V&T Inverter Pumping Unit Frequency Control Scheme-2015-03-20

一、the pumping unit frequency conversion speed regulation transformation adopts three schemes

◆ Inverter plus brake unit control

As shown in the figure below: Add braking resistance and braking unit at both ends of the DC link of the main circuit of the inverter (this method/price ratio was high). Since the pumping unit needs a large torque when starting, the rwasing section also needs a large torque. In the falling section motor was in the power generation state. The most important thing was the descending section. this process was continuous operation. At the same time, with the conswastency of the oil, the depth of the well, the output adjusts the number of reciprocating movements/MIN, which causes the motor to enter the regenerative power generation state, and the excess energy was fed back to the grid, causing the main inverter main. The voltage of the loop DC bus rwases, and the electric energy does not flow back to the grid. It must be consumed locally by the resistance. this was the reason why we must use the brake unit and the braking resistance on the inverter. The brake unit can be built in, and the ideal control effect can be achieved.

Figure 1 Inverter plus brake unit

◆ Inverter plus feedback unit control

As shown in the figure below, the feedback circuit was added to the DC link of the inverter, and the electric energy generated by the motor power generation state was fed back to the power grid.

Figure 2 Inverter plus feedback unit

◆ Inverter automatic intelligent control, no brake unit or feedback unit

Under normal circumstances, without the brake unit or feedback unit, the inverter can automatically adjust the operation according to the working conditions of the boring machine, the system cost was low, the reliability was higher, the harmonic pollution was reduced, and the operating voltage was more adaptable.

二、the frequency control system two places control

The following picture: the frequency conversion speed adjustment system diagram

According to the user's needs, each frequency conversion speed control cabinet uses a V5-H-4T15G/18.5L frequency drive, which was automatically controlled by open loop speed. The control cabinet has power frequency and frequency conversion function switching, switching power frequency. , frequency conversion, stop three gear positions, easy to operate. When switching to frequency conversion, the inverter runs automatically. The speed adjustment was input by the potentiometer analog input of the control cabinet to the AI1 terminal. During operation, the current current, voltage, power and frequency status can be viewed on the panel dwasplay. It does not require any switching to the upper computer control, and directly controls the start and stop of the inverter, the running status of the inverter and the setting of the running frequency, and can also copy the current data into the document. (see attached)

product advantages:

◆The external equipment has all-round protection functions such as short circuit, phase loss, overload and unbalance;

◆High integration, high reliability and high cost performance;

◆ Remote, local control, RS-485 communication function;

◆ cabinet type, can be installed in the open air;

三、the inverter Commissioning

Power on the inverter: Set the corresponding P9 group function code according to the motor nameplate parameter, then set P9.15=1, press the run key to perform parameter auto-tuning.

The function code setting of the inverter: P0.04=1, P0.06=1, P5.00=02, P5.01=50, PA.09=1, Pb.15=1, Pb.16=2.