acquisition of the characteristic quantity G is performed on the rising edge or the falling edge of the signal PWM2.

[0098] Specifically, in a non-limiting variant embodiment, the collection of the feature quantity G is triggered at the following locations:

[0099] - on a rising edge when the signal PWM2 has a bipolarity P1; and

[0100] - On the falling edge when the signal PWM2 has a unipolarity P2.

[0101] Thus, in a non-limiting embodiment, if the signal PWM1 comprises a main duty cycle α1 with α1 ≤ 50%, the triggering of the acquisition occurs at a time t equal to the main duty cycle α1 divided by 2 plus 50%.

[0102] In a non-limiting embodiment, if the signal PWM1 comprises a main duty cycle α1 with α1>50%, the triggering of the acquisition occurs at a time t equal to the main duty cycle α1 divided by two.

[0103] The trigger time t is calculated according to the rising edge or falling edge of the signal PWM2 and its polarity, as described below.

[0104] ■Rising edge

[0105] based on Figure 3a According to a first non-limiting variant embodiment, if the signal PWM1 comprises a main duty cycle α1 of α1≤50% and the signal PWM2 has a bipolarity P1, the acquisition is triggered at time t=α1 / 2+50%. Figure 3aIn the non-limiting example of , it is the case that α1 = 20%, and t = 60% is obtained.

[0106] The triggering occurs at the rising edge of the bipolar signal PWM2 P1.

[0107] Thus, there is a trigger on the rising edge of the signal PWM2 at a distance from the rising edge of the signal PWM1 and at a distance from the falling edge of the signal PWM1. In addition, there is a trigger centered on the falling edge of the signal PWM1 and the subsequent rising edge of the signal PWM1. Thus, there is a trigger centered on two consecutive operations of switching the switch Swi to the low state.

[0108] based on Figure 3b According to a second non-limiting variant embodiment, if the signal PWM1 comprises a main duty cycle α1 of α1>50% and the signal PWM2 has a bipolarity P1, the acquisition is triggered at time t=α1 / 2. Figure 3b In the non-limiting example of , it is the case that α1 = 60%, and t = 30% is obtained.

[0109] The triggering occurs on the rising edge of the bipolar signal PWM2 P1.

[0110] Thus, a trigger occurs on the rising edge of the signal PWM2 at a distance from the rising edge of the signal PWM1 and at a distance from the falling edge of the signal PWM1. In addition, there is a trigger centered on the rising edge of the signal PWM1 and the subsequent falling edge of said signal PWM1. Thus, there is a trigger centered on two consecutive operations of switching the switch Swi to the high state.

[0111] ■Falling edge

[0112] based on Figure 4a According to a first non-limiting variant embodiment, if the signal PWM1 comprises a main duty cycle α1 of α1≤50% and the signal PWM2 has a unipolarity P2, the acquisition is triggered at time t=α1 / 2+50%. Thus, in a non-limiting example, if it is the case that α1=20%, the acquisition at t=60% is obtained.

[0113] The trigger occurs at the falling edge of the unipolar signal PWM2.

[0114] Thus, there is a trigger on the falling edge of the signal PWM2 at a distance from the rising edge of the signal PWM1 and at a distance from the falling edge of the signal PWM1. In addition, there is a trigger centered on the falling edge of the signal PWM1 and the subsequent rising edge of said signal PWM1. Thus, there is a trigger centered on two consecutive operations of switching the switch Swi to the low state.

[0115] based on Figure 4b According to a second non-limiting variant embodiment, if said signal PWM1 comprises α1>50% of α1 and has a unipolarity P2, the acquisition is triggered at time t=α1 / 2. Thus, if it is the case that α1=60%, the acquisition occurs at t=30%.

[0116] The trigger occurs at the falling edge of the unipolar signal PWM2.

[0117] Thus, a trigger occurs on the falling edge of the signal PWM2 at a distance from the rising edge of the signal PWM1 and at a distance from the falling edge of the signal PWM1. In addition, there is a trigger centered on the rising edge of the signal PWM1 and the subsequent falling edge of said signal PWM1. Thus, there is a trigger centered on two consecutive operations of switching the switch Swi to the high state.

