FR3084757A1 - PILOTAGE SYSTEM FOR HIGH SIDE SWITCHES AND ELECTRICAL SYSTEM COMPRISING SUCH A PILOTAGE SYSTEM - Google Patents

Abstract

This control system (201) comprises: - for each high side switch (108U, 108V, 108W), a control unit (202U, 202V, 202W) for selectively opening and closing this high side switch (108U, 108V, 108W), the control unit (202U, 202V, 202W) having a positive supply terminal and a negative supply terminal connected to the lower terminal of the high side switch (108U, 108V, 108W); - an intermediate capacity (C); - a connection system (208, 210U, 210V, 210W, 212) of the intermediate capacity (C) designed to respectively connect two terminals of the intermediate capacity (C) to the two terminals of one selectively from a supply (204) and the control units (202U, 202V, 202W). The control system (201) further comprises, for each control unit (202U, 202V, 202W), a priming capacity (CU, CV, CW) connected between the positive supply terminal of the control unit (202U, 202V, 202W) and the lower terminal of the high side switch (108U, 108V, 108W) associated with the control unit (202U, 202V, 202W).

Description

TITLE

HIGH SIDE SWITCHING PILOTAGE SYSTEM AND ELECTRICAL SYSTEM COMPRISING SUCH A PILOTAGE SYSTEM

TECHNICAL AREA

The present invention relates to a high-side switch control system and an electrical system comprising such a control system.

TECHNOLOGICAL BACKGROUND

The publication of American patent application No. US 2005 0077075 A1 describes a control system for switches on the high side of respective switching arms, each high side switch having a lower terminal connected to a midpoint of the associated switching arm, the control system being of the type comprising:

- for each high side switch, a control unit designed to receive an input control signal and to supply, as a function of the input control signal, an output control signal to the high side switch in order to selectively open and close this high side switch, the control unit having a positive supply terminal and a negative supply terminal connected to the lower terminal of the high side switch,

- an intermediate capacity,

- an intermediate capacity connection system designed to respectively connect two terminals of the intermediate capacity to the two terminals of one selectively from a power supply and the control units.

In the previous publication, the control units consist of controllable switches each arranged between the grid and the source of the respective high side switch. In addition, the connection system comprises two controllable switches respectively connecting the two terminals of the intermediate capacity to the two terminals of the power supply, and, for each control unit, two controllable switches respectively connecting the two terminals of the intermediate capacity to the two control unit terminals.

To open a high side switch, the switch forming the associated control unit is closed to connect the gate and the source of the high side switch. Thus, a zero voltage is applied between the grid and the source of the high side switch, which causes the opening of the latter.

To close a high side switch, the switch forming the control unit is open and the other switches are closed to connect the intermediate capacity to this high side switch. Thus, the voltage of the intermediate capacity is applied between the grid and the source of the high side switch, which causes the closure of the latter.

A problem with the control system described in the previous publication is that it is not possible to close two high-side switches at the same time, since in this case these two switches would be connected at the same time to the intermediate capacity, so that the two associated midpoints would be connected to each other and therefore be set to the same potential.

The object of the invention is to at least partially overcome this problem.

SUMMARY OF THE INVENTION

To this end, a piloting system of the aforementioned type is proposed, characterized in that it further comprises, for each piloting unit, a priming capacity connected between the positive supply terminal of the piloting unit and the lower terminal of the high side switch associated with the control unit.

Thanks to the invention, each control unit is powered through its associated priming capacity, which is recharged punctually by the intermediate capacity. Thus, the control of each high side switch, that is to say for example the supply of a voltage between its gate and its source, is independent of the connection or not to the intermediate capacity. In particular, to supply a non-zero control voltage to several high-side switches, it is not necessary to connect them all to the intermediate capacity since the priming capacities provide the necessary energy. When the high side switches belong to an inverter connected to a rotating electrical machine, this allows for example to make continuous control (comprising in particular times when all the high side switches are closed).

Optionally, the intermediate capacity connection system is designed for each of a plurality of cycles:

- connect the two terminals of the intermediate capacity to the two terminals of the power supply for a time interval, then

- successively connect the respective terminals of the intermediate capacity to the two terminals of each of the control units for respective time intervals.

Also optionally, the intermediate capacity connection system is designed for, for each of a plurality of cycles, for successively each control unit:

- connect the two terminals of the intermediate capacity to the two terminals of the power supply for a time interval, then

- connect the two terminals of the intermediate capacity to the two terminals of the control unit for a time interval.

