The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Most control papers related to variable speed drives are focused on the current and torque control of the electric machine. However, the slower outer loop is also very important. This considers the control of a variable parameter resonant rotating load using a novel control algorithm called Local Vector Control (LVC). Resonant loads naturally occur in, for example, building elevator applications....
Current control is the most basic control loop for a current controlled inverter-fed machine. Current controllers fall into two categories depending on the reference frames they operate in — rotating reference frame controllers, and stationary frame controllers. This paper introduces a novel current control technique for inverter controlled machines known as Local Vector Control (LVC). This control...
The Modular Multilevel Converter (MMC) has many features that make it suitable for photovoltaic systems. It has good output performance, flexibility in control and its modular and scalable design allow it to directly connect to high voltage networks. The converter's isolated DC links also allow for the connection of many individual PV arrays. This paper presents an MMC control scheme which, by controlling...
This paper presents the Local Vector Control (LVC) algorithm that is applicable to power electronic systems. This controller does not differentiate between linear or non-linear systems and can operate, without change, in stationary or rotating reference frames. The performance of this current controller with particular emphasis on current clamp minimisation will be the paper's focus. A comparison...
The Modular Multilevel Converter (MMC) is a relatively new converter topology which has been favoured for high voltage DC transmission due to its performance, flexibility in control and its modular and scalable design which allow it to be used over a wide variety of system voltage levels and power ratings. The converter consists of a number of cascaded half bridge cells with isolated capacitors to...
Multilevel Cascaded H-Bridge (CHB) converters have attractive features for the implementation of large scale photovoltaic systems. They can be directly connected to high voltages and the multilevel voltage synthesis reduces the harmonic distortion introduced. In addition, they have individual DC links ideal for connecting photovoltaic arrays. Existing high performance voltage balancing techniques...
Cascaded H-Bridge (CHB) multilevel converters provide a number of attractive features for photovoltaic (PV) power systems. They have high quality output waveforms, high efficiency and the ability to incorporate multiple Maximum Power Point Tracking (MPPT) schemes. This paper investigates the ability of the CHB PV system to export maximum power for different configurations of PV arrays among the H-Bridges...
The control of Cascaded H-Bridge (CHB) photovoltaic (PV) systems typically requires the power generated by the PV arrays to be measured. The power measurement is used to generate the reference current to inject power into the grid as well as for Maximum Power Point Tracking (MPPT). The number of current sensors required for high level number systems increases their cost and complexity. Power estimation...
Multilevel Cascaded H-Bridge (CHB) converters have attractive features for the implementation of large scale photovoltaic systems. They can be directly connected to high voltages and the multilevel voltage synthesis reduces the harmonic distortion introduced. In addition, they have individual DC links ideal for connecting photovoltaic arrays. Existing high performance voltage balancing techniques...
Model Predictive Control (MPC) can provide performance benefits over traditional schemes in power electronic converter control. A key variable in predictive control schemes is the prediction horizon. This paper examines the impact of increasing the prediction horizon of a five level StatCom via simulation and experimental results.
Phase shifted carrier modulation enforces harmonic cancellation through each phase-leg in a multi-level H-bridge StatCom (H-StatCom). The implementation of this scheme, while achieving excellent harmonic performance suffers from control interactions between the voltage balancing loops. This paper first analyses these interactions and then develops a phase shifted carrier modulation scheme which avoids...
A novel droop controller is developed employing parallel voltage and current control algorithms. P-F droop is performed by a voltage controller in the direct axis of the rotating reference frame, whilst Q-V droop is achieved via a deadbeat current controller in the quadrature axis. Simulation and hardware results are presented to demonstrate the control schemes ability to provide matched and mismatched...
A companion paper provided the theoretical basis for a comparison between phase shifted carrier and space vector modulation schemes. This paper utilises the analysis techniques developed to investigate some non-ideal implementation aspects of the modulation strategies as well as the effect of increasing the level number on the performance of the cascaded H-bridge static compensator (H-StatCom). Specifically,...
Phase shifted carrier modulation has become an industry standard in its application to multi-level H-bridge Stat-Coms. The technique uses the cancellation of harmonics within each phase-leg to significantly improve the harmonic performance relative to the switching frequency. The purpose of this paper is to investigate whether the practical implementation of the technique deteriorates the harmonic...
This paper refers to a "DC Motor Duty Meter" project which aims to develop a comprehensive condition monitoring tool for DC motors used in mining excavators. The paper presents experimental waveforms measured internally and externally to the motor at different rotation velocities. The paper focuses on analysis of these waveforms both in time and frequency domains. The findings of the analysis...
This paper describes the development of a 2.2 MW DC electric machine based dynamometer for the cyclic testing of motors used in mining applications. The dynamometer, through the application of sophisticated control, is able to simulate the real dynamic digging conditions of an electric rope shovel. The paper will discuss the facility and the control algorithms to implement the dynamic dynamometer...
A multi-level H-bridge StatCom inherently contains redundancy in the available switching states. This paper develops a Model Predictive Control (MPC) scheme which is able to exploit this redundancy to optimise three competing objectives. The scheme can simultaneously balance the H-bridge capacitor voltages, provide excellent current reference tracking and optimise converter switching losses. A variation...
This paper studies different rotor topologies for the design of a 2 MW doubly-fed reluctance generator for a wind turbine application. There have been several papers that put forward different options for this type of machine and the control has been extensively studied. This paper uses the same stator size and application to enable comparative operation. This machine has two 3-phase winding sets...
DC machines continue to be widely used in many applications including mining. No comprehensive condition monitoring tools for large industrial DC machines are available on the market. Recent advances in sensoring, data acquisition and signal processing technologies allow one to obtain real time chracteristics of DC machines directly related to their performance, such as flux density distribution inside...
Static Compensators are used to improve power quality. In order to achieve this objective the control system requires accurate knowledge of the positive and negative sequences and user selected harmonics. This paper presents a technique based on an unusual PLL that simultaneously estimates the sequence components and several harmonics. Both simulation and experimental results demonstrating the technique...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.