DC-AC voltage converter, charger, solar panel and motor vehicle

Abstract

The utility model relates to a DC voltage-AC voltage converter, a charger, a solar panel and a motor vehicle. A converter circuit is configured to convert a DC voltage to an AC voltage using first and second thyristors connected in series in a first branch, third and fourth thyristors connected in series in a second branch configured anti-parallel with the first branch, and first and second transistors connected in series in a third branch. When the AC voltage is equal to zero, and when the first thyristor is turned on and the first transistor and the second transistor are not turned on, a first positive current is applied to a gate of an anti-parallel third thyristor to control the turn-on and ensure that a current circulating in the first thyristor drops below a holding current.

Description

[0001] Priority claim

[0002] This application claims the benefit of priority of French Patent Application No. 2303012 filed on March 29, 2023, the contents of which are hereby incorporated by reference in their entirety to the maximum extent permitted by law. Technical Field

[0003] The present disclosure generally relates to voltage conversion problems, and in particular, to the problem of converting direct current (DC) voltage into alternating current (AC) voltage. More specifically, the present disclosure relates to a device or circuit for converting DC voltage into AC voltage and a control method thereof. Background Art

[0004] Voltage conversion, especially the conversion of DC voltage into AC voltage, is a continuously developing and expanding field of technology.

[0005] It would be desirable to be able to at least partially improve certain aspects of known voltage conversion circuits, and in particular to improve methods of controlling such conversion circuits.

[0006] A more efficient voltage conversion device or circuit is needed.

[0007] There is a need for a more efficient DC voltage to AC voltage conversion device or circuit.

[0008] What is needed is a method for controlling a voltage conversion device or circuit so that such a device or circuit can be more efficient.

[0009] There is a need to address all or some of the disadvantages of known methods for controlling voltage conversion devices or circuits. Utility Model Content

[0010] One aspect of the present disclosure provides a DC voltage-AC voltage converter, comprising: a first thyristor having an anode coupled to a first input node and a cathode coupled to a first output node; a second thyristor having an anode coupled to the first output node and a cathode coupled to a second input node; a third thyristor having an anode coupled to the first output node and a cathode coupled to the first input node; a fourth thyristor having an anode coupled to the second input node and a cathode coupled to the first output node; a first transistor having a first conduction terminal coupled to the first input node and a second conduction terminal coupled to the second output node; a second transistor having a first conduction terminal coupled to the second output node and a second conduction terminal coupled to the second input node; and a circuit configured to apply a first positive current to a gate of the third thyristor in response to the AC voltage being equal to zero and when the first thyristor is conducting and the first and second transistors are not conducting.

[0011] According to at least one embodiment of the present disclosure, the circuit includes: a first resistor, which is coupled between a supply node and a first node; a capacitor, which is coupled between the first node and a cathode of the third thyristor; a bipolar transistor, which has a collector coupled to the first node and an emitter coupled to the gate of the third thyristor; wherein the base of the bipolar transistor is controlled to be equal to zero in response to the AC voltage, and the bipolar transistor is turned on when the first thyristor is turned on and the first transistor and the second transistor are not turned on.

[0012] According to at least one embodiment of the present disclosure, the converter further includes an optocoupler circuit coupled to the base of the bipolar transistor.

[0013] According to at least one embodiment of the present disclosure, the converter further includes a second resistor coupled between an emitter of the bipolar transistor and a gate of the third thyristor.

[0014] According to at least one embodiment of the present disclosure, the first positive current is delivered by a power supply circuit.

[0015] According to at least one embodiment of the present disclosure, the circuit is further configured to apply a second positive current to the gate of the fourth thyristor in response to the AC voltage being equal to zero and when the second thyristor is conducting and the first transistor and the second transistor are not conducting.

[0016] According to at least one embodiment of the present disclosure, the second positive current is delivered by a power supply circuit.

[0017] According to at least one embodiment of the present disclosure, the first transistor and the second transistor are NMOS transistors.

