Often, for safe use of, for example, a TV, usually in rural areas, you need a single-phase voltage stabilizer 220V, which, when the voltage in the electrical network is greatly reduced, produces a rated output voltage of 220 volts at its output.
In addition, when operating most types of consumer electronic equipment, it is desirable to use a voltage stabilizer that does not create changes in the output voltage sine wave. Schemes of similar stabilizers for 220 volts are given in many magazines on radio electronics.
In this article we give an example of one of the options for such a device. The stabilizer circuit, depending on the actual voltage in the network, has 4 ranges of automatic setting of the output voltage. This contributed to a significant expansion of the stabilization limits of 160...250 volts. And with all this, the output voltage is ensured within normal limits (220V +/- 5%).
The electrical circuit of the device includes 3 threshold blocks, made according to the principle, consisting of a zener diode and resistors (R2-VD1-R1, VD5-R3-R6, R5-VD6-R6). Also in the circuit there are 2 transistor switches VT1 and VT2, which control electromagnetic relays K1 and K2.
Diodes VD2 and VD3 and filter capacitor C2 form a constant voltage source for the entire circuit. Capacities C1 and C3 are designed to absorb minor voltage surges in the network. Capacitor C4 and resistance R4 are “spark arresting” elements. To prevent self-induction voltage surges, two diodes VD4 and VD7 were added to the circuit in the relay windings when they are turned off.
With perfect operation of the transformer and threshold blocks, each of the 4 regulation ranges would create a voltage range from 198 to 231 volts, and the probable mains voltage could be in the region of 140...260 volts.
However, in reality, it is necessary to take into account the spread of parameters of radio components and the instability of the transformer transformation ratio under different loads. In this regard, for all 3 threshold blocks the output voltage range is reduced in relation to the output voltage: 215 ± 10 volts. Accordingly, the oscillation interval at the input has narrowed to 160...250 volts.
1. When the mains voltage is less than 185 volts, the voltage at the rectifier output is low enough for one of the threshold blocks to operate. At this moment, the contact groups of both relays are located as indicated on the circuit diagram. The voltage at the load is equal to the mains voltage plus the boost voltage removed from windings II and III of transformer T1.
2. If the network voltage is in the range of 185...205 volts, then the zener diode VD5 is in the open state. The current flows through relay K1, zener diode VD5 and resistances R3 and R6. This current is not enough for relay K1 to operate. Due to the voltage drop across R6, transistor VT2 opens. This transistor, in turn, turns on relay K2 and contact group K2.1 switches winding II (voltage booster)
3. If the network voltage is in the range of 205...225 volts, then the zener diode VD1 is already in the open state. This leads to the opening of transistor VT1, which is why the second threshold block and, accordingly, transistor VT2 are turned off. Relay K2 is turned off. At the same time, relay K1 and contact group K1.1 are turned on. moves to another position, in which windings II and III are not involved and therefore the output voltage will be the same as at the input.
4. If the network voltage is in the range of 225...245 volts, the zener diode VD6 opens. This contributes to the activation of the third threshold block, which leads to the opening of both transistor switches. Both relays are switched on. Now winding III of transformer T1 is already connected to the load, but in antiphase with the mains voltage (“negative” voltage boost). In this case, the output will also have a voltage in the region of 205...225 volts.
When setting the control range, you need to carefully select zener diodes, since, as is known, they can differ significantly in the stabilization voltage spread.
Instead of KS218Zh (VD5), it is possible to use KS220Zh zener diodes. This zener diode must certainly have two anodes, since in the mains voltage range of 225...245 volts, when the zener diode VD6 opens, both transistors open, the circuit R3 - VD5 bypasses the resistance R6 of the threshold block R5-VD6-R6. To eliminate the shunting effect, the VD5 zener diode must have two anodes.
Zener diode VD5 for a voltage of no more than 20V. Zener diode VD1 - KS220Zh (22 V); it is possible to assemble a circuit of two zener diodes - D811 and D810. Zener diode KS222Zh (VD6) for 24 volts. It can be replaced with a circuit of zener diodes D813 and D810. Transistors from the series. Relays K1 and K2 - REN34, passport HP4.500.000-01.
