Control system for the motorized micro-blower of a respiratory assistance device

Abstract

Title of the invention Control system for the motorized micro-blower of a respiratory assistance device The invention relates to a respiratory assistance device (100) comprising a micro-blower (2) with an electric motor (3), a motor control system (5) and a power supply (4) supplying the electric motor (3) and the control system (5) via a power bus (20). The control system (5) comprises a transistor bridge circuit (80), arranged between the power supply (4) and the electric motor (3), comprising 3 transistor bridges (90, 91, 92) arranged in parallel, each transistor bridge (90, 91, 92) connecting the bus (20) to the motor (3) and comprising a pair of transistors (T1-T6). A motor control circuit (100) controls at least the accelerations and decelerations of the motor (3), and is electrically connected to the motor (3) and to the transistors (T1-T6).Voltage regulating diodes (D1-D6) are arranged in parallel with the transistors (T1-T6) to limit the overvoltages of the motor (3), during deceleration or braking of the motor (3). Abstract figure: Fig. 4.

Description

Title of the invention: Control system for the motorized micro-blower of a respiratory assistance device

[0001] The invention relates to a system for controlling the operation of the motorized micro-blower of a respiratory assistance device, i.e. a medical ventilator, used to supply a respiratory gas, such as a flow of air enriched or not with oxygen, to a patient to treat one or more respiratory pathologies in this patient, in particular accelerations and braking of the micro-blower.

[0002] In order to assist certain patients in their respiratory function, respiratory assistance devices, also called "medical ventilators", are used, delivering a respiratory gas, such as air or oxygen-enriched air, at a non-zero flow rate and / or at a pressure higher than atmospheric pressure (> 1 atm).

[0003] These respiratory assistance devices use a motorized micro-blower, also called a “blower”, “compressor” or “turbine”, used to suck in ambient air and deliver it at a given pressure to patients.

[0004] The suction of air by the micro-blower, during the operation of its electric motor, is done by means of one or more vaned wheels arranged on a rotating shaft or axis driven in rotation by an electric motor, the vaned wheel(s) being mobile in rotation in the internal compartment of a volute.

[0005] The air may be enriched with oxygen, i.e. supplemental oxygen may be added, in particular when the patient is to receive, as part of his treatment, a proportion of oxygen greater than 21% by volume. The oxygen may be mixed with the air upstream or downstream of the internal compartment of the volute.

[0006] Examples of such technologies are given by EP-A-2165078, EP-A-2102504, WO-A-2012 / 139681, US-A-2008 / 304986 and WO-A-2013 / 020167.

[0007] During operation of the medical ventilator, the electric motor of the micro-blower is controlled by control means of the medical ventilator and cyclically undergoes successive acceleration and deceleration phases, i.e. braking or slowing down, modeled on the inspiratory and expiratory phases of the patient, respectively.

[0008] However, during braking phases, i.e. decelerations or slowdowns, of the electric motor, the existence of significant electrical overvoltages is observed which are generated by the motor, when the short circuit of each motor phase is released in a braking situation.

[0009] More specifically, energy stored in the coils of the electric motor is suddenly released into the power bus connecting the current source to the motor, causing an increase in the general supply voltage and potentially causing damage to the components located on this bus.

[0010] Furthermore, these phenomena are harmful to the medical ventilator because they reduce the performance, in particular of the means of controlling the electric motor and affect their lifespan.

[0011] It is therefore necessary to protect the sensitive components of the medical ventilator against overvoltages or other energy peaks which may occur during operation of the ventilator, in particular during braking phases of the electric motor of the micro-blower, i.e. during decelerations or slowdowns of the motor.

[0012] US-A-2011 / 162647 attempts to solve this problem by recovering energy from braking and storing it in the medical ventilator's battery. This solution is, however, complicated to implement because it requires the installation of a specific and fairly complex energy recovery circuit, the efficiency of which is questionable.

[0013] EP-A-3017345 proposes installing an absorption diode circuit transient, i.e. with one or more transient voltage absorption diodes or TVS (i.e. Transient Voltage Suppressor), on the bus between the power supply and the motor to absorb the energy generated during braking. However, such a transient blocking circuit arranged on the bus is not ideal because it does not always effectively protect the components, due to a protection threshold of this type of diode being rather imprecise.

