A Revolutionary Solution in the Field of Electrical Rectifiers

We present to your attention the development of a powerful transformerless secondary power supply operating on a new principle — TAPS, a mains rectifier. 

1. The history of the mains transformer and classical rectifiers: advantages and disadvantages

1.1 The birth of the mains transformer

The history of the transformer is the result of the collective work of scientists from different countries.

Main stages and contributors

1. Discovery of the principle

Michael Faraday (United Kingdom): In 1831, he discovered the law of electromagnetic induction — the key principle underlying the operation of transformers.

2. The first working transformer (induction coil):

Pavel Yablochkov (Russia/France): In 1876, he received a patent in France describing the use of a transformer for lighting Yablochkov candles, which made it practical.

3. Materials:

Robert Hadfield (England): At the beginning of the 20th century, he developed silicon transformer steel.
Norman Gross (USA): In the 1930s, he improved the properties of silicon steel, reducing losses.

A real breakthrough occurred in the 1880s:
The transmission of electrical energy using high-voltage alternating current became possible after the creation of a single-phase transformer with a closed magnetic system that had sufficiently good operational characteristics.

The first transformers of the Budapest factory “Ganz & Co”:

a) toroidal; b) shell-type; c) core-type (serial production). 

Such a transformer, in several modifications (toroidal, shell-type, and core-type), was developed in 1884–1885 by the Hungarian electrical engineers Miklós Déri, Ottó Bláthy (1860–1938), and Károly Zipernowsky (1853–1942), who were also the first to propose the term “transformer” itself. In their patent application (February 1885), they emphasized the importance of a closed laminated core, especially for high-power power transformers. Figure 1 shows the first examples of toroidal and shell-type transformers, as well as a general view of the serial transformer of the Bláthy–Déri–Zipernowsky system, produced by the electrical engineering factory of the Ganz & Co. company in Budapest. These transformers contained all the main elements of modern single-phase transformer designs.

Thus, the invention of the transformer is the result of the successive contributions of scientists and engineers from the United Kingdom, Russia, France, Hungary, Germany, and the United States.

Fig. 4 — External view of a modern mains transformer (https://market.yandex.ru) 

1.2. Classical Rectifiers: From Vacuum Tubes to Semiconductors

A transformer produces alternating current (AC), while most devices (and the first radio stations) required direct current (DC). This created the need for a “valve” that allows current to pass in only one direction.

The vacuum tube era: At the beginning of the 20th century, vacuum diodes (kenotrons) were used. They were very large, generated a lot of heat, and required time to “warm up.”

The selenium and copper era: In the 1930s, selenium rectifiers appeared — bulky stacks of plates.

The silicon revolution (1950s): The emergence of semiconductor diodes changed everything. They became tiny and reliable.

The classical circuit:

1. Transformer (steps down 220 V to the required 12 V).
   
   

2. Diode bridge (rectifies the current).
   
   

3. Electrolytic capacitor (smooths the ripple).

Fig. 5 — Diagram of a simple classical rectifier. 

1.3. Advantages and Disadvantages of Classical Rectifiers

Classical rectifiers based on transformers have very important advantages:

1.3.1. The ability to operate under extremely hot working conditions (around +55 °C).
1.3.2. Stable operation during mains voltage fluctuations.

In other words, with an optimized enclosure design and circuit configuration, these devices are capable of withstanding both extreme temperatures and voltage surges.

However, classical rectifiers also have a major drawback: the greater the power, the heavier the copper and iron required. An old Soviet television weighed 30–50 kg (largely because of the huge transformer). Even heavier are rectifiers used in cathodic protection stations (CPS), which are applied for the electrochemical protection of gas pipelines and other metal structures against corrosion. At power levels of about 500 W or more, the weight of the rectifier itself becomes significant — around or more than 50 kg.

Thus, classical rectifiers do not meet the following important requirement for equipment:

1.3.3. Optimal weight and size characteristics from the standpoint of manufacturing and operation.

First example:

Fig. 6 — Cathodic protection station UKZT-AU OPE TM-GSM 2.0 U1 with a power of 2.0 kW. The weight of this CPS is 68 kg at a power of 2.0 kW.

Second example: 

Fig. 7 — Parameters of the cathodic protection device KZU-3.0A, plastic enclosure. 

As can be seen from the parameters shown in Figure 7, the weight of these cathodic protection devices depends on their power, and at a power of 5 kW it reaches as much as 152 kg.