The transformer is assembled on an OL50/80-25 magnetic core made of E360 (or E350) steel. The tape is 0.08 mm thick. Winding I - 2400 turns wound with PETV-2 0.355 wire (for rated voltage 220V). Windings II and III are equal, each containing 300 turns of PETV-2 0.9 wire (13.9 V).
It is necessary to adjust the stabilizer with a connected load in order to take into account the load on transformer T1.
The voltage of the home electrical network is often low, never reaching the normal 220 V. In such a situation, the refrigerator does not start well, the lighting is weak, and the water in the electric kettle does not boil for a long time. The power of an outdated voltage stabilizer, designed to power a black-and-white (tube) TV, is usually insufficient for all other household appliances, and the network voltage often drops below what is permissible for such a stabilizer.
There is a known simple way to increase the voltage in the network using a transformer with a power significantly less than the load power. The primary winding of the transformer is connected directly to the network, and the load is connected in series with the secondary (step-down) winding of the transformer. With appropriate phasing, the voltage on the load will be equal to the sum of the network voltage and that removed from the transformer.
Mains voltage stabilizer circuit operating on this principle is shown in Fig. 1. When the field-effect transistor VT2 connected to the diagonal of the diode bridge VD2 is closed, winding I (primary) of transformer T1 is disconnected from the network. The load voltage is almost equal to the mains voltage minus a small voltage drop on winding II (secondary) of transformer T1. If you open the field-effect transistor, the power circuit of the primary winding of the transformer will be closed, and the sum of the voltage of its secondary winding and the mains voltage will be applied to the load.
Rice. 1 Voltage stabilizer circuit
The load voltage, reduced by transformer T2 and rectified by the diode bridge VD1, is supplied to the base of transistor VT1. The trimmer resistor R1 must be set to a position in which transistor VT1 is open and VT2 is closed if the load voltage is greater than the rated voltage (220 V). When the voltage is less than the rated one, transistor VT1 will be closed and VT2 will be open. Negative I feedback organized in this way maintains the load voltage approximately equal to the rated voltage
The voltage rectified by the VD1 bridge is also used to power the collector circuit of the transistor VT1 (via the integrated stabilizer DA1). Circuit C5R6 suppresses unwanted surges in the drain-source voltage of transistor VT2. Capacitor C1 reduces interference entering the network during operation of the stabilizer. Resistors R3 and R5 are selected to achieve the best and most stable voltage stabilization. Switch SA1 turns the stabilizer on and off along with the load. By closing switch SA2, the automation is turned off, which maintains the voltage across the load unchanged. In this case, it becomes the maximum possible at a given network voltage.
Most of the stabilizer parts are mounted on the printed circuit board shown in Fig. 2. The rest are connected to it at points A-D.
Selecting a replacement diode bridge KTs405A(VD2), it should be borne in mind that it must be designed for a voltage of at least 600 V and a current equal to the maximum load current divided by the transformation ratio of transformer T1. The requirements for the VD1 bridge are more modest: voltage and current - at least 50 V and 50 mA, respectively
Rice. 2 PCB installation
Transistor KT972A can be replaced by KT815B,a IRF840- on IRF740. The field-effect transistor has a heat sink measuring 50x40 mm.
The “voltage booster” transformer T1 is made from the ST-320 transformer, which was used in the BP-1 power supplies for ULPCT-59 televisions. The transformer is disassembled and the secondary windings are carefully wound up, leaving the primary windings intact. New secondary windings (identical on both coils) are wound with enameled copper wire (PEL or PEV) in accordance with the data given in the table. The more the voltage in the network drops, the more turns are required and the lower the permissible load power.
After rewinding and assembling the transformer, terminals 2 and 2" of the halves of the primary winding, located on different cores of the magnetic circuit, are connected by a jumper. The halves of the secondary winding must be connected in series so that their total voltage is maximum (if connected incorrectly, it will be close to zero). The maximum total voltage of the secondary winding and the network must determine which of the remaining free terminals of this winding should be connected to terminal 1 of the primary, and which to the load.
Transformer T2 - any network transformer with a voltage on the secondary winding close to that indicated in the diagram with a current consumed from this winding of 5O...1OOmA.