[0014] In view of this, the problem is therefore to propose a respiratory assistance device, i.e. a medical ventilator, equipped with a system for controlling the motorized micro-blower which allows effective control of the accelerations and decelerations (i.e. braking / slowing down) of the micro-blower and which is also effectively protected against electrical surges, energy peaks or the like, generated during the deceleration / braking phases of the electric motor of the micro-blower, so as to avoid or limit the deterioration of the electronic components sensitive to these electrical surges or the like.

[0015] The invention relates to a respiratory assistance apparatus, i.e. a medical ventilator, for providing respiratory gas to a patient (i.e. a human being) comprising:

[0016] - a micro-blower equipped with an electric motor, i.e. a motorized micro-blower, - a motor control system for controlling the electric motor of the micro-blower, and - a power supply electrically supplying the electric motor and the control system via a power bus connecting the power supply to the electric motor of the micro-blower.

[0017] According to the invention, the control system comprises:

[0018] - a transistor bridge circuit, arranged between the power supply and the electric motor, comprising 3 transistor bridges arranged in parallel, each transistor bridge connecting the bus to the motor and comprising a pair of transistors, - a motor control circuit for controlling at least the accelerations and decelerations (i.e. braking or slowing down) of the motor, said motor control circuit being electrically connected to the motor and to the transistors, and - a plurality of voltage regulating diodes arranged in parallel with the transistors to limit at least part of the overvoltages (i.e. voltage or energy peaks) of the motor during decelerations (i.e. braking or slowing down) of the motor.

[0019] In the context of the present invention, by "voltage regulating diode" is meant a diode making it possible to have a fixed reverse voltage threshold, that is to say equal to a given value varying little or not at all as a function of the current, typically a Zener diode or the like, and this, unlike a T VS diode which has a voltage varying significantly with the current, that is to say which is a variable voltage diode.

[0020] Depending on the embodiment considered, the respiratory assistance device, i.e. the medical ventilator, according to the invention may comprise one or more of the following characteristics:

[0021] - it further comprises, arranged between the power supply and the electric motor, a switching device for controlling the flow of current in the power supply bus towards the motor. - the switching device includes a MOS transistor. - the switching device is controlled by the control circuit. - it further comprises, arranged between the power supply and the electric motor, at least one current blocking diode rising to block the current generated by the motor and flowing in the power supply bus towards the power supply, during deceleration of the motor, i.e. braking or the like. - said at least one upstream current blocking diode is at least one Schottky diode or the like. - it further comprises arranged between the power supply and the electric motor, typically on the bus, at least one clipping diode, i.e. an additional voltage regulating diode, used to limit at least one part of the power supply surges flowing in the bus. said at least one clipping diode is at least one Zener diode or the like. it further comprises at least one capacitor, arranged between the power supply and the electric motor, to supply current to the motor, during acceleration of the motor, and to limit at least part of the motor overvoltages during deceleration of the motor. the switching device and / or the rising current blocking diode(s) are arranged on the power bus, in particular on the (+) branch of the bus. it also includes a current limiting circuit configured to limit the current flowing in the bus to the motor, when the switching device is closed. The current limiting circuit comprises a resistor and capacitor RC circuit, configured to set a control time constant of the switching device. the current limiting circuit is controlled by the driver circuit, preferably a driver circuit microcontroller. the transistor bridge circuit comprises a first, a second and a third transistor bridge and the motor comprises a first, a second and a third phase, the first, second and third transistor bridges being respectively connected to the first, second and third phases of the motor, that is to say that each transistor bridge is electrically connected to only one of the 3 phases of the motor and each of the 3 phases of the motor is electrically connected to only one of the 3 transistor bridges. the first, second and third phases of the motor are, respectively, electrically connected to the first, second and third transistor bridges respectively between the two transistors of each pair of transistors and between the two voltage regulating diodes of the pairs of voltage regulating diodes arranged in parallel with said transistors. The voltage regulating diodes are Zener diodes or similar. The voltage regulator diodes are not TVS transient suppression diodes, especially not Transil® or Transzorb® type diodes. The micro-blower is equipped with a brushless electric motor (i.e. "brushless" in English). the motor control circuit comprises a microprocessor, preferably it comprises a microcontroller.