[0018] According to at least one embodiment of the present disclosure, the first thyristor, the second thyristor, the third thyristor, and the fourth thyristor are configured to receive a maximum voltage of about 1200 V at their conduction terminals.

[0019] According to at least one embodiment of the present disclosure, the converter further includes a capacitor coupling the first input node and the second input node.

[0020] According to at least one embodiment of the present disclosure, the converter further includes a coil coupling the second output node to an intermediate node between the first transistor and the second transistor.

[0021] According to at least one embodiment of the present disclosure, the DC voltage is applied between the first input node and the second input node, and the AC voltage is supplied between the first output node and the second output node.

[0022] Another aspect of the present disclosure provides a charger comprising the above converter.

[0023] Yet another aspect of the present disclosure provides a solar panel comprising the above-mentioned converter.

[0024] Yet another aspect of the present disclosure provides a motor vehicle comprising the above-mentioned converter.

[0025] One embodiment provides a method for controlling a DC voltage-AC voltage converter, the converter comprising: a first thyristor, an anode of the first thyristor coupled to a first input node and a cathode coupled to a second output node; a second thyristor, an anode of the second thyristor coupled to the second output node and a cathode coupled to a third input node; a third thyristor, an anode of the third thyristor coupled to the second output node and a cathode coupled to the first input node; a fourth thyristor, an anode of the fourth thyristor coupled to the third input node and a cathode coupled to the second output node; a first transistor, a first conduction terminal of the first transistor coupled to the first input node and a second conduction terminal coupled to a fourth output node; a second transistor, a first conduction terminal of the second transistor coupled to the fourth output node and a second conduction terminal coupled to the third input node; wherein when the AC voltage is equal to zero and when the first thyristor is conducting and the first transistor and the second transistor are not conducting, a first positive current is applied to the gate of the third thyristor.

[0026] Another embodiment provides a DC voltage-AC voltage converter, the converter comprising: a first thyristor, wherein an anode of the first thyristor is coupled to a first input node and a cathode is coupled to a second output node; a second thyristor, wherein an anode of the second thyristor is coupled to the second output node and a cathode is coupled to a third input node; a third thyristor, wherein an anode of the third thyristor is coupled to the second output node and a cathode is coupled to the first input node; a fourth thyristor, wherein an anode of the fourth thyristor is coupled to the third input node and a cathode is coupled to the second output node; a first transistor, wherein a first conduction terminal of the first transistor is coupled to the first input node and a second conduction terminal is coupled to a fourth output node; a second transistor, wherein a first conduction terminal of the second transistor is coupled to the fourth output node and a second conduction terminal is coupled to the third input node; wherein when the AC voltage is equal to zero and when the first thyristor is turned on and the first transistor and the second transistor are not turned on, a first positive current is sent to the gate of the third thyristor.

[0027] According to one embodiment, the first current is delivered by a power supply circuit.

[0028] According to one embodiment, when the second thyristor is conducting and the first transistor and the second transistor are not conducting, a second positive current is applied to the gate of the fourth thyristor.

[0029] According to one embodiment, the second current is delivered by a power supply circuit.

[0030] According to one embodiment, the first transistor and the second transistor are NMOS type transistors.

[0031] According to one embodiment, the first thyristor, the second thyristor, the third thyristor and the fourth thyristor are configured to receive a maximum voltage of about 1200 V at their conduction terminals.

[0032] According to an embodiment, the converter further includes a capacitor coupling the first input node with the third input node.

[0033] According to one embodiment, the converter further includes a coil coupling the fourth output node to a fifth intermediate node between the first transistor and the second transistor.

[0034] According to one embodiment, the DC voltage is adapted to be applied between the first input node and the third input node, and the AC voltage is adapted to be supplied between the second output node and the fourth output node.

[0035] Another embodiment provides a charger including the previously described circuit.

[0036] Another embodiment provides a solar panel including the previously described circuit.

