Converters for home, work, transport and industry
Converters can be found everywhere: at home, in commercial workplaces or in industrial environments. Examples of converter usage include applications in mobile equipment (mobile phones and laptops), LED lighting, transport (car, metro, train) solar panels and production machines. A converter is an electrical or electromechanical device purpose-built to convert specific electrical characteristics (voltage, current, frequency) at the input to different values at the output.
Sectors and areas in which converters are used include (wharf) cranes, steel companies, cable manufacturers (extruders), welding machines, robots, LV industrial networks (chemical plants, paper factories, automobile industry), data centers and hospitals.
Examples of converter usage:
- Conversion of AC voltage into DC voltage (or vice versa)
- Increasing or decreasing input voltage
- Changing the frequency, for example from 50Hz (Europe) to 60Hz (USA)
- Driving and controlling the speed of synchronous motors
- Stabilizing mains voltage (clean net)
- Feeding equipment that is sensitive to power fluctuations (laboratories, lightning, etc.)
Different types of converters
There are different types of converters, the operating according to different methods. For example: some converters convert AC voltage to DC voltage and vice versa. Other possible functionalities include changing voltage level or voltage frequency. Combinations of these different transformations are also possible. This means many options and types exist, as well as a very wide range of applications such as electrical machine control, light drives, active power filters, renewable energy conversion, energy storage systems and energy generation and distribution. Available converter power levels vary from microelectronics to high-voltage power transmission. There are also devices and methods available for converting between power systems designed for single and three-phase operation.
Classification of converter types
We can distinguish four categories of converters, based on source input voltage and output voltage.
- AC to DC converter, or ‘rectifier’
- DC to AC converter, or ‘inverter’
- AC to AC frequency converter, or ‘transformer’
- DC to DC voltage, or ‘current converter’
DC to AC converters – Inverters
DC to AC converters are static devices that convert a fixed DC input voltage to a variable AC output voltage. The output voltage of the converter can be a variable or fixed alternating voltage with variable or fixed frequency. This type of converter can be a single-phase or three-phase converter, depending on the supply voltage.
We onderscheiden 2 types gelijkrichters:
- Uncontrolled diode rectifiers
This type of rectifier contains diodes and converts the alternating voltage of the network into a fixed direct voltage. Because diodes are uncontrollable components (which do not require triggering), these converters are also referred to as uncontrolled rectifiers, as they produce a fixed voltage. The input voltage can be single-phase or three-phase.
- Switching-mode rectifiers
This type of rectifier contains thyristors instead of diodes and converts alternating network voltage into a variable direct voltage. These rectifiers are also called phase-controlled rectifiers. Their operation is comparable to that of uncontrolled rectifiers. The difference is the fact that the uncontrolled diodes have been replaced by thyristors such as SCRs. Unlike diodes, thyristors can be controlled by triggering them at desired times to vary the output voltage.
AC to AC converters – Frequency converter
AC to AC converters are mainly used to convert the frequency of the input voltage/current from the source to desired load level. Some of these converters can also control the magnitude of the voltage as well as frequency. These are mainly used for adjusting the speed of AC drives and for induction heating. A transformer is a good example of an AC to AC converter. The input voltage is AC, the output voltage is AC, only the level of the voltage may vary between input and output. In addition, owing to its natural characteristics, a transformer ensures galvanic isolation in most cases (no direct electrical connection between input and output).
There are two types of AC/AC converter:
- Cycloconverters (CCV)
Cycloconverters are used to convert the frequency of a power supply to a desired load frequency. These converters are mainly used in high power applications - up to tens of megawatts - for frequency reduction. Cycloconverter applications include high-power AC drives, propulsion systems, high-frequency induction heating and synchronous motors in shipping.
- Matrix converters
Matrix converters offer a large number of frequency conversion options. They are built using fully controlled static devices, usually with bi-directional switches. When using these switches in three-phase matrix converters, any phase of the load can be connected to any phase of the input source.
DC to DC converters
DC to DC converters are devices that convert a DC input voltage to a desired DC output voltage level. This type of converter consists of power electronic switching devices, such as thyristors, connected in such a way that they supply the required DC voltage to the load.
There are two main types of DC-DC converter:
- Isolation converters: a transformer in between the input and the output eliminates the DC path and adds a layer of security during conversion
- Non-isolation converters: these feature a DC path between input and output
In many industrial applications, a DC-DC converter is required to convert a fixed-voltage DC source into a variable-voltage DC source. These applications include ship lifts, forklifts, subways, control in large DC motors and traction motor control in electric cars.
HyTEPS expertise and high-quality products
We are happy to support you in dimensioning the correct type and size of converter. We have the knowledge and experience to arrive at the most suitable solution. In addition, we work together with several suppliers that manufacture high-quality products, which we fully support. Our aim: knowledge, quality and service.