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CN-122029732-A - Hybrid DC/DC converter with push-pull full bridge topology and secondary side resonant circuit

CN122029732ACN 122029732 ACN122029732 ACN 122029732ACN-122029732-A

Abstract

The invention relates to a converter device comprising a primary unit having two DC voltage inputs for connection to a fuel cell and a secondary unit having two DC voltage outputs for connection to a consumer, wherein the primary unit and the secondary unit are coupled via a transformer, wherein the transformer has a series circuit of a first primary coil (Lp 1) and a second primary coil (Lp 2) and a secondary coil (Ls), wherein a first DC voltage input of the DC voltage inputs is connected to a connection point of the first and second primary coils (Lp 1, lp 2) via a first inductance (L1), wherein a bridge point of the inverter is connected in parallel to a series circuit of the first and second primary coils (Lp 1, lp 2), wherein the secondary unit has a rectifier, an AC input of the rectifier is connected in parallel to the secondary coil (Ls) and a second inductance (L2), and wherein the inductance is connected to a series circuit of the second inductance (L2) via a series capacitor, wherein the two series circuit of the two resonators (L2) forms a series circuit of the two resonators.

Inventors

  • KRAUSS AXEL

Assignees

  • 布鲁萨超动力公司

Dates

Publication Date
20260512
Application Date
20241017
Priority Date
20231026

Claims (13)

  1. 1. A converter device, comprising: A primary unit having two DC voltage inputs for connection to the fuel cell and a secondary unit having two DC voltage outputs for connection to the powered device; -wherein the primary unit and the secondary unit are coupled via a transformer; Wherein the transformer has a series circuit of a first primary winding (Lp 1) and a second primary partial winding (Lp 2) and a secondary winding (Ls), -Wherein a first one of the DC voltage inputs is connected via a first inductance (L1) to a connection point of the first and second primary part-coils (Lp 1, lp 2); -wherein the primary unit comprises an inverter, the bridge point of which is connected in parallel to the series circuit of the first and second primary coils (Lp 1, lp 2); -wherein the secondary unit comprises a rectifier, the AC input of which is connected in parallel to the series circuit of the secondary coil (Ls) and a second inductance (L2), and -Wherein one of the AC input and two DC outputs of the rectifier connected to the second inductance (L2) is connected via a resonance capacitor Cr, wherein the second inductance (L2) and the resonance capacitor Cr form a series resonance circuit.
  2. 2. The transducer assembly of claim 1, Wherein the AC input of the rectifier connected to the secondary coil (Ls) is connected to a bridge point of an inverter, the inputs of the inverter being each connected in parallel to two DC voltage outputs of the rectifier.
  3. 3. The converter device according to any one of claim 1 or 2, Wherein the AC input of the rectifier connected to the second inductance (L2) is connected to a bridge point of an inverter, the inputs of the inverter being each connected in parallel to two DC voltage outputs of the rectifier.
  4. 4.A converter device according to any one of claims 1 to 3, Wherein the AC input of the rectifier connected to the second inductance (L2) and the two DC outputs are each connected via a resonant capacitor Cr 1 、Cr 2 .
  5. 5. The converter device according to any one of claims 1 to 4, Wherein the inverter has an intermediate circuit capacitor C Z .
  6. 6. The converter device according to any one of claims 1 to 5, Wherein the inverter is a full bridge inverter.
  7. 7. The converter device according to any one of claims 1 to 6, Wherein a capacitor C in is connected between the two DC voltage inputs.
  8. 8. The converter device according to any one of claims 1 to 7, Wherein a capacitor C a is connected between the two DC voltage outputs.
  9. 9. A method for operating a converter device according to any of claims 1 to 8, Wherein the two half-bridges of the inverter have a clock frequency Operates with the same PWM signal of the clock frequency Offset by half a period (180 °).
  10. 10. The method for operating a converter device according to claim 9, Wherein the clock frequency is selected in the range of 10kHz to 150kHz, in particular 50kHz or 49kHz or 48kHz or 47kHz or 46kHz or 45kHz.
  11. 11. The method for operating a converter device according to claim 10, Wherein the duty cycle of the PWM signal and/or the clock frequency of the PWM signal used to control the inverter is varied in order to adjust the input voltage between the DC voltage inputs and/or to adjust the output voltage between the DC voltage outputs and/or to adjust the transmission power of the converter means.
  12. 12. A drive system for a vehicle comprising a converter device according to any one of claims 1 to 8.
  13. 13. A vehicle, in particular a road vehicle, an aircraft, a rail vehicle, a ship or an underwater vehicle, having a drive system according to claim 12.