[0037] Another embodiment provides a motor vehicle comprising the circuit previously described. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The above features and advantages and others will be described in detail in the following description of specific embodiments given by way of illustration and not limitation with reference to the accompanying drawings, in which:

[0039] Figure 1 An embodiment of a voltage conversion circuit is illustrated;

[0040] Figure 2 The diagram shows Figure 1 An image of the operation of the circuit;

[0041] Figure 3 The diagram shows Figure 1 Two images of the operation of the circuit;

[0042] Figure 4 The diagram shows the control Figure 1 The electrical scheme of the circuit method for implementation;

[0043] Figure 5 Pictured Figure 1 An example embodiment of a power supply circuit of a circuit;

[0044] Figure 6 The diagram shows Figure 5 an image of the operation of the circuit; and

[0045] Figure 7 The diagram shows Figure 4 The details of the control method are shown in the figure. DETAILED DESCRIPTION

[0046] In the various drawings, similar features have been designated by similar reference symbols. In particular, common structural and / or functional features between the various embodiments may have the same reference symbols and may have the same structure, dimensions, and material properties.

[0047] For the sake of clarity, only the operations and elements useful for understanding the embodiments described herein are illustrated and described in detail. Figure 1 With respect to the common detailed operation of voltage conversion circuits of the type described herein, it should be considered that such operation is within the capabilities of those skilled in the art.

[0048] Unless otherwise indicated, when reference is made to two elements being connected together, this means a direct connection without any intermediate elements other than conductors, and when reference is made to two elements being coupled together, this means the two elements may be connected or they may be coupled via one or more other elements.

[0049] In the following disclosure, unless otherwise indicated, when referring to absolute position qualifiers such as terms "front", "back", "top", "bottom", "left", "right", etc., or relative position qualifiers such as terms "above", "below", "higher", "lower", etc., or orientation qualifiers such as "horizontal", "vertical", etc., reference is made to the orientation shown in the figure.

[0050] Unless otherwise specified, the terms "about," "substantially," and "approximately" mean within 10%, and preferably within 5%.

[0051] Figure 1 An embodiment of a voltage conversion circuit 100 is illustrated.

[0052] The circuit 100 enables a DC voltage VDC to be converted into an AC voltage VAC. According to one embodiment, the circuit 100 is a bidirectional conversion circuit, and also enables an AC voltage VAC to be converted into a DC voltage VDC. The embodiments described hereinafter only relate to the operation of the circuit 100 for converting a DC voltage VDC into an AC voltage VAC. According to a preferred example, the circuit 100 is configured to receive a minimum DC voltage VDC of 380V, and transmit an AC voltage having a minimum effective voltage of 85V and a minimum frequency of about 40Hz.

[0053] According to one embodiment, circuit 100 is a bidirectional conversion circuit using totem-pole-type components, ie, using cascode (push-pull) components, where the active components are identical transistors receiving the same signals but in opposite phases.

[0054] According to one embodiment, the circuit 100 includes two electrical nodes IN-DC101 and IN-DC102, whose potential difference is equal to the DC voltage VDC. Since the situation described here involves converting the DC voltage VDC into the AC voltage VAC, the nodes IN-DC101 and IN-DC102 are hereinafter referred to as input nodes of the circuit 100.

[0055] Similarly, according to one embodiment, the circuit 100 includes two electrical nodes OUT-AC101 and OUT-AC102 , whose potential difference is equal to the AC voltage VAC. The nodes OUT-AC101 and OUT-AC102 are hereinafter referred to as input nodes of the circuit 100 .

[0056] The circuit 100 includes a capacitor C-DC coupled to input nodes IN-DC101 and IN-DC102.

[0057] The circuit 100 also includes a first branch including a thyristor T1 and a thyristor T2 between its input nodes IN-DC101 and IN-DC102. The anode of the thyristor T1 is coupled (preferably connected) to the input node IN-DC101, and the cathode of the thyristor T1 is coupled (preferably connected) to the output node OUT-AC102. The anode of the thyristor T2 is coupled (preferably connected) to the output node OUT-AC102, and the cathode of the thyristor T2 is coupled (preferably connected) to the input node IN-DC102. The gates of the thyristors T1 and T2 are configured to receive a control current.

