Sudden and significant fluctuations in AC voltage in the network lead to unstable operation of electronic equipment and electrical household appliances. In extreme cases, such surges can cause electronics to break down and fail. In this case, the use of power supply voltage stabilizers is indispensable. Increasingly, users are opting for inverter voltage stabilizers for the home.
Overview of Voltage Stabilizers
AC line voltage stabilizers have historically evolved using various circuit designs. Currently, there are several types of stabilizers:
- relay voltage stabilizers;
- electromechanical servo stabilizers;
- electronic thyristor or triacstabilizers;
- inverter voltage regulators.
The output voltage of relay stabilizers is changed in steps by switching the windings of the mains transformer with contacts of powerful electromagnetic relays. The stabilization accuracy is determined by the number of switched windings. There can be from 5 to 10 such windings. When switching from one winding to an adjacent one, the output voltage changes its value by approximately (15-20) V.
In electromechanical stabilizers, a DC servo drive moves a graphite current collector brush along the turns of an autotransformer winding. The value of the control signal depends on the difference between the input voltage and the reference voltage corresponding to 220 V. When the difference is eliminated, the servo motor control device enters the tracking mode.
In electronic stabilizers, the switching of the transformer windings used by the actuators 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 operation of the inverter voltage stabilizer is based on the principle of double conversion. First, the input AC voltage is converted to DC, and then the reverse conversion is performed. Ensuring the output of the device is stable alternating voltage 220 V is carried out by the electronics of inverter voltage stabilizers.
It doesn't have bulky power transformers. The composition of the stabilizers includes the following electronic components:
- input network LC filter;
- semiconductor diode full-wave rectifier;
- power factor correction device;
- block of storage capacitors;
- inverter converter;
- quartz stable frequency clock;
- high pass output filter;
- microprocessor controller.
Passive input mains filter is used to eliminate high-frequency interference and smooth out short surges in mains voltage. The rectifier converts the alternating voltage into a direct one, part of the electrical energy of which is stored in a block of high-capacity electrolytic capacitors. They are a backup source that comes into operation in the event of mains voltage failures or its short-term shutdown.
The task of the corrector is to normalize the power taken from the network, preventing overload of the stabilizer during its operation. The inverter-converter restores AC voltage from DC. 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 output voltage stabilization circuits and evaluates the state of individual blocksdevices with the issuance of results to the display elements. It issues commands to automatically turn off the operation of the stabilizer in the event that the input voltage value goes beyond the regulation range determined by the technical characteristics.
Specifications of stabilizers
When choosing a home network AC voltage stabilizer, great attention should be paid to its main technical characteristics, which include the following:
- maximum allowable load power that the stabilizer can provide while maintaining the mains voltage quality parameters;
- permissible mains voltage fluctuations at which the voltage at the output of the stabilizer retains its value, taking into account the requirements of quality standards;
- leveling speed, which determines the response time of the regulator to short-term fast-changing changes in mains voltage to keep the output voltage unchanged;
- output signal shape, ideally approaching a sinusoid;
- accuracy of stabilized voltage parameters;
- degree of protection that determines the ability of the stabilizer to operate in conditions of extreme temperatures and high relative humidity levels;
- form factor that determines the dimensions of the stabilizer;
- The level of interference created by the device to the surrounding equipment.
An additional factor influencing the choice of stabilizer may be the presence of elements of visual indication and signaling.
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 winding structure in them greatly facilitated the design. Inverter voltage stabilizers do not contain moving parts of servo drives, which does not require their periodic maintenance during operation and makes the operation of the stabilizers almost silent. IGBT or MOSFET semiconductor devices manufactured using modern technologies are used as power elements.
The use of quartz clock generators allows you to get an output alternating voltage, the shape of which approaches a pure sine. Circuit solutions allow you to correct the non-ideal shape of the input mains voltage. All functions are controlled by a microcontroller.
Inverter stabilizer performance
Scheme and technical solutions implemented in inverter voltage stabilizers make it possible to produce finished products, the performance of which differs significantly from that 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 from 300 VA. The 10 kW (kVA) inverter voltage regulator is not the last in this series.
As for other indicators. Inverter voltage regulators with double conversion maintain a stabilized voltage of 220 V at the output with a deviation of no more than 1% with changes in the mains voltage in the range of 90-310 V. The frequency reading error does not exceed 0.5%. The stabilization speed is at the level of 10 ms, which will allow the use of precision measuring instruments as a load. In this case, complete suppression of impulse noise is performed.
Conclusion
Inverter voltage stabilizers are gradually conquering the network stabilizer market. After reading the materials of the article, readers will understand that this is well deserved. The technical and circuit solutions used in such products make it possible to achieve performance that is unattainable for other types of stabilizers. Their gradually decreasing price justifies the benefits that users of such devices receive after purchasing them.
