Power factor correction device

Abstract

An electrical power factor correction device comprising: A first interface and a second interface, the first interface comprising a plurality of terminals, the second interface comprising two terminals, the first interface being suitable for connection to an alternating voltage source and the second interface being suitable for connection to a direct voltage electrical circuit; A high-frequency switching half-bridge comprising two controllable semiconductor switches arranged in series between the two terminals of the second interface and on either side of a first midpoint, and an inductor connected on one side to a terminal of the first interface and on the other side to said midpoint; A low-frequency switching half-bridge comprising two switches arranged in series between the two terminals of the second interface and on either side of a second midpoint.This midpoint being connected to a respective terminal of the first interface, and a half-bridge comprising two capacitors arranged in series between the two terminals of the second interface and on either side of a third midpoint, the second midpoint being connected to the third midpoint by an additional controllable switch, the device being characterized in that it is capable of effecting an energy transfer from the second interface to the first interface, the additional controllable switch being kept closed during this energy transfer.

Description

Title of the invention: Power factor correction device

[0001] The present invention relates to an electrical power factor correction device.

[0002] Such devices are present in particular within the on-board charger devices of electrical energy storage units of vehicles.

[0003] Power factor correction devices are capable of rectifying an alternating voltage to a direct current voltage and applying gain and phase margins to this alternating voltage. The gain margins are capable of raising or lowering the voltage during the rectification of the alternating voltage, while the phase margins are capable of correcting phase shifts between the alternating voltage and current. These phase shifts cause power losses within the device, reducing its performance.

[0004] Power factor correction devices are available in various forms. The present invention specifically refers to power factor correction devices comprising: a high-frequency switching half-bridge comprising two controllable semiconductor switches arranged in series between two terminals of an interface and on either side of a first midpoint, and an inductor connected on one side to a terminal of another interface and on the other side to said midpoint; and a low-frequency switching half-bridge arranged in parallel with the preceding switching half-bridge, comprising two switches arranged on either side of a second midpoint, this midpoint being connected to a terminal of the other interface.

[0005] The so-called high-frequency switching half-bridge is so named because its controllable switches are, in known examples, controlled at frequencies above 1 kHz, for example 5 kHz, 9 kHz, or 10 kHz. The so-called low-frequency switching half-bridge operates, in known examples, at a frequency equal to the electrical network frequency, for example 50 Hz or 60 Hz.

[0006] Power factor correction devices as described above are called "totem-pole" devices. This variant is advantageous due to its good efficiency and reduced number of components compared to other popular variants of power factor correction devices.

[0007] Another advantage of these "totem-pole" devices is that they can operate in a so-called reverse direction, and therefore function as inverters for a direct voltage.

[0008] These circuits have a known disadvantage, which is that the alternating current within the device contains distortions. These distortions can take the form of positive and negative current peaks around the zero-ampere transition.

[0009] These distortions can be even more significant when operating the power factor correction device in reverse, creating undesirable effects that can damage the electronic components of on-board charger devices including such power factor correction devices.

[0010] There is a need to eliminate such distortions.

[0011] The invention achieves this, according to one of its aspects, by means of an electrical power factor correction device comprising: - A first interface and a second interface, the first interface comprising a plurality of terminals, the second interface comprising two terminals, the first interface being suitable for connection to an alternating voltage source and the second interface being suitable for connection to a direct voltage electrical circuit, - A so-called high-frequency switching half-bridge, comprising two controllable semiconductor switches arranged in series between the two terminals of the second interface and on either side of a first midpoint, and an inductor connected on one side to a terminal of the first interface and on the other side to said midpoint, - A so-called low-frequency switching half-bridge, comprising two switches arranged in series between the two terminals of the second interface and on either side of a second midpoint, this midpoint being connected to a respective terminal of the first interface, and - A half-bridge comprising two capacitors arranged in series between the two terminals of the second interface and on either side of a third midpoint,

[0012] The second midpoint being connected to the third midpoint by an additional controllable switch,

[0013] The device being characterized in that it is capable of carrying out an energy transfer from the second interface to the first interface, the additional controllable switch being kept closed during this energy transfer.

[0014] The capacitors of the half-bridge can correspond to DC voltage smoothing capacitors.

[0015] Controlling this additional switch in the closed position during a power transfer from the second interface to the first interface allows the power factor correction device to operate similarly to a half-bridge inverter. As a result, the alternating current within the device is distortion-free.

[0016] The switches of the so-called low-frequency switching half-bridge may include semiconductor controllable switches, the switches of said half-bridge being controlled in the open position during the transfer of energy from the second interface to the first interface.

[0017] Alternatively, the switches of the so-called low-frequency switching half-bridge include diodes, the diodes being arranged within the half-bridge in such a way that they are blocked during the transfer of energy from the second interface to the first interface.