Also optionally, the connection system is designed so that a dead time is provided between two consecutive time intervals, during which the intermediate capacity is connected neither to the power supply nor to any of the control units.

Also optionally, each dead time has a duration substantially equal to 0.5 ps.

Also optionally, each dead time has a duration not exceeding 20%, preferably 15%, of the duration of each of the two time intervals between which it is interposed.

Also optionally, the intermediate capacity connection system comprises:

- two controllable switches respectively connecting the two terminals of the intermediate capacity to the two terminals of the power supply, and

- for each control unit, two controllable switches respectively connecting the two terminals of the intermediate capacity to the two terminals of the control unit.

Also optionally, the control system also includes the power supply.

An electrical system is also proposed comprising:

- a source of DC voltage,

- a rotating electric machine,

- a voltage converter connected, on the one hand, to the DC voltage source and, on the other hand, to the rotating electrical machine, the voltage converter comprising switching arms, and

- a control system for the switches on the top side of the switching arms, according to the invention.

Optionally, the electrical system further comprises a voltage converter control system designed to operate the voltage converter selectively as an alternator and as an inverter.

DESCRIPTION OF THE FIGURES

Figure 1 is a diagram illustrating an electrical system implementing the invention.

FIG. 2 is a diagram illustrating a system for controlling switches on the high side of the electrical system of FIG. 1.

FIG. 3 is a timing diagram illustrating a first example of commands for switches of the piloting system of FIG. 2.

FIG. 4 is a timing diagram illustrating a second example of commands for the switches of the piloting system of FIG. 2.

DETAILED DESCRIPTION

Referring to Figure 1, an electrical system 100 according to the invention will now be described. The electrical system 100 is for example intended to be implemented in a motor vehicle.

The electrical system 100 comprises first of all a DC voltage source 102 comprising a positive terminal and a negative terminal, the latter being generally connected to a first electrical ground, denoted GND1 (from the English “ground”) in the figures, for example connected to a chassis of the motor vehicle. The DC voltage source 102 is designed to supply a DC input voltage E between these terminals, for example around 12 V.

The electrical system 100 further comprises a rotary electrical machine 104 comprising stator phases (three in the example described, respectively denoted U, V, W, but the invention also applies to any number of the phases, for example five or six phases). Furthermore, in the example described, respective first ends of the phases U, V, W are connected to the same neutral point N. In the example described, the rotary electrical machine 104 is part of an alternator-starter coupled to a heat engine (not shown) of the motor vehicle. The rotary electrical machine 104 is thus designed to operate alternately in motor mode in which it assists the heat engine and in alternator mode in which it transforms part of the mechanical energy generated by the heat engine into electrical energy to recharge the voltage source. continues 102.

The electrical system 100 further comprises a voltage converter 106 connected, on the one hand, to the terminals of the DC voltage source 102 and, on the other hand, to the rotating electrical machine 104.

The voltage converter 106 comprises switching arms respectively associated with the stator phases U, V, W. Each switching arm comprises a high side switch 108u, 108v, 108w connected to the positive terminal of the DC voltage source 102 and a low side switch 110u, 110v, 110w connected to the negative terminal of the DC voltage source 102. The high side switch 108u, 108v, 108w and the low side switch 110u, 110v, 110w are further connected l 'to each other at a midpoint connected to the associated stator phase U, V, W. Each switching arm is intended to be controlled to switch between two configurations. In the first, called high configuration, the high side switch 108u, 108v, 108w is closed and the low side switch is open 110u, 110v, 110w so that the input voltage E is applied to a second end of the associated stator phase U, V, W. In the second, called low configuration, the high side switch 108u, 108v, 108w is open and the low side switch 110u, 110v, 110w is closed so that a zero voltage is applied to the second end of the associated stator phase U, V, W.

The voltage converter 106 is intended to be controlled to switch each switching arm between these two configurations, so as to supply electrical energy to the rotary electrical machine 104 when it is desired for it to operate in motor mode and to supply electrical energy to the DC voltage source 102 when it is desired that the rotary electrical machine 104 operate in alternator mode.

Thus, the electrical system 100 further comprises a control system 112 of the voltage converter 106 comprising in particular a control system for the high side switches 108u, 108v, 108w.

