System for converting first voltage into second voltage comprising at least one passive voltage limiting means
By introducing passive voltage limiting components into electric or hybrid vehicle chargers, the imbalance between switching losses and conduction losses is solved, resulting in a more balanced chip junction temperature and improved electrical performance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SCHAEFFLER TECHNOLOGIES AG & CO KG
- Filing Date
- 2024-11-19
- Publication Date
- 2026-05-01
AI Technical Summary
In existing electric or hybrid vehicle chargers, there is an imbalance between the switching losses and conduction losses of the switching components, which leads to uneven chip junction temperatures and affects the electrical performance of the converter.
Introducing passive voltage limiting components, such as Zener diodes, into the converter thermally coupled between the control electrode and the conduction electrode of the electronic switch, and using their negative temperature coefficient to regulate the junction temperature of the switch chip, reduces loss imbalance.
By adjusting the junction temperature of the switching chip, the imbalance between switching losses and conduction losses is reduced, thereby improving the electrical performance of the converter.
Smart Images
Figure CN121970251A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a system for converting a first voltage to a second voltage, the system comprising a converter for converting the first voltage to the second voltage and means for controlling the converter. The invention also relates to a charger for an electric or hybrid vehicle, the charger including such an energy conversion system, and to an electric or hybrid vehicle, particularly a motor vehicle, including such a charger. Background Technology
[0002] Chargers for electric or hybrid vehicles are known in the prior art. These chargers are located on such vehicles and are designed to connect to charging stations for supplying electrical power to the vehicles. On-board chargers can operate in several operating modes within electric or hybrid vehicles, including: - Grid to vehicle (or G2V); - Vehicle to the grid (or V2G); - Vehicle to home (or V2H); - Vehicle to load (or V2L).
[0003] In vehicle-to-load (V2L) mode, electrical energy is typically drawn from the vehicle's high-voltage battery (a battery with a nominal voltage of 400 V or 800 V) and delivered as AC current (typically single-phase 230 V) by converting it into AC current (using a power conversion stage present in the charger). An external electrical device can then be connected to the vehicle to supply AC current to that device. The power conversion stage typically includes a system for converting a first DC voltage into a second AC voltage, the conversion system comprising a converter and means for controlling the converter.
[0004] A converter that converts a first DC voltage to a second AC voltage typically has a topology consisting of three electronic switching branches (or arms). Each switching branch includes two switching half-branches connected in series to a middle terminal. Each half-branches includes one or more current-switching elements connected in parallel. Each switching element includes a transistor-type electronic switch, typically a metal-oxide-semiconductor field-effect transistor (MOSFET). A control device is connected to each of these electronic switches to enable control of these switches.
[0005] However, due to the geometry of the converter (especially the geometry of its printed circuit board, which allows current to flow from the control device to the switch), different current paths exist between the switches. This results in different parasitic inductance values and causes different switching losses within each chip of the electronic switch. More specifically, the parasitic inductance is higher for the electronic chip with the longest current path, resulting in a smaller switching current and thus more switching losses. This imbalance between switching losses is accompanied by another imbalance related to conduction losses, which is due to differences in electrical parameters between the chips.
[0006] This imbalance between switching losses and conduction losses leads to differences in junction temperatures between individual chips, which is critical for converters from the perspective of limiting converter performance (and thus their ability to deliver AC current). In fact, higher losses within a given electronic switch chip result in higher temperatures, and this temperature imbalance significantly degrades the converter's electrical performance.
[0007] Therefore, there is a need to reduce the imbalance between switching losses and conduction losses among the switching components of a system used to convert a first voltage to a second voltage, in order to coordinate and regulate the junction temperature between the chips of these switching components, thereby improving the electrical performance of the system. Summary of the Invention
[0008] To achieve this objective, the present invention, in its broadest sense, proposes a system for converting a first voltage into a second voltage, the system comprising: - A converter that converts a first voltage into a second voltage, the converter including at least two input terminals, at least two output terminals, and at least one electronic switch branch connected between the two input terminals, the branch or each branch including two switch half-branches connected in series to an intermediate terminal, the at least one half-branches including at least one switch element, the switch element or each switch element including a controllable electronic switch, the controllable electronic switch being provided with a control electrode and two conducting electrodes; - A means for controlling the electronic switch or each electronic switch of the branch or each branch; The converter further includes a resistor and a passive voltage limiting component for the electronic switch or each electronic switch. The resistor is connected between the control device and the control electrode of the electronic switch, and the passive voltage limiting component is connected between the control electrode of the electronic switch and one of the conducting electrodes of the electronic switch, thermally coupled to the electronic switch, and has a negative temperature coefficient.
