FR3098042A1 - COIL ROTOR ELECTRIC MOTOR SYSTEM - Google Patents

Abstract

A motor system (100) includes: an electric motor (106), an inverter (110) for connecting a first power supply (102) to the stator of the electric motor, an H-bridge (120) for connect the first power supply to at least one phase (L) of the rotor of the electric motor, a control system (190) of the H-bridge and of the inverter comprising a control device (160) of the switches (1181, 1182, 1183, 1201, 1202, 1203) of the inverter a control device (180) of the switches (Q1, Q2, Q3) of the H-bridge comprising a safety device (1941, 1942) designed for, in the event of absence control voltage for the low side switches of the H-bridge, apply a safety voltage to close these low side switches. Figure for the abstract: Figure 1

Description

ELECTRIC MOTOR SYSTEM WITH COIL ROTOR

The present invention relates to the safety of wound-rotor electric motors.

It is known to use an electric motor system comprising:

• an electric motor comprising a stator and a wound rotor having at least one phase,
• an inverter for connecting a first power supply to the stator of the electric motor, said first power supply being designed to provide a first DC voltage with respect to a first electrical ground, the inverter comprising, for each phase of the stator, an arm comprising a high side switch and a low side switch, the high side switch being connected between one end of the stator phase and the first power supply, the low side switch being connected between the end of the stator phase and the first electrical mass,
• an H-bridge intended to connect the first electric power supply to said at least one phase of the rotor of the electric motor, said H-bridge comprising:
  • a first arm for connecting a first end of said at least one phase of the rotor to the first power supply, said first arm comprising a high side switch and a low side switch, the high side switch being intended to be connected by a first terminal at a first end of said at least one rotor phase and by a second terminal at the first power supply, the low side switch being intended to be connected between the first end of said at least one rotor phase and the first electrical ground, and
  • a second arm for connecting a second end of said at least one phase of the rotor to the first power supply, said second arm comprising a high side switch and a low side switch, the high side switch being intended to be connected by a first terminal to said second end of said at least one phase of the rotor and by a second terminal to the first power supply, the low side switch being intended to be connected between said second end of said at least one phase and the first electrical ground,
• an H-bridge and inverter control system comprising:
  • a device for controlling the high side switch of the first arm and the low side switches of the H-bridge,
    • for each arm of the H-bridge, a low side connection connected to the control device and connected to the low-side switch of the considered arm of the H-bridge,
    • for the first arm of the H-bridge, a high side connection connected to the driver device and connected to the high side switch of said first arm of the H-bridge,
    • the driving device being adapted to apply control voltages on the high side connection and on the low side connections to selectively open and close the switches,
  • a device for controlling the switches of the inverter,
    • for each arm of the inverter, a high side connection and a low side connection connected to the control device and connected respectively to the high side switch and to the low side switch of the considered arm of the inverter,
    • the control device being adapted to apply control voltages to the high side connections and to the low side connections to selectively open and close the switches of the inverter,

However, for a wound-rotor electric motor, the safe state of the electric motor requires that the phases of the stator and the rotor are short-circuited.

The H-bridge and inverter control system has several electrical components powered by a power supply. To make it possible to place the electric motor in its secure state in the event of failure of one of its components, or even of the power supply itself, it is known to make these components redundant and to supply them in addition by another power supply. electric, for example the one connected to the inverter. Due to the redundancy of the electrical components, this solution is complex and costly.

The aim of the invention is to propose a simple control system which is nevertheless capable of placing the phases of an electric motor in short circuit.

For this purpose, an engine system is proposed comprising:

• an electric motor comprising a wound rotor and a stator, said rotor comprising at least one phase,
• an inverter for connecting a first power supply to the stator of the electric motor, said first power supply being designed to provide a first DC voltage with respect to a first electrical ground, the inverter comprising, for each phase of the stator, an arm comprising a high side switch and a low side switch, the high side switch being connected between one end of the stator phase and the first power supply, the low side switch being connected between the end of the stator phase and the first electrical mass,
• an H-bridge for connecting the first power supply to said at least one phase of the rotor of the electric motor, said H-bridge comprising
  • a first arm for connecting a first end of said at least one phase of the rotor to the first power supply, said first arm comprising a high side switch and a low side switch, the high side switch being intended to be connected by a first terminal at a first end of said at least one rotor phase and by a second terminal at the first power supply, the low side switch being intended to be connected between the first end of said at least one rotor phase and the first electrical ground, and
  • a second arm for connecting a second end of said at least one phase of the rotor to the first power supply, said second arm comprising a high side switch and a low side switch, the high side switch being intended to be connected by a first terminal to said second end of said at least one phase of the rotor and by a second terminal to the first power supply, the low side switch being intended to be connected between said second end of said at least one phase and the first electrical ground,
• an H-bridge and inverter control system comprising
  • a device for controlling the high side switch of the first arm and the low side switches of the H-bridge,
    • for each arm of the H-bridge, a low side connection connected to the control device and connected to the low-side switch of the considered arm of the H-bridge,
    • for the first arm of the H-bridge, a high side connection connected to the driver device and connected to the high side switch of said first arm of the H-bridge,
    • the driving device being adapted to apply control voltages on the high side connection and on the low side connections to selectively open and close the switches,
  • a device for controlling the switches of the inverter,
    • for each arm of the inverter, a high side connection and a low side connection connected to the control device and connected respectively to the high side switch and to the low side switch of the considered arm of the inverter,
    • the control device being adapted to apply control voltages to the high side connections and to the low side connections to selectively open and close the switches of the inverter,
• the control system being characterized in that it further comprises, for each low side connection connected to the piloting device, a first safety device designed to, in the event of absence of control voltage on the low side connection considered, applying to the low side connection considered a first safety voltage intended to close the low side switch connected to the low side connection considered.

