Frequency converter and energy saving: How it works

Most frequency converters have two modes of operation: steady-state for loads where the load is independent of speed (e.g. conveyor, hoist, compressor, etc.), and M~n² mode where the load is quadratic with speed (e.g. centrifugal pump, fan, etc.). In the constant load mode, the frequency converter tries to maintain a high torque while keeping the magnetic field as strong as possible. In the second mode, the torque is reduced according to the calculated curve, which helps to achieve energy savings.However, neither of these modes takes into account the actual behaviour of the load.

The Optimal Excitation Control of the Mitsubishi frequency converter takes into account the load behaviour in real time and provides just the amount of motor torque the load requires at a given moment.

Optimum Excitation Control

Optimum Excitation Control (OEC) is a feature of Mitsubishi frequency converters designed to optimize the energy consumption of the motor by providing precise control and reducing unnecessary energy consumption. This feature allows the frequency converter to automatically adjust the excitation of the motor (i.e. the electrical energy required to generate the magnetic field) according to the actual load and operating conditions.

Optimal excitation control helps to increase motor efficiency and reduce energy consumption. This function works particularly accurately in Mitsubishi converters thanks to the high CPU performance and precise measurement: this enables the frequency converter to measure the motor parameters more closely and accurately, thereby enabling even more efficient control and energy efficiency.

Optimal excitation control working principles

1. Excitation Adjustment: The function continuously monitors changes in motor load and adjusts the excitation to achieve the best possible energy efficiency. As the load decreases, the frequency converter reduces the motor excitation to reduce the energy loss that normally occurs at underload.

   The frequency converter continuously monitors the motor's excitation to ensure that the motor is always running at the correct speed.

2. Realtime control and monitoring software: Mitsubishi frequency converters incorporate advanced algorithms inside the motor that monitor the motor's performance and adjust its excitation according to load conditions. This allows the motor to run with the power it needs at the moment, avoiding both unnecessary overheating and underpowering.

   The algorithms use advanced algorithms to monitor and control the motor's performance.

3. Less heat loss: When the motor is running at lower excitation, energy loss to heat is also reduced. As a result, the motor runs at a lower temperature, which extends its operating life and reduces cooling costs.

   The lower the heat output, the lower the cooling costs.
   The engine operates at a lower temperature.

4. Balancing energy efficiency and performance: Optimal excitation control of Mitsubishi frequency converters allows balancing motor performance and energy consumption. This means that the frequency converter is able to maintain the motor performance at the required level even when energy consumption is optimised and reduced.

   The optimum frequency converter balances the motor performance to achieve the optimum energy balance.

How to configure

.

Select P.60 in the frequency converter and change its value to 9

. . . .

Pr.	Name	Initial Value	Setting Range	Description
60, G030	Energy saving control selection	0	0	Normal operation
			4	Energy saving operation
			9	Optimum excitation control