Method for starting a single-phase asynchronous motor with a permanent capacitor and electromechanical actuator therewith

Description

Technical Field

[0001] The present invention relates to a method for starting an asynchronous electric motor with a permanent capacitor. The invention also relates to an electromechanical actuator comprising such an electric motor and means for implementing such a method. State of the Art

[0002] A single-phase asynchronous electric motor with a permanent capacitor is configured to be electrically connected to a phase conductor and a neutral conductor of an alternating voltage source. The stator of the electric motor comprises two windings, one winding of the two windings, called the main winding, is electrically connected in series with a switch, the other winding called the auxiliary winding is electrically connected in series with a phase-shifting capacitor and the switch.An electronic control unit comprising a device for detecting the sector zero crossing is configured to, when a control order is communicated to it, start the electric motor directly by a full-wave control of the switch with respect to the alternating voltage, this full-wave control making it possible both to initiate the rotational drive of the electric motor and to maintain the rotational drive of the electric motor.

[0003] The electronic control unit further comprises a resistive circuit electrically connected between the phase conductor and the neutral conductor and configured to electrically power the electronic control unit from the AC voltage source. The series impedance value of the resistive circuit is generally sized to allow the electric motor to start in full-wave control. In standby, that is to say when the electric motor is stopped and no control command is communicated to it, the electronic control unit therefore has a level of electrical energy consumption directly linked to the series impedance value of the resistive circuit.

[0004] If this electrical energy consumption value exceeds a predetermined threshold, for example 0.5 watts set to meet the standard requirements for reducing standby consumption of electrical products, it is desirable to increase the value of the series impedance of the resistive circuit in order to reduce this electrical energy consumption value. However, such a modification leads to a reduction in the electrical energy available when starting the electric motor and may thus prevent the electric motor from starting to rotate.

[0005] Also known is document EP 1 186 741 A2 which discloses a method for determining the direction in which an AC Venetian blind motor will rotate, in which the triac receives a single ignition pulse, the ignition pulse causing a brief phase shift between a first line connected to an alternating voltage and a second line connected to the first line via a capacitor of the AC Venetian blind motor. This phase shift is detected by the control unit of the AC Venetian blind motor and makes it possible to determine in which direction the AC Venetian blind motor will rotate.

[0006] It is therefore desirable to have an electronic control unit consuming a maximum of 0.5 watts in standby mode while allowing the electric motor to start rotating and to maintain the electric motor rotating. Summary of the invention

[0007] The invention is defined in independent claims 1 and 4, respectively defining a method and a device.

[0008] Embodiments relate to a method for starting an electric motor configured to be electrically connected to a phase conductor and a neutral conductor of an alternating voltage source, the electric motor comprising a stator, the stator of the electric motor comprising two windings, the two windings each comprising a common end so as to electrically connect them together, the common end being electrically connected to the neutral conductor via a switch, each of the two windings comprising another end constituting respectively a first phase terminal and a second phase terminal, the first phase terminal being electrically connected to the second phase terminal via a phase shift capacitor,the phase conductor being selectively either electrically connected to the first phase terminal to control the rotational drive of the electric motor in a first direction, or electrically connected to the second phase terminal to control the rotational drive of the electric motor in a second direction, the second direction being opposite to the first direction, the switch being controlled by an electronic control unit, the electronic control unit being configured to detect the zero crossing of the alternating voltage. The starting method is implemented by the electronic control unit, and the electronic control unit controls, during a starting period, the switch in phase angle with respect to the alternating voltage, then, following the starting period, controls the switch in full wave with respect to the alternating voltage.,

[0009] The electronic control unit includes a device for detecting the zero crossing of the alternating voltage.

[0010] The electronic control unit comprises a device for detecting the zero crossing of the alternating voltage, and the phase angle control of the switch consists of a first series of pulses, each pulse of the first series of pulses being emitted in phase angle with respect to each instant of zero crossing of the alternating voltage and having a first width, and in that the full wave control of the switch consists of a second series of pulses, each pulse of the second series of pulses being emitted in synchronism with each instant of zero crossing of the alternating voltage, the first width and the second width being adapted to maintain the switch in a closed state between each pulse of the first series of pulses and between each pulse of the second series of pulses.

[0011] According to one embodiment, the phase angle of the phase angle switch control is between one twentieth and one eighth of a period of the alternating voltage.

[0012] According to one embodiment, the switch is constituted by a triac or by two thyristors mounted head to tail.

[0013] According to one embodiment, the duration of the start-up period is determined so that the rotational drive of the electric motor is initiated during the start-up period.

[0014] Embodiments may also relate to an electromechanical actuator comprising at least one electric motor configured to be electrically connected to a phase conductor and a neutral conductor of an alternating voltage source, the electric motor comprising a stator, the stator of the electric motor comprising two windings, the two windings each comprising a common end so as to electrically connect them together, the common end being electrically connected to the neutral conductor via a switch, each of the two windings comprising another end constituting respectively a first phase terminal and a second phase terminal, the first phase terminal being electrically connected to the second phase terminal via a phase shift capacitor,the phase conductor being selectively either electrically connected to the first phase terminal to control the rotational drive of the electric motor in a first direction, or electrically connected to the second phase terminal to control the rotational drive of the electric motor in a second direction, the second direction being opposite to the first direction, the switch being controlled by an electronic control unit, , characterized in that the electronic control unit is configured to implement the starting method as previously defined.,

[0015] According to one embodiment, the electronic control unit comprises a device for detecting the zero crossing of the alternating voltage.