[0022] - the motor control circuit comprises a microprocessor arranged on an electronic card, i.e. printed circuit card. The power bus includes electrical connections such as printed circuits, cables or electrical wires. The power supply includes one or more rechargeable batteries and / or a power cord, an AC / DC converter and a mains connection plug (i.e. 110 / 220 V). the power supply is of the AC / DC type (alternating voltage / direct voltage) providing a voltage of less than 30 V (direct voltage), for example around 28 V. the power supply provides electric current to all components or elements of the device requiring electric current to operate, in particular to the micro-blower motor, the control circuit, etc. the micro-blower is controlled by the motor control circuit to operate according to cycles alternating phases of gas supply and non-supply (i.e. stopping) of gas to the patient. during the gas supply phases, the micro-blower motor undergoes accelerations. during the phases of non-supply of gas, the micro-blower motor undergoes decelerations, i.e. braking or slowing down. The electric motor of the micro-blower is protected by an external protective casing, preferably rigid. The micro-blower comprises a volute delimiting an internal compartment in which the impeller is arranged. The micro-blower is equipped with an electric motor driving a shaft, also called a rotary axis, carrying one or more impellers. the volute comprises an upper opening serving as a gas inlet into the internal compartment, said gas being drawn in by the impeller during its operation. the volute comprises a gas outlet conduit in fluid communication with the internal compartment, for extracting from said internal compartment, a gas flow generated by the impeller, when said impeller is rotated by the shaft. the volute is formed of two half-volutes, namely a lower volute and an upper volute fixed to each other in a watertight manner. the two half-volutes define the internal compartment between them. The micro-blower delivers air or an air / oxygen mixture. it also includes a box, i.e. case or similar, within which is arranged the motorized micro-blower. - the box includes an air inlet in fluid communication with an air inlet orifice through which air enters the device. - according to one embodiment, the housing comprises an oxygen inlet in fluid communication with an oxygen inlet port, typically an oxygen supply connection, through which oxygen from an oxygen source, such as an oxygen cylinder or an oxygen supply line, can enter the apparatus. - the box includes a gas flow outlet (e.g. air or air / O2) in fluid communication with the gas outlet duct of the volute. - the box is made of polymer or any other material. - according to one embodiment, the box is formed of two box parts, that is to say typically of 2 half-boxes, fixed to each other. - the box is arranged in the frame of the medical ventilator. - alternatively, the micro-blower is arranged directly in the casing of the medical ventilator. - the engine is controlled to rotate at a speed of up to 50,000 to 70,000 rpm, typically 30,000 to 40,000 rpm. - the electric motor consists of a rotor and a stator. - it includes an HMI or human-machine interface. - it includes a display screen, i.e. information display. - it is of the continuous pressure (CPAP) type, with continuous flow, with two levels of pressure (BiPAP), or other, and / or emergency.

[0023] The invention also relates to an installation for supplying respiratory gas to a patient comprising a respiratory assistance device according to the invention, a flexible conduit fluidically connected to said respiratory assistance device and supplied with gas by the micro-blower of said respiratory assistance device, and a respiratory interface, for example a mask, nasal cannulas, a tracheal tube or the like, supplied with gas by said flexible conduit, typically air or an air / O2 mixture.

[0024] Advantageously, a source of oxygen, such as a pressurized oxygen cylinder, is fluidically connected to the respiratory assistance device according to the invention in order to provide it with oxygen enabling the air to be enriched and an air / O2 mixture to be obtained.

[0025] The invention will now be better understood thanks to the following detailed description, given for illustrative but non-limiting purposes, with reference to the appended figures among which:

[0026] [fig. 1] shows schematically an embodiment of a respiratory assistance device with motorized micro-blower according to the invention,

[0027] [fig.2] details the micro-blower compartment of the device of [fig.l],

[0028] [fig.3] is a schematic side view of the micro-blower of [fig.2] and

[0029] [fig.4] schematizes an embodiment of a system for controlling the engine of the micro-blower according to the invention.

[0030] [fig.l] schematizes an embodiment of a respiratory assistance device 1, also called a medical ventilator 1, equipped with a motorized micro-blower 2 (visible in [fig.2]]), also called a turbine or compressor, a control system 5 according to the invention, and a power supply 4, for example one (or more) battery(ies) and / or means of connection to the mains (110 / 220 V), such as an electric cord, an AC / DC converter and a mains connection socket or others. Preferably, the power supply is of the AC / DC type providing a voltage of the order of 28 V.