[0058] The circuit 100 also includes a second branch including a thyristor T3 and a thyristor T4 between its input nodes IN-DC101 and IN-DC102. The cathode of the thyristor T3 is coupled (preferably connected) to the input node IN-DC101, and the anode of the thyristor T3 is coupled (preferably connected) to the output node OUT-AC102. The cathode of the thyristor T4 is coupled (preferably connected) to the output node OUT-AC102, and the anode of the thyristor T4 is coupled (preferably connected) to the input node IN-DC102. The gates of the thyristors T3 and T4 are configured to receive a control current.

[0059] The circuit 100 includes a third branch including two transistors M1 and M2 constituting a totem pole type component between its input nodes IN-DC101 and IN-DC102. According to one embodiment, the transistors M1 and M2 are insulated gate field effect transistors or metal oxide semiconductor structure field effect transistors, which are more commonly referred to as MOSFET transistors (metal oxide semiconductor field effect transistors) or MOS transistors. More specifically, the transistors M1 and M2 are N-channel MOS type transistors, which are also referred to as NMOS transistors. The first conduction terminal of the transistor M1 is coupled (preferably connected) to the input node IN-DC101, and the second conduction terminal of the transistor M1 is coupled (preferably connected) to the node N101. The first conduction terminal of the transistor M2 is coupled (preferably connected) to the node N101, and the second conduction terminal of the transistor M2 is coupled (preferably connected) to the input node IN-DC101. The node N101 is also referred to as an intermediate node between the transistors M1 and M2. The control terminals of the transistors M1 and M2 are configured to receive a control voltage.

[0060] The circuit 100 also includes a coil (inductor) L101 coupling the node N101 to the output node OUT-AC101 .

[0061] The circuit 100 finally includes an optional filtering capacitor C_AC coupled to the output nodes OUT-AC101 and OUT-AC102 .

[0062] and Figures 2 to 4 The operation of the circuit 100 is described with reference to FIG. Figure 4 The implementation of the control method of the circuit 100 is described in detail.

[0063] Figure 2 The diagram shows Figure 1 Two curves 201 and 202 depict the operation of the circuit 100 in relation to each other.

[0064] More specifically, curves 201 and 202 are two time diagrams representing the evolution of the AC voltage VAC and the AC current IAC, respectively, both delivered at the output of the circuit 100. More specifically, as previously mentioned, the AC voltage VAC is delivered between the nodes OUT-AC101 and OUT-AC102. The current IAC is delivered at the node OUT-AC101.

[0065] When the voltage VAC and the current IAC are positive, the thyristor T1 is controlled to be non-conductive, and the thyristor T2 is controlled to be conductive. The transistor M1 is controlled to be periodically conductive, and the transistor M2 is controlled to be non-conductive. The thyristors T3 and T4 are non-conductive.

[0066] When the voltage VAC and the current IAC are negative, the thyristor T1 is controlled to be conductive, and the thyristor T2 is controlled to be non-conductive. The transistor M1 is controlled to be non-conductive, and the transistor M2 is controlled to be periodically conductive. The thyristors T3 and T4 are non-conductive.

[0067] Figure 3 A more detailed representation includes Figure 1 Two images (A) and (B) relatedly depict the operation of circuit 100 .

[0068] Image (A) includes curve 301 and curve 302. Curves 301 and 302 are two time diagrams illustrating the evolution of AC voltage VC_AC and current IL, respectively. More specifically, AC voltage VC_AC is the voltage across the terminals of capacitor C_AC. Current IL is the current delivered at the output of coil L101.

[0069] Similarly, graph (B) comprises a curve 351 and a curve 352. Curves 351 and 352 are two time diagrams illustrating the evolution of the previously defined AC voltage VC_AC and current IL, respectively.

[0070] Images (A) and (B) illustrate the AC voltage VAC and the AC current IAC just before they change their signs (i.e., just before they cross zero). Figure 1 The operation of the circuit 100. Figure 3 In the example presented in , images (A) and (B) illustrate the operation of the circuit 100 when the AC voltage VAC and the AC current IAC are positive and are about to become negative. At this time, the conductive thyristor T2 becomes non-conductive, and the non-conductive thyristor T1 becomes conductive after the AC voltage VAC passes zero. Thyristors M1 and M2 are non-conductive at this time. Therefore, the current IL flowing through the coil is equal to the current flowing through the thyristor T2.