[0016] According to one embodiment, the electromechanical actuator is configured to actuate a heating and / or ventilation and / or air conditioning device.

[0017] According to one embodiment, the phase conductor comprises a switch configured to selectively either electrically connect the first phase terminal to the phase conductor to control the rotational drive of the electric motor in a first direction, or electrically connect the second phase terminal to the phase conductor to control the rotational drive of the electric motor in a second direction, the second direction being opposite to the first direction.

[0018] According to one embodiment, the electromechanical actuator is configured to actuate a concealment device.

[0019] According to one embodiment, the switch is constituted by a triac or two thyristors mounted head to tail.

[0020] According to one embodiment, the electronic control unit further comprises a resistive circuit electrically connected to the first phase terminal, to the second phase terminal, and to the neutral conductor, the resistive circuit being configured to electrically power the electronic control unit from the AC voltage source when the phase conductor is electrically connected to one or the other of the two phase terminals. Brief description of the figures

[0021] The present invention will be better understood with the aid of the following description with reference to the appended figures, in which identical reference signs correspond to structurally and / or functionally identical or similar elements. There figure 1 schematically represents an actuator comprising an electric motor and an electronic unit for controlling the electric motor according to a first embodiment. The figure 2schematically represents an actuator comprising an electric motor and an electronic unit for controlling the electric motor according to a second embodiment. The figure 3 represents steps of a startup method according to one embodiment. The figure 4 represents a timing diagram of different signals passing through the electronic control unit and through the electric motor, according to the first embodiment or the second embodiment. Detailed description

[0022] There figure 1 represents an electromechanical actuator ACT according to a first embodiment of the invention. The electromechanical actuator ACT can be configured to actuate a heating and / or ventilation and / or air conditioning device.

[0023] The electromechanical actuator ACT is configured to be electrically connected to a phase conductor ACP and to a neutral conductor ACN of an alternating voltage source U0, which may be, for example, an electrical distribution network of an alternating voltage commonly called "mains", the alternating voltage U0 being, for example, of the 230 V - 50 Hz type. The electrical voltage of the alternating voltage source present between the phase conductor ACP and the neutral conductor ACN is subsequently called alternating voltage U0. The electromechanical actuator ACT is configured to be electrically powered, in other words is electrically powered by the alternating voltage U0.

[0024] The ACT electromechanical actuator includes a single-phase asynchronous electric motor MOT with permanent capacitor, an electronic control unit CC, and a switch TR.

[0025] The electric motor MOT comprises a stator and a rotor. The stator of the electric motor MOT comprises two windings L1, L2. The two windings L1, L2 each comprise a common end N0 so as to electrically connect them together, the common end N0 being electrically connected to the neutral conductor ACN via the switch TR. Each of the two windings L1, L2 comprises another end constituting respectively a first phase terminal P1 and a second phase terminal P2. The first phase terminal P1 is electrically connected to the second phase terminal P2 via a phase shift capacitor CM, in other words, the phase shift capacitor CM is arranged between the first phase terminal P1 and the second phase terminal P2. The phase shift capacitor CM here constitutes the permanent capacitor of a single-phase asynchronous electric motor with a permanent capacitor.The phase shift capacitor CM can optionally be arranged in the electromechanical actuator ACT and outside the electric motor MOT. Each winding of the two windings L1, L2 can consist of one or more windings.

[0026] Here, the winding L1 whose end, constituting a first phase terminal P1, is electrically connected to the phase conductor ACP, is called the main winding, the other winding L2 being called the auxiliary winding. Thus, when an electrical voltage is applied between the first phase terminal P1 and the common end N0, the phase shift capacitor CM is placed in series with the second winding L2 and the electric motor MOT rotates in a first direction DIR1. The winding L2 located in series with the phase shift capacitor CM is called the auxiliary, the other winding L1 then being called the main. The electrical voltage U2 present at the terminals of the winding L2 located in series with the phase shift capacitor CM is called the auxiliary voltage, and the electrical voltage U1 present at the terminals of the other winding L1 is then called the main voltage.When the phase conductor ACP is electrically connected to the first phase terminal P1, the auxiliary voltage is out of phase by a quarter of a period (90°) with respect to the main voltage, the auxiliary voltage being ahead of the main electrical voltage.

[0027] Advantageously, the MOT electric motor further comprises a parking brake and a reducer which are not shown.

[0028] The electronic control unit CC includes a resistive circuit CR, and a zero crossing detection device CS1, CS2 of the alternating voltage U0.

[0029] Advantageously, the electronic control unit CC further comprises a processing circuit MC, the processing circuit MC comprising a processor or a microcontroller, and at least one memory, the memory being able to be internal or external to the processor or microcontroller. The electronic control unit can further be controlled by a remote command reception circuit not shown, such as for example a radio command receiver.