[0118] According to these four non-limiting variant embodiments, it can be seen that Figures 3a to 4b The triggering of the acquisition represented by Trig in occurs at a certain distance from the rising edge or falling edge of the primary pulse width modulation signal PWM1 at time t. Therefore, the acquisition of the acquisition device ADC will not be disturbed by the switching of the switch Swi of the driver device MC.

[0119] o Second Non-Limiting Example

[0120] like Figure 2 As shown, according to this second non-limiting embodiment, the acquisition device ADC forms part of said driver device MC, ie it is an electronic component inside said driver device MC.

[0121] like Figure 5a and Figure 5b As shown, according to this second non-limiting embodiment, the trigger signal S is an interrupt signal IT, which is synchronized and offset relative to the primary pulse width modulation signal PWM1. That is, the interrupt signal is offset relative to the rising and falling edges of the signal PWM1.

[0122] Therefore, the driver device MC includes the primary duty cycle α1 of the signal PWM1 stored in the memory, and the primary frequency f1 or the primary period T1. It uses a timer depending on the primary duty cycle α1 and the primary frequency f1 or the primary period T1 to send an interrupt signal IT to the acquisition device ADC, so that the interrupt signal IT is offset relative to the signal PWM1. Therefore, in a non-limiting example, the acquisition of the same characteristic quantity G is performed every 50 microseconds.

[0123] based on Figure 5aAccording to a first non-limiting variant embodiment, if said signal PWM1 comprises a main duty cycle α1 with α1≤50%, said interruption signal IT is sent at time t=α1 / 2+50%. Thus, in the non-limiting example shown, it is the case of α1=20% and t=60% is obtained.

[0124] Thus, triggering occurs at a distance from a rising or falling edge of the signal PWM1. In addition, there is triggering centered on a falling edge of the signal PWM1 and a subsequent rising edge of said signal PWM1. Thus, there is triggering centered on two consecutive operations of switching the switch Swi to a low state.

[0125] based on Figure 5b According to a second non-limiting variant embodiment, if the signal PWM1 comprises a main duty cycle α1 with α1>50%, the interrupt signal IT is sent at time t=α1 / 2. Thus, in the non-limiting example shown, it is the case of α1=60% and t=30% can be obtained.

[0126] Thus, there is a trigger at a distance from the rising or falling edge of the signal PWM1. In addition, there is a trigger centered on the rising edge of the signal PWM1 and the subsequent falling edge of said signal PWM1. Thus, there is a trigger centered with respect to two consecutive operations of switching the switch Swi to the high state.

[0127] According to these two non-limiting variant embodiments, Figure 5a and Figure 5b It can be seen that the triggering of the acquisition represented by Trig, that is, the sending of the interrupt signal IT, occurs at a time t that is a certain distance away from the rising edge and the falling edge of the primary pulse width modulation signal PWM1.

[0128] Therefore, the acquisition of the acquisition device ADC will not be disturbed by the switching of the switch Swi of the driver device MC.

[0129] By collecting the characteristic quantity G by the collection device ADC, an analog value of the measurement sample is obtained, and the analog value will be converted into a digital value by the collection device ADC.

[0130] In a non-limiting embodiment, the driver device MC compares the digital value with a threshold value Vs or a set value Vc ( Figure 1 and Figure 2 The function (COMP(MC, G, Vc, Vs)) shown is used to confirm whether the feature quantity G measured in this way exceeds the threshold value Vs, or reaches the set value Vc, for example.

[0131] The measurement samples of the characteristic quantity G are stable, that is, they are not disturbed by the switching of the switch Swi of the driver device MC, resulting in a more stable and more responsive driving of the electric motor MOT.

[0132] In the case where the acquisition device ADC acquires a plurality of measurement samples, after conversion into digital values, in a non-limiting embodiment, the driver device MC is further configured to digitally filter the measurement samples ( Figure 1 and Figure 2 This makes it possible to confirm the value of the characteristic quantity G measured based on the measurement samples. In a non-limiting example, digital filtering makes it possible to filter out those measurement samples whose values ​​differ too far from the average value. In a non-limiting example, digital filtering is an averaging of the measurement samples.