[0071] Image (A) illustrates the case of standard operation, during which the current IL present in coil L101 also becomes zero before the voltage VC_AC of capacitor C_AC reverses. The current in thyristor T2 is equal to the current IL, but less than the holding current of thyristor T2. Therefore, thyristor T2 becomes non-conductive.

[0072] Image (B) illustrates a case of abnormal operation during which, when the voltage VC_AC of the capacitor C_AC becomes zero, the current IL present in the coil that circulates in the thyristor T2 is greater than the holding current of the thyristor T2. When the voltage VC_AC reverses, the thyristor T2 is still conducting. This reversal of the voltage VC_AC causes the current in the thyristor T2 to increase and prevents it from turning off. This resonance phenomenon is a parasitic phenomenon that delays the stopping of the thyristor T2. Figure 4 The control method of the circuit 100 described in relation enables such abnormal operating situations to be avoided.

[0073] Similarly, this parasitic resonance phenomenon may also occur when the AC voltage VAC and the AC current IAC are negative and become positive. In this case, it is the thyristor T1 that is conducting and becomes non-conducting.

[0074] It will be noted that in the case of the resonance phenomenon, the presence of the freewheeling current flowing through the intrinsic diodes of the transistors M1 and M2 is not sufficient to offset the current circulating in the thyristors T1, T2 (e.g. under certain voltage and current conditions). Additional circuit control is required to ensure that the current circulating in the thyristor T2 drops below the holding current of the thyristor T2 so that the thyristor T2 can be turned off at the correct time.

[0075] Figure 4 The diagram shows Figure 1 The circuit 100 is described in relation to one another and enables an implementation of a method for controlling the circuit 100 to be illustrated.

[0076] According to one embodiment, to avoid Figure 3The occurrence of the parasitic resonance phenomenon related to the AC voltage VAC and the AC current IAC changes its sign, and the thyristor T3 or T4 connected in anti-parallel with the thyristor T1 or T2 that stops conducting becomes conducting to absorb the residual current flowing through the coil L101. In addition, the current absorbed is also any freewheeling current in the intrinsic diode of the MOS transistor. For this purpose, a positive current is applied to the gate of the thyristor T3 or T4 to control the conduction. The effect is to empty the current in the thyristor T1 or T2 to a level below the holding current level and turn off the thyristor.

[0077] More specifically, in Figure 4 In the case shown in FIG. 1 , the AC voltage VAC and the AC current IAC are positive and become negative. The thyristor T2 stops conducting, and the thyristor T4 becomes conducting due to the positive control current applied to its gate. Figure 4 The charge path of the residual current of the coil L101 is illustrated by a dashed arrow F400 in FIG. In fact, in this configuration, the thyristor T4 is reverse biased and its performance approaches that of a low-gain bipolar transistor.

[0078] In the opposite case, that is, when the AC voltage VAC and the AC current IAC are negative and become positive, the thyristor T1 stops conducting and the thyristor T3 becomes conducting due to application of a control current on its gate.

[0079] Thus, for example, the proposed solution is to turn on thyristor T4 at the moment when the AC voltage changes sign, so as to redirect the current from the coil to thyristor T4 and divert this current from thyristor T2 (in addition to the current diversion that occurs through the current flowing through the intrinsic diode of transistor M2). This has the effect of "emptying" the current in thyristor T2, thus turning it off (cutting off).

[0080] and Figure 5 and Figure 6 An example embodiment of a circuit for controlling the thyristors T3 and T4 and its operation which enables the control current to be applied to the gates of the thyristors T3 and T4 is described in relation.

[0081] Figure 5 An example embodiment of a control circuit 500 for a thyristor T501 for delivering a control current I_T501 at the gate of the thyristor T501 is illustrated. According to an example, the thyristor T501 is connected to Figure 1 The thyristor T3 or T4 of the circuit 100 is described in relation.