Thanks to the invention, and in particular to the presence of the first safety devices, the redundancy of certain electrical components of the control system can be avoided.

The engine system can advantageously comprise at least one of the improvements below, the technical characteristics forming these improvements being able to be taken alone or in combination.

Optionally, the control system further comprises for each low side connection connected to the control device, a second safety device designed to, in the event of absence of control voltage on the considered low side connection, apply to the considered low side connection a second safety voltage intended to close the low side switch connected to the considered low side connection.

Optionally, each low side connection includes a low side main conductor and a low side reference conductor, each control or safety voltage applied to a low side connection is applied between the low side main conductor and the low side reference conductor. low side reference conductor.

Optionally, each first and each second safety device comprises a first resistor having a first terminal connected to the main low-side conductor and a second terminal intended to be connected to the first power supply.

Optionally, at least a first or a second safety device comprises a second resistor having a first terminal connected to the low-side main conductor and a second terminal intended to be connected to the first electrical ground.

Optionally, at least a first safety device includes a Zener diode having a cathode connected to the low side main conductor and an anode connected to the first electrical ground.

Optionally, at least a second safety device includes a Zener diode having a cathode connected to the low side main conductor and an anode connected to the first electrical ground.

Optionally, the piloting device comprises a first pilot, each low side connection connected to the piloting device being connected to the first pilot, the first pilot (188) is intended to be connected, for its power supply, to a second power supply electrical device for supplying the first driver with a second DC voltage with respect to a second electrical ground, and the first driver is adapted to present, on each low-side connection connected to the first driver, in the event of the absence of electrical power, a output resistance greater than the first resistance of the first associated safety device, for example at least 10 times greater, preferably at least 100 times greater.

Optionally, the control device comprises a first driver, each low side connection connected to the control device being connected to the first driver, the first driver is intended to be connected, for its power supply, to a third power supply intended to supplying the first driver with a third DC voltage with respect to a third electrical ground, and wherein the first driver is adapted to present, on each low side connection connected to the first driver, in the absence of electrical power, a resistance output greater than the first resistance of the second associated safety device, for example at least 10 times greater, preferably at least 100 times greater.

Optionally, the third power supply is the second power supply.

The invention will be better understood in the light of the following description, given solely by way of non-limiting example and referring to the following figures.

BRIEF DESCRIPTION OF FIGURES

shows an engine system according to one embodiment of the invention.

shows a control device, a second low-side and high-side safety device and an inverter of an electrical system according to one embodiment of the invention.

shows a steering device, a first low side safety device and an H-bridge of an electrical system according to one embodiment of the invention.

shows an electrical circuit of an alternative embodiment of a first or second low side safety device.

DETAILED DESCRIPTION

With reference to the , a motor system 100 according to the invention will now be described. The engine system 100 is for example intended to be used in a motor vehicle.

The motor system 100 includes a first power supply 102 designed to provide a first DC voltage A, for example 48V, with respect to a first electrical ground GND. The first power supply 102 comprises for example a first battery.

The motor system 100 further comprises a second power supply 103 designed to provide a second DC voltage, preferably lower than the first DC voltage A, for example at least twice lower, for example 12V, with respect to a second electrical ground. GND2. The second power supply 103 comprises for example a second battery.

The first power supply 102 and the second power supply 103 are different and independent of each other, that is to say that the shutdown of one does not lead to the shutdown of the other. For example, the first battery is different from the second battery. Further, the first power supply 102 and the second power supply 103 are isolated from each other. This means in particular that when an electrical component is connected to both the first power supply 102 and the second power supply 103, it comprises an electrical isolator (isolation barrier) with the first power supply 102 and/or the second power supply 103.

The first electrical ground GND and the second electrical ground GND2 can be interconnected and form a single electrical ground, or else be separated from each other.

The motor system 100 further comprises a capacitor 104 connected between the terminals B+ and B- of the first power supply 102. The capacitor 104 comprises for example one or more capacitors, for example chemical capacitors.

Motor system 100 further includes an electric motor 106. Electric motor 106 is a wound rotor electric motor. In other words, the electric motor 106 includes a multi-phase stator 114 ₁ , 114 ₂ , 114 ₃ and a wound rotor. In the example described, the stator of the electric motor 106 comprises three phases 114 ₁ , 114 ₂ , 114 ₃ , of which in the example described, respective first ends are connected to a neutral point N. In addition, in the example describes the wound rotor comprises a single phase L. The electric motor 106 is for example a GMG (Gearbox Motor Generator) type electric motor designed to be coupled to the gearbox of the motor vehicle.

The motor system 100 further includes an inverter 110 configured to connect the first power supply 102 to the stator of the electric motor 106 in order to regulate the currents flowing through the phases of the stator.