Table 1
| Additional voltage, V | 70 | 60 | 50 | 40 | 30 | 20 |
| Maximum load power, kW | 1 | 1.2 | 1.4 | 1,8 | 2,3 | 3,5 |
| Number of turns of winding II | 60+60 | 54+54 | 48+48 | 41+41 | 32+32 | 23+23 |
| Wire diameter, mm | 1.5 | 1,6 | 1,8 | 2 | 2,2 | 2,8 |
Having connected the assembled stabilizer to the network, use trimming resistor R1 to set the load voltage to 220 V. It should be taken into account that the described device does not eliminate fluctuations in the mains voltage if it exceeds 220 V or falls below the minimum accepted when calculating the transformer.
A stabilizer installed in a damp room must be placed in a grounded metal case.
Note: in heavy operating conditions of the stabilizer, the power dissipated by transistor VT2 can be quite increased. It is this, and not the power of the transformer, that can limit the permissible load power. Therefore, care should be taken to ensure good heat dissipation of the transistor.
Modern life involves the constant use of various technologies, and some areas are simply unthinkable without it. Naturally, every person wants the service life of such devices to be maximum; for this purpose, some buy only products from well-known brands for greater reliability. However, high cost does not always guarantee safety under critical operating conditions. These include sudden changes in network voltage. This is especially true for those categories of household appliances that require a permanent network connection, for example, a refrigerator.
In order to protect yourself from the unpleasant consequences of such voltage surges, you can acquire a special technical device that stabilizes the output current. There are two methods used to regulate the voltage:
1. Mechanical. For this method, a linear stabilizer is used, consisting of 2 elbows and a rheostat connecting them. The voltage is supplied to the first elbow and transmitted through a rheostat to the second, which distributes the flow further. This method is effective when there is a small difference between the input and output current; in other cases, the efficiency decreases.
2. Pulse. The design of the stabilizer includes a switch that periodically breaks the circuit for a certain time. This makes it possible to supply current in portions and accumulate it evenly in the capacitor. After the capacitor is fully charged, a leveled flow is supplied to the devices without surges.
The main disadvantage of this method is the inability to set a specific parameter value. Therefore, if you decide to assemble a 220V voltage stabilizer with your own hands, you need to focus on the mechanical method. To create a simple linear single-phase current equalizer you will need:
A transformer is a pair of coils that form an inductive electromagnetic coupling, i.e. reaching the primary winding, the current charges it, and the resulting electromagnetic field charges the other coil. This relationship between voltage (U), current (I) and number of turns (N) on both windings is expressed by the formula:
I2/I1 = N2/N1 = U2/U1
The inductive coils themselves can be found in every electrical store. The number of turns on the first should not be less than 2000. By measuring the voltage in the network, you can calculate the required number of turns on the secondary winding. For example, the actual voltage is 198V, then the second coil should have x/2000 = 220/198 = 2223 turns. The generated current is determined using the same principle. According to this scheme, with a sharp increase in power at the input, the voltage will increase proportionally at the output. Therefore, to regulate such situations, a rheostat is needed to change the network resistance. The path followed by the current after the transformer is marked on the stabilizer chip.
From the transformer, the current is output to capacitors of the same capacity to accumulate and equalize the flow; approximately 16 of them will be required. Next, the capacitors must be connected to the rheostat. Its resistance at a voltage of 220 V and a current of 4.75 A (average value of the range 4.5-5 A) after the transformer should be 46 Ohms. To level the voltage as smoothly as possible, you can install several rheostats, distributing the resistance equally to each. After the circuit passes the rheostats, it is again connected into a single stream and follows the diode, which is connected directly to the outlet.
These operations apply to a wire with a phase, the zero is directly passed to the socket. Such stabilizers are best suited to constant voltage conditions and are assembled based on the parameters of a particular device, which significantly increases the efficiency of the device.
The ideal option for the operation of electrical networks is to change the values of current and voltage both in the direction of decreasing and increasing by no more than 10% of the nominal 220 V. But since in reality surges are characterized by large changes, electrical appliances directly connected to the network are in danger of losing their design capabilities and even failure.