[0082] The control circuit 500 includes two resistors R501 and R502 and an NPN bipolar transistor TB501. The first terminal of the resistor R501 is coupled (preferably connected) to the output node of the circuit 500, that is, in fact, coupled (preferably connected) to the gate of the thyristor T501. The second terminal of the resistor R501 is coupled (preferably connected) to the emitter of the transistor TB501. The collector of the transistor TB501 is coupled (preferably connected) to the first terminal of the resistor R502, which is also referred to as the node N501. The second terminal of the resistor R502 is coupled (preferably connected) to a node receiving a power supply voltage VDD500 of, for example, about 5V.

[0083] The control circuit 500 further comprises a capacitor C501 coupling the node N501 to the cathode of the thyristor T501. According to an example, the capacitor C501 is a bias capacitor. According to an example, the cathode of the thyristor is a reference node, for example receiving a reference potential, such as ground.

[0084] The control circuit 500 further includes a resistor R503 and an optical coupler OT501. The first terminal of the resistor is coupled (preferably connected) to the base of the transistor TB501. The second terminal of the resistor R503 is coupled (preferably connected) to the first conduction terminal of the optical coupler OT501. The second conduction terminal of the optical coupler OT501 is coupled (preferably connected) to the node receiving the power supply voltage VDD500.

[0085] Figure 6 The diagram shows the implementation and Figure 4 An image of the operation of the control circuit 500 during the control method is described in relation.

[0086] More specifically, Figure 6 The image includes: a curve IG illustrating the evolution of the control current transmitted to the gate of the thyristor T501 over time; a curve I_T501 illustrating the evolution of the current reaching the cathode of the thyristor T501 over time; a curve I_R502 illustrating the evolution of the charging current of the resistor R502 over time; and a curve V_C501 illustrating the change of the voltage across the capacitor C501 over time.

[0087] The control circuit 500 is sized so as to deliver a positive control current of approximately 4.5 A at the gate of the thyristor whenever the AC voltage VAC and the AC current IAC become zero, as previously described. Figure 7 An example of determining the control current value is described in detail.

[0088] For this purpose, capacitor C501 is charged by power supply voltage VDD500 and resistor R502. Optocoupler OT501 periodically drives bipolar transistor TB501 to conduct. Then, capacitor C501 discharges and transmits control current to the gate of thyristor T501.

[0089] Figure 7 A graph 701 showing the gain of a reverse biased thyristor as a function of the current applied to its gate is illustrated.

[0090] The graph 701 indicates that the larger the gate current, the lower the thyristor gain. Figure 5 With regard to the control method described above, it is necessary to use a sufficiently high control current, but during a relatively short period of time, so that not too much energy is consumed.

[0091] and Figure 4 Specific examples of applications of the circuit 100 and the control method described in relation thereto are bidirectional power converters for the automotive industry (e.g., in particular, the hybrid and electric motor vehicle industry), the field of high-power chargers (e.g., car chargers for private households and / or public places), the field of renewable energy (e.g., solar panels), the field of uninterruptible power supplies, etc. The power converters involved in these fields are suitable for converting AC voltage into DC voltage and / or converting DC voltage into AC voltage.

[0092] Various embodiments and variations have been described. Those skilled in the art will appreciate that certain features of these embodiments may be combined, and those skilled in the art will readily conceive of other variations.

[0093] Finally, based on the functional description provided above, actual implementation of the embodiments and variations described herein is within the capabilities of those skilled in the art.

[0094] One aspect of the present disclosure provides a method for controlling a DC voltage-AC voltage converter, wherein the converter includes: a first thyristor having an anode coupled to a first input node and a cathode coupled to a first output node; a second thyristor having an anode coupled to the first output node and a cathode coupled to a second input node; a third thyristor having an anode coupled to the first output node and a cathode coupled to the first input node; a fourth thyristor having an anode coupled to the second input node and a cathode coupled to the first output node; a first transistor having a first conduction terminal coupled to the first input node and a second conduction terminal coupled to the second output node; and a second transistor having a first conduction terminal coupled to the second output node and a second conduction terminal coupled to the second input node; the method includes applying a first positive current to a gate of the third thyristor when the AC voltage is equal to zero and when the first thyristor is conducting and the first and second transistors are not conducting.

