Abrupt and significant changes in AC voltage in the network lead to unstable operation of electronic equipment and electrical household appliances. In extreme cases, such jumps can cause damage to the electronics and its failure. Indispensable in this case is the use of voltage regulators of the supply network. Increasingly, users opt for inverter voltage stabilizers for the home.
Overview of Voltage Regulators
AC voltage regulators have historically evolved using a variety of circuitry solutions. Currently, there are several types of stabilizers:
- relay voltage stabilizers;
- electromechanical stabilizers with servo drive;
- electronic thyristor or triac stabilizers;
- inverter voltage stabilizers.
The output voltage of the relay stabilizers is changed in steps by switching the windings of the network transformer with the contacts of powerful electromagnetic relays. The stabilization accuracy is determined by the number of switched windings. Such windings can be from 5 to 10. When switching from one winding to an adjacent output voltage, it changes its value by approximately (15-20) V.
In electromechanical stabilizers, a DC servo drive moves the graphite brush of the current collector along the turns of the autotransformer winding. The value of the control signal depends on the difference between the input and reference voltage corresponding to the value of 220 V. When the difference is eliminated, the control unit of the servo motor motor switches to the tracking mode.
In electronic stabilizers, the switching of the used transformer windings by the actuating elements is controlled by the controller.
The switching unit is made on semiconductor triacs or thyristors. The operation of the controller is determined by the software installed at the factory of the product.
The principle of operation of the inverter stabilizer
The inverter voltage stabilizer is based on the principle of double conversion. First, the input AC voltage is converted to direct current, and then the inverse conversion is performed. Providing the output of the device with a stable AC voltage of 220 V is carried out by the electronics of inverter voltage stabilizers.
It does not have bulky power transformers. The composition of the stabilizers includes the following electronic components:
- input mains LC filter;
- semiconductor diode half-wave rectifier;
- power factor correction device;
- block of storage capacitors;
- inverter converter;
- stable frequency crystal oscillator;
- high-frequency output filter;
- microprocessor controller.
A passive input line filter is used to eliminate high-frequency interference and smooth out short surges in the supply voltage. The rectifier converts the alternating voltage to direct, part of the electrical energy of which is accumulated in the block of electrolytic capacitors of large capacity. They are a backup source that comes into operation when network voltage dips or short-term shutdown occurs.
The corrector's task is to normalize the power taken from the network, avoiding overload of the stabilizer during its operation. The inverter-converter restores the alternating voltage from constant. Due to the participation of a quartz oscillator in its operation, the output voltage has the form of a pure sinusoid with a frequency of 50 Hz with an error not exceeding 0.5%.
The controller controls the operation of the stabilization circuits of the output voltage and evaluates the status of individual units of the device with the output of the results on the display elements. It issues commands to automatically turn off the stabilizer in the event that the input voltage exceeds the control range determined by the technical characteristics.
Technical characteristics of stabilizers
When choosing an AC voltage stabilizer for a home network, great attention should be paid to its main technical characteristics, which include the following:
- the maximum allowable load power that the stabilizer can provide while maintaining the quality parameters of the mains voltage;
- permissible fluctuations in the mains voltage at which the voltage at the output of the stabilizer retains its value, taking into account the requirements of quality standards;
- alignment speed, which determines the response time of the stabilizer to short-term rapidly varying changes in the mains voltage to keep the output voltage unchanged;
- output waveform ideally approaching a sine wave;
- accuracy of stabilized voltage parameters;
- degree of protection, determining the possibility of operation of the stabilizer in conditions of extreme temperatures and elevated values of the relative humidity level;
- form factor determining the dimensions of the stabilizer;
- the level of interference created by the device for the operation of the surrounding equipment.
An additional factor affecting the choice of stabilizer can be the presence of elements of visual indication and alarm.
It should inform the user in full about the values of the input and stabilized parameters and warn about the occurrence of critical situations.
Features of inverter stabilizers
The absence of bulky ferromagnetic transformers with a complex structure of the windings in them greatly facilitated the design. Inverter voltage stabilizers do not contain moving parts of servos, which does not require periodic maintenance during operation and makes the operation of the stabilizers almost silent. As power elements, IGBT or MOSFET semiconductor devices manufactured using modern technologies are used.
The use of quartz clock generators allows you to get an output alternating voltage, the shape of which is approaching a pure sine. Circuit solutions allow you to correct the not perfect shape of the input mains voltage. All functions are controlled by the microcontroller.
Inverter stabilizer performance
Circuit and technical solutions implemented in inverter voltage stabilizers allow the manufacture of finished products, the performance of which significantly differs from the performance of other types of stabilizers for the better. Leading domestic and foreign manufacturers create product lines designed for different power levels of consumers. They start at 300 VA. An inverter voltage stabilizer of 10 kW (kVA) is not the last in this series.
As for other indicators. Double-inverter inverter voltage stabilizers maintain a stabilized voltage of 220 V at the output with a deviation of not more than 1% when the mains voltage changes in the range of 90-310 V. The frequency error in this case does not exceed 0.5%. The stabilization speed is at the level of 10 ms, which will allow using precision measuring instruments as a load. This completely suppresses the impulse noise.
Conclusion
Inverter voltage stabilizers gradually conquer the market of network stabilizers. After reading the article, readers will understand that this is well deserved. Technical and circuit solutions used in such products allow achieving indicators unattainable for other types of stabilizers. Their price, gradually decreasing, justifies the benefits that users of such devices receive after their purchase.