[0133] In a non-limiting example, the filtering speed is of the order of a few milliseconds. Thus, if the filtering speed is 2 ms, a quarter of the measurement samples are used. The measurement samples thus retained are the first sample, the fourth sample, the eighth sample, etc. In the case of a period T2 = 50 μs, 10 measurement samples are obtained.

[0134] The digital filtering is applied to protection values, such as, in a non-limiting example, to slowly varying circuit board temperature tp or battery voltage Vbat, and not to feedback values.

[0135] By filtering a plurality of measurement samples, this can for example determine the value of the circuit board temperature tp and can determine that the circuit board temperature value tp is not an isolated one-time value. Thus, this non-limiting embodiment, for example, makes it possible to filter one or more values ​​of the characteristic quantity G that are particularly different from other values. The filtering includes, for example, the average value of all measurement samples or twice the standard deviation of all measurement samples.

[0136] It should be noted that by filtering a plurality of measurement samples having the same characteristic quantity G, a slight delay is induced in the feedback loop for driving the electric motor MOT. Moreover, it is not necessary to apply this non-limiting embodiment to the physical quantity G as a feedback value, such as the motor current i or the motor voltage Uv in some non-limiting examples. It should be noted that, unlike a low-pass filter that requires about twenty measurement samples, digital filtering uses fewer measurement samples to confirm the value of the characteristic quantity G.

[0137] Therefore, when digital filtering is present, the driver device MC compares said filtered measurement samples, ie their average value in a non-limiting example, with the threshold value Vs. In a non-limiting example with a filtering speed of 2 ms, the driver device MC performs a comparison with the average value of 10 measurement samples.

[0138] Thus, the motor-fan unit GMV is configured to implement a control method PR for controlling the electric motor MOT of the motor-fan unit GMV of the motor vehicle. In a non-limiting embodiment, the control method PR comprises: Figure 6 The following steps are shown. In this non-limiting embodiment, there is no digital filtering.

[0139] In step 1), the driver device MC sends a trigger signal S for triggering the acquisition device ADC to acquire at least one characteristic quantity G of the motor-fan unit GMV, wherein the trigger signal S is offset and synchronized with respect to the primary pulse width modulation signal PWM1.

[0140] In step 1'), the acquisition device ADC receives the trigger signal S.

[0141] In step 2), the acquisition device ADC acquires the at least one characteristic quantity G.

[0142] The feature quantity G is in analog form.

[0143] In step 3), the acquisition device ADC performs analog-to-digital conversion on the feature quantity G to obtain a digital value of the feature quantity G.

[0144] In step 4), the driver device MC drives the electric motor MOT through the primary pulse width modulation signal PWM1 and according to the acquired characteristic quantity G.

[0145] In a non-limiting embodiment, the driver device MC performs a comparison of the characteristic quantity G (ie its digital value) with a threshold value Vs or a set value Vc (step 4a).

[0146] Of course, the description of the present invention is not limited to the above-mentioned embodiments.

[0147] Therefore, in another non-limiting application, the motor-fan unit GMV is a front motor-fan unit for cooling the electric motor MOT.

[0148] Therefore, the invention can be applied to any motor-fan unit comprising a driver device including a switch Swi whose switching causes noise.

[0149] The described invention therefore has, inter alia, the following advantages:

[0150] - It is an easy and cheap solution to implement;

[0151] - avoid the use of too large and too expensive low-pass filters, which slow down the drive of the electric motor MOT, in particular the response speed of the feedback loop using at least one characteristic variable G as an input parameter. An optimized response time can be achieved with respect to the set motor voltage, so that the drive of the electric motor MOT can be kept in a controlled state;

[0152] - During the acquisition of the physical quantity G, it is possible to reduce the noise interfering with the measurement caused by the switching of the switch Swi of the driver device MC, since said acquisition is carried out outside the switching times. It is thus possible to avoid switching at times interfering with the measurement. Therefore, in a non-limiting example, it is no longer possible to measure the battery voltage peak value Vbat which would damage the motor voltage Uv, and thus the electric motor speed Vit and therefore the overall drive of said electric motor MOT.