[0031] For example, the medical ventilator 1 may be a respiratory assistance device delivering gas at one or more pressure levels, i.e. of the CP AP or BPAP type. In general, the medical ventilator 1 is intended to treat respiratory pathologies in human patients, adults and / or children.

[0032] The motorized micro-blower 2 is, in this embodiment, arranged in an internal box 10 itself inserted in the peripheral casing 9 or external shell of the medical ventilator 1. According to another embodiment, the micro-blower 2 can be installed directly in the casing 9 of the medical ventilator 1, that is to say without using a box 10.

[0033] Furthermore, the casing 9 of the medical ventilator 1 comprises, in this embodiment, an air inlet 11 used to supply air to the micro-blower 2, an oxygen inlet 12 used to supply oxygen in order to be able to enrich the air with oxygen and thus obtain air / O2 mixtures, and a respiratory gas outlet 13 making it possible to supply the patient with respiratory gas, typically air or an air / O2 mixture, coming from the outlet of the micro-blower 2.

[0034] The oxygen inlet 12 of the medical ventilator 1 is in fluid communication with an oxygen inlet 22 of the box 10 and, similarly, the air inlet 11 and the respiratory gas outlet 13 of the ventilator 1 are in fluid communication with, respectively, an air inlet 21 and a respiratory gas outlet 23 of the box 10. According to another embodiment, it can be provided that the injection of oxygen takes place rather downstream of the micro-blower.

[0035] Optionally, the frame 9 of the medical ventilator 1 may include a carrying handle 14 facilitating its transport by a user.

[0036] Of course, the medical ventilator 1 can also include other conventional elements or components (not shown diagrammatically) commonly used in this type of device, such as pressure and / or flow sensors, pneumatic control devices, a display screen, a human-machine interface (HMI) for adjusting or selecting ventilation parameters (pressure levels, volumes, ventilation modes, etc.) including selection devices (e.g. buttons, digital keys, sliders, etc.), a button for starting or stopping (i.e. “on / off” button) the ventilator 1, etc.

[0037] [fig.2] illustrates the arrangement of the motorized micro-blower 2 within the box 10. The box 10 is formed here of two box parts, that is to say two half-boxes which are fixed to each other, for example by taking the motorized micro-blower 1 in a 'sandwich'. Of course, a different architecture of the box is possible. The box 10 may comprise other elements, in particular one or more gas circuits or the like, sensors or others. The box 10 is optional, that is to say that the micro-blower 2 could be arranged directly in the casing 10 of the fan 1.

[0038] As shown schematically in [fig.3], the motorized micro-blower 2 comprises a casing 16 containing an electric motor (not visible) and serving to protect it, in particular the stator and the rotor of the motor. The external casing 16 may be formed from a metal alloy, for example an aluminum alloy or ZAMAK (zinc, aluminum, magnesium and copper alloy), or from polymer or thermoplastic, for example PET or PA. The casing 16 generally has a circular section, that is to say a generally cylindrical shape. It may also include cooling fins or structures acting as a radiator.

[0039] The electric motor 3 is a rotary motor, typically with rotor and stator, preferably brushless. It is designed to reach a rotation speed, at the end of acceleration, of the order of 30,000 to 40,000 rpm, or even up to 50,000 to 70,000 rpm. The control of the operation (i.e. accelerations and decelerations / braking) of the electric motor 3 is explained below.

[0040] The electric current supply to the electric motor 3 of the micro-blower 2 to enable its operation is done in a conventional manner by means of suitable connections 17 including a power supply bus 20, for example electric wires or cables, bringing the electric current from the power supply 4 (see [fig.l]), for example one (or more) electric power supply batteries, as explained above, to the electric motor 3.

[0041] During its operation, the motor of the micro-blower 1 drives in rotation a shaft or rotary axis, also called 'motor axis', carrying a vaned wheel, also called 'blade wheel'. This vaned wheel preferably has a circular section with a diameter of between 20 and 80 mm, typically between 30 and 60 mm. The vaned wheel comprises a first face carrying vanes, also called 'blades' and a second face without fins, i.e. flat, which is further located opposite the motor and the casing 16. The impeller is arranged so as to be movable in rotation within the internal compartment 18 of the volute 7 surmounting the electric motor 3 and the casing 16, so as to generate a gas flow at a pressure higher than atmospheric pressure (> 1 atm).