The inverter 110 comprises, for each phase 114 ₁ , 114 ₂ , 114 ₃ of the stator of the electric motor 106, a switching arm comprising a high side switch 118 ₁ , 118 ₂ , 118 ₃ and a low side switch 120 ₁ , 120 ₂ , 120 ₃ . The high side switch 118 ₁ , 118 ₂ , 118 ₃ is connected between a second end of the phase 114 ₁ , 114 ₂ , 114 ₃ considered and the B+ terminal of the first power supply 102. The low side switch 120 ₁ , 120 ₂ , 120 ₃ is connected between the second end of the phase 114 ₁ , 114 ₂ , 114 ₃ considered and the first electrical ground GND. The high side switch 118 ₁ , 118 ₂ , 118 ₃ and the low side switch 120 ₁ , 120 ₂ , 120 ₃ are also connected to each other at a midpoint P _{114_1} , P _{114_2} , P _{114_3} connected to the second end of the associated phase 114 ₁ , 114 ₂ , 114 ₃ .

The electrical system 100 further comprises an H-bridge 120 designed to connect the first power supply 102 to the phase L of the rotor of the electric machine 106 to drive said rotor.

The H-bridge 120 comprises two arms respectively associated with two ends of the phase L of the rotor. The first arm has a high side switch Q1 connected to the B+ terminal of the first power supply 102 and a low side switch Q2 connected to the first electrical ground GND. Switch Q1 and switch Q2 are further connected to each other at a midpoint connected to a first end of phase L of the rotor. The second arm has a low side switch Q4 connected to the first electrical ground GND and a high side switch Q3 connected to the B+ terminal of the first power supply 102. Switch Q3 and switch Q4 are further connected l to each other at a midpoint connected to a second end of phase L of the rotor.

Each switch 118 ₁ , 118 ₂ , 118 ₃ , 120 ₁ , 120 ₂ , 120 ₃ of the inverter 100 and each switch Q1, Q2, Q3, Q4 of the H bridge 120 in the example described is an effect transistor insulated gate field (also designated by the acronym MOSFET from English "Metal Oxide Semiconductor Field Effect Transistor"), or an insulated gate bipolar transistor (also designated by the acronym IGBT, from English "Insulated Gate Bipolar Transistor "). Preferably, the switches 118 ₁ , 118 ₂ , 118 ₃ , 120 ₁ , 120 ₂ , 120 ₃ , Q1, Q2, Q3 and Q4 are of the “normally open” type.

The control system 190 comprises a control device 160 for the switches 118 ₁ , 118 ₂ , 118 ₃ , 120 ₁ , 120 ₂ , 120 ₃ of the inverter 110 and a control device 180 for the switches Q1, Q2, Q3, Q4 of the H-bridge 120.

The control system 190, the control device 160 and the piloting device 180 are powered by the second power supply 103.

The control system 190 further comprises for each arm of the inverter 110, a high side connection 132 ₁ , 132 ₂ , 132 ₃ and a low side connection 134 ₁ , 134 ₂ , 134 ₃ connected to the control device 160 and respectively connected to the high side switch 118 ₁ , 118 ₂ , 118 ₃ and to the low side switch 120 ₁ , 120 ₂ , 120 ₃ of the considered arm of the inverter 110.

The control system 190 further comprises for each arm of the H-bridge 120, a high side connection 182 ₁ , 182 ₂ and a low side connection 184 ₁ , 184 ₂ connected to the control device 180 and respectively connected to the high side switch Q1, Q3 and to the low side switch Q2, Q4 of the considered arm of the H-bridge 120.

The control device 160 is designed to apply control voltages V_118 ₁ , V_118 ₂ , V_118 ₃ on the high side connections 132 ₁ , 132 ₂ , 132 ₃ to selectively open/close the high side switches 118 ₁ , 118 ₂ , 118 ₃ and control voltages V_120 ₁ , V_120 ₂ , V_120 ₃ on the low side connections 134 ₁ , 134 ₂ , 134 ₃ to selectively open/close the low side switches 120 ₁ , 120 ₂ , 120 ₃ .

Thus, each arm of the inverter 110 is intended to be controlled by the control device 160 to switch between two configurations. In the first, called high configuration, the high side switch is closed and the low side switch is open so that the input voltage A is applied to the second end of the phase 114 ₁ , 114 ₂ , 114 ₃ associated. In the second, called low configuration, the high side switch is open and the low side switch is closed so that a zero voltage is applied to the second end of the associated phase 114 ₁ , 114 ₂ , 114 ₃ . The inverter 110 is controlled to cause each arm to switch between these two configurations, so as to regulate the currents flowing through the phases 114 ₁ , 114 ₂ , 114 ₃ .

The driver device 180 is designed to apply control voltages V_Q1, V_Q3 on the high side connections 182 ₁ , 182 ₂ to selectively open/close the high side switches Q1, Q3 and control voltages V_Q2, V_Q4 on the low side connections 184 ₁ , 184 ₂ for selectively opening/closing the low side switches Q2, Q4 in order to apply a variable rotor voltage VR making it possible to regularly switch the direction of the current flowing through phase L of the rotor when the latter is powered by the H-bridge 120 connected to the first power supply 102 in order to rotate the rotor.