Using special equipment will help you avoid trouble. But since it has a very high price, many people prefer to assemble a voltage stabilizer made by themselves. How justified is such a step and what will be required to implement it?
Device design
If you decide to assemble the device yourself, you will have to look inside the body of the industrial model. It consists of several main parts:
The operating principle of the simplest stabilizer is based on the operation of a rheostat. It increases or decreases resistance depending on the current. More modern models have a wide range of functions and are able to fully protect household appliances from power surges in the network.
Types and their applications
The classification of equipment depends on the methods used to regulate the current. Since this quantity represents the directional movement of particles, it can be influenced in one of the following ways:
The first is based on Ohm's law. Devices whose operation is based on it are called linear. They include two elbows that are connected using a rheostat. The voltage applied to one element passes through the rheostat and thus appears on the other, from which it is supplied to consumers.
Devices of this type allow you to very simply set the output current parameters and can be upgraded with additional components. But it is impossible to use such stabilizers in networks where the difference between the input and output current is large, since they will not be able to protect household appliances from short circuits under heavy loads.
Let's watch the video, the operating principle of the pulse device:
Pulse models operate on the principle of amplitude modulation of current. The stabilizer circuit uses a switch that breaks it at certain intervals. This approach allows current to be evenly accumulated in the capacitor, and after it is fully charged, further to devices.
Unlike linear stabilizers, pulse ones do not have the ability to set a specific value. There are step-up and step-down models on sale - this is an ideal choice for the home.
Voltage stabilizers are also divided into:
But since most household appliances operate from a single-phase network, in residential premises they usually use equipment belonging to the first type.
Since a triac device is considered the most effective, in our article we will look at how to independently assemble just such a model. It should be immediately noted that this DIY voltage stabilizer will equalize the current provided that the input voltage is in the range from 130 to 270V.
The permissible power of devices connected to such equipment cannot exceed 6 kW. In this case, the load will be switched in 10 milliseconds.
As for components, to assemble such a stabilizer you will need the following elements:
The tools I will need are a soldering iron and tweezers.
To assemble a 220V voltage stabilizer for your home with your own hands, you first need to prepare a printed circuit board measuring 115x90 mm. It is made of foil fiberglass. The layout of the parts can be printed on a laser printer and transferred to the board using an iron.
Let's watch the video, a homemade simple device:
electrical circuit diagram
The first wire is used to create one winding, and its diameter is 0.064 mm. The number of turns should be 8669.
The two remaining wires will be needed to make other windings. They differ from the first one in diameter being 0.185 mm. The number of turns for these windings will be 522.
If you want to simplify your task, you can use two ready-made TPK-2-2 12V transformers. They are connected in series.
In the case of making these parts yourself, after one of them is ready, they move on to creating the second. It will require a toroidal magnetic circuit. For the winding, choose the same PEV-2 as in the first case, only the number of turns will be 455.
Also in the second transformer you will have to make 7 taps. Moreover, for the first three, a wire with a diameter of 3 mm is used, and for the rest, buses with a cross-section of 18 mm² are used. This will help prevent the transformer from heating up during operation.
connection of two transformers
It is better to purchase all other components for a device you create yourself in a store. Once everything you need has been purchased, you can begin assembly. It is best to start by installing a microcircuit that acts as a controller on a heat sink, which is made of aluminum platinum with an area of more than 15 cm². Triacs are also mounted on it. Moreover, the heat sink on which they are supposed to be installed must have a cooling surface.
If assembling a 220V triac voltage stabilizer with your own hands seems complicated to you, then you can opt for a simpler linear model. It will have similar properties.
What pushes a person to make this or that device? Most often - its high cost. And in this sense, a voltage stabilizer assembled with your own hands is, of course, superior to a factory model.
The advantages of homemade devices include the possibility of self-repair. The person who assembled the stabilizer understood both its operating principle and structure and therefore will be able to eliminate the malfunction without outside help.
In addition, all the parts for such a device were previously purchased in the store, so if they fail, you can always find a similar one.
If we compare the reliability of a stabilizer assembled with our own hands and manufactured at an enterprise, then the advantage is on the side of factory models. At home, it is almost impossible to develop a model with high performance, since there is no special measuring equipment.