[0042] Preferably, the impeller and the volute 7 are made of polymer material(s), for example a thermoplastic (eg PEEK, PA, etc.), or of a metal alloy, for example an aluminum-based alloy.

[0043] Depending on the embodiment chosen, the volute 7 may be formed of two half-volutes, namely a lower half-volute and an upper half-volute assembled and fixed in a solid and sealed manner to each other, for example by gluing or otherwise. A sealing gasket may be interposed between these half-volutes. The volute 7 has a generally circular section. It further comprises an upper opening 15 through which the gas, typically air or an air / O2 mixture, is sucked into the internal compartment 18 of the volute 7, during rotations of the wheel, and an outlet duct 19 through which the flow of respiratory gas generated in the compartment 18, during rotations of the wheel, leaves the micro-blower 2. The air / O2 mixture entering the volute 7 is preferably produced upstream of the upper opening 15, for example in a mixing chamber (not shown) arranged in the box 10.

[0044] The outlet duct 19 is in fluid communication with the respiratory gas outlet 23 of the box 10 and the respiratory gas outlet 13 of the ventilator 1 so that the gas leaving the internal compartment 18 of the volute 7 circulates successively in the outlet duct 19, the respiratory gas outlet 23 of the box 10 and the respiratory gas outlet 13 of the ventilator 1, before being conveyed to the patient's airways via a flexible pipe or the like supplying a respiratory interface, such as a respiratory mask or a tracheal tube for example.

[0045] During operation of the medical ventilator 1, the electric motor 3 of the micro-blower 2 is controlled by the control system 5 of the medical ventilator 1 acting as control means.

[0046] As detailed below, the control system 5 comprises one (or more) electronic microprocessor card(s), typically a microcontroller, implementing one or more algorithms. The control system 5 is configured to control the operation of the electric motor 3. It is supplied with electric current from the power supply 4.

[0047] More precisely, the electric motor 3 of the micro-blower 2 is controlled by the control system 5 to cyclically operate successive acceleration and deceleration / braking phases so as to match the patient's inspiratory and expiratory phases.

[0048] However, during the braking phases, that is to say decelerations / slowing down, of the electric motor 3, significant electrical surges or energy peaks are generated by the motor 3, when the short circuit of each motor phase is released in a braking situation. Energy stored in the coils of the electric motor 3 is then suddenly released into the power supply bus 20 connecting the current source 4 to the electric motor 3 of the micro-blower 2, thereby causing an increase in the general power supply voltage and consequent heating of the components located on this bus 20, which can damage them.

[0049] To remedy this, according to the invention, as illustrated in [fig.4], the control system 5 comprises a transistor bridge circuit 80, arranged between the electrical power supply 4 and the electric motor 3 of the micro-blower 2.

[0050] The transistor bridge circuit 80 comprises 3 transistor bridges 90, 91, 92 which are arranged in parallel with each other. Each transistor bridge 90, 91, 92 connects the bus 20 to the motor 3 of the micro-blower 2, and comprises a pair of transistors T1 / T4, T2 / T5, T3 / T6, i.e. three pairs of transistors T1-T6. The transistor bridges 90, 91, 92 are used to control the rotation of the motor 3 of the micro-blower 2.

[0051] More specifically, the transistor bridge circuit 80 comprises a first, a second and a third transistor bridge 90, 91, 92 which are respectively connected to the first, second and third phases A, B, C of the motor 3, as illustrated in [fig.4]. The first, second and third phases A, B, C of the motor 3 are, respectively, electrically connected to the first, second and third transistor bridges 90, 91, 92, respectively between the two transistors T1-T6 of each pair of transistors T1-T6, and furthermore, between the two voltage regulating diodes D1-D6 of the pairs of voltage regulating diodes D1-D6 arranged in parallel with said transistors T1-T6.

[0052] The voltage regulation diodes D1-D6, namely here 6 diodes, are arranged in parallel with the transistors T1-T6 to limit at least part of the overvoltages or the like of the motor 3, during braking / deceleration of the motor 3 of the micro-blower 2. Preferably, the voltage regulation diodes D1-D6 are Zener diodes.