[0009] The presence of such a passive voltage-limiting component in the converter, for the electronic switch or each electronic switch, allows for the balancing of the junction temperatures between the chips of the switching components, thereby improving the electrical performance of the system. In practice, by arranging this passive voltage-limiting component within the converter and by thermally coupling it to the associated electronic switch, the temperature of this component becomes very close to the temperature of the electronic switch's chip. Therefore, when the chip of the switch is heated more than the other chips of the switch during converter operation, the passive voltage-limiting component associated with this switch has a lower breakdown voltage (due to the component's negative temperature coefficient). Now, for a transistor-type electronic switch with a control electrode and two conducting electrodes, its internal resistance is proportional to the voltage applied to the control electrode (the voltage applied between the control electrode and one of the conducting electrodes). Therefore, when the chip of the switch is heated more than the chips of other switches during converter operation, the voltage value of the control electrode decreases, and thus the chip of the switch in question has a higher resistance, resulting in less current flowing within the switch (and therefore less conduction loss). This mechanism, made possible by the presence of a passive voltage-limiting component for the electronic switch or for each electronic switch, thus allows for automatic temperature regulation between the chips of the switching components. In itself, the resistor enables the decoupling of the voltage between the control electrode and one of the conducting electrodes of the electronic switch.
[0010] According to one variant, the passive voltage limiting component, or each passive voltage limiting component, is a Zener diode.
[0011] According to one variant, a Zener diode is arranged in a switching element that includes an electronic switch to which the Zener diode is connected.
[0012] According to one variation, the Zener diode is arranged in the converter such that it is located at a distance of less than 0.5 cm, preferably about 1 mm or 2 mm, from the chip of the electronic switch to which it is connected. This allows for further improvement in the regulation of the junction temperature between the chips of the switching components, and thus further improves the electrical performance of the system.
[0013] According to one variant, the resistor, or each resistor, has a value in 1. With 10 The resistance values between.
[0014] According to one variant, the electronic switch, or each electronic switch, includes semiconductor electronic switching components, such as transistors or thyristors.
[0015] According to one variant, the semiconductor electronic switching component is a metal-oxide-semiconductor field-effect transistor, and the passive voltage limiting component is connected between the gate and source of the metal-oxide-semiconductor field-effect transistor.
[0016] According to one variant, the Zener diode makes its breakdown voltage between 16 V and 22 V for temperatures between 150°C and 200°C.
[0017] This allows for the acquisition of the breakdown voltage of the Zener diode, which is close to the nominal gate-source voltage of the corresponding metal-oxide-semiconductor field-effect transistor (in its closed state) when the chip is near its maximum temperature (between 150°C and 200°C).
[0018] The present invention also relates to a charger for electric or hybrid vehicles, the charger comprising the system described above for converting a first voltage into a second voltage.
[0019] The present invention also relates to an electric or hybrid vehicle, particularly a motor vehicle, that includes a charger as described above. Attached Figure Description
[0020] The embodiments of the invention will now be described by way of non-limiting example with reference to the accompanying single figure, in which: - [ Figure 1 [Illustrated description of an energy conversion system according to an embodiment of the present invention.] Detailed Implementation
[0021] refer to Figure 1 The diagram illustrates a system 2 for converting a first voltage U1 into a second voltage U2 according to an embodiment of the present invention. The power conversion system 2 is typically installed in an electric or hybrid motor vehicle, more specifically in the vehicle's charger, and includes a converter 4 for converting the first voltage U1 into the second voltage U2, and means 6 for controlling the converter 4.
[0022] For example, converter 4 is connected on one side to the high-voltage battery 3 of an electric or hybrid vehicle, which supplies power to its two input terminals 5 ( Figure 1 Only one of them is depicted in the image) delivers the first voltage U1, and on the other hand is connected to the load 7, which is located at its output terminal 8 ( Figure 1 Only one of them is depicted in the diagram, showing the transfer of the second voltage U2 between them. Figure 1 In the example of the depicted embodiment, the first voltage U1 is a DC voltage from the vehicle's battery after conversion by one or more other stages of the charger, and the second voltage U2 is, for example, a three-phase AC voltage. According to this same example, the converter 4 includes two input terminals 5 and three output terminals 8. As a variant, the first voltage U1 may be an AC voltage. As a variant or additionally, the second voltage U2 may be a DC voltage.
[0023] The converter 4, which converts the first voltage U1 to the second voltage U2, includes at least one electronic switch branch 10 connected between its two input terminals 5. Figure 1 In a specific embodiment, the converter 4 includes three electronic switch branches 10. The converter 4 also includes three passive voltage limiting components 12 and three resistors 14. Each component consisting of the electronic switch branches 10, the passive voltage limiting components 12, and the resistors 14 corresponds to a different phase of the AC voltage U2.
[0024] Each electronic switch branch 10 includes two switch half-branches 16 connected in series to the intermediate terminal 8. For clarity, Figure 1 Only one half-branch 16 of each switch branch 10 is depicted (the other half-branch 16 not depicted should be imagined as a mirror image of the depicted half-branch 16 and connected to another input terminal of the converter 4). Figure 1 (Not visible in the image). Each intermediate terminal 8 of the electronic switch branch 10 corresponds to the output terminal of the converter 4. The three intermediate terminals 8 appear to be connected to each other.
[0025] Each switch half-branch 16 includes a switch element 19. As a variant (not depicted), each switch half-branch 16 includes a number of N1 switch elements 19, where N1 is an integer greater than or equal to two. As another variant, only one switch half-branch 16 includes a number of N3 switch elements, where N3 is an integer greater than or equal to one.
