Synchronous Reluctance Generator LVRT Control
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Solution Overview
Problem
Existing power units face challenges in dynamic grid support during faults, particularly with synchronous generators that can desynchronize and require complex control algorithms, leading to mechanical damage and difficulties in maintaining active power feed-in post-fault.
Innovation Solution
A power unit comprising a synchronous reluctance or squirrel-cage rotor generator with a compensation system and a control device that switches off at least one cylinder of the internal combustion engine during faults, using capacitors to manage reactive power and throttle valves to maintain power transmission, thereby reducing mechanical stress and ensuring rapid active power recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If synchronous generators are used to feed energy into the power supply network, then the generator can be synchronized with the network, but the generator may desynchronize under certain circumstances such as network faults
Solution Approach 1:
The patent extracts the problematic synchronization control function from the synchronous generator and replaces it with a self-synchronizing asynchronous generator (squirrel-cage or synchronous reluctance type). The asynchronous generator inherently synchronizes with the grid without requiring complex control algorithms, thereby eliminating the desynchronization risk while maintaining grid connection reliability.
Solution Approach 2:
The patent replaces the mechanical/electrical synchronization mechanism of synchronous generators with the electromagnetic field-based self-synchronization of asynchronous generators. This substitution eliminates the need for complex control systems while achieving reliable grid synchronization through the generator's inherent electromagnetic characteristics.
2Loss of energy
If reactive power compensation systems are connected in parallel with the generator, then the reactive power requirement is compensated during operation, but the reactive power requirement remains present during grid faults
Solution Approach 1:
The patent applies preliminary action by pre-configuring the reactive power compensation system to automatically adjust its operation during grid faults. The compensation system is designed to provide reactive power support precisely when needed during voltage dips or faults, ensuring continuous grid support without requiring additional complex control interventions.
Solution Approach 2:
The asynchronous generator with integrated reactive power compensation serves itself by automatically adjusting its reactive power output in response to grid conditions. The generator's inherent characteristics and the compensation system work together to maintain voltage stability and provide dynamic grid support without external control intervention.
3Speed
If complex control algorithms are used for rapid regulation during faults, then fast control is achieved, but turbocharger pumping occurs leading to potential mechanical damage
Solution Approach 1:
The patent converts the potential harm of rapid control actions into a benefit by using the asynchronous generator's inherent electromagnetic characteristics. Instead of applying complex control algorithms that cause turbocharger pumping, the system leverages the generator's natural response to grid faults, transforming what would be a harmful mechanical stress into a beneficial passive response that protects the turbocharger.
4Loss of energy
If the position of the throttle valve is changed to reduce active power output during faults, then reactive power consumption is reduced, but the control system inertia creates difficulties in maintaining required time constants
Solution Approach 1:
The patent extracts the throttle valve control function from the system and replaces it with the inherent electromagnetic characteristics of the asynchronous generator. The generator's natural response to grid faults automatically adjusts power output without requiring mechanical throttle valve adjustments, thereby eliminating control inertia and achieving rapid response within required time constants.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables optimized dynamic network support during faults by reducing reactive power consumption, minimizing mechanical damage, and ensuring quick active power feed-in post-fault, meeting grid support requirements without complex control algorithms.
Implementation Method 1
The internal combustion engine converts the chemical energy of a fuel, in particular a gas such as biogas, wood gas, mine gas, natural gas or propane, into kinetic energy
Implementation Method 2
The generator converts the kinetic energy into electrical energy, which is fed into the power grid
Implementation Method 3
a compensation system assigned to the generator, which includes three-phase capacitors connected in parallel with the generator and which is designed to provide the power supply network with a second reactive power that eliminates the purchase of the first reactive power from the power supply network
Data Source
Figure 1a
Figure 1b
Figure 2
AI summary
A power generator (10) for feeding energy into an electrical power supply network (N) comprises an internal combustion engine (11) having at least one cylinder (Z1 to Z6); a generator designed as a synchronous reluctance generator (12) or as a squirrel-cage generator, which can be driven by the internal combustion engine (11); a compensation system (16) associated with the generator (12), which is suitable for providing reactive power (Q2) to the power supply network (N);a control device (20) which, for dynamic grid support when driving through a fault in the power supply network (N), in particular in a Low Voltage Ride Through - LVRT - case, shuts down at least one cylinder (Z1 to Z6) of the internal combustion engine (11), and preferably at least one throttle valve (14) for throttling the power of the internal combustion engine (11), which is designed such that the position of the throttle valve (14) remains almost unchanged when driving through the fault in the power supply network (N).