[0053] Generally speaking, a Zener diode is an assembly of semiconductors allowing the passage of current in the forward direction, i.e. normal direction, but also in the reverse direction when the voltage across its terminals is higher than its reverse voltage threshold, i.e. Zener or avalanche voltage, from which the avalanche effect of the diode is triggered, for example a threshold of the order of 30 to 33 V in the context of the present invention. Unlike a TVS diode, a Zener diode does not absorb the transient current but maintains or limits the voltage at its threshold level. From the moment the voltage becomes higher than its holding voltage, it will absorb all the current to limit this voltage, thus providing a relatively fixed regulation voltage. A Zener diode is therefore a voltage regulation diode.

[0054] As illustrated in [fig.4], a motor control circuit 100 is also provided to control at least the accelerations and decelerations of the motor 3 of the micro-blower 2, which is electrically connected to the motor 3, via the links S_A, S_B and S_C, and to the 6 transistors T1-T6, via the links CDE_T1 / T4, CDE_T2 / T5, and CDE_T3 / T6.

[0055] The control circuit 100 of the motor comprises at least one microprocessor, preferably at least one microcontroller, which implements one or more algorithms. It is arranged on at least one electronic card.

[0056] The control circuit 100 of the motor, in particular the microcontroller, also controls the speed of the motor 3 of the micro-blower 2, that is to say the stabilized speed of the motor 3. To do this, the control circuit 100, in particular the microcontroller, generates a pulse width modulation (PWM) of average voltage between 0 and 5 V approximately which controls the speed of the motor 3 of the micro-blower 2.

[0057] The control means 100 are supplied with electric current by the bus 20, via a voltage step-down device arranged between them.

[0058] The motor control circuit 100 further comprises inputs and outputs, namely:

[0059] - a braking control output F allowing braking to be activated by controlling only the transistors T4, T5 and T6 of the transistor bridge circuit 80. - 3 inputs S_A, S_B and S_C connected to the hall effect sensors present in motor 3 of micro-blower 2 and allow to indicate the position of the rotor of motor 3 and, with the speed setpoint, to position the levels (for example 0 or 1) on the controls (CDE_T1, CDE_T2, CDE_T3, CDE_T4, CDE_T5 and CDE_T6) of transistors T1-T6. - a speed control input V connected to the speed control output of the microcontroller of the control circuit 100, which sets the speed of the motor 3 of the micro-blower 2 according to the patient's ventilation cycle.

[0060] The motor control circuit 100 may comprise one or more electronic cards including a card carrying the transistor bridge circuit 80.

[0061] Arranged between the power supply 4 and the electric motor 3, there is also provided a switching device 30, for example a MOS transistor, which is configured to control the flow of current in the power supply bus 20 towards the motor 3 and a current limiting circuit 40 which is configured to limit the current flowing in the bus 20 towards the motor 3, when the switching device 30 is closed. The power supply 4 is coupled to the switching device 30.

[0062] The current limiting circuit 40 comprises a resistor and capacitor RC circuit, which makes it possible to set the control time constant of the switching device 30. The current limiting circuit 40 is itself controlled by the microcontroller of the control circuit 100, via the input P of the current limiting circuit 40.

[0063] In addition, the control system 5 also comprises, arranged between the power supply 4 and the electric motor 3, a current-blocking diode 50, for example a Schottky diode or the like having a fairly low forward voltage threshold, for example less than 0.7 V, configured to block the current generated by the motor 3 and flowing in the power supply bus 20 towards the power supply 4, during decelerations of the motor 3, and a clipping diode 60 or additional voltage-regulating diode, for example a Zener diode or the like, configured to limit any possible overvoltage of the power supply 4. The threshold of the clipping diode 60 is preferably of the order of 30 to 33 V.

[0064] Alternatively, instead of the rising current blocking diode 50, a MOSFET transistor and an ideal diode driver or controller may be used.

[0065] Finally, one or more capacitors 70 are arranged between the power supply 4 and the electric motor 3. It makes it possible to supply electric current to the rotary electric motor 3 of the micro-blower 2, during current calls at the time of acceleration of the motor 3, and to limit at least part of the overvoltages of the motor 3 during decelerations of said motor 3 of the micro-blower 2.

[0066] As seen in [fig.4], the switching device 30 and the rising current blocking diode 50 are arranged on the power supply bus 20 on the (+) branch of the bus.