The control system 190 further comprises, for each of the low side connections 134 ₁ , 134 ₂ , 134 ₃ , a second low side safety device 144 ₁ , 144 ₂ , 144 ₃ . Each second low side safety device 144 ₁ , _{144 2} , _{144 3} is designed to apply to the latter _a second safety voltage intended to close the low side switch 120 ₁ , 120 ₂ , 120 ₃ associated.

The control system 190 further comprises, for each of the low side connections 184 ₁ , 184 ₂ a first low side safety device 194 ₁ , 194 ₂ . Each first low side safety device 194 ₁ , 194 ₂ is designed to, in the event of absence of control voltage on the considered low side connection 184 ₁ , 184 ₂ , apply to the latter a first safety voltage intended to close the low side switch Q2, Q4.

The first and the second safety voltage are for example between 9 and 18V. The first and second low side safety devices 144 ₁ 144 ₂ , 144 ₃ , 194 ₁ , 194 ₂ are powered by the first power supply 102 which already powers the switches 118 ₁ , 118 ₂ , 118 ₃ , 120 ₁ , 120 ₂ , 120 ₃ , Q1, Q2, Q3, Q4.

With reference to the , the structure of the control device 160 and of a second safety device 1441 will now be detailed.

The control device 160 of the switches 118 ₁ , 118 ₂ , 118 ₃ , 120 ₁ , 120 ₂ , 120 ₃ of the inverter 110 comprises a high side driver 126 and a low side driver 128.

Controller 160 further includes a high side power supply 132 for powering high side driver 126 from second power supply 103.

The controller 160 further includes a low side power supply 131 for powering the low side driver 128 from the second power supply 103.

The high side connections 132 ₁ , 132 ₂ , 132 ₃ are connected, on the one hand, to the high side driver 126 and, on the other hand, to the high side switches 118 ₁ , 118 ₂ , 118 ₃ respectively. Each high side connection 132 ₁ , 132 ₂ , 132 ₃ includes a high side main conductor 136 ₁ , 136 ₂ , 136 ₃ and a high side reference conductor 138 ₁ , 138 ₂ , 138 ₃ . Each high side main conductor 136 ₁ , 136 ₂ , 136 ₃ is connected to the gate of the MOSFET or of the IGBT of the associated high side switch 118 ₁ , 118 ₂ , 118 ₃ . Each high side reference conductor 138 ₁ , 138 ₂ , 138 ₃ is connected to the source of the MOSFET or of the IGBT of the associated high side switch 118 ₁ , 118 ₂ , 118 ₃ .

Similarly, the low side connections 134 ₁ , 134 ₂ , 134 ₃ are connected, on the one hand, to the low side driver 128 and, on the other hand, respectively to the low side switches 120 ₁ , 120 ₂ , 120 ₃ . Each low side connection 134 ₁ , 134 ₂ , 134 ₃ includes a low side main conductor 140 ₁ , 140 ₂ , 140 ₃ and a low side reference conductor 142 ₁ , 142 ₂ , 142 ₃ . Each low side main conductor 140 ₁ , 140 ₂ , 140 ₃ is connected to the gate of the MOSFET or of the IGBT of the associated low side switch 120 ₁ , 120 ₂ , 120 ₃ . Each low side reference conductor 142 ₁ , 142 ₂ , 142 ₃ is connected to the source of the MOSFET or of the IGBT of the associated low side switch 120 ₁ , 120 ₂ , 120 ₃ . In the example described, the source of the transistors of the low side switches 120 ₁ , 120 ₂ , 120 ₃ is connected to the first electrical ground GND, so that the low side reference conductors 142 ₁ , 142 ₂ , 142 ₃ are connected to the first electrical ground GND.

The high side driver 126 and the low side driver 128 are designed so that each control voltage they apply alternately takes a high level, for example between 9 and 18V, of closing the switch 118 ₁ , 118 ₂ , 118 ₃ , 120 ₁ , 120 ₂ , 120 ₃ , and a low level, for example 0V, of opening of the switch 118 ₁ , 118 ₂ , 118 ₃ , 120 ₁ , 120 ₂ , 120 ₃ .

Furthermore, the low side driver 128 is designed to present on each low side connection 134 ₁ , 134 ₂ , 134 ₃ , in the event of absence of electrical power supply, a high output resistance, for example greater than a threshold between 50 kΩ and 200 kΩ, for example 100 kΩ.

In the example described, the second low-side safety device 144 ₁ includes a first resistor 146 having a first terminal connected to the low-side main conductor 140 ₁ and a second terminal connected to the first power supply 102. The first resistor 146 is equal to for example between 30 Ω and 120 Ω, for example 60 Ω. The second low side safety device 144 ₁ further comprises a second resistor 148 having a first terminal connected to the low side main conductor 140 ₁ and a second terminal connected to the low side reference conductor 142 ₁ , i.e. say to the first electrical ground GND. The second resistor 148 is for example between 10 Ω and 40 Ω, for example 20 Ω.

The second low side safety devices 1442 and 1443 (not shown in the ) has the same structure as the second low side safety device 1441, namely a resistor connected between the low side main conductor 1402, 1403 and the first power supply 102 and a resistor connected to the low side main conductor 1402, 1403 and to the low side reference conductor 1422, 1423.

