GFD233A 3BHE022294R0103 励磁控制器模块

GFD233A 3BHE022294R0103 励磁控制器模块

发电机励磁功率取自发电机端，经过励磁变压器LB降压，可控硅整流器KZL整流后给发电机励磁。自动励磁调节器根据装在发电机出口的电压互感器TV和电流互感器TA采集的电压、电流信号以及其它输入信号，按事先确定的调节准则控制触发三相全控整流桥可控硅的移相脉冲，从而调节发电机的励磁电流，使得在单机运行时实现自动稳压，在并网时实现自动调节无功功率，提高电力系统的稳定性。

发电机的线电压UAC和相电流IB分别经电压互感器和电流互感器变送后，经鉴相电路产生电压周期的方波脉冲和电压电流相位差的方波脉冲信号送PIC16F877微控制器，用PIC的计数器测量这两脉冲的宽度，便可得到相位差计数值，即电网的功率因素角。然后通过查表得出相应的功率因素，进一步求出有功功率和无功功率。

控制单元选用一片PIC16F877单片机，因PIC16F877单片机内部有A/D转换功能，从而不用外部A/D模块，这样减少了外部器件，降低了成本，增强了抗干扰能力。PIC单片机根据从输入通道采集的发电机运行状态变量的实时数据，进行控制计算和逻辑判断，求得控制量。在可控硅整流电路中，要求控制电路按照交流电源的相位向可控硅控制极输出一系列的脉冲，才能实现可控硅顺利导通和自然换相。“同步和数字触发控制电路”的作用就是将计算机CPU计算出来的、用数字量表示的可控硅控制角转换为触发脉冲。由功率放大电路将触发脉冲放大后去触发可控硅，从而控制励磁电流。

GFD233A 3BHE022294R0103 励磁控制器模块

The excitation power of the generator is obtained from the generator end, reduced by the excitation transformer LB, and the thyristor rectifier KZL excites the generator after rectification. According to the voltage and current signals collected by the voltage transformer TV and the current transformer TA installed at the generator outlet and other input signals, the automatic excitation regulator controls and triggers the phase shift pulse of the three-phase fully controlled rectifier bridge thyristor according to the regulation criteria determined in advance, so as to adjust the excitation current of the generator and realize automatic voltage regulation during the operation of a single machine. The automatic adjustment of reactive power during grid connection can improve the stability of power system.

After the line voltage UAC and phase current IB are transmitted by the voltage transformer and the current transformer respectively, the square wave pulse of voltage period and the square wave pulse signal of voltage and current phase difference are generated by the phase detection circuit and sent to the PIC16F877 microcontroller. The width of the two pulses is measured by the PIC counter, and the phase difference meter value can be obtained, that is, the power factor Angle of the grid. Then the corresponding power factors are obtained by looking up the table, and the active power and reactive power are further calculated.

The control unit selects A PIC16F877 microcontroller. Because the PIC16F877 microcontroller has A/D conversion function inside, it does not need an external A/D module, which reduces the external devices, reduces the cost and enhances the anti-interference ability. Based on the real-time data of the generator running state variables collected from the input channel, PIC microcontroller performs control calculation and logical judgment, and obtains the control quantity. In the thyristor rectifier circuit, the control circuit is required to output a series of pulses to the thyristor control pole according to the phase of the AC power supply, so as to realize the smooth conduction and natural commutation of the thyristor. The function of the "synchronous and digital trigger control circuit" is to convert the thyristor control Angle calculated by the computer CPU and represented by a digital quantity into a trigger pulse. The power amplifier circuit amplifies the trigger pulse to trigger the thyristor, thus controlling the excitation current.