[0018] The device may be a single-phase device, comprising only a so-called high-frequency switching half-bridge and a so-called low-frequency switching half-bridge.

[0019] The device may be a polyphase device, comprising a plurality of so-called high-frequency switching half-bridges, the inductance of said half-bridges being connected to a respective terminal of the first interface.

[0020] In particular, the device may be a three-phase device, comprising three half-bridges so-called high-frequency switching.

[0021] The additional switch can be bidirectional in voltage and current.

[0022] The additional switch may be an electromechanical relay

[0023] Alternatively, the additional switch may be a bidirectional semiconductor switch, for example a four-quadrant GaN (Gallium Nitride) based transistor, or for example two unidirectional transistors, for example two N-type MOSFETs, arranged in anti-series or anti-parallel.

[0024] According to another aspect of it, the invention relates to an electrical device for an on-board charger of an electrical energy storage unit, comprising - A first interface capable of being connected to an alternating voltage source, for example from an electrical network, - A second interface suitable for connection to an electrical energy storage unit, - An electromagnetic compatibility device connected to the first interface, - An electrical power factor correction device as described above, connected to the electromagnetic compatibility device via its first interface - An electrical DC-DC voltage conversion device connected to the second interface of the power factor correction device on one side and to the second interface on the other, and - A control unit, capable of operating the switches of the on-board charger device.

[0025] The electromagnetic compatibility device connected to the first interface may include a common mode filtering circuit, a differential mode filtering circuit and / or a surge protection circuit.

[0026] The control unit can be one or more microprocessors and / or one or more integrated circuits of type ASIC or FPGA, capable of controlling the controllable switches within the electrical device of the charger.

[0027] The invention will be better understood upon reading the following description of non-limiting examples of its implementation. Brief description of the figures

[0028] - Fig. 1 represents an example of an on-board charger electrical device employing a power factor correction device according to the invention.

[0029] -Fig.2 represents a first example of implementation of a power factor correction circuit according to the invention.

[0030] -Fig.3 represents a second example of implementation of a power factor correction circuit according to the invention. Detailed description of the invention

[0031] Fig. 1 represents an example of an on-board charger electrical device 1 of an electrical energy storage unit for a plug-in hybrid or electric vehicle.

[0032] The device 1 includes a first interface 10 suitable for connection to a charging station. The interface 10 may be suitable for receiving an alternating voltage from an electrical network, for example a single-phase or three-phase voltage, with an effective voltage between 220V and 240V, having a frequency of 50Hz or 60Hz.

[0033] The device 1 also includes a second interface 14, this interface 14 being suitable for being connected to an electrical energy storage unit.

[0034] An electromagnetic compatibility device 11 is connected to the interface 10, this device may include in known examples one or more electromagnetic filters, for example a common mode circuit and / or a differential mode circuit, and one or more surge protection circuits.

[0035] Device 1 also includes a power factor correction device 12. The power factor correction device 12 rectifies the voltage from the filter device 11 and is capable of correcting phase shifts between the voltage and the current flowing through it. This phase shift correction reduces power losses within the on-board charger device 1 and generally reduces disturbances within circuit 1.

[0036] A DC-DC voltage conversion device 13 converts the rectified voltage from the power factor correction device 12 into a voltage suitable for supplying to an electrical energy storage unit connected to interface 14. Ideally, this voltage converter 13 is an isolated voltage converter.

[0037] Device 1 further includes a control unit 15, which may be one or more microprocessors and / or one or more integrated circuits of type ASIC or FPGA, capable of controlling the controllable switches and of carrying out voltage or current measurements within devices 11, 12 and 13.

[0038] By controlling the switches, it is understood that the control unit 15 includes the means of generating control signals adapted to these switches; in known examples, the control unit 15 may include a pulse-width modulated signal generator.

[0039] Within this device 1, the electromagnetic compatibility device 11, the power factor correction device 12 and the DC-DC voltage conversion device 13 are capable of operating in a power transfer direction from the first interface 10 to the second interface 14 and in a so-called reverse power transfer direction from the second interface 14 to the first interface 10.

[0040] With reference to [Fig.2], a first example of implementation of the power factor correction device 12 according to the invention is presented.

[0041] The power factor correction device 12 of [Fig.2] is adapted to receive a single-phase alternating voltage, supplied to its first interface 101. This interface 101 comprises two terminals 111 and 121, terminal 111 being suitable for receiving the phase of the alternating voltage and terminal 121 the neutral.

[0042] The power factor correction device 12 of [Fig.2] also includes a second interface 102, comprising two terminals 112 and 122. The voltage between the terminals 112 and 122 of the interface 102 is a DC voltage.

