Grid Driver Research Articles

Detecting Cyber Attacks on Renewable Distributed Generation for Future Smart Electric Meters to Prevent Electricity Theft

Electricity theft represents a pressing problem that has brought enormous fiscal losses to electric mileage companies worldwide. In the United States alone, $ 6 billion of electricity is stolen annually. Traditionally, electricity theft is committed in the consumption sphere via physical attacks that include line tapping or cadence tampering. With the advanced metering structure (AMI), smart measures are installed at the guests’ demesne and regularly report the guests’ consumption for monitoring and billing purposes. In this environment, vicious guests can launch cyber-attacks on smart measures to manipulate the readings in a way that reduces their electricity bill. Second, the smart grid paradigm enables guests to install renewable-grounded distributed generation (DG) units at their demesne to induce energy and send it back to the grid driver and hence make a profit.

A Gate Drive Circuit for Dual N-type H-bridge Power Transistors

A new grid driver of a high-side N-type switch tube is designed, which is easy to integrate. The circuit has the characteristics of low cost and fast speed and solves the problem of the unstable output voltage of a high-side switch tube when a low-side switch tube is not working in a traditional bootstrap circuit. The power supply voltage of the circuit is 30 V, including the voltage bias module, a high-level voltage shift circuit module, and a charge pump module. It can meet the driving requirements of a large size and high-side N-type switch tube. In this study, the 0.18 μm MGN process was used for design and simulation. The simulation results show that the grid driver has good driving ability.

Development of a gating grid driver of TPC for exotic beam experiments

The Multi-purpose Time Projection Chamber (TPC) for nuclear AsTrophysical and Exotic beam experiments (MATE) is being upgraded for the decay and active target experiments at the Heavy Ion Research Facility in Lanzhou (HIRFL). We have developed a gating grid driver to control the transitions between the closed and open states of the gating grid of the MATE-TPC to detect interesting rare decay events from a large amount of implanted ions. The gating grid driver is mainly composed of a digital control unit and a high-voltage switch unit. The digital control unit responds to the external trigger and generates control signals for the operation of the high-voltage control part based on the presetting instruction. The high-voltage switch unit is connected to two negative high voltages with different values and changes the voltages of neighboring wires of the gating grid based on the request for closing or opening the gate. A 500 ns switching time of the gating grid driver has been achieved from the closed to open state. The duration of the open state can be adjusted from 1 µs to 99 ms based on the experimental requirements. This gating grid driver can be used in a particle detector with a high voltage bias of up to ± 3000 V.

A gating grid driver for time projection chambers

A simple but novel driver system has been developed to operate the wire gating grid of a Time Projection Chamber (TPC). This system connects the wires of the gating grid to its driver via low impedance transmission lines. When the gating grid is open, all wires have the same voltage allowing drift electrons, produced by the ionization of the detector gas molecules, to pass through to the anode wires. When the grid is closed, the wires have alternating higher and lower voltages causing the drift electrons to terminate at the more positive wires. Rapid opening of the gating grid with low pickup noise is achieved by quickly shorting the positive and negative wires to attain the average bias potential with N-type and P-type MOSFET switches. The circuit analysis and simulation software SPICE shows that the driver restores the gating grid voltage to 90% of the opening voltage in less than 0.20µs, for small values of the termination resistors. When tested in the experimental environment of a time projection chamber larger termination resistors were chosen so that the driver opens the gating grid in 0.35µs. In each case, opening time is basically characterized by the RC constant given by the resistance of the switches and terminating resistors and the capacitance of the gating grid and its transmission line. By adding a second pair of N-type and P-type MOSFET switches, the gating grid is closed by restoring 99% of the original charges to the wires within 3µs.

A double output pulsed high current thyratron driver

The design and development of a double output pulsed high current driver for high power multi-grid thyratron is reported. The driver generates a 100 A current pulse of 2 μs duration with a compliance voltage of 1000 V for driving grid-1. A voltage pulse of 1200 V and 1.2 μs duration, superimposed with -150 V bias has been generated for driving grid-2. A delay of 1 μs between the two drive pulses is achieved with the use of a simple circuit. The rate of rise of voltage better than 10 kV/μs and jitter of ±3 ns is achieved for grid-2 pulse. This driver module has been successfully used in a 50 kV, CX1575C thyratron switched pulsed power supply to drive a multi-joule transversely excited atmospheric CO(2) laser at 100 Hz. The grid driver module can also be used for driving any high current thyratrons with minor external changes.

Circuit Modeling and Feedback Controller Development of the 8.4MW Modulator/Regulator Power System for the Electron Cyclotron Heating Facility Upgrade at DIII–D

As part of the Electron Cyclotron Heating (ECH) Facility upgrade at DIII–D an 8.4 MW Modulator/Regulator Power System was designed and constructed using acquired hardware from the Mirror Fusion Test Facility (MFTF) at Lawrence Livermore National Laboratory (LLNL) program as a foundation.1 Design changes in the feedback control of the modulator/regulator (M/R) was motivated by the need for improved output voltage regulation and improved capability to modulate the output voltage consistent with reference command signals containing modulation patterns (typically square wave). The regulation characteristics of the old ECH M/R power system had previously constrained gyrotron operation due to marginal voltage control loop stability and slow response to voltage step changes. The technical approach was to develop models of the circuit functions of the M/R controller from the circuit diagrams, and then examine the control characteristics using circuit analysis software. MATLAB® Simulink® and Intusoft IsSPICE4® (SPICE) codes were used to examine the control issues. These analysis software tools were used to simulate the controller functions and yielded identical results. The SPICE circuit model was selected as a baseline for future maintenance by the engineering staff. The analysis of the controller model blocks provided the needed information to modify the controller circuits. Changes made to the controller included addition of a voltage feedback loop around the grid driver amplifier for the power tetrode control grid in the M/R, and changes to the feedback loop compensation of the main error amplifier. The implemented revised controller performance matches the model performance predictions remarkably well. This paper describes the circuit models, implementation of the revisions to the controller, and recent operational results.

The Performance of the 8.4 MW Modulator/Regulator Power Systems for the Electron Cyclotron Heating Facility Upgrade at DIII-D

The DIII-D National Fusion Facility at General Atomics is completing the upgrade of its electron cyclotron heating (ECH) capability from the previous 3 MW at 110 GHz to 6 MW of generated microwave power.1 An 8.4 MW modulator/regulator (M/R) power system has been designed and constructed.2 Surplus hardware that was acquired from the Lawrence Livermore National Laboratory (LLNL) Mirror Fusion Test Facility (MFTF program) was used as part of the design foundation. The power system, with a nominal output of −80 kV and 80 A, can supply a pair of gyrotrons with up to 10 second long pulses that may or may not be modulated.The modulator/regulator was designed about the BBC CKQ200-4 tetrode, which was the key component acquired from the LLNL program. In order to meet the performance goals of the program, substantial design modifications were needed to be made on the grid driver amplifier and the closed-loop feedback regulator circuits.3 Also, a newly designed crowbar switch system, featuring a high speed, thyratron-like triggered gas switch, was implemented. The modulator/regulator performance to date has been demonstrated as having <0.06% peak-to-peak ripple and square wave modulation of 50% amplitude at 2 kHz. The key features of the design of the power system and its performance will be presented in this paper.