As can be seen in FIG. 2, each high-side switch 108u, 108v, 108w has a control terminal, an upper current input terminal connected to the positive terminal of the voltage source 102 supplying the voltage E and a lower current output terminal connected to the midpoint of the associated switching arm. Each high side switch 108u, 108v, 108w is for example an insulated gate field effect transistor (from the English “Metal Oxide Semiconductor Field Effect Transistor” or MOSFET) having a gate, a drain and a source respectively forming the control terminal, the upper current input terminal and the lower current output terminal.

Each high side switch 108u, 108v, 108w is designed to be controlled according to a voltage applied between its control terminal and its lower terminal. As the latter is connected to a phase of the rotating machine 104, the control of the switch 108u, 108v, 108w is floating on the phase.

The control system will be described with reference to FIG. 2, where it bears the reference 201.

The control system 201 first comprises, for each high side switch 108u, 108v, 108w, a control unit 202u, 202v, 202w. Each a control unit 202u, 202v, 202w has an input, an output connected to the control terminal of the switch 108u, 108v, 108w considered, and two supply terminals: positive and negative (denoted respectively + and - on Figure 2) intended to receive a supply voltage. The negative power terminal is connected to the lower terminal of the switch 108u, 108v, 108w considered. The control unit 202u, 202v, 202w is designed to receive on its input an input control signal cmdu, cmdv, cmdw, for example in the form of a voltage relative to its negative supply terminal. The 202u, 202v control unit,

202w is further designed to supply on its output, from the input control signal cmdu, cmdv, cmdw, an output control signal CMDu, CMDv, CMDw, in the form of a voltage relative to its terminal negative feed. Thus, this output control signal CMDu, CMDv, CMDw is applied between the control terminal and the lower terminal of the high side switch 108u, 108v, 108w considered. The output control signal CMDu, CMDv, CMDw is intended to take a low value, generally zero to place the high side switch 108u, 108v, 108w in a first state, for example the open state, and a high value , generally greater than 10 V, to place the high side switch 108u, 108v, 108w in a second state, for example the closed state.

The control system 201 further comprises a power supply 204 designed to supply a voltage V, preferably direct, with respect to a second electrical ground GND2. This second electrical ground GND2 can, like the electrical ground GND1, be connected to the chassis of the motor vehicle.

The control system 201 also includes a charge pump system 206.

The charge pump system 206 firstly comprises, for each high side switch 108u, 108v, 108w, a priming capacity Cu, Cv, Cw (from the English "bootstrap capacitor") connected between the terminals d positive and negative supply of the associated control unit 202u, 202v, 202w, in order to supply the latter with its supply voltage. As the negative supply terminal of the 202u, 202v, 202w control unit is connected to the lower terminal of the high side switch 108u, 108v, 108w, the ignition capacity Cu, Cv, Cw is connected between the positive supply terminal of the control unit 202u, 202v, 202w and the lower terminal of the high side switch 108u, 108v, 108w.

The charge pump system 206 further comprises a single intermediate capacity C (generally called “flying capacitor” in English)

The charge pump system 206 further includes an intermediate capacity connection system C designed to respectively connect the two terminals of the intermediate capacity C to the two terminals of one selectively from the supply 204 and the control units 202u , 202v, 202w.

The connection system firstly comprises two controllable switches 208 respectively connecting the two terminals of the intermediate capacity C to the two terminals of the supply 204.

The connection system further comprises, for each control unit 202u, 202v, 202w, two controllable switches 210u, 210v, 210w respectively connecting the two terminals of the intermediate capacity C to the two terminals of the control unit 202u, 202v, 202w considered, and therefore also at the two limits of the starting capacity Cu, Cv, Cw associated.

The connection system further comprises a control device 212 for switches 208, 210u, 210v, 210w.

The control device 212 is for example designed to control the switches 208, 210u, 210v, 210w in accordance with the commands illustrated in FIG. 3 (first control strategy). The first line illustrates the commands of the switches 208, the following three lines respectively illustrate the commands of the switches 210u, 210v, 210w. A high value indicates the closing of the switches, while a low value indicates their opening.

According to these commands, at each of a plurality of cycles CY, for successively each control unit 202u, 202v, 202w:

- the two terminals of the intermediate capacity C are connected to the two terminals of the supply 204, then

- the two terminals of the intermediate capacity C are connected to the two terminals of the control unit 202u, 202v, 202w considered and therefore also to the two terminals of the starting capacity Cu, Cv, Cw associated.

Thus, in the example described, each cycle CY comprises the following time intervals PI, P2, P3, P4, P5, P6.