[0030] The resistive circuit CR is electrically connected to the first phase terminal P1, the second phase terminal P2, and the neutral conductor ACN. The resistive circuit CR is configured to electrically power the electronic control unit CC from the alternating voltage source U0 when the phase conductor ACP is electrically connected to either of the two phase terminals P1, P2.

[0031] Advantageously, the electronic control unit CC comprises a first diode D1 and a second diode D2, the anode of the first diode D1 being electrically connected to the first phase terminal P1, the anode of the second diode D2 being electrically connected to the second phase terminal P2. The resistive circuit CR comprises a first resistor R1, a Zener diode Z1, and a capacitor C1. The anode of the first diode D1 and the anode of the second diode D2 are electrically connected together at one end A of the first resistor R1, the other end of the first resistor R1 constituting a floating electrical ground GND of the electronic control unit CC. The floating electrical ground GND is electrically connected to the neutral conductor ACN via the Zener diode Z1 and the capacitor C1 electrically connected in parallel.The processing circuit MC is electrically powered by an electrical voltage present at the terminals of the Zener diode Z1 and the capacitor C1, between the neutral conductor ACN electrically connected to a positive supply terminal VDD of the processing circuit MC, and the floating electrical ground GND of the electronic control unit electrically connected to a negative supply terminal VSS of the processing circuit MC. The details of the electrical power supply of the processing circuit MC, which includes electrical voltage step-down and regulating components, are not shown in the figures.

[0032] Advantageously, the resistive circuit CR of the electronic control unit CC is sized so that the standby electrical energy consumption of the electronic control unit CC is less than or equal to a predetermined threshold, the predetermined threshold preferably being less than or equal to 0.5 watts. Advantageously, the value of the resistance R1 of the resistive circuit CR is between 59 kilo-ohms and 62 kilo-ohms, for example 61.9 kilo-ohms. Thus, the series impedance of the resistive circuit CR is sized so that the electronic control unit CC consumes less than 0.5 watts in standby, that is to say when the electric motor MOT is stopped and no control command is communicated to it.

[0033] The zero crossing detection device CS1, CS2, is configured to detect each zero crossing instant (also called "mains zero crossing" or "crossing through the mains zero") of the alternating voltage U0. The detection of each zero crossing instant allows the electronic control unit CC to synchronize the control of the switch TR with respect to each zero crossing instant of the alternating voltage U0.

[0034] There are many devices for detecting each zero crossing instant of the alternating voltage U0. The zero crossing detection device CS1, CS2 could, for example and according to a first variant, consist of a current sensor CS1, the current sensor CS1 being inserted into the electronic control unit CC to detect a current flowing in the first diode D1. An output of the first current sensor CS1 is electrically connected to a first logic input IN1 of the processing circuit MC. The current sensor CS1 switches the logic input IN1 to the high state when the first diode D1 conducts. The processing circuit MC is thus able to identify the conduction or blocking state of the first diode D1.

[0035] By current sensor is meant any means for detecting the passage of an electric current in a branch in which the current sensor is inserted. The current sensor is preferably an optocoupler comprising a light-emitting diode electrically connected in series with the diode whose conduction state is to be determined, and configured as a current sensor, however other semiconductor devices can be used, for example a current transformer, a magnetoresistive sensor, or a Hall effect sensor. Equivalently, by current sensor is meant here any means for identifying the conduction of a diode. Thus, a device for detecting an electric voltage greater than the conduction threshold of the diode and capable of transmitting this conduction information to a logic input of the processing circuit MC is here a current sensor.

[0036] The main interest of this assembly is that the instant of end of conduction of the first diode D1 corresponds to the instant at which the alternating voltage U0 is cancelled when passing from a negative half-wave to a positive half-wave, in other words at the zero crossing of the alternating voltage U0 when passing from a negative half-wave to a positive half-wave. Here, as the phase conductor ACP is electrically connected to the first phase terminal P1, the instant of end of conduction of the first diode D1 therefore indicates the zero crossing of the alternating voltage U0 when passing from a negative half-wave to a positive half-wave. The frequency of the alternating voltage U0 being known because it is equal to the frequency of the alternating voltage source U0, the processing circuit MC simply has to calculate each zero crossing instant following the instant of end of conduction of the first diode D1 by the formula tn = t1 + n.(1 / 2.fs), where t1 corresponds to the instant of end of conduction of the first diode D1, n corresponds to one of the following iterations of the instant of end of conduction of the first diode D1, and fs corresponds to the value of the frequency of the alternating voltage source U0. For example, if the value of the frequency of the alternating voltage source U0 is equal to 50 Hertz, each instant of zero crossing of the alternating voltage U0 will be repeated periodically every 10 milliseconds from the instant of end of conduction of the first diode D1.

[0037] According to a second variant, the zero crossing detection device CS1, CS2, could consist of an open-loop comparator not shown, electrically connected to the phase conductor ACP, and whose output is connected to an input of the processing circuit MC. This comparator delivers a signal whose edges indicate the zero crossing of the alternating voltage U0 and therefore allow the processing circuit MC to synchronize the control of the switch TR with respect to each instant of zero crossing of the alternating voltage U0.

