What is a Power Converter?

What is a Voltage Stabilizer?

A voltage stabilizer or voltage regulator refers to a device that automatically maintains a constant voltage in electronic engineering. A regulator may be a simple feedforward design or may contain a negative feedback control loop. Regulators may also use electromechanical mechanisms or electronic modules. According to different designs, voltage regulators can be divided into DC voltage regulators and AC voltage regulators.

A voltage regulator can provide a constant voltage when the power supply changes or the load current changes. Voltage stabilizers are often used in power supply systems, working in conjunction with rectifiers, electronic filters, etc., to provide stable output voltages, such as the working voltage required by microprocessors and other components. In alternators and even large generators in power plants, voltage regulators control the stability of the output voltage. In a distributed power distribution system, the voltage stabilizer may be installed in a substation or along the direction of the conductor to ensure that users can get a stable voltage regardless of the power level.

What is a Power Converter?

A converter is a device that transforms AC voltage, current, and impedance. When an AC flows through the primary coil, an AC magnetic flux is generated in the iron core or magnetic core, which induces a current in the secondary coil. The transformer consists of an iron core or a magnetic core and a coil. The coil has two or more windings. The winding connected to the power supply is called the primary coil, and the rest of the windings are called secondary coils. In the generator, whether the coil moves through the magnetic field or the magnetic field moves through the fixed coil, an electric potential can be induced in the coil. In both cases, the value of the magnetic flux is unchanged, but the amount of magnetic flux that intersects the coil is different. Change is the principle of mutual induction. A transformer is a device that uses the electromagnetic mutual inductance effect to transform voltage, current, and impedance.

The transformer method first requires the AC voltage to be stepped down to the proper AC voltage through a transformer. This is an AC/AC conversion, and the step-down value is set by the winding ratio of the transformer. Then, the AC voltage stepped down by the transformer is full-wave rectified by a diode bridge rectifier and converted into a pulse voltage. Finally, the capacitor smoothers and outputs a DC voltage with a small ripple, which is the traditional AC/DC conversion method. The main components of the transformer are the primary coil, the secondary coil, and the iron core (magnetic core). The main functions are voltage transformation, current transformation, impedance transformation, isolation, and voltage regulation.

The Working Principle of the Converter:

The transformer consists of an iron core (or magnetic core) and a coil. The coil has two or more windings. The winding connected to the power supply is called the primary coil, and the rest of the windings are called secondary coils. It can transform AC voltage, current, and impedance. The simplest core transformer consists of a core made of soft magnetic material and two coils with different turns on the core.

The function of the iron core is to strengthen the magnetic coupling between the two coils. To reduce the eddy current and hysteresis loss in the iron, the iron core is made of laminated silicon steel sheets. There is no electrical connection between the two coils, and the coils are wound by insulated copper wires. to make. One coil connected to the AC power supply is called the primary coil, and the other coil connected to the electrical appliance is called the secondary coil. The actual transformer is very complicated, and there is inevitably copper loss (coil resistance heating), iron loss (iron core heating), and magnetic leakage (magnetic induction line closed by air).

What is AC?

Alternating Current (AC) is a current whose magnitude and polarity (direction) vary periodically with time. The number of times the current polarity changes in 1 second is called the frequency and is expressed in Hz.

What is DC?

Direct Current (DC) is a current whose polarity (direction) of flow does not change with time. A current that flows neither in polarity (direction) nor in magnitude with time is generally referred to as DC. Although the current whose polarity does not change with time and whose magnitude changes, is also DC, it is generally called Ripple current.

What is a DC/DC Converter?

A DC/DC converter is a machine that converts DC into DC and is a device that converts voltage using DC. Since electronic devices such as ICs have different operating voltage ranges, it is necessary to produce corresponding voltages one by one. A voltage lower than the original voltage is called a buck converter, and a voltage higher than the original voltage is called a boost converter.

Electrical products that are plugged into an outlet to operate require an AC/DC converter to convert AC to DC, and most semiconductor components operate with DC. Each of the ICs mounted on a set of substrates has a fixed operating voltage range, and the requirements for voltage accuracy are also different. If a power supply with unstable voltage is supplied arbitrarily, it will cause problems such as malfunction or deterioration of characteristics. Therefore, to convert the required voltage or to stabilize it, a DC/DC converter is required.

A DC/DC converter is a voltage converter that effectively outputs a fixed voltage after converting the input voltage. DC/DC converters are classified into step-up DC/DC converters, step-down DC/DC converters, and buck-boost DC/DC converters. Three types of controls can be used according to requirements.

What are the Modulation Methods?

• PFM (Pulse Frequency Modulation):
  The switching pulse width is fixed, and the output voltage can be stabilized by changing the frequency of the pulse output. The PFM control type has the advantage of low power consumption even if it is used for a long time, especially when the load is small.
• PWM (Pulse Width Modulation):
  The frequency of the switching pulse is fixed, and the output voltage can be stabilized by changing the pulse output width. The PWM control type is highly efficient and has good output voltage ripple and noise.
• PWM/PFM conversion type:
  In general, the performance differences of DC-DC converters using two different modulation methods, PFM and PWM, are as follows. The PWM/PFM conversion type implements PFM control at light loads and automatically switches to PWM control at heavy loads. PWM frequency, PFM duty cycle selection method.