R.A. Lukaszewski

Rockwell Automation · Low Voltage & Medium Voltage Drives

Mixed Flow Gas testing is widely used in industry as a means to accelerate corrosion in electronics. Although the science behind mixed flow gas testing is well-documented, the challenges of performing mixed flow gas testing on electrically powered products are not often discussed in the literature. This paper describes the authors’ experiences with...

Two specifications, ISA 71.04-1985 and IEC 60721-3-3, that are used to specify corrosive environments for electronics have created confusion for manufacturers that create products for use in these environments due to inconsistencies and incomplete information. These standards also do not specify how the products should be tested to show compliance...

Vibrational spectroscopy can provide rapid, label-free, and objective analysis for the clinical domain. Spectroscopic analysis of biofluids such as blood components (e.g. serum and plasma) and others in the proximity of the diseased tissue or cell (e.g. bile, urine, and sputum) offers non-invasive diagnostic/monitoring possibilities for future heal...

A fixture was designed and built to test power cycling reliability at maximum junction temperatures of 150°C and 175°C. A 1200V, 150A IGBT six pack module was mounted on a single cold plate and three sets of cold plates were connected to DC power supplies controlled by LabView. The IGBTs on each cold plate were cycled to give a junction-to-case tem...

Vibrational spectroscopy can provide rapid, label-free, and objective analysis for the clinical domain. Spectroscopic analysis of biofluids such as blood components (e.g. serum and plasma) and others in the proximity of the diseased tissue or cell (e.g. bile, urine, and sputum) offers non-invasive diagnostic/monitoring possibilities for future heal...

Adjustable speed drives (ASDs) with regenerative PWM rectifiers - both voltage source rectifiers (VSR) and current source rectifiers (CSR) - have LC filters on their input to attenuate the high frequency components of current and achieve reduced levels of total harmonic distortion (THD). The capacitors used in these filters are predominantly of the...

A double fed induction generator (DFIG) converter method are presented in which rotor side current spikes are attenuated using series-connected damping resistance in response to grid fault occurrences or grid fault clearances.

The long-term reliability of the thermal interface material (TIM) between an IGBT and heat sink is a critical aspect of motor drive design and customer satisfaction. Studies in the literature have focused on TIM characterization using idealized flat surfaces that are not representative of the wavy mounting surface found on IGBT base plates. In the...

Biofluids, such as serum and plasma, represent an ideal medium for the diagnosis of disease due to their ease of collection, that can be performed worldwide, and their fundamental involvement in human function. The ability to diagnose disease rapidly with high sensitivity and specificity is essential to exploit advances in new treatments, in additi...

With the conventional space vector pulsewidth modulation (SVPWM) scheme, ac drives generate high-peak common-mode currents (CMCs), particularly at a very low modulation index. This occurs because of the low dwell times on the active voltage vectors, resulting in nearly simultaneous switching on all three phases. High-peak CMCs present several issue...

The present techniques include methods and systems for detecting the grounding condition of an electrical system to automatically determine a suitable electrical drive configuration. The drive includes a test resistor which may be connected or disconnected from the drive to measure different drive voltages. The measured drive voltages are analyzed...

The primary objective of this paper is to investigate three distinct solutions to stabilize performance of a mechanical load that has resonance. In this case, the load inertia varies from 0.25 PU to 2.0 PU of the motor inertia.

The present techniques include methods and systems for operating converter to maintain a lifespan of the converter. In some embodiments, the operating frequency of the converter may be increased such that stress may be reduced on the bond wires of the converter. More specifically, embodiments involve calculating the aging parameters for certain ope...

A double fed induction generator (DFIG) system and controller are presented in which the rotor side converter is preloaded with one or more initial values for resuming regulated operation to counteract transients upon deactivation of the crowbar protection circuit to provide grid fault ride through.

Power conversion systems and control techniques are presented in which a bus transient control component bypasses selected phases of a rectifier during a protective mode of operation to reduce common mode voltages or currents.

Adjustable speed drives (ASDs) experience several power quality events occurring on the AC line - the most common are voltage sags and interruptions, and voltage unbalance. ASD manufacturers test the immunity of AC drives to voltage sags, to conform to the requirements of SEMI F47-0706 and IEC 61000-4-34 standards. Immunity to voltage unbalance is...

The present techniques include methods and systems for operating an inverter to maintain a lifespan of the inverter. In some embodiments, the switching frequency and/or the output current of the inverter may be changed such that stress may be reduced on the inverter bond wires of the inverter. More specifically, embodiments involve calculating the...