[0038] Advantageously, the TR switch is formed by a triac or by two thyristors mounted head to tail, that is to say by connecting the output of one of the two thyristors to the input of the other thyristor and vice versa.

[0039] Advantageously, an output terminal OUT of the processing circuit MC is electrically connected to a control terminal of the switch TR via an electrical signal shaping circuit SC. The electrical signal shaping circuit SC is configured to shape a control signal of the switch TR emitted by the processor or the microcontroller so that the control signal is compatible, in other words can cooperate with the switch TR. The detail of the electrical signal shaping circuit SC which comprises passive and / or active discrete components is not shown in the figures.

[0040] In a second embodiment of the invention, shown in figure 2, elements similar to those of the first embodiment bear the same references and function as explained above. In the following, we mainly describe what distinguishes this second embodiment from the first embodiment. In the following, when a reference sign is used in the description without being reproduced on the figure 2 or reproduced on the figure 2 without being mentioned in the description, it corresponds to the object bearing the same reference on the figure 1 .

[0041] We now describe, with reference to the figure 2 , the electromechanical actuator ACT according to the second embodiment of the invention and, more particularly, the electronic control unit CC of this electromechanical actuator ACT.

[0042] Here, the electromechanical actuator ACT can be configured to actuate a closing, occulting and / or sun protection device, such as a motorized blind, installed in a building having an opening in which a window or a door is arranged. This closing, occulting and / or sun protection device is equipped with a screen. The closing, occulting and / or sun protection device is hereinafter referred to as a occulting device, the occulting device comprising the screen.

[0043] Here, the electronic control unit CC further comprises a switch K. The switch K has at least two closed positions in which the phase conductor ACP is electrically connected to one or other of the two phase terminals P1, P2. The switch K may be manually operated, or be controlled by a relay coil which can itself be controlled by a remote command reception circuit not shown, such as for example a radio command receiver. The switch K may, furthermore, have a third open position in addition to the two closed positions, in which the phase conductor ACP is electrically disconnected from the two phase terminals P1, P2. The switch K may optionally not be part of the electromechanical actuator ACT.

[0044] Here, depending on whether the switch K is presented either in the first closed position or in the second closed position, the phase conductor ACP is selectively electrically connected either to the first phase terminal P1 to control the rotational drive of the electric motor MOT in a first direction DIR1, or to the second phase terminal P2 to control the rotational drive of the electric motor MOT in a second direction DIR2, the second direction DIR2 being opposite to the first direction DIR1.

[0045] In this case, the winding L1, L2 whose end, constituting a first phase terminal P1 or a second phase terminal P2, is selectively electrically connected to the phase conductor ACP, is referred to as the main winding, the other winding being referred to as the auxiliary winding. Thus, depending on whether a voltage is applied between the first phase terminal P1 and the common end N0, or between the second phase terminal P2 and the common end N0, either the phase shift capacitor CM is placed in series with the second winding L2 and the electric motor MOT rotates in a first direction DIR1, or the phase shift capacitor CM is placed in series with the first winding L1 and the electric motor MOT rotates in a second direction DIR2. The winding L1, L2 being in series with the phase shift capacitor CM is referred to as the auxiliary, the other winding L1, L2 then being referred to as the main.The electrical voltage U1, U2 present at the terminals of the winding L1, L2 located in series with the phase shift capacitor CM is called auxiliary voltage, and the electrical voltage present at the terminals of the other winding L1, L2 is then called main voltage.

[0046] The actuator ACT is assumed to be initially at rest. If the switch K is switched to the first phase terminal P1, in other words if the phase conductor ACP is electrically connected to the first phase terminal P1, the voltages U1 and U2 are out of phase by a quarter of a period (90°), the auxiliary voltage U2 being ahead of the main voltage U1. If the switch K is switched to the second phase terminal P2, in other words if the phase conductor ACP is electrically connected to the second phase terminal P2, the voltages U1 and U2 are out of phase by a quarter of a period (90°), the auxiliary voltage U1 being ahead of the main voltage U2.

[0047] Here, the zero crossing detection device CS1, CS2, of the electrical voltage U1, U2, present at the terminals of the main winding could for example and according to a first variant of the second embodiment, consist of two current sensors CS1, CS2, the two current sensors CS1 and CS2 being inserted in the electronic control unit CC to detect a current flowing in the first diode D1 and in the second diode D2. An output of the first current sensor CS1 is electrically connected to a first logic input IN1 of the processing circuit MC, and an output of the second current sensor CS2 is electrically connected to a second logic input IN2 of the processing circuit MC. Each current sensor CS1, CS2 switches the corresponding logic input IN1, IN2 to the high state when the corresponding diode conducts.The processing circuit MC is thus able to identify the conduction or blocking state of the first diode D1 and the second diode D2.