Low side driver 128 is designed to present, in the absence of power, an output resistance on each low side connection 134 ₁ , 134 ₂ , 134 ₃ greater than both first resistor 146 and the second resistance 148 of the associated low side safety device 144, for example at least 10 times greater, preferably at least 100 times greater.

Since the output resistance of the low side driver 128 is very high, each second low side safety device 144 ₁ , 144 ₂ , 144 ₃ behaves as a voltage divider bridge and the values of the first resistor 146 and the second resistor 148 are chosen with respect to the first DC voltage A to obtain the second safety voltage. For example, in the case where the first DC voltage A is 48V, the first resistor 146 is for example 60 Ω and the second resistor 148 is for example 20 Ω, which makes it possible to obtain a second safety voltage of approximately 10V .

The control system 190 further comprises, for each of the high side connections 1321, 1322, 1323, a high side safety device 150. On the , only that of the high side connection 1321 is shown, but the other high side connections 1322, 1323 are also provided with it. The high side safety device 150 is designed to, in the absence of control voltage on the considered high side connection 1321, 1322, 1323, apply to the considered high side connection 1321, 1322, 1323 a third voltage safety intended to open the high side switch 1181, 1182, 1183 associated. The third safety voltage is for example 0V.

In the example described, each high side safety device 150 comprises a resistor 152 having a first terminal connected to the high side main conductor 136 ₁ , 136 ₂ , 136 ₃ and a second terminal connected to the high side reference conductor 138 ₁ , 138 ₂ , 138 ₃ . Resistor 152 is for example between 10 kΩ and 40 kΩ, for example 20 kΩ.

With reference to the , the structure of the control device 180 and of a first safety device 1941 will now be detailed.

The driver 180 of the switches Q1, Q2, Q3, Q4 of the H-bridge 120 includes a high side driver 186 and a low side driver 188.

Driver 180 further includes a high side power supply 188 for powering high side driver 186 from second power supply 103.

Driver 180 further includes a low side power supply 187 for powering low side driver 188 from second power supply 103.

The high side connections 182 ₁ , 182 ₂ are connected, on the one hand, to the high side driver 186 and, on the other hand, respectively to the high side switches Q1, Q3. Each high side connection 182 ₁ , 182 ₂ includes a high side main conductor 181 ₁ , 181 ₂ and a high side reference conductor 183 ₁ , 183 ₂ . Each high side main conductor 181 ₁ , 181 ₂ is connected to the gate of the MOSFET or of the IGBT of the associated high side switch Q1, Q3. Each high side reference conductor 183 ₁ , 183 ₂ is connected to the source of the MOSFET or of the IGBT of the associated high side switch Q1, Q3.

Similarly, the low side connections 184 ₁ , 184 ₂ are connected, on the one hand, to the low side driver 188 and, on the other hand, respectively to the low side switches Q2, Q4. Each low side connection 184 ₁ , 184 ₂ includes a low side main conductor 185 ₁ , 185 ₂ and a low side reference conductor 186 ₁ , 186 ₂ . Each low side main conductor 185 ₁ , 185 ₂ is connected to the gate of the MOSFET or of the IGBT of the associated low side switch Q2, Q4. Each low side reference conductor 186 ₁ , 186 ₂ is connected to the source of the MOSFET or the IGBT of the associated low side switch Q2, Q4. In the example described, the source of the transistors of the low side switches Q2, Q4 is connected to the first electrical ground GND, so that the low side reference conductors 186 ₁ , 186 ₂ are connected to the first electrical ground GND .

The high side driver 186 and the low side driver 188 are designed so that each control voltage they apply alternately takes a high level, for example between 9 and 18V, of closing the switch Q1, Q2, Q3, Q4 and a low level, for example 0V, of opening of switch Q1, Q2, Q3, Q4.

Furthermore, the low side driver 188 is designed to present on each low side connection 184 ₁ , 184 ₂ , in the event of a power supply failure, a high output resistance, for example greater than a threshold comprised between 50 kΩ and 200 kΩ, for example 100 kΩ.

In the example described, the first low-side safety device 194 ₁ includes a first resistor 196 having a first terminal connected to the low-side main conductor 185 ₁ and a second terminal connected to the first power supply 102. The first resistor 196 is equal to for example between 30 Ω and 120 Ω, for example 60 Ω. The first low side safety device 194 ₁ further comprises a second resistor 198 having a first terminal connected to the low side main conductor 185 ₁ and a second terminal connected to the low side reference conductor 186 ₁ , i.e. say to the first electrical ground GND. The second resistor 198 is for example between 10 Ω and 40 Ω, for example 20 Ω.

The first low side safety device 1942 (not shown in the ) has the same structure as the first low side safety device 1941, namely a resistor connected between the low side main conductor 1852 and the first power supply 102 and a resistor connected between the low side main conductor 1852 and the low side reference 1862.

The low side driver 188 is designed to present, in the absence of power, an output resistance on each low side connection 184 ₁ , 184 ₂ greater than both the first resistor 196 and the second resistor. 198 of the associated first low side safety device 194 ₁ , 194 ₂ , for example at least 10 times greater, preferably at least 100 times greater.

Since the output resistance of the low side driver 188 is very high, each first low side safety device 194 ₁ , 194 ₂ behaves as a voltage divider and the values of the first resistor 196 and the second resistor 198 are chosen with respect to the first DC voltage A to obtain the first safety voltage. For example, in the case where the first DC voltage A is 48V, the first resistor 196 is for example 60 Ω and the second resistor 198 is for example 20 Ω, which makes it possible to obtain a first safety voltage of approximately 10V .