[0153] - The physical quantity can be measured synchronously with respect to the control signal for controlling the electric motor MOT, ie with respect to the signal PWM1, instead of being measured asynchronously at any time point as in the prior art. Therefore, the exact time of collecting the at least one characteristic quantity G can be determined.

Claims

1. A motor-fan unit (GMV) for a motor vehicle (V), comprising an electric motor (MOT) and a control circuit board (CD) for controlling the electric motor (MOT), the control circuit board (CD) comprising: - an acquisition device (ADC) for acquiring at least one characteristic quantity (G) of the motor-fan unit (GMV); - a driver device (MC) configured to drive said electric motor (MOT) via a primary pulse width modulated signal (PWM1); Characterized in that the driver device (MC) is also configured to send a trigger signal (S) for triggering the acquisition to the acquisition device (ADC), wherein the trigger signal (S) is offset and synchronized with respect to the primary pulse width modulation signal (PWM1), Wherein, if the primary pulse width modulation signal (PWM1) includes a primary duty cycle (α1) less than or equal to 50%, the triggering of the acquisition occurs at a time (t) equal to the primary duty cycle (α1) divided by 2 plus 50%.

2. The motor-fan unit (GMV) according to claim 1, wherein: The at least one characteristic quantity (G) is a motor current (i), a motor voltage (Uv), a battery voltage (Vbat) or a circuit board temperature (tp).

3. A motor-fan unit (GMV) according to claim 1 or 2, wherein: The trigger signal (S) is a secondary pulse width modulation signal (PWM2).

4. The motor-fan unit (GMV) according to claim 3, wherein: The acquisition is performed on a rising edge or a falling edge of the secondary pulse width modulated signal (PWM2).

5. The motor-fan unit (GMV) according to claim 4, wherein: The acquisition is performed on a rising edge when the secondary pulse width modulated signal (PWM2) has a bipolarity (P1), or on a falling edge when the secondary pulse width modulated signal (PWM2) has a unipolarity (P2).

6. A motor-fan unit (GMV) according to any one of claims 1 or 2, wherein: If said primary pulse width modulated signal (PWM1) comprises a primary duty cycle (α1) higher than 50%, said triggering of said acquisition occurs at a time (t) equal to the primary duty cycle (α1) divided by two.

7. A motor-fan unit (GMV) according to claim 1 or 2, wherein: The trigger signal (S) is an interrupt signal (IT).

8. The motor-fan unit (GMV) according to claim 7, wherein: The interrupt signal (IT) is sent at the following time (t): - if the primary pulse width modulated signal (PWM1) comprises a primary duty cycle (α1) less than or equal to 50%, at a time (t) equal to the primary duty cycle (α1) of the primary pulse width modulated signal (PWM1) divided by 2 plus 50%; or - if the primary pulse width modulated signal (PWM1) comprises a primary duty cycle (α1) greater than 50%, at a time (t) at which the primary duty cycle (α1) of the primary pulse width modulated signal (PWM1) is divided by 2.

9. A control method (PR) for controlling an electric motor (MOT) of a motor-fan unit (GMV) of a motor vehicle (V), the control method (PR) comprising: - collecting at least one characteristic quantity (G) of the motor-fan unit (GMV) by means of a collection device (ADC); - driving the electric motor (MOT) by means of a driver device (MC) via a primary pulse width modulation signal (PWM1); Characterized in that the control method (PR) further comprises: the driver device (MC) sends a trigger signal (S) for triggering the acquisition to the acquisition device (ADC), wherein the trigger signal (S) is offset and synchronized with respect to the primary pulse width modulation signal (PWM1), Wherein, if the primary pulse width modulation signal (PWM1) includes a primary duty cycle (α1) less than or equal to 50%, the triggering of the acquisition occurs at a time (t) equal to the primary duty cycle (α1) divided by 2 plus 50%.

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