[0048] The main advantage of this assembly is that, when the phase conductor ACP is electrically connected to the first phase terminal P1, the instant of end of conduction of the first diode D1 corresponds to the instant at which the electrical voltage U1 is cancelled when passing from a negative half-wave to a positive half-wave, in other words when the electrical voltage U1 passes through zero when passing from a negative half-wave to a positive half-wave, and that the instant of start of conduction of the second diode D2 corresponds to the instant at which the electrical voltage U2 is cancelled when passing from a positive half-wave to a negative half-wave, in other words when the electrical voltage U2 passes through zero when passing from a positive half-wave to a negative half-wave.Similarly, when the phase conductor ACP is electrically connected to the second phase terminal P2, the instant of end of conduction of the second diode D2 corresponds to the instant at which the electrical voltage U2 is cancelled when passing from a negative half-wave to a positive half-wave, in other words when the electrical voltage U2 passes through zero when passing from a negative half-wave to a positive half-wave, and the instant of start of conduction of the first diode D1 corresponds to the instant at which the electrical voltage U1 is cancelled when passing from a positive half-wave to a negative half-wave, in other words when the electrical voltage U1 passes through zero when passing from a positive half-wave to a negative half-wave.

[0049] Here, the detection device CS1, CS2 is configured to identify the main winding by analyzing the instantaneous switching between the first diode D1 and the second diode D2, determine a first zero crossing instant of the alternating voltage U0 based on the identification of the main winding, then determine each zero crossing instant of the alternating voltage U0.

[0050] When the processing circuit MC detects, via the two current sensors CS1, CS2, an instantaneous switching of the second diode D2 to the first diode D1, it identifies the winding L1 as being the main winding, and determines a first instant of zero crossing of the alternating voltage U0 corresponding to an instant of end of conduction of the first diode D1. This instant of end of conduction of the first diode D1 indicating the zero crossing of the alternating voltage U0 during the transition from a negative half-wave to a positive half-wave, the processing circuit MC simply has to calculate each instant of zero crossing following the instant of end of conduction of the first diode D1 by the formula tn = t1 + n.(1 / 2.fs), where t1 corresponds to the instant of end of conduction of the first diode D1, n corresponds to one of the following iterations of the instant of end of conduction of the first diode D1, and fs corresponds to the value of the frequency of the alternating voltage source U0.

[0051] When the processing circuit MC detects, via the two current sensors CS1, CS2, an instantaneous switching of the first diode D1 to the second diode D2, it identifies the winding L2 as being the main winding, and determines a first instant of zero crossing of the alternating voltage U0 corresponding to an instant of end of conduction of the second diode D2. This instant of end of conduction of the second diode D2 indicating the zero crossing of the alternating voltage U0 during the transition from a negative half-wave to a positive half-wave, the processing circuit MC simply has to calculate each instant of zero crossing following the instant of end of conduction of the second diode D2 by the formula tn = t1 + n.(1 / 2.fs), where t1 corresponds to the instant of end of conduction of second diode D2, n corresponds to one of the following iterations of the instant of end of conduction of the second diode D2, and fs corresponds to the value of the frequency of the alternating voltage source U0.

[0052] According to a second variant of the second embodiment, the zero crossing detection device CS1, CS2, could consist of two open-loop comparators not shown, an input of the first comparator being electrically connected to the phase conductor ACP, the output of the first comparator being electrically connected to an input of the processing circuit MC. The comparator delivers a signal whose edges indicate the zero crossing of the alternating voltage U0, thus allowing the processing circuit MC to synchronize the control of the switch TR with respect to each instant of zero crossing of the alternating voltage U0.

[0053] There figure 3illustrates steps S1 to S4 of a method for starting a single-phase asynchronous type MOT electric motor with permanent capacitor, according to one embodiment. The starting method is implemented by the electronic control unit CC.

[0054] Steps S1 to S4 are described in the following, in correspondence with the figure 4which represents a time diagram of the electrical voltages U1 and U2 present at the terminals of the first winding L1 and the second winding L2 respectively, in the case where the phase conductor ACP is electrically connected to the first phase terminal P1. This case makes it possible to jointly illustrate the starting method implemented for an electromechanical actuator ACT according to the first embodiment and the second embodiment when the switch K is switched to the first position. In this case, the winding L1 is referred to as the main winding, the winding L2 being referred to as the auxiliary winding. On the figure 4 , the conduction periods of the first diode D1 and the second diode D2 are represented by double arrows.

[0055] The method comprises a first step S1 of detecting the zero crossing of the alternating voltage U0.

[0056] Advantageously, the first step S1 can be implemented from a predetermined time tc. Advantageously, the implementation of the first step S1 is implemented by the processing circuit MC of the electronic control unit CC when the processing circuit MC detects at time tc the fulfillment of a predetermined condition or a combination of predetermined conditions. For example, the processing circuit MC can trigger the implementation of the first step S1 when a first condition of stopping the electric motor MOT is met, and a second condition of changing the position of the switch K is met.The change in position of switch K can be detected by the processing circuit MC when the instantaneous switching sequence from the first diode D1 to the second diode D2 changes into an instantaneous switching sequence from the second diode D2 to the first diode D1, thus signifying a switch from the second closed position of switch K to the first closed position of switch K. A trigger condition for the implementation of the first step S1 can also be the reception of a control order received by the remote order reception circuit controlling the electronic control unit CC.