The control system 190 further includes, for each of the high side connections 1821, 1822, a high side safety device 170. On the , only that of the high side connection 1821 is shown, but the other high side connection 1822 is also provided with it. The high side safety device 170 is designed to, in the absence of control voltage on the considered high side connection 1821, 1822, apply to the considered high side connection 1821, 1822 a third safety voltage intended to open the high side switch Q1, Q3 associated. The third safety voltage is for example 0V.

In the example described, each high side safety device 170 comprises a resistor 172 having a first terminal connected to the high side main conductor 181 ₁ , 181 ₂ and a second terminal connected to the high side reference conductor 183 ₁ , 183 ₂ . Resistor 172 is for example between 10 kΩ and 40 kΩ, for example 20 kΩ.

An example of operation of motor system 100 will now be described.

In normal operation, the high side driver 126 of the inverter 110 is powered by the high side power supply 132 and applies to each of the high side connections 132 ₁ , 132 ₂ , 132 ₃ a control voltage alternately taking the high level and the low level described previously, to respectively open/close the high side switches 118 ₁ , 118 ₂ , 118 ₃ respectively. Similarly, the low side driver 128 of the inverter 110 is powered by the low side power supply 131 and applies to each of the low side connections 134 ₁ , 134 ₂ , 134 ₃ a control voltage alternately taking the level high and the low level described previously, to respectively open/close the low side switches 120 ₁ , 120 ₂ , 120 ₃ respectively.

Similarly, in normal operation, the high side driver 186 of the H-bridge 120 is powered by the high side power supply 188 and applies to each of the high side connections 182 ₁ , 182 ₂ a control voltage alternately taking the high level and the low level described previously, to respectively open/close the high side switches Q1, Q3 respectively. Similarly, the low side driver 188 of the H-bridge 120 is powered by the low side power supply 187 and applies to each of the low side connections 184 ₁ , 184 ₂ a control voltage alternately taking the high level and the low level. low level described previously, to respectively open/close the low side switches Q2, Q4 respectively.

The first low side safety devices 194 ₁ , 194 ₂ , the second low side safety devices 144 ₁ , 144 ₂ , 144 ₃ , and the high side devices 150, 170 then have no effect.

If the second power supply 103 fails, the high side power supplies 132, 188 and the low side power supplies 131, 187 cease to operate. The high side drivers 126, 186 and the low side drivers 128, 188 are then no longer powered and therefore no longer apply a control voltage to the high side connections 132 ₁ , 132 ₂ , 132 ₃ , 182 ₁ , 182 ₂ and the low side connections 134 ₁ , 134 ₂ , 134 ₃ , 184 ₁ , 184 ₂ . The potential of the high side main conductors 136 ₁ , 136 ₂ , 136 ₃ , 181 ₁ , 181 ₂ and of the low side main conductors 140 ₁ , 140 ₂ , 140 ₃ , 185 ₁ , 185 ₂ is then floating.

Each first 194 ₁ , 194 ₂ , respectively second 144 ₁ , 144 ₂ , 144 ₃ low side safety device then imposes the first safety voltage, respectively the second safety voltage on the low side connection 134 ₁ , 134 ₂ , 134 ₃ , 184 ₁ , 184 ₂ associated, which causes the closing of all the low side switches 120 ₁ , 120 ₂ , 120 ₃ , Q2, Q4. The phases of the stator 114 ₁ , 114 ₂ , 114 ₃ and of the rotor L of the electric motor 106 are then short-circuited, so that the electric motor 106 is in a safe state. In the example described, the first and the second safety voltage are obtained by dividing the first DC voltage A supplied by the first power supply 102, according to a predetermined division ratio depending on the choice of the first resistors 146, 196 and the second resistors 148, 198.

In addition, each high side safety device 150, 170 then imposes the third safety voltage on the associated high side connection 132 ₁ , 132 ₂ , 132 ₃ , 182 ₁ , 182 ₂ . In the example described, the third safety voltage is obtained by the fact that the high side main conductor 136 ₁ , 136 ₂ , 136 ₃ , 181 ₁ , 181 ₂ and the high side reference conductor 138 ₁ , 138 ₂ , 138 ₃ , 183 ₁ , 183 ₂ are both connected to the first electrical ground GND, so that the third safety voltage is 0V, which causes all the high side switches 118 ₁ , 118 ₂ to open. , 118 ₃ , Q1, Q3.

More precisely, the high side reference conductor 138 ₁ , 138 ₂ , 138 ₃ , 183 ₁ , 183 ₂ is connected to the first electrical ground GND by the low side switch 120 ₁ , 120 ₂ , 120 ₃ , Q2, corresponding Q4, which, thanks to the low side safety device 144, 194, is closed. The high side main conductor 136 ₁ , 136 ₂ , 136 ₃ , 181 ₁ , 181 ₂ is connected to the high side reference conductor 138 ₁ , 138 ₂ , 138 ₃ , 183 ₁ , 183 ₂ through the resistor 152, 172.

It was determined that the first and second low side safety devices 144 ₁ , 144 ₂ , 144 ₃ , 194 ₁ , 194 ₂ and the high side safety devices 150, 170 could be triggered in less than 100 μs, from so that there is no transient problem.