There are different types of voltage stabilizers, and some of them are quite possible to make with your own hands. But to do this, you will have to understand the nuances of the operation of the equipment, purchase the necessary components and carry out their proper installation. If you are not confident in your abilities, then the best option is to purchase a factory-made device. Such a stabilizer costs more, but the quality is significantly superior to models assembled independently.
Household devices are sensitive to power surges, wear out faster, and malfunctions appear. In the electrical network, the voltage often changes, decreases or increases. This is due to the remoteness of the energy source and poor quality power line.
To connect devices to a stable power supply, voltage stabilizers are used in residential premises. At its output, the voltage has stable properties. The stabilizer can be purchased at a retail chain, but such a device can be made with your own hands.
There are tolerances for voltage changes of no more than 10% of the nominal value (220 V). This deviation must be observed both upward and downward. But there is no ideal electrical network, and the voltage in the network often changes, thereby aggravating the operation of devices connected to it.
Electrical appliances react negatively to such vagaries of the network and can quickly fail, losing their intended functions. To avoid such consequences, people use homemade devices called voltage stabilizers. A device made using triacs has become an effective stabilizer. We will look at how to make a voltage stabilizer with your own hands.
This stabilization device will not have increased sensitivity to changes in voltage supplied through the common line. Voltage smoothing will be carried out if the input voltage is in the range from 130 to 270 volts.
Devices connected to the network will be powered by a voltage ranging from 205 to 230 volts. From such a device it will be possible to power electrical devices with a total power of up to 6 kW. The stabilizer will switch the consumer load in 10 ms.
Stabilization device diagram.
The voltage stabilizer according to the specified circuit includes the following parts:
Let's look at how it works.
After connecting the power, capacitance C1 is in a discharge state, transistor VT1 is open, and VT2 is closed. VT3 transistor also remains closed. Through it, current flows to all LEDs and an optitron based on triacs.
Since this transistor is in a closed state, the LEDs do not light up, and each triac is closed, the load is turned off. At this moment, current flows through resistance R1 and arrives at C1. Then the capacitor begins to charge.
The shutter speed range is three seconds. During this period, all transition processes are carried out. After their completion, a Schmitt trigger based on transistors VT1 and VT2 is triggered. After this, the 3rd transistor opens and the load is connected.
The voltage coming from the 3rd winding T1 is equalized by diode VD2 and capacitance C2. Next, the current flows to the divider at resistances R13-14. From resistance R14, a voltage, the magnitude of which directly depends on the magnitude of the voltage, is included in each non-inverting comparator input.
The number of comparators becomes equal to 8. They are all made on DA2 and DA3 microcircuits. At the same time, direct current is supplied to the inverted input of the comparators, supplied using dividers R15-23. Next, the controller comes into action, receiving the input signal of each comparator.
When the input voltage drops below 130 volts, a small logic level appears at the outputs of the comparators. At this moment, transistor VT4 is open, the first LED is blinking. This indication indicates the presence of low voltage, which means that the adjustable stabilizer cannot perform its functions.
All triacs are closed and the load is turned off. When the voltage is in the range of 130-150 volts, then signals 1 and A have the properties of a high logic level. This level is low. In this case, transistor VT5 opens and the second LED begins to signal.
Optosimistor U1.2 opens, just like triac VS2. The load current will flow through the triac. Then the load will enter the upper terminal of the autotransformer coil T2.
If the input voltage is 150 - 170 V, then signals 2, 1 and B have an increased logical level value. Other signals are low. At this input voltage, transistor VT6 opens and the 3rd LED turns on. At this moment, the 2nd triac opens and current flows to the second terminal of the T2 coil, which is 2nd from the top.
A self-assembled 220-volt voltage stabilizer will connect the windings of the 2nd transformer if the input voltage level reaches, respectively: 190, 210, 230, 250 volts. To make such a stabilizer, you need a 115 x 90 mm printed circuit board made of foil fiberglass.
The board image can be printed on a printer. Then, using an iron, this image is transferred to the board.