[0057] Advantageously, the first step S1 comprises a first sub-step S11 of determining the identity of the main winding of the electric motor MOT, a second sub-step S12 of detecting a first zero crossing instant of the alternating voltage U0, then a third sub-step S13 of determining the zero crossing instants of the alternating voltage U0 following the first zero crossing instant of the alternating voltage U0 detected during the second sub-step S12. During the first sub-step S11 of determining the identity of the main winding, the processing circuit MC can read from the memory a data item indicating the identity of the main winding, or analyze the instantaneous switching order of the first diode D1 and the second diode D2.

[0058] Advantageously, the first step S1 can be implemented at any time before the execution of the second step S2.

[0059] Advantageously, the first step S1 can be repeated periodically during the execution of the second step S2 and / or the third step S3, thus allowing the electronic control unit CC to adapt automatically when the frequency of the alternating voltage source U0 varies over time.

[0060] The starting method further comprises a second step S2 in which the electronic control unit CC controls, during a starting period T3, the switch TR in phase angle with respect to the alternating voltage U0.

[0061] Advantageously, the phase angle is between one twentieth (π / 10) and one eighth (π / 4) of a period of the alternating voltage U0.

[0062] The control of the switch TR in phase angle consists of a first series of pulses PL1, each pulse of the first series of pulses PL1 being emitted in phase angle with respect to each instant of zero crossing of the alternating voltage U0, and having a width PW1 adapted to maintain the switch TR in a closed state between each pulse of the first series of pulses PL1. Well known to the person skilled in the art, the emission of a pulse in phase angle with respect to the alternating supply voltage means that the pulse is emitted with a delay of a predetermined duration with respect to the instant of zero crossing of the alternating voltage. As illustrated in figure 4 , each pulse of the first series of pulses PL1 is emitted with a delay of a predetermined duration T1 relative to the corresponding instant of zero crossing of the alternating voltage U0.

[0063] Advantageously, the first width PW1 is determined so that a current Im passing through the motor at an instant corresponding to the falling edge of each pulse of the first series of pulses PL1 is greater than the holding current iL of the switch TR, the switch TR being made up of a triac or two thyristors mounted head to tail.

[0064] During the start-up period T3, the resistive circuit CR is electrically powered by the electrical energy present at the first phase terminal P1 and at the second phase terminal P2, the electrical energy available at each instant offset by the duration T1 relative to the zero crossing instant of the alternating voltage U0 being strictly greater than the energy available during the start-up period T3 at each zero crossing instant of the alternating voltage U0. In this way, the switch TR is maintained in an underpowered mode in which it receives electrical energy from the resistive circuit CR just sufficient to keep it active during the start-up period T3.

[0065] Advantageously, the width PW1 of each pulse of the first series of pulses PL1 can be set to a value between 0.2 milliseconds and 0.5 milliseconds.

[0066] The second step S2 may consist of a first sub-step S21 in which a first pulse is emitted with a predetermined delay T1 relative to a first zero crossing instant of the alternating voltage U0, then a second sub-step S22 in which, for a predetermined duration T3-T1, each pulse following the first pulse is emitted periodically at a predetermined interval T2, the predetermined interval T2 corresponding to the duration between each zero crossing instant of the alternating voltage U0.

[0067] Advantageously, the starting period T3 is determined so that the rotational drive of the electric motor MOT is initiated during the starting period T3, in other words so that the rotor of the electric motor MOT has overcome the starting torque of the electric motor MOT. In the example of the figure 4, the first series of pulses PL1 comprises six control pulses of the switch TR. For this purpose, the start period T3 can be set to a duration greater than 40 milliseconds, for example equal to 100 milliseconds, which corresponds to a number of pulses PL1 emitted greater than 4 and for example equal to 10.

[0068] The starting method further comprises a third step S3 in which the electronic control unit CC controls, following the starting period T3, the switch TR in full wave with respect to the alternating voltage U0. The control of the switch TR in full wave makes it possible in particular to reduce the electromagnetic emissions of the electric motor MOT, and thus to make the control of the electric motor MOT compliant with the standards in force.

[0069] The full-wave control of the TR switch consists of a second series of pulses PL2. Each pulse of the second series of pulses PL2 is emitted in synchronism with each instant of zero crossing of the alternating voltage U0. Each pulse of the second series of pulses PL2 has a width PW2 adapted to maintain the TR switch in a closed state between each pulse of the second series of pulses PL2.

[0070] Advantageously, the first width PW1 is determined so that a current Im passing through the motor at an instant corresponding to the falling edge of each pulse of the second series of pulses PL2 is greater than the holding current threshold iL of the switch TR, the switch TR being made up of a triac or two thyristors mounted head to tail.

[0071] Advantageously, the width PW2 of each pulse of the second series of pulses PL2 can be set to a value between 1 millisecond and 2 milliseconds, for example 1.2 milliseconds.

[0072] Advantageously, each pulse of the second series of pulses PL2 is centered on the corresponding zero crossing instant of the electrical voltage U1, U2 present at the terminals of the main winding. Alternatively, each rising edge or falling edge of each pulse of the second series of pulses PL2 is centered on the corresponding zero crossing instant.

