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The IF output frequency converter is in MPWM mode with microprocessor as the core, designed with active component IGBT module, which uses digital frequency division, D/A conversion, instantaneous value feedback and sinusoidal pulse width modulation, etc.
The technology of separating transformer output is used to improve the stability of the whole machine.
The frequency converter the alternating current of the main power supply from AC→DC→AC to a pure sinusoidal waveform output, and its output voltage and frequency can be adjusted within a certain range.
Currently, there are two main types of frequency
converters: SPWM switching type and linear
amplifier type.
Currently, there are two main types of inverter power supplies in China: analog and program-controlled. What they have in common is the use of sinusoidal pulse width modulation (SPWM) technology.
All SPWM circuits use full-bridge inverter circuits realized by hardware.
The difference is that the analog full frequency and voltage adjustment knobs are realized by hardware settings, frequency and voltage adjustments are done in hardware, and the main circuits are completely separated from the measured display parameters, so that abnormal measurement displays will not affect the normal outputs, and the human-machine dialogue cannot reach the ideal state, and communication with the host computer is inconvenient.
The program control type is actually a hybrid digital-analog system which uses 196 microcontrollers as the control core, the frequency and voltage are adjusted programmatically, the program also adjusts the RMS value of the voltage, and the microcontroller monitors tasks such as the measurement display.
Advanced computers make it easier to transfer data to a microcomputer, but if the process is not well laid out or programmed, a crash reset can occur.
There are also two types abroad: one is almost the
same as the analog principle, and the other is a
program control type that uses a DSP as the
control core.
Compared with micro-controllers, DSPs are faster than CPUs, have a higher degree of integration, and have a higher memory capacity. As a Reduced Instruction System Computer (RISC), a DSP can use PI to adjust the error between the RMS value of the feedback voltage and the RMS value of the given voltage.
In addition, measurements and displays can be accomplished by the DSP, with most instructions completing most instructions in one cycle. Multiple instructions can be completed using internal parallel processing techniques, allowing the DSP to form a precision waveform generator with an external A/D converter to provide a reference voltage signal.
Not only can you simulate grid voltage fluctuations and generate the dynamic disturbance voltages needed to check the supply voltage performance of your equipment in the presence of dynamic disturbances, but you can also emit sine waves.
You can also simulate frequencies and voltages around the world and in the power grid. When the supply voltage is distorted, the voltage distortion produces the periodic strain voltage needed to test the performance of the instrument. PWM control is a technique used to modulate the width of a pulse.
That is, by modulating the width of a series of pulses, the desired waveform can be obtained equivalently. PWM waveforms can be categorized into two types: constant amplitude PWM waves and unequal amplitude PWM waves.
The PWM waveform generated by a DC power supply is usually an equal amplitude PWM waveform. If the amplitude of each pulse is equal and the width varies according to the law of sines, the PWM waveform becomes an SPWM waveform.
Medium frequency output frequency converter working principle
The following is an example of the operating principle of a 400 HZ IF frequency converter.The 400 HZ IF power supply inputs a single AC voltage and frequency and passes it internally from AC to DC in order to convert and rectify DC to AC and produce a very stable pure sine wave.
The principle is as follows. As shown in the figure, the power supply is fed with an AC grid voltage and frequency. After internal conversion f from AC to DC and DC to AC, it produces a very stable signal. It is itself a pure sine wave.
IF output frequency converter function
GBT’s inverter output technology is an advanced frequency converter technology currently used internationally. The high performance precision power supply is designed with advanced microprocessor control technology.
With over-voltage, under-voltage, over-current, overload, short-circuit and other alarm fault display and protection functions. The ability to ensure the safety of frequency conversion power supply and other electrical equipment.
It has good man-machine interface, good output waveform quality, strong load adaptability, easy operation, light weight and small size. The frequency converter with sinusoidal output, adjustable output frequency and voltage can provide high quality AC power required by many electrical installations.
Currently, these medium-frequency output variable frequency converters are easy to use and cost-effective, and play an important role in areas such as practical research and development, industrial production, aerospace and military.
