Self-adaptive current control method of pumped storage static frequency converter
A static frequency converter and current control technology, which is applied to the starter of a single multi-phase induction motor, motor generator/starter, etc., and can solve problems such as startup failure, startup overtime, and improper current control
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Embodiment 1
[0039] see figure 1 , a method for self-adaptive current control of a pumped storage static frequency converter, comprising the following steps:
[0040] 1) The inverter for static start of pumped storage is composed of input reactor, rectifier bridge, DC reactance and inverter bridge. At the same time, it cooperates with the excitation system and control protection system to complete the soft start of the inverter for the entire pumped storage unit.
[0041] 2) The current flows from the power grid side through the transformer into the static inverter, and then flows into the rectifier bridge after being filtered by the input reactor. It is converted into alternating current and input to the stator side of the motor, so as to realize the function of soft start with frequency change.
Embodiment 2
[0043] see figure 1 , figure 2, a method for self-adaptive current control of pumped-storage static frequency converters, the start-up control strategy of the static frequency converter comprises the following steps:
[0044] 1) The rectifier unit receives the signal of the current controller to adjust the magnitude of the DC current.
[0045] 2) The current controller signal is obtained from the comprehensive calculation of the CT sampling current on the AC input side, the calculated value of the start-up time, and the speed regulator exceeding the threshold.
[0046] 3) The actual speed is judged by the threshold. When the speed exceeds the threshold, the actual start-up time is calculated, and the actual start-up time is compared with the planned start-up time to determine whether the actual start-up time is over. If it is overtime, reverse the time to adjust the DC current and increase the torque, so as to complete the variable frequency start within the planned time. ...
Embodiment 3
[0049] see image 3 , Figure 4 , through the comparison of the theoretical start-up curve and the measured start-up curve, when the pumped storage unit is started using this method, the speed of the unit can maintain a uniform increase during the start-up process, and it is basically free from fluctuations due to external physical factors. Therefore, this method can be effective Improve the start-up success rate of the pumped storage unit.
[0050] see Figure 5 , the v / f curve during the start-up process, the curve shows that during the start-up process, the voltage and frequency ratio maintains a relatively stable state with less fluctuation. It shows that the starting stability of the unit is better.
[0051] Compared with the prior art, this embodiment has the following beneficial effects:
[0052] 1) This method can not only be used for the static variable frequency start of large pumped storage units, but also can be extended to the variable frequency start of relat...
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