In the time interval PI, the switches 208 are closed and the switches 210u, 210v, 210w are open. The intermediate capacity C is therefore recharged at voltage V by the supply 204. The control units 202u, 202v, 202w are respectively supplied by the ignition capacities Cu, Cv, Cw.

In the time interval P2, the switches 210u are closed and the switches 208, 210v, 210w are open. The intermediate capacity C thus recharges the priming capacity Cu and supplies the control unit 202u. The other control units 202v, 202w are respectively supplied by the priming capacities Cv, Cw.

In the time interval P3, identical to the time interval PI, the switches 208 are closed and the switches 210u, 210v, 210w are open.

In the time interval P4, identical to the time interval P2 but for the control unit 202v, the switches 210v are closed and the switches 208, 210u, 210w are open.

In the time interval P5, identical to the time interval PI, the switches 208 are closed and the switches 210u, 210v, 210w are open.

In the time interval P6, identical to the time interval P2 but for the control unit 202w, the switches 210w are closed and the switches 208, 210u, 210v are open.

Alternatively, the control device 212 is designed to control the switches 208, 210u, 210v, 210w in accordance with the commands illustrated in FIG. 4 (second piloting strategy).

According to these commands, at each of a plurality of cycles CY:

- the two terminals of the intermediate capacity C are connected to the two terminals of the supply 204, then

- the two terminals of the intermediate capacity C are successively connected to the two terminals of each of the control units 202u, 202v, 202w and therefore also to the two terminals of each of the ignition capacities Cu, Cv, Cw.

Thus, in the example described, each cycle CY comprises the following time intervals PI, P2, P3, P4.

In the time interval PI, the switches 208 are closed and the switches 210u, 210v, 210w are open. The intermediate capacity C is therefore recharged at voltage V by the supply 204. The control units 202u, 202v, 202w are respectively supplied by the ignition capacities Cu, Cv, Cw.

In the time interval P2, the switches 210u are closed and the switches 208, 210v, 210w are open. The intermediate capacity C thus recharges the priming capacity Cu and supplies the control unit 202u. The other control units 202v, 202w are respectively supplied by the priming capacities Cv, Cw.

In the time interval P3, identical to the time interval P2 but for the control unit 202v, the switches 210v are closed and the switches 208, 210u, 210w are open.

In the time interval P4, identical to the time interval P2 but for the control unit 202w, the switches 210w are closed and the switches 208, 210u, 210v are open.

In both control strategies, a dead time is preferably provided between two consecutive time intervals, during which the intermediate capacity C is connected neither to the power supply 204 nor to any of the control units 202u, 202v, 202w.

For example, each dead time has a duration substantially equal to 0.5 ps. In other words, each timeout has a duration greater than 0.4 ps and less than 0.63 ps.

Preferably, each dead time has a duration not exceeding 20%, preferably 15%, of the duration of each of the two time intervals between which it is inserted.

The two consecutive time intervals may include a charging time interval of the intermediate capacity C (time interval during which the two terminals of the intermediate capacity C are connected to the two terminals of the supply 204) and a time interval of discharge in one of the starting capacitors Cu, Cv, Cw (time interval during which the two terminals of the intermediate capacity C are connected to the two terminals of another of the control units 202u, 202v, 202w) (for example, between the time intervals PI and P2 of the first or second control strategy). The two consecutive time intervals can also include a discharge time interval in one of the initiation capacities Cu, Cv, Cw and a discharge time interval in another of the initiation capacities Cu, Cv, Cw (for example , between the time intervals P2 and P3 of the second control strategy).

Thus, when the intermediate capacity C is connected to one of the control units 202u, 202v, 202w (as well as the associated starting capacity Cu, Cv, Cw), it is disconnected from the supply 204 so that it can charge the ignition capacity Cu, Cv, Cw and supply the control unit 202u, 202v, 202w with respect to a floating potential reference.

The control units 202u, 202v, 202w, and the switches 208, 210u, 210v, 210w are for example produced in an integrated circuit such as an ASIC (acronym of the English "application-specific integrated circuit", it is ie literally "integrated circuit specific to an application"). Capacities C, Cu, Cv, Cw are generally large components located outside the integrated circuit and connected by pins of the integrated circuit.