You can make transformers T1 and T2 yourself. For T1, whose power is 3 kW, it is necessary to use a magnetic core with a cross section of 1.87 cm 2, and 3 PEV wires - 2. 1st wire with a diameter of 0.064 mm. The first coil is wound with it, with a number of turns of 8669. The other 2 wires are used to form the remaining windings. The wires on them must be of the same diameter 0.185 mm, with the number of turns 522.
In order not to make such transformers yourself, you can use ready-made versions of TPK - 2 - 2 x 12 V, connected in series.
To make a 6 kW transformer T2, a toroidal magnetic core is used. The winding is wound with PEV-2 wire with the number of turns 455. 7 taps must be installed on the transformer. The first 3 of them are wound with 3 mm wire. The remaining 4 branches are wound with tires with a cross section of 18 mm 2. With such a wire cross-section, the transformer will not heat up.
The taps are made on the following turns: 203, 232, 266, 305, 348 and 398. The turns are counted from the bottom tap. In this case, the electric current of the network must flow through tap 266 turns.
The remaining elements and parts of the stabilizer for self-assembly are purchased in the retail chain. Here is a list of them:
Optocouplers MOS 3041 are replaced with MOS 3061. KR 1158 EN 6A stabilizer can be replaced with KP 1158 EN 6B. The comparator K 1401 CA 1 can be installed as an analogue of LM 339 N. Instead of diodes, KTs 407 A can be used.
The KR 1158 EN 6A microcircuit must be installed on the heat sink. For its manufacture, an aluminum plate of 15 cm 2 is used. It is also necessary to install triacs on it. For triacs it is allowed to use a common heat sink. The surface area must exceed 1600 cm2. The stabilizer must be equipped with a KR 1554 LP 5 microcircuit, which acts as a microcontroller. Nine LEDs are arranged so that they fit into the holes on the front of the instrument panel.
If the housing design does not allow them to be installed in the same way as in the diagram, then they are placed on the other side where the printed tracks are located. LEDs must be installed as a flashing type, but non-blinking diodes can also be installed, provided that they glow bright red. For such purposes, use AL 307 KM or L 1543 SRC - E.
You can assemble simpler versions of the devices, but they will have certain features.
If we list the advantages of stabilizers made independently, the main advantage is low cost. Manufacturers of devices often inflate prices, and in any case, their own assembly will cost less.
Another advantage can be determined by such a factor as the ability to easily repair the device with your own hands. After all, who, if not you, knows better about a device assembled with your own hands.
In the event of a breakdown, the owner of the device will immediately find the faulty element and replace it with a new one. Easy replacement of parts is created by the fact that all parts were purchased in a store, so they can be easily purchased again at any store.
The disadvantage of a self-assembled voltage stabilizer is its complex configuration.
Let's look at how you can make your own 220-volt stabilizer with your own hands, having a few simple parts on hand. If the voltage in your electrical network is significantly reduced, then such a device will come in handy. To make it, you will need a ready-made transformer and a few simple parts. It is better to take note of such an example of a device, since it turns out to be a good device with sufficient power, for example, for a microwave.
For refrigerators and various other household devices, a decrease in network voltage is very harmful, more than an increase. If you increase the network voltage using an autotransformer, then while the network voltage decreases, the voltage at the device output will be normal. And if the voltage in the network becomes normal, then at the output we will get an increased voltage value. For example, let’s take a 24 V transformer. With a line voltage of 190 V, the output of the device will be 210 V; with a network value of 220 V, the output will be 244 V. This is quite acceptable and normal for the operation of household devices.
For manufacturing we need the main part - this is a simple transformer, but not an electronic one. You can find it ready-made, or you can change the data on an existing transformer, for example, from a broken TV. We will connect the transformer according to the autotransformer circuit. The output voltage will be approximately 11% higher than the mains voltage.
In this case, you need to be careful, since during a significant voltage drop in the network upward, the output of the device will produce a voltage that significantly exceeds the permissible value.
The autotransformer will add only 11% to the line voltage. This means that the power of the autotransformer is also taken at 11% of the consumer’s power. For example, the power of a microwave oven is 700 W, which means we take a transformer of 80 W. But it is better to take power with a reserve.
The SA1 regulator makes it possible, if necessary, to connect the consumer load without an autotransformer. Of course, this is not a full-fledged stabilizer, but its production does not require large investments and a lot of time.
