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• SMALL-SIZED WELDING INVERTER FOR SEMI-AUTOMATIC WELDING WITH HIGH FREQUENCY AC CURRENT

  V. V. Burlaka, S.V. Gulakov, А. Y. Golovin, D. S. Mironenko

  2025-01-30

  Abstract ▼

  The design of a small-sized high-efficiency welding inverter with high-frequency alternating current
  output for semi-automatic welding is considered. The inverter is distinguished by good power density and
  lowered power losses due to absence of output power rectifier. It is shown that when high-frequency alternating
  current is supplied to the welding arc, several problems arise: the non-constant inductance of the
  welding circuit presents a significant reactance at conversion frequencies of tens of kHz, limiting the arc
  current; at high frequency, a surface effect (skin effect) begins to manifest itself. To solve the problem of
  current limitation, a scheme with reactance compensation is proposed by connecting a capacitor in series
  with the welding circuit and introducing frequency control of the current in the resulting series-resonant
  circuit. The aim of the work is to develop a welding inverter for semi-automatic welding with highfrequency
  alternating current, ensuring high-quality process flow. As a result of the research, a smallsized
  welding inverter for semi-automatic arc welding with high-frequency alternating current was developed
  and prototyped. Laboratory tests of the designed inverter have shown steady arc burning and stable
  process flow. The developed inverter can be easily modified to increase the welding current. The structure
  of the power section of the developed welding power supply also allows it to be used for induction heating
  tasks by connecting an inductor with an inductance of 2...7 μH to the output terminals and introducing
  minor adjustments into the microcontroller control program to implement inductor current control.
  Thanks to the increased power factor, the developed inverter current drawn from the supply grid is
  25...40% lower than that of the widespread welding inverters without a power factor corrector. This reduces
  the load on the distribution supply grid and allows welding operations to be carried out when powered
  from a "weak" grid or with a long power cable

• WIRELESS UAV CHARGING SYSTEM WITH BATTERY BALANCING FUNCTIONALITY

  V.V. Burlaka, S. V. Gulakov, А. Y. Golovin, D. S. Mironenko

  2025-01-14

  Abstract ▼

  The issue of creating a wireless charging system for an on-board battery of an unmanned aerial vehicle
  (UAV) is considered, taking into account the need to balance the voltages of its elements. When designing
  the system, based on a brief overview of the principles of wireless energy transmission, the principle
  of using magnetically coupled circuits is taken as the most suitable in terms of its technical and economic
  properties. The aim of the work is to develop a circuit solution for a UAV's wireless battery charging
  system with the ability to balance voltages both during charging and during load operation. The use of
  such a system will improve the safety of battery operation and extend its service life by leveling the degree
  of wear (aging) of the elements. As a result of the research, a circuit was developed and an experimental
  sample of the specified wireless charging system was manufactured. When synthesizing the circuit, the
  task was to minimize the number of components in the power circuits in order to reduce the mass of the
  system and its cost. The maximum power of the experimental wireless charging system exceeds 100 Watts
  (25 V · 4 A) and is somewhat excessive for an on-board battery with a capacity of 1,500 mAh. Forced
  cooling of the receiving part is not required. The weight of the receiving part mounted on an unmanned
  aerial vehicle is 79 g (40 g is the receiving coil and 39 g is the electronics unit) and has reserves for reduction
  by reducing the cross–section of the receiving coil conductors, using a textolite with a lower
  thickness in the electronics unit, sealing the installation and using a two–sided arrangement of components.
  Laboratory tests have been carried out, confirming the operability of the proposed technical solutions,
  and the effectiveness of balancing during charging has been evaluated. In order to evaluate the
  effectiveness of the balancing system during the experiments, the output resistance of the receiver (U/I)
  was calculated relative to one of the elements of the on-board battery when the voltage on it changes.
  The result was 1.9 ohms with a charge current of 0.8 A (6S 1500 mAh battery).

• UNIVERSAL BIDIRECTIONAL DC-AC CONVERTER

  V.V. Burlaka, S.V. Gulakov, А.Y. Golovin, D.S. Mironenko

  2023-12-11

  Abstract ▼

  The paper presents a schematic solution and a description of the operation of a bidirectional
  DC-AC converter with transformer isolation. The topology is based on the principles used in
  resonant LLC converters and dual active bridges (DAB), but the proposed design uses bipolar
  inverter topology on the AC voltage side, as well as combined frequency and pulse width control.
  This makes it possible to implement a number of functions in a single converter using a small
  number of commutations in the power circuit. So, it is possible to implement the following operating
  modes: an uninterruptible power supply (conversion of a battery DC voltage to a 220 V 50 Hz
  AC); a grid-tie inverter for alternative sources (solar panels); a battery charger (operating both
  from the mains and from solar panels); a welding inverter for semi-automatic welding (and welding
  can be carried out both from mains, and from the battery); an AC voltage regulator; a DC/DC
  voltage converter (for “cranking up” batteries with different voltages or state-of-charge). A device
  with the listed set of functions can be used, for example, in the field – for organizing power supply
  of various loads, charging batteries, as well as performing minor welding operations. The circuit
  topology of the converter allows, when using appropriate control algorithms, to work with a power
  factor close to unity on the AC voltage side. This makes it possible to ensure operation in a
  "weak" grid – from an autonomous generator, with a large length of the power cord, etc.

• THE WIRELESS ELECTRIC POWER TRANSFER SYSTEM

  V.V. Burlaka, S.V. Gulakov, А.Y. Golovin, D.S. Mironenko

  2023-12-11

  Abstract ▼

  The equipment powered by built-in batteries has become widespread: unmanned aerial vehicles,
  portable radios, tactical flashlights, electric vehicles, etc. Charging of batteries is often
  carried out in a contact way – by connecting a power source by means of a detachable connection.
  This requires the presence of technical personnel for maintenance and replacement of batteries;
  requires the organization of protection of the battery connection from environmental influences
  (moisture, dirt, etc.), as well as protection against electric shock to personnel. The purpose of the
  research is to develop technical means of wireless transmission of electrical energy, which will
  eliminate the use of detachable connections, improve electrical safety, and, most importantly, will
  make it possible to make the charging process automatic. The results of the work are relevant for
  the implementation of automatic cargo delivery systems using unmanned vehicles; for the implementation
  of automatic charging systems for urban electric vehicles; for the implementation of automatic charging of unmanned land, floating (including underwater) and aircraft (reconnaissance,
  patrol, etc.). The design of a wireless power transmission system with a power of up to
  250 W, suitable for charging 6-cell lithium batteries, is described. The system works with coils
  with a diameter of 200 mm, full operability is maintained for a distance between the coils centers
  up to 100 mm. The efficiency in the entire range of operation modes is not lower than 74%, when
  measured from the 220 V mains to the output to the battery. When designing, the goal was to minimize
  the weight of the receiving part to facilitate its installation on the UAV and minimize the
  impact on its thrust-to-weight ratio.