With reference to the , an alternative low side safety device 302 to the first and second low side safety device 144, 194 will now be described.

This low side safety device 302 can be used in place of each first 1941, 1942 and second 1441, 1442, 1443 low side safety device of the , [fig.2] and [fig.3].

The low side safety device 302 differs from that of the and [fig.3], in that the second resistor 148, 198 is replaced by a Zener diode 304 having a cathode connected to the low side main conductor 1401, 1402, 1403, 1851, 1852 and an anode connected to the reference conductor low side 1421 ,1422, 1423, 1861, 1862 (the first electrical ground GND). The first electrical power supply 102 is then chosen so as to provide a first DC voltage A sufficiently large for the Zener diode 304 to be in the breakdown configuration. Thus, the second safety voltage corresponds to the breakdown voltage of the Zener diode 304. The use of a Zener diode is interesting because the first and the second safety voltage are not likely to change in the event of an untimely change of the first DC voltage A provided by the first power supply 102.

The low side safety devices 144, 194, 302 act when the motor system 100 is in operation and a loss of control voltage occurs in an undesired manner, for example due to a loss of the low side power supply 131, as previously explained. On the other hand, when the motor system 102 is stopped, the first and second power supplies 102, 103 are disconnected and the switches 118 ₁ , 118 ₂ , 118 ₃ , 120 ₁ , 120 ₂ , 120 ₃ , Q1, Q2, Q3, Q4 are then in the open state, since they are of the “normally open” type.

The present invention is not limited to the embodiments described above, but is on the contrary defined by the claims which follow. It will indeed be apparent to those skilled in the art that modifications can be made thereto.

For example, in an alternative embodiment to that described in relation to the in [Fig.4], the H-bridge 120 may comprise only one high side switch Q1 realized in the form of MOSFETs or IGBTs. In this alternate embodiment, the high side transistor Q3 is made as a diode. Further, in this alternate embodiment, there is no high side lead 1822 connected to driver 180 and switch Q3.

Furthermore, the invention could apply to a machine whose stator has N phases, N being greater than or equal to three.

Furthermore, the invention could apply to a machine whose rotor has N phases, N being greater than or equal to one.

Further, the first and second security devices 144; 194 could be powered by a third power supply, independent of both the first power supply 102 and the second power supply 103.

Furthermore, the terms used in the claims should not be understood as being limited to the elements of the embodiments described above, but must on the contrary be understood as covering all the equivalent elements that the person skilled in the art can deduce from his knowledge. general.

Claims (9)

Motor system (100) comprising:
- an electric motor (106) comprising a wound rotor and a stator, said rotor comprising at least one phase (L),
- an inverter (110) for connecting a first power supply (102) to the stator of the electric motor (106), said first power supply being designed to provide a first DC voltage (A) with respect to a first electrical ground (GND) , the inverter (110) comprising, for each phase of the stator (114₁, 114₂, 114₃), an arm including a high side switch (118₁, 118₂, 118₃) and a low side switch (120₁, 120₂, 120₃), the high side switch (118₁, 118₂, 118₃) being connected between one end of the stator phase (114₁, 114₂, 114₃) and the first power supply (102), the low side switch (120₁, 120₂, 120₃) being connected between the phase end of the stator (114₁, 114₂, 114₃) and the first electrical ground (GND),
- an H-bridge (120) intended to connect the first power supply (102) to said at least one phase (L) of the rotor of the electric motor (106), said H-bridge (120) comprising

1. a first arm (Q ₁ , Q ₂ ) intended to connect a first end of said at least one phase (L) of the rotor to the first power supply (102), said first arm (Q ₁ , Q ₂ ) comprising a switch of high side (Q ₁ ) and a low side switch (Q ₂ ), the high side switch (Q ₁ ) being intended to be connected by a first terminal to a first end of said at least one phase (L) of the rotor and by a second terminal to the first electrical power supply (102), the low side switch (Q ₂ ) being intended to be connected between the first end of the said at least one phase (L) of the rotor and the first electrical ground (GND), and
2. a second arm (Q ₃ , Q ₄ ) intended to connect a second end of said at least one phase (L) of the rotor to the first power supply (102), said second arm (Q ₃ , Q ₄ ) comprising a switch of high side (Q ₃ ) and a low side switch (Q ₄ ), the high side switch (Q ₃ ) being intended to be connected by a first terminal to said second end of said at least one phase (L) of the rotor and by a second terminal to the first power supply (102), the low side switch (Q ₄ ) being intended to be connected between said second end of said at least one phase (L) and the first electrical ground (102 ),

- a control system (190) of the H-bridge (120) and of the inverter (110) comprising