[0095] According to at least one embodiment of the present disclosure, the method further includes applying a second positive current to a gate of the fourth thyristor when the AC voltage is equal to zero and when the second thyristor is conducting and the first transistor and the second transistor are not conducting.

[0096] According to at least one embodiment of the present disclosure, the first transistor and the second transistor are NMOS transistors.

[0097] According to at least one embodiment of the present disclosure, the first thyristor, the second thyristor, the third thyristor, and the fourth thyristor are configured to receive a maximum voltage of about 1200 V at their conduction terminals.

[0098] According to at least one embodiment of the present disclosure, the converter further includes a coil coupling the second output node to an intermediate node between the first transistor and the second transistor.

[0099] According to at least one embodiment of the present disclosure, the DC voltage is applied between the first input node and the second input node, and the AC voltage is supplied between the first output node and the second output node.

Claims

1. A DC voltage to AC voltage converter, characterized in that: The converter comprises: a first thyristor having an anode coupled to the first input node and a cathode coupled to the first output node; a second thyristor having an anode coupled to the first output node and a cathode coupled to a second input node; a third thyristor having an anode coupled to the first output node and a cathode coupled to the first input node; a fourth thyristor having an anode coupled to the second input node and a cathode coupled to the first output node; a first transistor having a first conduction terminal coupled to the first input node and a second conduction terminal coupled to a second output node; a second transistor having a first conduction terminal coupled to the second output node and a second conduction terminal coupled to the second input node; and A circuit configured to apply a first positive current to a gate of the third thyristor in response to the AC voltage being equal to zero and when the first thyristor is conducting and the first transistor and the second transistor are not conducting.

2. The converter according to claim 1, characterized in that The circuit comprises: a first resistor coupled between the supply node and the first node; a capacitor coupled between the first node and a cathode of the third thyristor; a bipolar transistor having a collector coupled to the first node and an emitter coupled to the gate of the third thyristor; The base of the bipolar transistor is controlled to be responsive to the AC voltage being equal to zero and to turn on the bipolar transistor when the first thyristor is conducting and the first transistor and the second transistor are not conducting.

3. The converter according to claim 2, characterized in that The converter also includes an optocoupler circuit coupled to the base of the bipolar transistor.

4. The converter according to claim 2, characterized in that The converter further includes a second resistor coupled between an emitter of the bipolar transistor and a gate of the third thyristor.

5. The converter according to claim 1, characterized in that The first positive current is delivered by a power supply circuit.

6. The converter according to claim 1, characterized in that The circuit is further configured to apply a second positive current to the gate of the fourth thyristor in response to the AC voltage being equal to zero and when the second thyristor is conducting and the first transistor and the second transistor are non-conducting.

7. The converter according to claim 6, characterized in that The second positive current is delivered by a power supply circuit.

8. The converter according to claim 1, characterized in that The first transistor and the second transistor are NMOS type transistors.

9. The converter according to claim 1, characterized in that The first thyristor, the second thyristor, the third thyristor and the fourth thyristor are configured to receive a maximum voltage of approximately 1200 V at their conduction terminals.

10. The converter according to claim 1, characterized in that The converter also includes a capacitor coupling the first input node and the second input node.

11. The converter according to claim 1, characterized in that The converter also includes a coil coupling the second output node to an intermediate node between the first transistor and the second transistor.

12. The converter according to claim 1, characterized in that The DC voltage is applied between the first input node and the second input node, and the AC voltage is supplied between the first output node and the second output node.

13. A charger, characterized in that: The charger comprises the converter according to claim 1 .

14. A solar panel, characterized in that: The solar panel comprises a converter according to claim 1 .

15. A motor vehicle, characterized in that: The motor vehicle comprises a converter according to claim 1 .

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