Thus, high-power power supplies, including cathodic protection stations (CPS), assembled according to the classical scheme with mains transformers, have a weight ranging from 49 to 152 kg. The necessity of lifting and moving such heavy equipment during both manufacturing and operation creates a health hazard for workers.

2. Rules for Lifting and Moving Heavy Equipment

For such work, special regulations have of course been developed:

“According to the labor protection rules for loading and unloading operations, approved by Order No. 642n of the Ministry of Labor of Russia dated September 17, 2014, the following weight limits are established:

Single lift (without movement): for men — no more than 50 kg; for women — no more than 15 kg.
Lifting and moving (alternating with other work, up to 2 times per hour): for men — up to 30 kg; for women — up to 10 kg.
Continuous lifting and moving during a work shift: for men — up to 15 kg; for women — up to 7 kg.

According to the rules approved by Order No. 753n of the Ministry of Labor and Social Protection of the Russian Federation dated October 28, 2020, loads weighing from 50 to 80 kg may be carried by two workers.

When working with heavy loads, it is important to comply with the established standards and safety regulations and to operate under the supervision of a person responsible for the safe movement of the load. During the production of this type of rectifier, manufacturing workshops are likely equipped with special tools and devices that minimize potential harm to employees’ health. However, during the operation of these heavy rectifiers, occupational safety rules are often not strictly followed. On more than one occasion, we have witnessed violations of labor protection regulations during loading and unloading operations.

The fact is that we also have experience in the development and manufacture of CPS.

Fig. 8 — Cathodic protection station EHG-3000 W. 

Fig. 9 — External view of the cathodic protection station SKZ EHG-3000 W. During the implementation of a batch of these CPS units produced by us, we assisted the customer with the installation and commissioning of this new equipment for them.

A scene from real life, depicted with the help of a neural network:

Fig. 10 — Three exhausted workers struggling to carry a very heavy CPS rectifier. 

If one of them suddenly stumbles, they may suffer injuries.

Thus, unfortunately, during the operation of heavy rectifiers, occupational safety rules are not strictly followed, and workers performing such tasks may suffer health damage — spinal curvature, spinal hernias, and similar conditions with serious consequences that they may not even suspect. This situation вызывает compassion and a strong desire to solve the problem that has persisted for decades.

3. The Creation of Switching Power Supplies: Advantages and Disadvantages

Thus, classical transformers have a major drawback: the greater the power, the heavier they become, and this creates problems related to handling heavy loads. To make rectifiers lighter, engineers resorted to a clever solution — they decided to increase the frequency of the current.

The idea was to use, instead of 50 Hz (the standard frequency of the electrical grid), frequencies of 50,000 Hz or higher. At such frequencies, a transformer capable of transmitting the same power can be tens of times smaller:

Fig. 11 — Printed circuit board of a switching power supply. 

How it works: First, the current from the outlet is rectified into high-voltage direct current. Then a powerful transistor switch “chops” it into ultra-fast pulses, which pass through a tiny high-frequency transformer and are rectified again.

3.1. The Result of Evolution — Advantages

1960s: The first developments appeared for the aerospace industry (NASA needed to save every gram on board rockets).
1970s: Apple was one of the first companies to introduce a switching power supply into a personal computer (Apple II). This made it possible to eliminate the heavy transformer and the cooling fan, since efficiency increased sharply.

If an old Soviet television weighed 30–50 kg (largely because of the huge transformer), then modern flat TVs or smartphone chargers weigh only grams precisely because of the transition from mains transformers to switching power supplies.

Leading companies have achieved unprecedented success in minimizing the size of switching power supplies (SMPS), while simultaneously increasing their output power and improving their “functional behavior.”

Fig. 12 — External view of an SMPS: small size, yet a power of 150 W. 

3.2. Disadvantages of Switching Power Supplies

However, switching power supplies (SMPS), in addition to their advantages, also have disadvantages.

3.2.1. They often do not meet requirement 1.3.2 — reliability during mains voltage surges.

Although switching power supplies have a wider input voltage range (for example, 85–265 V) and are generally more tolerant of voltage fluctuations than traditional ones, they are still vulnerable to:

Powerful impulse surges (overvoltages): These are short-term but very high voltage spikes (for example, up to 600 V or higher) caused by lightning discharges or switching processes in the power grid.

Such surges can lead to the failure of fuses, varistors (protective elements), or even damage to the capacitors at the input of the power supply.

Prolonged overvoltage of the permissible input level: If the mains voltage significantly and for a long time exceeds the upper limit specified by the manufacturer (for example, 265 V), this may cause overheating and failure of power supply components.