[0067] Such an architecture of the control system of the motorized micro-blower of a respiratory assistance device or medical ventilator according to the invention allows effective control of the accelerations and decelerations / braking of the micro-blower while being effectively protected against electrical surges, energy peaks or the like, which are generated during the deceleration / braking phases of the electric motor of the micro-blower, which makes it possible to avoid or limit the deterioration of the electronic components sensitive to these electrical surges or the like.

Claims

Claims

1. Respiratory assistance apparatus (1) comprising: - a micro-blower (2) equipped with an electric motor (3), - a motor control system (5) for controlling the electric motor (3) of the micro-blower (2), and - a power supply (4) electrically supplying the electric motor (3) and the control system (5) via a power supply bus (20) connecting the power supply (4) to the electric motor (3) of the micro-blower (2), characterized in that the control system (5) comprises: - a transistor bridge circuit (80), arranged between the power supply (4) and the electric motor (3), comprising 3 transistor bridges (90, 91, 92) arranged in parallel, each transistor bridge (90, 91, 92) connecting the bus (20) to the motor (3) and comprising a pair of transistors (T1, T4; T2, T5 ;T3, T6), - a motor control circuit (100) for controlling at least the accelerations and decelerations of the motor (3), said motor control circuit (100) being electrically connected to the motor (3) and to the transistors (T1, T4; T2, T5; T3, T6), and - a plurality of voltage regulating diodes (D1-D6) arranged in parallel with the transistors (T1, T4; T2, T5; T3, T6) to limit at least part of the overvoltages of the motor (3) during decelerations of the motor (3).;

2. Apparatus according to claim 1, characterized in that it further comprises, arranged between the power supply (4) and the electric motor (3), a switching device (30) for controlling the flow of current in the power supply bus (20) towards the motor (3).

3. Apparatus according to claim 1, characterized in that it further comprises arranged between the power supply (4) and the electric motor (3): - at least one rising current blocking diode (50) for blocking the current generated by the motor (3) and flowing in the power supply bus (20) towards the power supply electrical (4), during decelerations of the motor (3), and / or - at least one clipping diode (60) to limit at least part of the overvoltages (20) of the electrical supply (4) circulating in the bus (20).

4. Apparatus according to claim 1, characterized in that it further comprises at least one capacitor (70), arranged between the power supply (4) and the electric motor (3), to supply current to the motor (3), during accelerations of the motor (3), and to limit at least part of the overvoltages of the motor (3) during decelerations of the motor (3).

5. Apparatus according to one of claims 2 to 4, characterized in that the switching device (30) and / or the upstream current blocking diode(s) (50) are arranged on the power supply bus (20), in particular on the (+) branch of the bus.

6. Apparatus according to one of claims 2 or 5, characterized in that it further comprises a current limiting circuit (40) for limiting the current flowing in the bus (20) to the motor (3), when the switching device (30) is closed.

7. Apparatus according to claim 3, characterized in that: - at least one upstream current blocking diode (50) is at least one Schottky diode, - and / or at least one clipping diode (60) is at least one Zener diode.

8. Apparatus according to claim 1, characterized in that the transistor bridge circuit (80) comprises a first, a second and a third transistor bridge (90, 91, 92) and the motor (3) comprises a first, a second and a third phase (A, B, C), the first, second and third transistor bridges (90, 91, 92) being respectively connected to the first, second and third phases (A, B, C) of the motor (3).

9. Apparatus according to claim 8, characterized in that the first, second and third phases (A, B, C) of the motor (3) are, respectively, electrically connected to the first, second and third transistor bridges (90, 91, 92), respectively: - between the two transistors (T1-T6) of each pair of transistors (Tl, T4; T2, T5; T3, T6) and - between the two voltage regulating diodes (D1-D6) pairs of voltage regulating diodes (Dl, D4; D2, D5; D3, D6) arranged in parallel with said transistors (Tl, T4; T2, T5; T3, T6).

10. Apparatus according to one of the preceding claims, characterized in that the voltage regulating diodes (D1-D6) are Zener diodes.

11. Apparatus according to one of the preceding claims, characterized in that the micro-blower (2) is equipped with a brushless electric motor.

12. Installation for supplying respiratory gas to a patient comprising a respiratory assistance device (1) according to one of the preceding claims, a flexible conduit fluidically connected to said respiratory assistance device (1) and supplied with gas by the micro-blower (2) of said respiratory assistance device (1), and a respiratory interface () supplied with gas by said flexible conduit.

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