[0026] As is known per se, each switching element 19 is bidirectional in terms of current and unidirectional in terms of voltage. Each switching element 19 includes a controllable electronic switch 20 having a control electrode 20A and two conducting electrodes 20B, 20C. Each switch 20 is formed, for example, by a metal-oxide-semiconductor field-effect transistor (MOSFET). For example, all MOSFETs 20 are identical. The gate 20A of each MOSFET 20 is connected to the control device 6 to receive a corresponding control signal. As a variation, the MOSFET 20 may be replaced by any semiconductor electronic component including the control electrode and two conducting electrodes, such as a bipolar transistor, field-effect transistor, thyristor, gate-off thyristor, IGCT (insulated-gate commutated thyristor), or MCT (MOS-controlled thyristor).
[0027] Each passive voltage limiting component 12 is thermally coupled to the chip of one of the MOSFETs 20 and connected between the gate 20A and the source 20C of this transistor. Each passive voltage limiting component 12 is typically a Zener diode, which has a breakdown voltage between 16 V and 22 V for temperatures between 150°C and 200°C. Each passive voltage limiting component 12 has a negative temperature coefficient. For example, when each passive voltage limiting component 12 is a Zener diode, each Zener diode 12 has a breakdown voltage of 19 V for a temperature equal to 175°C and a breakdown voltage of 17 V for a temperature equal to 200°C, which is non-limiting in the context of this invention.
[0028] Each Zener diode 12 is arranged, for example, in a switching member 19, which includes a MOSFET 20 connected thereto. Each Zener diode 12 is typically arranged in a converter 4 such that each Zener diode is located at a distance of less than 0.5 cm, preferably about 1 mm or 2 mm, from the chip of the MOSFET 20 to which the Zener diode is connected.
[0029] Each resistor 14 is connected between the control device 6 and the gate 20A of the corresponding MOSFET 20. Each resistor 14 has, for example, a value of 1... With 10 The resistance values between.
[0030] The power conversion system 2 according to the invention enables the reduction of imbalances between switching losses and conduction losses among the switching components 19, so as to coordinate and regulate the junction temperature between the chips of these switching components 19, thereby improving the electrical performance of the system 2.
Claims
1. A system (2) for converting a first voltage (U1) into a second voltage (U2), the system comprising: - A converter (4) that converts a first voltage (U1) into a second voltage (U2), the converter (4) including at least two input terminals (5), at least two output terminals (8), and at least one electronic switch branch (10) connected between the two input terminals (5), the branch or each branch (10) including two switch half-branches (16) connected in series to the intermediate terminal (8), at least one half-branches (16) including at least one switch member (19), the switch member or each switch member (19) including a controllable electronic switch (20), the controllable electronic switch being provided with a control electrode (20A) and two conducting electrodes (20B, 20C); - A device (6) for controlling the electronic switch or each electronic switch (20) of the branch or each branch (10); The converter (4) is characterized in that, for the electronic switch or each electronic switch (20), it further includes a resistor (14) and a passive voltage limiting component (12), the resistor (14) being connected between the control device (6) and the control electrode (20A) of the electronic switch (20), and the passive voltage limiting component (12) being connected between the control electrode (20A) of the electronic switch (20) and one of the conducting electrodes (20C) of the electronic switch, thermally coupled to the electronic switch (20), and having a negative temperature coefficient.
2. The power conversion system (2) as described in claim 1, characterized in that, The passive voltage limiting component or each passive voltage limiting component (12) is a Zener diode.
3. The power conversion system (2) as described in claim 2, characterized in that, The Zener diode (12) is arranged in the switching member (19), which includes the electronic switch (20) to which the Zener diode is connected.
4. The power conversion system (2) as described in claim 2 or 3, characterized in that, The Zener diode (12) is arranged in the converter (4) such that the Zener diode is located at a distance of less than 0.5 cm, preferably about 1 mm or 2 mm, from the chip of the electronic switch (20) to which the Zener diode is connected.
5. The power conversion system (2) as described in any one of claims 1 to 4, characterized in that, The resistor, or each resistor (14), has a value in 1 With 10 The resistance values between.
6. The power conversion system (2) as described in any one of claims 1 to 5, characterized in that, The electronic switch or each electronic switch (20) includes a semiconductor electronic switch component, such as a transistor or thyristor.
7. The power conversion system (2) as described in claim 6, characterized in that, The semiconductor electronic switch component (20) is a metal-oxide-semiconductor field-effect transistor, and the passive voltage limiting component (12) is connected between the gate (20A) and the source (20C) of the metal-oxide-semiconductor field-effect transistor.
8. The power conversion system (2) as described in claim 7 when dependent on claim 2, characterized in that, The Zener diode (12) makes its breakdown voltage between 16 V and 22 V for temperatures between 150°C and 200°C.
9. A charger for electric or hybrid vehicles, characterized in that, The charger includes a system (2) for converting a first voltage (U1) into a second voltage (U2) as claimed in any one of claims 1 to 8.