In the event of a strong surge, the power supply may not cope with the load and may fail itself, and in some cases it can also cause the failure of the connected equipment.

3.2.2. Switching power supplies do not withstand operation in hot climates.

Manufacturers often state, despite all the careful measures taken during design and manufacturing, that when operating at elevated temperatures (for example, above +40 °C), the maximum output current (power) of the power supply must be reduced (the so-called derating) in order to prevent overheating of components and to preserve their service life.

As can be seen from the derating graph in Figure 13, at +60 °C a power supply rated at 150 W at +25 °C may be limited to 110 W, and when operating without a fan its power is reduced to only 25 W.

Thus, switching power supplies can reliably operate mainly in rooms with air conditioning, where the temperature does not exceed 20–25 °C. This is because they are unable to meet requirement 1.3.1 — the ability to function under extremely hot operating conditions in the working temperature range from +40 to +55 °C.

Building a rectifier based on the SMPS scheme that operates reliably outdoors in countries with hot climates is therefore problematic.

4. Classical Transformerless Power Supplies (without a mains transformer)

Another way to combat the excessive weight of single-phase, or mains, transformers — which require a large amount of copper and/or aluminum for their manufacture — is to eliminate them entirely from the rectifier circuit and thereby develop and produce a transformerless rectifier.

The history of transformerless power supplies is a history of the struggle for compactness and low cost, where the main price paid was safety.

If a classical transformer is a “diplomat” that transfers energy through a magnetic field without allowing the wires from the outlet to touch your device, then a classical transformerless circuit is a “dangerous conductor” that connects the electronics directly to the 220 V mains.

The history of their emergence: from vacuum tubes to cost reduction

The idea of eliminating the transformer appeared almost simultaneously with its invention, but it became widespread mainly in two cases:

1930s–1950s (radio and television): In order to make radio receivers cheaper and lighter, engineers began connecting the heater filaments of vacuum tubes in series and powering them directly from the mains. Such devices were called “AC/DC” because it did not matter what type of current was in the outlet. However, one of the circuit wires was always connected directly to the mains line.

The era of the “dropping capacitor”: With the emergence of semiconductors, it became popular to use the reactive resistance of a capacitor. A capacitor does not dissipate the “excess” voltage (as a resistor does); instead, due to its capacitance, it simply limits the current. This made it possible to create tiny power supplies for LED lamps, motion sensors, and inexpensive chargers.

Do Transformerless Power Supplies “Shock” with the Phase?

Yes, and this is their main problem.

In a conventional classical rectifier or a switching power supply, there is galvanic isolation. In a transformerless power supply, it is absent. This means that any point in your circuit (even where there should be a “safe” 5 V) is directly connected to the mains outlet.

How exactly they can “shock”:

1. Direct contact with the phase:
If you plug the device into the outlet so that the phase passes through the dropping element, the entire low-voltage line of your circuit will have a potential of 220 V relative to ground. If you touch the wire with your hand (or the case, if it is metallic), current will flow through you to ground.

2. The “divider” effect:
Even if a rectifier bridge is installed at the output of the circuit, it does not isolate you. One of the bridge diodes will always be open, creating a “path” for current from the outlet directly to your fingers.

Where are they used today and why doesn’t this kill us all?

Despite the danger, transformerless power supplies surround us everywhere. You will encounter them:

• In LED lamps: the entire housing is plastic, so it is impossible to touch the circuit.
  
  

• In smart switches: they are hidden deep inside the wall.
  
  

• In inexpensive night lights.
  
  

The golden rule:
A transformerless power supply can only be used where the user will never be able to touch live parts. The enclosure must be completely insulated (plastic), and there must be no external connectors (such as USB or audio).

Transformerless power supplies are the “marathon runners of small tasks.” They are extremely efficient and inexpensive, but only as long as they are not required to deliver high power. However, there are exceptions, for example the development by S. Safonov (Fig. 15).

Fig. 15 — Circuit of a transformerless power supply for powering the power amplifier of transmitter vacuum tubes — a transformerless symmetric full-wave voltage multiplier with a maximum power of 3000 W (3000 V, 1 A), developed by S. Safonov (S. Safonov, 4X1IM (ex UT5DK), Haifa, International Master of Sport). 

The last example is a rare exception; the typical power of such devices ranges from 0.1 to 5 W.