Description

Hybrid DC/DC converter with push-pull full bridge topology and secondary side resonant circuit The present invention relates to a converter device for using a fuel cell as an energy source for vehicles, aircraft, rail vehicles, ships, etc., in particular a high-performance voltage converter, a method for operating the converter device, a drive system for a vehicle having the converter device, and a vehicle having the drive system. Vehicles having multiple fuel cells (i.e., fuel cell stacks) as energy sources are continually further evolving and are expected to play an important role in the near future. Their main application arises in the field of mobile transportation, where the amount of energy required is so great that carrying correspondingly large batteries becomes uneconomical or too heavy for the vehicle. Although fuel cell vehicles also have traction cells, they are relatively small. It enables dynamic compensation of energy recovery (recovery) and load fluctuations during braking, which is not immediately followed by a fairly slow fuel cell, and therefore, strictly speaking, a fuel cell vehicle is a series hybrid vehicle. Fuel cells as energy sources also have the advantage that the hydrogen gas required for operation can be filled in a relatively short time, whereas in order to charge a large cell correspondingly quickly, a very powerful and expensive infrastructure must be provided. This applies in particular to buses, trucks and ships, but in the near future also aircraft are conceivable. All of these applications as energy sources in vehicles have in common that they typically require high continuous electrical power outputs well in excess of 100kW to drive them. In order to ensure that the operating current and the required cable cross section do not become too large despite this high power, the operating voltage is selected to be correspondingly high. DC voltages in the range of 600V to 900V are commonly used, but higher voltages up to 1500V are conceivable in the future. On the other hand, the development of fuel cell stacks is exhibiting a certain technology driven "standardization", one stack having a nominal power of about 150kW and a maximum current of up to 900A, resulting in a nominal operating voltage of about 167V. In order to increase this voltage to the above-mentioned operating voltage range, a powerful voltage converter is required. Up to now, simple boost converters have proven to be an effective basic circuit (see fig. 1 (prior art)), where the power is typically distributed over several interleaved "phases" to achieve as continuous a power flow as possible (comparable to an internal combustion engine, where the smoothness increases with an increasing number of cylinders). This simple configuration also has its drawbacks as the power and operating voltage of the driver increases: the size of the electronic power switch (IGBT or SiC MOSFET) of the boost converter has to be set in terms of the maximum voltage (e.g. 900V) driving the intermediate circuit and the high fuel cell current (e.g. 900A) such that the so-called "peak power" (i.e. the product of the maximum current and the maximum voltage) is 900V x 900A = 810kVA, which is five times more than the usual nominal power of 150kW of the fuel cell, which represents a significant size being too large. The withstand voltage of the insulation between the fuel cell and the ground (vehicle chassis) must meet the more demanding criteria of the drive network (maximum 900V), although the fuel cell voltage itself hardly reaches 300V. In case of a failure of the boost converter (e.g. a short circuit of the freewheeling diode), elaborate safety measures have to be taken to prevent current from flowing back from the drive circuit to the fuel cell, otherwise the fuel cell stack would be immediately damaged, which would pose a certain risk in a hydrogen environment, which is particularly applicable to systems with multiple fuel cell stacks and thus multiple boost converters. Both the inverter and the boost converter of the drive undergo periodic fast switching operations, which lead to electromagnetic interference, which must be filtered out according to the prescribed EMC standard (emc= Electromagnetic compatibility, electromagnetic compatibility). Filters provided for this purpose use, among other things, Y capacitors for switching the disturbances from the traction circuit to electrical ground, wherein the maximum total energy of these capacitors, and thus their total capacitance, must not exceed a certain value for safety reasons. Since each component in the traction circuit, including the fuel cell, already has some capacitance to ground, in systems where multiple fuel cell stacks are connected to the same traction circuit, the technical potential for dissipating electromagnetic interference through additional Y-capacitors becomes smaller and smaller as the number of fuel cell stacks increases, even more systems produce more interferenc