The present techniques include methods and systems for operating a wind power system to maintain a lifespan of the rotor side converter. In some embodiments, the current of the rotor side converter may be minimized to reduce the stress and/or junction temperature variation in the switching transistors and bond wires of the converter. More specifica...

Electrical power quality test circuitry for testing response of an electrical device to input power disturbances is provided. The test circuitry includes a power structure having a rectifier configured to convert incoming AC voltage to DC voltage on a DC bus, and a power inverter configured to convert DC voltage from the bus to three-phase output A...

When the conventional space vector PWM (SVPWM) schemes are applied to regenerative AC drives, very high neutral to ground voltages are generated at the motor. This can result in premature failure of the motor bearings and stator winding insulation to ground. The DC bus to ground voltage may also be elevated to very high levels, resulting in failure...

Doubly Fed Induction Generator (DFIG) system is subject to high transient voltage at rotor side when there is voltage sag at stator/grid side, which is beyond the capability of rotor side converter to handle. Traditional approach is to apply crowbar circuit to shunt the transient rotor current from the rotor side converter. DC-link brake is also ty...

Variable frequency drive efficiency plays an important role in green energy applications. However, how to accurately measure drive loss and efficiency is still a question to the industry. This paper reviews the powermeter method, calorimeter method, and factors that affect accuracy. After a calorimeter is constructed and calibrated, a variable freq...

The doubly fed induction generator (DFIG) is one of the most popular topologies applied in wind power systems. Its main advantage is to adjust the speed of a large system with much lower power converters. This is because its rotor-side converter (RSC) operates under slip frequency and it needs only to support slip power to the overall system. Howev...

With the conventional space vector PWM (SVPWM) modulation scheme, AC drives generate high peak common-mode currents, particularly at very low modulation index. This occurs because of the low dwell times on the active voltage vectors, resulting in nearly simultaneous switching on all three phases. High peak common-mode currents present several issue...

Pulsewidth-modulated (PWM) ac drives generate high differential-mode (DM) motor voltages due to the reflected wave phenomenon. The common-mode (CM) voltage produced by a PWM inverter also has fast transitions that result in high peak currents to ground. For low-power ac drives, this can present several issues, such as pump-up of the dc bus and fail...

Studies show that the power cycling mean time to failure (MTTF) of the insulated-gate bipolar transistor (IGBT) bond wire in an adjustable speed drive may be very short under some very common conditions. This paper proposes a switching frequency reduction method based on the junction temperature variation (ΔT_j) of an inverter IGBT. It ha...

This paper analyzes the insulated gate bipolar transistor (IGBT) power cycling capability for a dual-bridge matrix converter (DBMC) used as a motor drive and compares the result with the traditional dc/ac inverter and the conventional matrix converter (CMC). Two pulsewidth modulation (PWM) control methods for the DBMC are investigated. One is calle...

The impact of common-mode voltage (CMV) generated by pulsewidth modulation (PWM) ac drives on motor bearings is well known. Several algorithms for CMV reduction have been proposed in the literature. While a few algorithms assume ideal switching and fall apart when nonidealities like inverter dead time are considered, some others are effective only...

PWM AC drives generate high differential mode motor voltages due to the reflected wave phenomenon. The common-mode voltage produced by a PWM inverter also has fast transitions that result in high peak currents to ground. For low power AC drives this can present several issues, such as pump-up of the DC bus and failure of the power module due to hig...

This paper analyzes the IGBT power cycling capability for dual bridge matrix converter (DBMC) used as a motor drive and compares the result with the traditional DC/AC inverter and the conventional matrix converter (CMC). Two PWM control methods for the DBMC are investigated. One is called zero current switching PWM (ZCPWM) that allows zero current...

This paper analyzes the power-cycling capability of insulated-gate bipolar transistor (IGBT) modules in a conventional matrix converter used as a motor drive. The analysis is made under various conditions for this topology, including low-speed-operation capability, high-speed thermal- and power-cycling capabilities, etc. It was found that the power...

AC motor drives contain several power bus structures, which include the DC bus structure between the capacitor bank and inverter, IGBT power module internal bus structure to parallel several chips to obtain high current rating, and bus structures between low power AC drive units that are paralleled to obtain a high power AC drive. It is necessary t...

This paper analyzes the power cycling capability of semiconductor under various conditions for adjustable speed drive (ASD). An analysis is made that calculates the mean time to failure (MTTF) of the semiconductor under various conditions, including low speed operation capability, high speed thermal capability and overload capability. After that, t...

High Resistance Ground (HRG) systems have gained popularity in process applications due to their ability to continue operation in lieu of a single line-ground fault and improved ability to limit escalation of the single line-ground fault into a multi-phase event. Guidelines for designing safe and reliable HRG equipment for use on grid systems with...