[0043] The first interface 101 is connected via its first terminal 111 to a so-called high-frequency switching half-bridge 103. This half-bridge comprises two switches 113, in the example of [Fig. 2] of type N MOSFETs, connected in series between the terminals 112 and 122 of the interfacer 102, and on either side of the midpoint 123. This midpoint 123 is connected to the first terminal 111 of the first interface 101 by an inductor 133. This half-bridge 103 is called high-frequency because, during a power transfer from the first interface 101 to the second interface 102, the switches 113 are driven by the control unit 15 of the device 1 of [Fig. 1] at frequencies higher than the mains voltage, for example, at a frequency higher than 1 kHz, for example, several tens of kHz, for example 65kHz.

[0044] The inductance 133 connected to the midpoint 123 of the half-bridge 103 also allows a gain to be achieved for the rectification of the voltage coming from the first interface 101.

[0045] The first interface 101 is also connected via its second terminal 121 to a so-called low-frequency switching half-bridge 104. This so-called low-frequency half-bridge 104 comprises, in the example of [Fig. 2], two diodes 114 arranged in series between the terminals 112 and 122 of the second interface 102 and on either side of the midpoint 124, the latter being connected to the second terminal 121 of the first interface 101. The half-bridge 104 is called low-frequency because the diodes 114 will act as switches at the frequency of the alternating voltage supplied to the first interface 101.

[0046] In the example of [Fig.2], a first diode 114 is conducting in the direction from the midpoint 24 of the switching half-bridge 114 to the first terminal 112 of the second interface 102 and the other diode 114 is conducting in the direction from the second terminal 122 of the second interface 102 to the midpoint 14 of the switching arm 104.

[0047] The power factor correction device 12 also includes a half-bridge 105 comprising capacitors 115 arranged in series between the terminals 112 and 122 of the second interface and on either side of a midpoint 125. These capacitors 115 can have the function of smoothing the output voltage of the half-bridges 103 and 104.

[0048] An additional controllable switch 108 is disposed between the midpoint 124 of the so-called low-frequency switching half-bridge 104 and the midpoint 125 of the half-bridge 105.

[0049] This additional switch 108 is bidirectional in voltage and current. For example, the switch 108 can be an electromechanical relay, a bidirectional transistor, for example a four-quadrant GaN-based transistor, or two unidirectional transistors, for example two N-type MOSFETs, arranged in anti-series or anti-parallel.

[0050] In the direction of power transfer from the first interface 101 to the second interface 102, the additional switch 108 is kept open.

[0051] The power factor correction device 12 of [Fig.2] is capable of carrying out a power transfer from the second interface 102 to the first interface 101, in a so-called reverse direction.

[0052] In this reverse power transfer direction, the additional switch 108 is controlled in the closed position for the entire duration of this power transfer. The closure of switch 108 causes the power factor correction device 12 of [Fig. 2] to operate similarly to a half-bridge inverter, with the diodes 114 of the switching arm 104 blocking current flow from the second interface 102.

[0053] With reference to [Fig.3], a second example of implementation of a power factor correction device 12 according to the invention is presented.

[0054] The power factor correction device 12 of [Fig.3] is adapted for a three-phase alternating voltage, supplied to its first interface 101. This interface 101 includes three terminals 111 suitable for being connected to a respective phase of the three-phase alternating voltage and one terminal 121 suitable for being connected to the neutral of this alternating voltage.

[0055] Each terminal 111 of the first interface 101 is connected to a respective high-frequency switching half-bridge 103. As in the power correction device 12 of [Fig. 1], each switching half-bridge 103 comprises two switches 113 arranged in series between the terminals 112 and 122 of the second interface 102 and on either side of a midpoint 123, connected to the terminal 111 of the first interface by an inductor 133. In the example shown in [Fig. 2], the switches 113 of the half-bridges 103 are N-type MOSFET transistors.

[0056] The power factor correction device 12 also includes a so-called low-frequency switching half-bridge 104, comprising two diodes 114 arranged in series between the terminals 112 122 of the second interface 102, and on either side of a midpoint 124, connected to the terminal 121 of the first interface, intended to be connected to the neutral of the alternating voltage.

[0057] A first diode 114 of the switching half-bridge 104 is conducting in the direction from the midpoint of the arm 124 of the switching half-bridge 114 to the first terminal of the second interface 112 and the other diode is conducting in the direction from the second terminal 122 of the second interface 102 to the midpoint 14 of the switching arm 104.

[0058] The power factor correction device 12 also includes a half-bridge 105 comprising capacitors 115 arranged in series between the terminals 112 and 122 of the second interface and on either side of a midpoint 125. These capacitors 115 can have the function of smoothing the output voltage of the half-bridges 103 and 104.

[0059] An additional controllable switch 108 is disposed between the midpoint 124 of the so-called low-frequency switching half-bridge 104 and the midpoint 125 of the half-bridge 105.