Compared to the case where there would be separate charge pumps for each starting capacity Cu, Cv, Cw (and therefore an intermediate capacity and two switches connecting it to the supply 204 for each starting capacity Cu, Cv, Cw), the invention makes it possible to reduce the number of switches used and therefore to reduce the size of the integrated circuit. In addition, the number of intermediate capacitors is also reduced to a single intermediate capacitor, which decreases the total number of components, as well as the number of pins for connecting to the capacitors to be provided on the integrated circuit.

Furthermore, each of these pins should have been protected, typically against electrostatic discharge from any pin to any pin, which would have considerably complicated the provision of protection against electrostatic discharge. The invention therefore makes it possible to simplify the protection against electrostatic discharges.

The present invention is not limited to the embodiment described above. It will indeed be apparent to those skilled in the art that modifications can be made to it.

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

Claims (9)

1. Control system (201) of high side switches (108u, 108v, 108w) of respective switching arms, each high side switch (108u, 108v, 108w) having a lower terminal connected to a midpoint of the arm associated switching, the control system (201) comprising: - for each high side switch (108u, 108v, 108w), a control unit (202u, 202v, 202w) designed to receive an input control signal (cmdu, cmdv, cmdw) and to supply, depending on the input control signal (cmdu, cmdv, cmdw), an output control signal (CMDu, CMDv, CMDw) to the high side switch (108u, 108v, 108w) in order to selectively open and close this switch high side (108u, 108v, 108w), the control unit (202u, 202v, 202w) having a positive supply terminal and a negative supply terminal connected to the lower terminal of the high side switch (108u , 108v, 108w), - an intermediate capacity (C), - a connection system (208, 210u, 210v, 210w, 212) of the intermediate capacity (C) designed to respectively connect two terminals of the intermediate capacity (C) to the two terminals of one selectively from a supply (204) and the control units (202u, 202v, 202w), the control system (201) being characterized in that it further comprises, for each control unit (202u, 202v, 202w), a starting capacity ( Cu, Cv, Cw) connected between the positive supply terminal of the control unit (202u, 202v, 202w) and the lower terminal of the high side switch (108u, 108v, 108w) associated with the unit piloting (202u, 202v, 202w). 2. Control system (201) according to claim 1, in which the connection system (208, 210u, 210v, 210w, 212) of the intermediate capacity (C) is designed for, each of a plurality of cycles ( CY): - connect for a time interval (PI) the two terminals of the intermediate capacity (C) to the two terminals of the power supply (204), then - successively connect for respective time intervals (P2, P3, P4) the two terminals of the intermediate capacity (C) to the two terminals of each of the control units (202u, 202v, 202w). 3. Control system (201) according to claim 1, in which the connection system (208, 210u, 210v, 210w, 212) of the intermediate capacity (C) is designed for each of a plurality of cycles ( CY), for successively each control unit (202u, 202v, 202w): - connect for a time interval (PI, P3, P5) the two terminals of the intermediate capacity (C) to the two terminals of the power supply (204), then - connect for a time interval (P2, P4, P6) the two terminals of the intermediate capacity (C) to the two terminals of the control unit (202u, 202v, 202w). 4. control system (201) according to claim 2 or 3, wherein the connection system (208, 210u, 210v, 210w, 212) is designed so that a dead time is provided between two consecutive time intervals, during which the intermediate capacity (C) is not connected either to the power supply (204) or to any of the control units (202u, 202v, 202w). 5. Control system (201) according to claim 4, in which each dead time has a duration substantially equal to 0.5 ps. 6. Control system (201) according to any one of claims 1 to 5, in which the connection system (208, 210u, 210v, 210w, 212) of the intermediate capacity (C) comprises: - two controllable switches (208) respectively connecting the two terminals of the intermediate capacity (C) to the two terminals of the power supply (204), and - for each control unit (202u, 202v, 202w), two controllable switches (210u, 210v, 210w) respectively connecting the two terminals of the intermediate capacity (C) to the two terminals of the control unit (202u, 202v, 202W). 7. Control system (201) according to any one of claims 1 to 6, further comprising the power supply (204). 8. Electrical system (100) comprising: - a DC voltage source (102), - a rotating electric machine (104), - a voltage converter (106) connected, on the one hand, to the DC voltage source (102) and, on the other hand, to the rotary electric machine (104), the voltage converter (106) comprising arms switching, and - a control system (201) for the high side switches of the switching arms, according to any one of claims 1 to 7. 9. The electrical system (100) according to claim 8, further comprising a control system (112) of the voltage converter (106) designed to operate the voltage converter (106) selectively as an alternator and as an inverter.