The transformerless power supplies listed above can be referred to as classical ones. Let us draw some important conclusions about their main disadvantages:

4.1. Classical transformerless power supplies can deliver only small power to the load, usually no more than 5 W.

4.2. Classical transformerless power supplies have a fundamental drawback — the absence of galvanic isolation from the mains. This creates a risk of electric shock and also limits the possibilities for their widespread application. For example, it excludes their use as Cathodic Protection Stations (CPS) — rectifiers used for the electrochemical protection of underground metal structures, particularly gas pipelines.

Fig. 16 — Structural diagram of the connection of a CPS to a gas pipeline. 

This method предусматривает connecting the “negative” output terminal of the CPS 7 to the protected pipeline 8, as shown in Fig. 16, and the “positive” terminal to the “anode” 9, which is made of conductive materials and buried in the ground. Since the “anode” 9 has contact with the ground, it is highly undesirable for the output terminals of CPS 7 to have a “low equivalent resistance relative to the power network terminals.” Such a CPS would not be able to protect the gas pipeline, because its current would flow not only from the “anode” 9 to the protected pipeline 8, but also toward the grounding of the neutral of the three-phase power transformer of the electrical network. In addition, its terminals would also be dangerous from the standpoint of human contact — creating further problems. Is it possible to solve them? Surprisingly, it turns out that yes, it is possible. This will be discussed in the next part of the story.

5. Development of an Innovative Transformerless Power Supply with Galvanic Isolation

In the first part of the discussion, the requirements for high-power (more than 500 W) secondary power supplies that convert electrical energy from the mains into direct voltage were listed:

1.3.1. The ability to operate even under extremely hot working conditions (around +55 °C).
1.3.2. Stable operation during mains voltage surges.
1.3.3. Optimal weight and size characteristics from the standpoint of manufacturing and operation.

From the previous sections it is clear that classical rectifiers with mains transformers do not meet requirement 1.3.3, while switching power supplies (SMPS) do not satisfy requirements 1.3.1 and 1.3.2.

This leaves the option of eliminating the transformer entirely. However, the classical transformerless power supplies discussed in Part 4 have even more significant disadvantages:

4.1. Classical transformerless power supplies (usually) can deliver only small power to the load, typically no more than 5 W.
4.2. Classical transformerless power supplies have a fundamental drawback — the absence of galvanic isolation from the mains, which creates a risk of electric shock and also limits the possibilities for their widespread use.

This circumstance can be illustrated by their structural diagram (Fig. 17).

Fig. 17 — Interpretation of the equivalent complex impedance of the galvanic isolation ZiZ_iZi​ of a “classical” transformerless power supply. 

The absolute value of the equivalent complex impedance (Fig. 17) is much less than 1 MΩ — therefore galvanic isolation is absent.

However, what we need is a radical solution to the problem: eliminating the shortcomings of classical transformerless power supplies, that is, creating such devices that:

• do not “shock” with phase current;
  
  

• can deliver, when necessary, significant power to the load — more than 500 W;
  
  

• can operate in hot conditions (at +55 °C).
  
  

“Impossible!” knowledgeable electronics specialists would say, adding that galvanic isolation between the mains and the rectifier output is provided either by a low-frequency mains transformer or by a high-frequency switching transformer. If neither of them is used, then the output will inevitably carry the so-called “mains phase,” which will certainly result in an electric shock upon contact.

It is quite possible that good intentions helped achieve the “impossible.” A religious-minded electronics engineer might say: “God supported the idea of reducing the weight of classical transformer rectifiers in order to lessen the suffering of workers and sent this idea to the developers.” Another engineer might think: “A parallel world supported the humanitarian idea of the developers.” Yet, incredible as it may seem, a solution to a problem that appeared impossible to solve has indeed been found.

As a result of difficult joint work over several months, an unexpected, innovative, and patentable solution was discovered — a new method for creating transformerless power supplies, as well as two device variants based on it. These new “non-classical” transformerless power supplies, operating according to the new method, turned out to provide galvanic isolation while also being capable of delivering high power.

Fig. 18 — Structural diagram of a transformerless power supply assembled according to the new innovative method. NBP — low-frequency conversion block; BKU — control and management block. 

The absolute value of the equivalent complex impedance (Fig. 18) is greater than 1 MΩ; therefore, the galvanic isolation complies with GOST 12.1.038-82 — Maximum Permissible Values of Touch Voltages and Currents. Thus, the issue of galvanic isolation has been resolved.

The question regarding the possibility of operating the rectifier under conditions of extreme heat has also been addressed. Since the method operates with conversion at low frequencies, it becomes possible to use thyristors, which, as is well known, are more reliable at high operating temperatures.