[0073] Each pulse of the second series of pulses PL2 is emitted substantially in synchronism with, in other words centered on, each zero crossing instant of the alternating voltage U0. Here the expression "substantially" is interpreted as a technical characteristic produced within the technical tolerance margin of its manufacturing method. Indeed, the zero crossing detector CS1, CS2 may consist of optocouplers having a large variability, for example between series of components, with temperature or because of disturbances during measurement. As a result, a zero crossing instant detected by the zero crossing detector CS1, CS2 may be substantially offset from the actual zero crossing instant, and that consequently, each pulse of the second series of pulses PL2 is substantially offset from the corresponding actual zero crossing instant.

[0074] Advantageously, the starting method further comprises a fourth step S4 in which the electronic control unit interrupts the third step S3 in response to the fulfillment of a stopping condition of the electric motor MOT. A stopping condition of the electric motor MOT may be the disappearance of the rising edges on the inputs IN1, IN2, that is to say when the switch K is placed in the open position or when the motor blocks, for example following the encounter of an obstacle.

[0075] The starting process described with reference to the figures 3 And 4allows the MOT electric motor to be started with an undersized CR resistive circuit, for example with a higher resistance value R1, i.e. 69.90 kilo-ohms instead of 22 kilo-ohms. With such a resistance of 69.90 kilo-ohms, the electrical power dissipated in the CC control electronic unit in standby reaches 0.5 watts instead of 0.9 watts when the resistance R1 is set to 22 kΩ.

[0076] According to an example of realization illustrated by the figures 3 And 4 , the electric motor MOT is powered by an alternating voltage of 230 V - 50 Hz, the value fs of the frequency of the alternating voltage source U0 being here equal to 50 Hertz. In this example of realization, the switch TR is a triac, the value of the resistance R1 of the resistive circuit CR is equal to 61.9 kilo-ohms.

[0077] It is assumed as initial conditions preceding an instant tk, that the value fs of the frequency of the alternating voltage source U0 recorded in the memory of the electronic control unit CC, that the electric motor MOT is in the rest state, that the switch K is positioned in the second closed position in which the second phase terminal P2 is electrically connected to the phase conductor ACP, and that the processing circuit MC of the electronic control unit CC has detected that the main winding is the winding L2 by analyzing the instantaneous switching order of the first diode D1 to the second diode D2. The electronic control unit CC consumes 0.5 watts in standby.

[0078] At time tk, switch K is switched from the second closed position to the first closed position in which the first phase terminal P1 is electrically connected to the phase conductor ACP. An electrical voltage U2 appears across the terminals of the second winding L2, and an electrical voltage U1 appears across the terminals of the first winding L1, the electrical voltage U2 being 90° ahead of the electrical voltage U1.

[0079] The electronic control unit CC determines at time tc an instantaneous switching of the second diode D2 to the first diode D1, and that thus two conditions for executing the starting method are fulfilled, the first condition corresponding to the rest state of the electric motor MOT, the second condition corresponding to an instantaneous change of switching order between the first diode D1 and the second diode D2.

[0080] The processing circuit MC of the electronic control unit CC implements the first step S1 in which it detects at a time t1 a first time t1 of zero crossing of the electrical voltage U1 present at the terminals of the main winding, the main winding corresponding here to the winding L1. The processing circuit MC then determines each time tn of zero crossing of the electrical voltage U1 following the first time t1 as a function of the value fs of the frequency of the alternating voltage source U0 recorded in the memory of the electronic control unit CC.

[0081] The processing circuit MC of the electronic control unit CC implements the second step S2 in which it emits during a start-up period T3 equal to 52.5 milliseconds, a first series PL1 of six control pulses of the triac TR, each pulse of the first series of pulses PL1 being emitted with a delay of 2.5 milliseconds with respect to each corresponding instant of zero crossing of the alternating voltage U0, and having a width PW1 of 0.5 milliseconds. The rotational drive in the direction DIR1 of the electric motor MOT is initiated as soon as the first pulse of the first series of pulses PL1 is emitted on the trigger of the triac TR.

[0082] The processing circuit MC of the electronic control unit CC implements, following the second step S2, the third step S3 in which it emits a second series PL2 of six control pulses of the triac TR, each pulse of the second series of pulses PL2 being emitted in synchronism with respect to each corresponding instant of zero crossing of the alternating voltage U0, and having a width PW2 of 2 milliseconds. The rotational drive in the direction DIR1 of the electric motor MOT is maintained throughout the duration of emission of the second series of pulses PL2.

[0083] It will be clear to those skilled in the art that the present invention is susceptible to various variant embodiments and various applications. In particular, the invention is not limited to particular values ​​of the phase angle of the control of the TR switch in phase angle. Indeed, values ​​other than those indicated above may be suitable for controlling the switch.