[0060] This additional switch 108 is bidirectional in voltage and current. For example, the switch 108 can be an electromechanical relay, a bidirectional transistor, for example a four-quadrant GaN-based transistor, or two unidirectional transistors, for example two N-type MOSFETs, arranged in anti-series or anti-parallel.

[0061] In the example shown in [Fig.3], during a power transfer from the first interface 101 to the second interface 102, the additional switch 108 is kept open if the alternating voltage from the network is a single-phase voltage and closed if the alternating voltage from the network is a three-phase voltage.

[0062] The power factor correction device 12 of [Fig.3] is capable of carrying out a power transfer from the second interface 102 to the first interface 101, in a so-called reverse direction.

[0063] In this reverse power transfer direction, the additional switch 108 is controlled in the closed position for the entire duration of this power transfer. The closing of switch 108 causes each high-frequency switching arm 103 of the power factor correction device 12 of [Fig. 3] to operate similarly to a half-bridge inverter in combination with the arm 105 comprising the capacitors, the diodes 114 of the switching arm 104 being blocking in the direction of current flow from the second interface 102.

[0064] The invention is not limited to what has been shown in the figures.

[0065] In the power factor correction devices of Figures 2 and 3, the diodes 114 of the arms 104 can be replaced by controllable switches comprising transistors, for example bipolar transistors. In this case, these transistors can be driven in the open position during the transfer of power from the second interface 102 to the first interface 101.

Claims

Demands

1. An electrical power factor correction device (12) comprising: - A first interface (101) and a second interface (102), the first interface (101) comprising a plurality of terminals (111, 121), the second interface (102) comprising two terminals (112, 122), the first interface (101) being capable of being connected to an alternating voltage source and the second interface (102) being capable of being connected to a direct voltage electrical circuit, - A high-frequency switching half-bridge (103) comprising two controllable semiconductor switches (113) arranged in series between the two terminals (112, 122) of the second interface (102) and on either side of a first midpoint (123), and an inductor (133) connected on one side to a terminal (111) of the first interface (101) and on the other side to said midpoint (123), - A so-called low-frequency switching half-bridge (104),comprising two switches (114) arranged in series between the two terminals (112, 122) of the second interface (102) and on either side of a second midpoint (124), this midpoint (124) being connected to a respective terminal (121) of the first interface (101), and - A half-bridge (105) comprising two capacitors (115) arranged in series between the two terminals (112, 122) of the second interface (102) and on either side of a third midpoint (125), the second midpoint (124) being connected to the third midpoint (125) by an additional controllable switch (108), the device (12) being characterized in that it is capable of carrying out an energy transfer from the second interface (102) to the first interface (101), the additional controllable switch (108) being kept closed during this energy transfer.

2. Electrical device (12) according to the preceding claim, the switches (114) of the so-called low-voltage switching half-bridge frequency (104) comprising controllable semiconductor switches, the switches (114) of said half-bridge (104) being controlled in the open position during the transfer of energy from the second interface (102) to the first interface (101).

3. Electrical device (12) according to claim 1, the switches (114) of the so-called low-frequency switching half-bridge (104) comprising diodes, the diodes being arranged within the half-bridge (104) in such a way that they are blocked during the transfer of energy from the second interface (102) to the first interface (101).

4. Electrical device (12) according to any one of the preceding claims, the device (12) being a single-phase device, comprising only a so-called high-frequency switching half-bridge (103) and a so-called low-frequency switching half-bridge (113).

5. Electrical device (12) according to any one of claims 1 to 3, the device (12) being a polyphase device, and comprising a plurality of so-called high-frequency switching half-bridges (103), the inductance (133) of said half-bridges (103) being connected to a respective terminal (111) of the first interface (101).

6. Electrical device (12) according to any one of the preceding claims, the additional switch being bidirectional in voltage and current.

7. Electrical device (12) according to the preceding claim, the additional switch (108) being an electromechanical relay.

8. Electrical device (12) according to claim 6, the additional switch (108) being a bidirectional semiconductor switch, for example a four-quadrant GaN-based transistor

9. An on-board electrical charger device (1) for an electrical energy storage unit, comprising: - A first interface (10) suitable for connection to an alternating voltage source, - A second interface (14) suitable for connection to an electrical energy storage unit, - An electromagnetic compatibility device (11) connected to the first interface (11), An electrical power factor correction device (12) according to any one of the preceding claims, connected to the electromagnetic compatibility device (11) by its first interface (101), An electrical DC-DC voltage conversion device (13) connected to the second interface (102) of the power factor correction device (12) on the one hand and to the second interface (14) on the other hand, and a control unit (15), capable of controlling the switches of the on-board charger device (10).

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