The automatic excitation regulator for the first phase consists of a silicon-controlled rectifier power unit, a phase-shift triggering unit, a DC amplification unit, a voltage feedback unit, a deviation control unit, a DC power supply unit, and a power supply monitoring unit. The rectifier power unit employs a three-phase bridge full-controlled rectifier circuit, which converts the alternating voltage into direct current to supply the excitation winding of the exciter; the phase-shift triggering unit is composed of six identical trigger plug-in modules. This unit changes the control angle of the thyristor according to the size of the input control signal Usm to control the output of the rectifier circuit and thereby regulate the excitation current of the motor/generator; the DC amplification unit consists of two stages of DC amplifiers, namely a PID amplifier and a comprehensive amplifier. The regulation process refers to the moment when the motor/generator is subjected to reactive disturbance voltage and the signal output by the PID changes in proportion to the rate of change (dv/dt) to modify the excitation to prevent the voltage change.
Due to the poor load-carrying capacity of the PID amplifier, a comprehensive amplifier needs to be set between the PID and the trigger to reverse and power amplify the output signal of the PID amplifier;
The reactive deviation control unit is capable of stabilizing the reactive current distribution among the units when the motor/generator operates in parallel, and when the motor/generator is connected to the grid through a step-up transformer, it can overcome the reactance voltage drop of the step-up transformer;
The reactive deviation control unit converts the change in the terminal voltage of the motor/generator into an AC voltage signal, while the input end of the PID requires a DC voltage feedback signal. Therefore, a voltage feedback unit is added between these two units to convert the AC voltage signal into a DC voltage signal;
The DC power supply unit provides +24V DC voltage to the excitation regulator;
The integrated components selected for this regulator have a working power supply of +15V, so a +15V stable power supply is required;
The power supply monitoring unit serves to monitor the two working power supplies, and can give an alarm when any one of the power supplies fails.
The second phase adopted the KFD-3 type rapid excitation regulator.
The regulator is powered by current transformers and voltage transformers, including controllable phase-recovery excitation transformers and voltage correctors.
The controllable phase-recovery excitation transformer BKF is the main component of the regulator. It is a transformer or magnetic amplifier with a DC magnetization and dual primary windings.
The first series winding is powered by current transformer LH;
The second parallel winding is powered by voltage transformer YH.
The induced electromotive force of the secondary winding is the geometric sum of the induced electromotive forces of these two windings.
The secondary current is rectified by the output rectifier group ZC and then sent to the excitation winding of the exciter.
The voltage corrector consists of three-phase measuring transformer BC and magnetic amplifier FC. The three-phase measuring transformer BC is powered by voltage transformer YH through an adjustable autotransformer TBZ.
It is a three-phase saturated transformer. The primary current of it has a non-linear characteristic, while the secondary current is linear. After being rectified by non-linear rectifier ZFL and linear rectifier ZXL, it is output to the two opposite polarity DC control windings of the magnetic amplifier FC. The magnitude of the output current of the magnetic amplifier is controlled by the difference of these two currents.
When the generator voltage increases, the linear and non-linear current difference output by the measuring mechanism increases rapidly, and accordingly the output current of the magnetic amplifier also increases sharply. Therefore, the voltage corrector composed of the measuring mechanism and the magnetic amplifier has an inverting characteristic. During normal operation, the corrector is supplied with a certain magnetizing current to the control winding of BKF, causing the core of BKF to work at a more saturated state, thereby controlling the output of BKF and achieving the purpose of controlling the excitation of the generator.
The third phase adopted the HWLT-4 type microcomputer excitation regulator. It enhanced the automation level of the motor > generator operation. All functions were implemented in a modular manner, and different functions were combined to meet the requirements of different users.
In terms of hardware, the regulator consists of two independent microcomputer channels and one independent analog channel.
Each microcomputer channel is divided into: voltage loop and current loop. The analog channel is the current loop.
The voltage loop is closed based on the terminal voltage signal from the machine, also known as the automatic loop;
The current loop is closed based on the rotor current signal, also known as the manual loop.
To ensure the rapidity of regulation, the system continuously samples and completes various calculations within one power frequency cycle. The operation circuit is completed jointly by the industrial control machine and relays.
In terms of software, the control mode of the regulator is divided into four types:
1. Automatic Voltage Regulation (AVR)
2. Magnetic Field Current Regulation (FCR)
3. Constant Reactive Power Regulation
4. Constant Power Factor Regulation
Under normal circumstances, the AVR mode can be manually switched to the FCR mode, and automatic switching occurs in case of faults. The latter two control modes can only be used in the AVR mode.
In addition, this regulator also has four limiting functions:
1. Stator Current Limiting
2. Magnetic Field Current Limiting
3. Under-Excitation Limiting
4. Volt-Hertz Limiting
The regulator controls the excitation current of the motor > generator through control functions, limiting functions, and some other auxiliary functions, so that the motor > generator operates in the optimal state.
For more questions about the generator set, please call the Beidou Power team. More than ten years of professional production and sales of power generation equipment experience, more professional engineer team to serve you, choose Beidou power is to choose rest assured, welcome on-site factory inspection.
Post time: Mar-16-2026