This paper analyzes the effect of the variation of machine parameters on flux observers in the steady-state condition by the frequency-domain method. Both the flux estimation and the torque estimation are evaluated. The frequency response function (FRF) expressed by the ratio of the estimated flux/torque to the corresponding physical one is derived...

This paper evaluates the optimal design of the main inductor for LCL filter in a three phase active front end (AFE) rectifier. The objective is to evaluate the optimal inductance of the main inductance and its cost under various switching frequency, air flow speed, and inductance. The paper presents a detailed step by step optimization procedure to...

A three-phase induction motor model that depicts the motor behavior over a wide range of frequencies from 10 Hz to 10 MHz is presented in this paper. The model is universal in the sense that common-mode, differential-mode, and bearing circuit models are combined into one three-phase equivalent circuit model. The proposed model is basically an exten...

This paper presents a detailed analysis to evaluate the performance changes of high power, high frequency inductor with the existence of mounting strap. 2D finite element analysis (FEA) is used thoroughly for the losses calculations of the strap in terms of materials, air gap distance, and mounting strap thickness. After that, an optimal way of sel...

Multipulse rectifier system has been shown to be a cost-effective harmonic solution in many industries where IEEE 519 is specified. However, it is susceptible to poor quality of the input source of the power distribution system where the phase unbalance of the source voltage and preexisting low-order harmonic voltages are presented. A small amount...

This paper develops a thermal model for a six-pack insulated gate bipolar transistor (IGBT) power module operating as a three phase voltage source inverter. With this model, the temperature of each chip can be derived directly from the losses of the silicon chips and a thermal impedance matrix. The losses of each chip can be calculated through the...

This paper proposes a new 3-phase transmission line model with the first successful use of 2D finite element analysis (FEA) to extract and predict cable R-L-C parameters over a wide range of frequencies. The significance is that the FEA methodology to extract high frequency parameters were shown to be accurate and eliminates costly cable testing. T...

This paper investigates utilization of silicon carbide (SiC) Schottky power diodes as inverter Free Wheel Diodes (FWD) in a commercially available standard Econopak module also packaged with latest generation low-loss IGBT silicon. Static and switching characteristics of SiC diodes over standard module operating temperature 25 0C to 125 0C (298 0K...

18 pulse rectifier systems have been shown to be a cost effective harmonic solution in many industries where IEEE 519 is specified. However, multi-pulse rectifiers are susceptible to phase unbalance of the source voltage and preexisting harmonic voltages. A small amount of voltage unbalance can cause a large amount of current harmonic injected back...

This paper describes a general method to measure inverter DC bus capacitor current in an indirect manner. The method measures input and output voltage and current and calculates DC bus capacitor current. The method applies to standard inverters and common bus inverters. Commonly available test equipment will be used. The investigation will develop...

The Shared/Common bus operation of AC drives is becoming popular in many industrial applications due to it's advantages such as cost reduction, reduced space requirements, and improved reliability. Depending on the application requirements, there are presently two methods to interconnect DC buses of AC drives; Shared-bus and common-bus. Very little...

A third order dynamical thermal model suitable for modeling diodes and IGBTs is proposed. The method for deriving model parameters from manufacturers data sheets is derived and verified. Models of the power circuit devices, IGBTs and diodes, together with a heat sink model are combined into a dynamical thermal model of 3-phase inverter bridge. The...

The loading of free wheel diodes (FWD) and IGBTs in the power modules of a voltage source power converter (VSC) are investigated. In converter duty, the FWD are utilized more then the IGBTs. Presently, most FWD in power modules are optimized for inverter duty. This practice tends to undersize the FWD from a converter viewpoint. This design philosop...

The shared/common bus operation of AC motor drives is becoming popular in many industrial applications due to its advantages such as cost reduction, reduced space requirements and improved reliability. Depending on the application requirements, there are presently two methods to interconnect DC buses of AC drives: shared-bus; and common-bus. Very l...

In this paper a simple circuit for feeding back the braking energy from the DC voltage link of a three-phase PWM AC drive system into the mains is proposed. The operating behavior of the system which consists of a series connection of a line-commutated three-phase bridge and a turn-off power semiconductor device and in principle does not require pa...

Modern high power insulated gate bipolar transistor (IGBT) modules typically have a package inductance of less than 50 nH and switching times as low as 30 ns. Proper characterization of high power fast switching devices requires total test fixture stray inductance be minimized to preferably less than module package inductance. Design and fabricatio...