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Understand the difference between inverter and inverter

This paper first introduces the working principle and function of the inverter, introduces the working principle and characteristics of the inverter several times, and finally explains the difference between the inverter and the inverter. Let's take a look at the small series.
 
 
 
Introduction to the inverter
 
 
 
Variable-frequency drive (VFD) is a power control device that controls the AC motor by changing the working frequency of the motor by applying variable frequency technology and microelectronic technology. The frequency converter is mainly composed of rectification (AC to DC), filtering, inverter (DC to AC), braking unit, drive unit, and detection unit micro processing unit. The inverter adjusts the voltage and frequency of the output power supply by the internal IGBT breaking, and supplies the required power supply voltage according to the actual needs of the motor, thereby achieving the purpose of energy saving and speed regulation. In addition, the frequency converter has many protection functions. Such as overcurrent, overvoltage, overload protection and so on. With the continuous improvement of industrial automation, inverters have also been widely used.
 
 
 
How the frequency converter works
 
 
 
Frequency conversion is a development of modern power electronics technology, and it is a common conversion device between DC and AC. It can also change the frequency of our AC to control the power control equipment of the AC motor. The frequency converter is mainly composed of rectification (AC to DC), filtering, inverter (DC to AC), braking unit, drive unit, and detection unit micro processing unit.

The inverter adjusts the voltage and frequency of the output power supply by the internal IGBT breaking, and supplies the required power supply voltage according to the actual needs of the motor, thereby achieving the purpose of energy saving and speed regulation. In addition, the frequency converter has many protection functions. Such as overcurrent, overvoltage, overload protection and so on.
 
P and N are converter circuits. The alternating current can be set to direct current and loaded to the load Z. When the pulse signal to P is sinusoidal, the set DC is sinusoidal and is the upper part of the sinusoid. The period is the sinusoidal periodic period of the pulse signal, which is an integer multiple of the alternating current period. Through the cooperation of P and N, a periodic sinusoidal current on the load Z is formed, and the frequency can be adjusted according to the pulse signal period, which is the working principle of the frequency converter.
 
 
 
Frequency converter
 
 
 
First, adjustable torque limit
 
 
 
After the frequency conversion speed regulation, the corresponding torque limit can be set to protect the machine from damage, thus ensuring the continuity of the process and the reliability of the product. The current frequency conversion technology makes not only the torque limit adjustable, but even the torque control accuracy can reach 3% to 5%. In the power frequency state, the motor can only be controlled by detecting the current value or thermal protection, and it is not possible to set an accurate torque value to operate as in the variable frequency control.
 
 
 
Second, controlled stop mode
 
 
 
Like controllable acceleration, in variable frequency speed regulation, the stop mode can be controlled, and different stop modes can be selected (deceleration stop, free stop, deceleration stop + DC brake), which can also reduce mechanical parts and The impact of the motor makes the entire system more reliable and the life expectancy increases accordingly.
 
 
 
Third, energy saving
 
 
 
The energy saving of the inverter is mainly reflected in the application of fans and pumps. In order to ensure the reliability of production, all kinds of production machinery have a certain margin when designing with power drive. When the motor can't run under full load, in addition to meeting the power drive requirements, the excess torque increases the consumption of active power, resulting in wasted power. Fans, pumps and other equipment traditional speed control method is to adjust the air volume and water supply by adjusting the baffle and valve opening of the inlet or outlet. The input power is large, and a large amount of energy is consumed in the interception process of the baffle and the valve. in. When using variable frequency speed regulation, if the flow demand is reduced, the speed can be met by reducing the speed of the pump or fan.
 
 
 
Fourth, reversible operation control
 
 
 
In the inverter control, to achieve reversible operation control without additional reversible control device, only need to change the phase sequence of the output voltage, which can reduce maintenance costs and save installation space.
 
 
 
Fifth, reduce mechanical transmission components
 
 
 
Since the current vector control inverter plus the synchronous motor can realize efficient torque output, the mechanical transmission components such as the gear box can be saved, and finally constitute a direct variable frequency transmission system. This reduces costs and space and improves stability.
 
Inverter introduction
 
 
 
The inverter converts DC power (battery, battery) into alternating current (typically 220V, 50Hz sine wave). It consists of an inverter bridge, control logic and filter circuits. Widely used in air conditioners, home theaters, electric grinding wheels, power tools, sewing machines, DVD, VCD, computers, televisions, washing machines, range hoods, refrigerators, video recorders, massagers, fans, lighting, etc.
 
 
 
Inverter working principle
 
 
 
Turn the AC power into DC power. The DC power is then switched using electronic components. Becomes an alternating current. The working process is generally divided into four major processes: rectifier circuit, smooth wave circuit, control circuit and inverter circuit.
 
 
 
1, the rectifier circuit
 
 
 
The function of the rectifier circuit is to convert the AC power to a DC power source. The rectifier circuit is generally a separate rectifier module.
 
 
 
2, flat wave circuit
 
 
 
The smoothing circuit contains the power supply 6 times the frequency ripple voltage in the rectifier and the rectified DC voltage. In addition, the ripple current generated by the inverter also causes the DC voltage to fluctuate. In order to suppress the voltage fluctuation, the inductor and the capacitor are used to absorb the ripple voltage (current). The DC part of the general-purpose inverter power supply has a margin for the main circuit, so the inductor is omitted and a simple capacitor filter smoothing circuit is used.
 
 
 
3, the control circuit
 
 
 
Now the inverter is basically a 16-bit, 32-bit microcontroller or DSP as the control core, thus achieving full digital control.
 
 
 
4, inverter circuit
 
 
 
The inverter circuit is opposite to the rectifier circuit, which converts the DC voltage into an AC voltage of a desired frequency, and turns on and off the power switching devices of the upper bridge and the lower bridge at a determined time. Thereby, a three-phase AC voltage with a phase difference of 120° electrical angle can be obtained on the three phases of the output terminals U, V and W.
 
 
 
Inverter features
 
 
 
1. High conversion efficiency and fast startup;
 
 
 
2. Good safety performance: The product has five kinds of protection functions: short circuit, overload, over/under voltage and over temperature;
 
 
 
3, good physical properties: the product uses a full aluminum shell, good heat dissipation, surface hard oxidation treatment, good friction resistance, and can resist extrusion or impact of a certain external force;
 
 
 
4, with load adaptability and stability

The difference between inverter and inverter
 
 
 
The difference one:
 
 
 
An inverter is a component used to convert direct current into alternating current.
 
 
 
The frequency converter is a component used to change the frequency of the alternating current.
 
 
 
Difference two:
 
 
 
The inverter converts DC power (battery, battery) into alternating current (typically 220V, 50Hz sine wave), and the frequency can also be adjusted;
 
 
 
The inverter converts the input AC power into an AC output of the desired frequency; the principle is “AC-DC-AC” or “AC-AC”, and the “AC-DC-AC” form is more common. "AC-DC-AC" first converts AC power to DC, then DC to AC, which is "Rectification + Inverter"
 
 
 
The difference is three:
 
 
 
The inverter must have a part to adjust the frequency, and the inverter only needs to have a fixed output frequency.

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