Date of the proposed method: August 9, 2024.

The first experiments were carried out in St. Petersburg using Soviet gate-turn-off thyristors KU208, with the mains voltage simulated by an alternating voltage of about 28 V. Subsequent experiments with real mains voltage were conducted in the city of Ashgabat, where an experimental prototype of a secondary power supply based on the new method was manufactured (Fig. 19).

Fig. 19 — Experimental prototype for studying and improving the parameters of the secondary power supply “TAPS” (Transformerless Asymmetrical Power Supply). 

6. Parameters of Transformerless Power Supplies Based on the New Method

Two types of power supplies proposed according to the new method are named TAPS (Transformerless Asymmetrical Power Supply) and TSPS (Transformerless Symmetrical Power Supply). In an electrical network with a nominal phase voltage of 220 V, TAPS will be able to deliver output voltages to the load ranging from 0 V up to 300 V, while TSPS can deliver up to 600 V. The upper voltage limit can be restricted, for example, to 50 or 100 V.

As of January 12, 2026, in order to master the new method and to develop new advanced secondary power supplies based on it, experiments have been conducted using a TAPS prototype.

Fig. 20 — Experimental TAPS prototype in a temperature testing chamber. 

The following results were achieved on the experimental prototype of the secondary power supply:

1. Output voltage from 0 to 200 V (it is also possible to reach up to 300 V),

2. Output current up to 20 A (if necessary, it can be increased or decreased),

3. Output power up to 3000 W (it can also be increased or reduced),

4. Efficiency depends on the operating mode and is higher than that of a classical transformer rectifier,

5. Successful temperature tests were carried out simulating operating temperatures from +55 to +60 °C,

6. It does not “shock,” meaning galvanic isolation between the mains and the output is ensured,

7. The weight is about 15–20 kg (including sensors for monitoring operating parameters), meaning the weight of the equipment has been reduced by approximately five times compared with the 3000 W prototype (see Fig. 7 in the second part of the discussion).

The dimensions can be further reduced — the photo shows only the first convenient experimental prototype, inside which there is currently a considerable amount of unused space.

7. Prospects for Innovative Transformerless Power Supplies and Cooperation

The new innovative method of constructing transformerless power supplies has promising prospects. It may allow:

• A significant reduction in the production cost of your mains rectifiers and other secondary power supplies by eliminating the mains transformer — the most expensive component of the rectifier. In the case of cathodic protection stations with a power of 3000 W, according to our calculations the production cost can be reduced by approximately 30%.

• In the same case, the weight of the product can be reduced by about five times.

• A significant increase in convenience during both manufacturing and operation, thereby improving the overall quality characteristics of the products.

For the first time in many decades after the invention of transformers and transformerless power supplies, an innovative method has provided galvanic isolation between the mains input and the output of the power supply. In simple terms, even though there is no mains transformer, the risk of electric shock from the “phase” current at the output terminals is eliminated, which significantly expands the range of possible applications.

Possible applications include:

• The development and manufacture, using the new method, of rectifiers for widespread use in both household and industrial applications, with power levels that may range, for example, from 100 W to 10,000 W or more.

• Use in electrochemical protection as cathodic protection stations, where the positive output of the rectifier is connected to ground. This can be applied both in countries with moderate and cold climates and in countries with hot climates. Unlike switching power supplies, the developed device operates reliably even at extreme temperatures around +60 °C. There is no need for “derating” — no reduction of the rated power. As noted above, this result is achieved because the circuit operates with low-frequency conversion, allowing the use of thyristors, which are known to be more resistant to operation at extreme ambient temperatures.

-- In order to safeguard our patented innovation and prevent unauthorized reproduction, the technical information presented here is intentionally limited. Detailed documentation can be provided to qualified partners interested in collaboration. --

Forms of Cooperation

We are open to various forms of partnership:

• Transfer of rights to use the patent,

• Transfer of technical information necessary for successful implementation of the method,

• Joint development and production of prototype devices according to your technical specifications,

• Joint manufacturing.

Publications: Information about us can be found at the following links:

• turkmenistan.gov.tm

• business.com.tm

• trade.com.tm

If our development interests you, we look forward to hearing from you through the contact channels indicated below.

CONTACT CHANNELS:

Turkmenistan, Ashgabat, Jahan Electronics

Phone: +993 652 860 52

IMO: +993 652 850 27

Email: jahanelektronik@yandex.ru   or   jefirm2025@gmail.com