Claims

1. A method for starting an electric motor (MOT) configured to be electrically connected to a phase conductor (ACP) and to a neutral conductor (ACN) of an alternating voltage source (U0), the electric motor (MOT) comprising a stator, the stator of the electric motor (MOT) comprising two windings (L1, L2), the two windings (L1, L2) each comprising a common end (N0) so as to electrically link them together, the common end (N0) being electrically linked to the neutral conductor (ACN) via a switch (TR), each of the two windings (L1, L2) comprising another end constituting a first phase terminal (P1) and a second phase terminal (P2) respectively, the first phase terminal (P1) being electrically linked to the second phase terminal (P2) via a phase-shifting capacitor (CM), the phase conductor (ACP) being selectively either electrically connected to the first phase terminal (P1) to control the rotational drive of the electric motor (MOT) in a first direction (DIR1), or electrically connected to the second phase terminal (P2) to control the rotational drive of the electric motor (MOT) in a second direction (DIR2), the second direction (DIR2) being opposite to the first direction (DIR1), the switch (TR) being operated by an electronic control unit (CC), the electronic control unit (CC) comprising a device (CS1, CS2) for detecting zero crossing of the alternating voltage (U0), characterized in that the starting method is implemented by the electronic control unit (CC), and in that the electronic control unit (CC) controls, during a starting period (T3), the switch (TR) in phase angle with respect to the alternating voltage (U0), then, following the starting period (T3), controls the switch (TR) in full wave with respect to the alternating voltage (U0), the phase angle control of the switch (TR) consisting of a first series of pulses (PL1), each pulse of the first series of pulses (PL1) being emitted in phase angle with respect to each instant of zero crossing of the alternating voltage (U0) and having a first width (PW1), the full wave control of the switch (TR) consisting of a second series of pulses (PL2), each pulse of the second series of pulses (PL2) being emitted in synchronism with each instant of zero crossing of the alternating voltage (U0) and having a second width (PW2), the first width (PW1) and the second width (PW2) being adapted to maintain the switch (TR) in a closed state between each pulse of the first series of pulses (PL1) and between each pulse of the second series of pulses (PL2).

2. The starting method according to claim 1, characterized in that the phase angle of the phase angle control of the switch (TR) is comprised between one twentieth and one eighth of a period of the alternating voltage (U0).

3. The starting method according to any one of the preceding claims, characterized in that the duration of the starting period (T3) is determined so that the rotational drive of the electric motor (MOT) is initiated during the starting period (T3).

4. An electro-mechanical actuator (ACT) comprising at least one electric motor (MOT) configured to be electrically connected to a phase conductor (ACP) and to a neutral conductor (ACN) of an alternating voltage source (U0), the electric motor (MOT) comprising a stator, the stator of the electric motor (MOT) comprising two windings (L1, L2), the two windings (L1, L2) each comprising a common end (N0) so as to electrically link them together, the common end (N0) being electrically linked to the neutral conductor (ACN) via a switch (TR), each of the two windings (L1, L2) comprising another end constituting a first phase terminal (P1) and a second phase terminal (P2) respectively, the first phase terminal (P1) being electrically linked to the second phase terminal (P2) via a phase-shifting capacitor (CM), the phase conductor (ACP) being selectively either electrically connected to the first phase terminal (P1) to control the rotational drive of the electric motor (MOT) in a first direction (DIR1), or electrically connected to the second phase terminal (P2) to control the rotational drive of the electric motor (MOT) in a second direction (DIR2), the second direction (DIR2) being opposite to the first direction (DIR1), the switch (TR) being operated by an electronic control unit (CC), the electronic control unit (CC) comprising a device (CS1, CS2) for detecting zero crossing of the alternating voltage (U0), characterized in that the electronic control unit (CC) is configured to implement the starting method according to any one of claims 1 to 3.

5. The electro-mechanical actuator (ACT) according to the preceding claim, characterized in that the electronic control unit (CC) comprises a device (CS1, CS2) for detecting zero crossing of the alternating voltage (U0).

6. The electro-mechanical actuator (ACT) according to any one of claims 4 or 5, characterized in that the electro-mechanical actuator is configured to actuate a heating and / or ventilation and / or air conditioning device.

7. The electro-mechanical actuator (ACT) according to any one of claims 4 to 6, characterized in that the phase conductor (ACP) comprises a switch (K) configured to selectively either electrically link the first phase terminal (P1) to the phase conductor (ACP) to control the rotational drive of the electric motor (MOT) in a first direction (DIR1), or electrically link the second phase terminal (P2) to the phase conductor (ACP) to control the rotational drive of the electric motor (MOT) in a second direction (DIR2), the second direction (DIR2) being opposite to the first direction (DIR1).

8. The electro-mechanical actuator (ACT) according to the preceding claim, characterized in that the electro-mechanical actuator (ACT) is configured to actuate a blackout device.

9. The electro-mechanical actuator (ACT) according to any one of claims 4 to 8, characterized in that the switch (TR) consists of a triac or two back-to-back mounted thyristors.

10. The electro-mechanical actuator (ACT) according to any one of claims 4 to 9, characterized in that the electronic control unit (UC) further comprises a resistive circuit (CR) electrically linked to the first phase terminal (P1), to the second phase terminal (P2), and to the neutral conductor (ACN), the resistive circuit (CR) being configured to electrically power the electronic control unit (CC) from the alternating voltage source when the phase conductor (ACP) is electrically connected to either one of the two phase terminals (P1, P2).