What is a frequencyconverter/ Inverter？

In the field of industrial production, it is the three-phase AC motor that plays a leading role, providing a continuous and powerful driving force for the production process. In the realm of industrial production, the three-phase AC motor takes center stage, providing a continuous and robust driving force for the production processes. In the realm of industrial production, the star performer is the three-phase AC motor, which supplies a steady and powerful driving force for the production processes. In the field of industrial production, the leading role is played by the three-phase AC motor, which provides a continuous and powerful driving force for the production process.

Using a frequency converter to control a motor primarily leverages its speed regulation capabilities to achieve the following:
①      Energy-saving operation: When operating below 50Hz, the operating voltage (and current) decreases, reducing power consumption and achieving significant energy savings.
 ② Excellent soft-start performance: By reducing voltage and frequency, it can limit the maximum starting current to within the rated current.
Frequency converters are classified into three major series:
 specialized for fans/pumps (P-type), general-purpose (G-type), and vector control (high-torque type).
 
· Specialized frequency converter: Suitable for loads with quadratic torque reduction, with slightly lower overload resistance.
· General-purpose frequency converter: Suitable for constant torque loads, with stronger overload resistance.
· Vector control frequency converter: Has strong load adaptability, enabling AC motors to achieve driving effects similar to those of DC motors.
From a maintenance perspective, the hardware circuit structure of the control circuit is actually the same for all three models, with the only differences lying in the software control and overload capacity. For the latter two models, the power output module (inverter module) selected is one power level higher. For example, a 5.5KW general-purpose model is actually equivalent to a 7.5KW specialized model for fans/pumps.
Basic Application of Frequency Converter:
The JienluAGD310 series vector control frequency converter features high-precision andhighly intelligent control functions. The wiring is as follows:
 
Main terminal wiring includes three-phase power input terminals, inverter voltage output terminals, externally (or internally) connected DC reactor terminals, brake unit connection terminals, etc. According to electrical standards, the three-phase power terminals are labeled as L1, L2, and L3, while the three-phase power input terminals of the frequency converter are labeled as R, S, and T; the output terminals of the frequency converter are labeled as U, V, and W.
1.       Points for attention in main terminal wiring:
2.       If the power input and output are connected incorrectly, and three-phase AC380V is mistakenly connected to the U, V, and W terminals, the "equivalent three-phase rectifier bridge" circuit formed by the parallel diodes inside the IGBT devices will create an unlimited charging current for the DC circuit's energy storage capacitor, which is highly likely to damage the internal inverter power module and energy storage capacitor. 
3.       During commissioning or maintenance, the terminal should be short-circuited to provide the internal working power supply for the machine.  
4.       Small power frequency converters below 11KW usually contain braking switching tubes and power braking resistors internally. For large and medium-sized power frequency converters, terminals are often led out from the DC circuit for external connection to braking units. Some small models contain braking switching tubes with terminals led out for external connection to braking resistors.

The role of control terminals: The control terminals of a frequency converter generally include digital signal input terminals, analog signal input terminals, digital signal output terminals, and analog signal output terminals, with the first three being more commonly used. The digital signal control terminals are for switching signal inputs, and external signal input devices can be switches, buttons, or contact signals from output relays, etc., used for controlling the start, stop, fault reset, and multi-speed operation of the frequency converter. External control components are connected to a 24V auxiliary power supply via the terminals to form a control command input circuit, which inputs signals into the internal circuit of the frequency converter. These control signals are also known as the control command sources of the frequency converter, determining its operating state.
Analog signal input terminals typically include 0~10V voltage signal input terminals and 0/4~20mA current signal input terminals. Which control signal is active can be set by parameters, and they can also simultaneously provide speed setpoints and related feedback signals for implementing PID closed-loop control. The 10V auxiliary power supply output from the terminals can be used to power external potentiometers, forming a frequency adjustment signal. Analog input signals are also known as the frequency command sources of the frequency converter, determining its output frequency.
 
Digital signal and analog signal output terminals indicate the operating state of the frequency converter through the contact status of the output signals. Most of these are programmable output signals, and the internal output signals can be set by parameters to supply external signal indicator lights, external frequency counters, or voltmeters to display the operating frequency, output voltage, and operating/stop/fault status of the frequency converter.
   The frequency converter also has a signal terminal, which is the 485 communication terminal. The signal flow of this terminal is bidirectional and does not distinguish between input or output ports.

5.     Control Parameters of the Frequency Converter:

Control Parameters of the Frequency Converter:
The basic control of a frequency converter includes starting, stopping, and speed regulation. Apart from using control terminals for control, the start/stop and speed regulation can also be controlled via the operation and display panel. Additionally, whether the frequency converter receives control from the operation panel or the control terminals, whether the frequency command is received as a voltage or current signal, or as a digital adjustment from the panel, and the operational functions of the control terminals, all need to be preset through working parameters.
Parking Methods:
(1) Free Parking: This parking method is the safest, but the disadvantage is that it cannot precisely control the parking time and position.
(2) Deceleration Parking: After receiving the stop signal, the frequency converter gradually reduces the operating frequency until it stops. This parking method can effectively reduce the "water hammer effect" in water supply control and mitigate the impact on the pipeline system. The disadvantage of deceleration parking is that when the motor overspeeds (due to a large system inertia), it generates regenerative energy that feeds back into the DC circuit of the frequency converter, requiring the installation of a braking unit and braking resistor to eliminate this harmful energy.
(3) DC Braking Parking: This method allows for more precise control of parking time and position.
The purpose of setting and adjusting the U/f curve is to make the U/f output characteristic of the frequency converter match the torque characteristic of the driven load, in order to achieve smooth starting, reduce operating current, and avoid phenomena such as stalling, ensuring scientific, reasonable, and efficient operation. According to the torque characteristics of the motor load, it can be divided into constant torque loads, constant power loads, and quadratic torque-reducing loads.

If you have a need to purchase a frequency converter, please contact Shanghai Jienlu Electronics customer service via
WhatAPP (WeChat ID): 15001775783