1. a control device (180) of the high side switch (Q ₁ ) of the first arm and of the low side switches (Q ₂ , Q ₄ ) of the H bridge (120),
   1. for each arm of the H-bridge (120), a low side connection (184 ₁ ,184 ₂ ) connected to the control device (180) and connected to the low side switch (Q ₂ , Q ₄ ) of the arm considered the H-bridge (120),
   2. for the first arm of the H-bridge (120), a high side connection (182 ₁ ) connected to the control device (180) and connected to the high side switch (Q ₁ ) of said first arm of the H-bridge ( 120),
   3. the driver device (180) being adapted to apply control voltages (V_Q ₁ , V_Q ₂ , V_Q ₃ ) on the high side connection and on the low side connections to selectively open and close the switches (Q ₁ , Q ₂ , Q ₃ ),
2. a control device (160) for the switches (118₁, 118₂, 118₃, 120₁, 120₂, 120₃) of the inverter (110),
   1. for each arm of the inverter (110), a high side connection (132₁, 132₂, 132₃) and a low side connection (134₁, 134₂, 134₃) connected to the controller (160) and respectively connected to the high side switch (118₁, 118₂, 118₃) and the low side switch (120₁, 120₂, 120₃) of the considered arm of the inverter (110),
   2. the control device (160) being adapted to apply control voltages (V_118₁, V_118₂, V_118₃, V_120₁, V_120₂, V_120₃) on the high side connections (132₁, 132₂, 132₃) and on the low side connections (134₁, 134₂, 134₃) to selectively open and close the switches (118₁, 118₂, 118₃, 120₁, 120₂, 120₃) of the inverter (110),

the control system (190) being characterized in that it further comprises, for each low side connection (184₁, 184₂) connected to the control device (180), a first safety device (194₁, 194₂) designed to, in the event of absence of control voltage on the considered low side connection, apply to the considered low side connection a first safety voltage intended to close the low side switch connected to the low side connection considered. Motor system (100) according to the preceding claim in which the control system (190) further comprises for each low side connection (134 ₁ , 134 ₂ , 134 ₃ ) connected to the control device (160), a second device (144 ₁ , 144 ₂ , 144 ₃ ) designed to, in the event of absence of control voltage on the low side connection in question, apply to the low side connection in question a second safety voltage intended to close the low side switch connected to the considered low side connection. Motor system (100) according to one of the preceding claims, in which each low-side connection (134 ₁ , 134 ₂ , 134 ₃ , 184 ₁ , 184 ₂ ) comprises a low-side main conductor (140 ₁ , 140 ₂ , 140 ₃ , 185 ₁ , 185 ₂ ) and a low side reference conductor (142 ₁ , 142 ₂ , 142 ₃ , 186 ₁ , 186 ₂ ) each control or safety voltage applied to a low side connection is applied between the low side main conductor (140 ₁ , 140 ₂ , 140 ₃ , 185 ₁ , 185 ₂ ) and the low side reference conductor (142 ₁ , 142 ₂ , 142 ₃ , 186 ₁ , 186 ₂ ), and wherein each first and each second safety device (144 ₁ , 144 ₂ , 144 ₃ , 194 ₁ , 194 ₂ ) comprises a first resistor (146, 196) having a first terminal connected to the low side main conductor (140 ₁ , 140 ₂ , 140 ₃ , 185 ₁ , 185 ₂ ) and a second terminal intended to be connected to the first power supply (102). Motor system (100) according to claim 3 wherein at least a first or a second safety device (144 ₁ , 144 ₂ , 144 ₃ , 194 ₁ , 194 ₂ ) comprises a second resistor (146, 196) having a first terminal connected to the low side main conductor (140 ₁ , 140 ₂ , 140 ₃ , 185 ₁ , 185 ₂ ) and a second terminal intended to be connected to the first electrical ground (GND). Motor system (100) according to one of claims 3 to 4, wherein at least a first safety device (194 ₁ , 194 ₂ ) comprises a Zener diode (304) having a cathode connected to the low side main conductor and an anode connected to the first electrical ground (GND). Motor system (100) according to one of Claims 3 to 5, in which at least a second safety device (144 ₁ , 144 ₂ , 144 ₃ ) comprises a Zener diode (304) having a cathode connected to the main conductor of low side and an anode connected to the first electrical ground (GND). A motor system (100) according to any of claims 2 to 6, wherein the driver device (180) includes a first driver (188), each low side connection (184 ₁ ,184 ₂ ) connected to the driver (180) being connected to the first driver (188), in which the first driver (188) is intended to be connected, for its power supply, to a second power supply (103) intended to supply the first driver (188) with a second DC voltage with respect to a second electrical ground (GND2), and wherein the first driver (188) is adapted to present, on each low side connection (184 ₁ ,184 ₂ ) connected to the first driver (188°, in in the event of a power supply failure, an output resistance greater than the first resistance (196) of the associated first safety device (194 ₁ , 194 ₂ ), for example at least 10 times greater, preferably at least 100 times greater . A motor system (100) according to any of claims 2 to 7, wherein the controller (160) includes a first driver (128), each low side connection (134 ₁ , 134 ₂ , 134 ₃ ) connected to the control device (160) being connected to the first driver (128), in which the first driver (128) is intended to be connected, for its power supply, to a third power supply (103) intended to supply the first driver ( 128) a third DC voltage with respect to a third electrical ground (GND2), and wherein the first driver (128) is adapted to present, on each low side connection (134 ₁ , 134 ₂ , 134 ₃ ) connected to the first pilot (128), in the event of absence of electrical power, an output resistance greater than the first resistance (146) of the second safety device (144 ₁ , 144 ₂ , 144 ₃ ) associated, for example at least 10 times higher, preferably at least 100 times higher. A motor system (100) according to claim 7 and 8 wherein the third power supply is the second power supply.