This paper presents a new modulation method for matrix converters based on the indirect modulation model. During the switching period, the proposed modulation method uses a combination of only one active vector and a zero vector in the inversion stage to achieve minimum flux error, while in the rectification stage a single current vector is selected, according to the error of the input current vector angle. This reduces the number of switching sequences in the switching period, improving the accuracy of generating the output voltage vector especially in the low modulation index range. Supplementary, the direct control of the input current vector is implemented. The estimation of the angle of the input current vector is done by applying the inverse transformation, that corresponds to the applied active vector, to the output currents.

This paper analyzes some aspects of integrating the matrix converter bi-directional switches into a power module. The analysis produces two optimal topologies for a power module: one for low-power and another for high-power matrix converters. The configuration of a power electronic building block for matrix converters is proposed. This includes the commutation control logic and the overcurrent protection, provides safe-operation and eliminates the problem of operating with bi-directional switches. A new power module topology for a low power three-phase to three-phase matrix converter is proposed. By using the bootstrap circuits to feed the gate-drivers, the proposed configuration requires only three insulated power supplies. A new input filter topology is proposed, using only two choke cores and providing the size reduction. The experimental results validate the solution by comparing the input current waveforms with the standard configuration. The two proposals constitute a solution recommended in the low power range, where low-cost and low-volume are the main objectives.

The research in matrix converters, a topology that reduces the size of reactive elements due to a single stage conversion, provides inherent bi-directional power flow and sine wave in-sine wave out operation, is obstructed by difficulties of building and working on an experimental prototype. Similar to the technology of standard converters, where the development of power electronic building blocks (PEBB) has provided fast, low-cost and wide access, the development of a matrix converter PEBB is expected to give the opportunity for many researchers to contribute with their work in the maturation process of this technology. This paper reports the development of a compact and safe-to-operate matrix converter PEBB, built with power modules with bi-directional switches, including the commutation control of bi-directional switches, the protections and providing galvanic insulation for the command signals, in order to release the user from any hardware mismatch problems.

The trend in electrical drives is to integrate the frequency converter, the electrical motor, and even the gear or the pump into a single unit, in order to reduce the costs, to increase the overall efficiency and the equipment reliability.This paper presents the first integrated regenerative frequency converter motor for industry applications, based on a matrix converter topology. The low volume, the sinusoidal input current, the bidirectional power flow, and the lack of the bulky and limited-lifetime electrolytic capacitors recommend this topology for this application. This paper shows how the matrix converter disadvantages-the lack of bidirectional power devices, the lower voltage transfer ratio, and the overvoltages caused by the input filter during power-up-that have delayed the industrial implementation have been overcome. In order to demonstrate the validity of the solution, a 4-kW matrix converter motor prototype is built using a standard frequency converter motor enclosure for testing the requirements for an industrial drive. The tests demonstrate the good performance of the drive.

Induction motors are traditionally controlled by standard pulsewidth modulation voltage-source inverters. An alternative is the matrix converter, which consists of nine bidirectional switches. This converter has benefits compared to a standard inverter, like sinusoidal input current and bidirectional power flow. The main disadvantage is the lack of a bidirectional switch, because such a switch may be done by two transistors and two diodes. An important topic is protection of the matrix converter, and this paper proposes two new protection circuits for matrix converters with a reduced number of components. The number of protection diodes is reduced by six. Design expressions of the protection circuit are calculated and validated by simulation. The standard protection circuit and the new circuits are demonstrated by simulation to have the same performance. Experimental results on an 8 kVA matrix converter show the design expressions are correct. It is concluded that it is possible to reduce the necessary power components in a matrix converter.

The voltage on the distribution line is in most cases distorted even at no load of the transformer. This is due to the "background" distortion on the medium voltage line caused by the large number of single-phase nonlinear loads such as PC's, TV, VCR etc. This paper proposes a method to mix single-phase and three-phase nonlinear loads and reduce the harmonic currents significantly. The dependence of the phase angle of the harmonic currents as a function of the short circuit impedance is investigated using SABER for the three-phase and the single-phase diode rectifier both with and without DC-link inductance. The phase angle of the 5/sup th/ and 7/sup th/ harmonic current of a three-phase diode rectifier is often in counter phase with the 5/sup th/ and 7/sup th/ harmonic current of a single-phase diode rectifier. This leads to the conclusion that adding a three-phase rectifier load often lowers the voltage and current distortion at the transformer. This is also validated by a number of measurements.

Induction motors are traditionally controlled by standard PWM-VS inverters. An alternative is the matrix converter which consists of nine bidirectional switches. This converter has benefits compared to a standard inverter like sinusoidal input current and bidirectional power flow. The main disadvantage is the lack of a bidirectional switch because such a switch may be done by two transistors and two diodes. An important topic is also protection of the matrix converter and this paper proposes two new components' reduced protection circuits for matrix converters. The number of protection diodes is reduced by 6. Design expressions of the protection circuit are calculated and validated by simulation. The standard protection circuit and the new circuits are demonstrated by simulation to have the same performances. Experimental results on an 8.5 kVA matrix converter show the design expressions are correct. It is concluded that it is possible to reduce the necessary power devices in a matrix converter

Acoustic noise emission from PWM-VSI inverter driven induction motors is a well-known problem. The generated noise depends mainly on two factors: the harmonic content of the supply voltage waveform; and the mechanical resonance frequencies of the induction motor. It is necessary to know the mechanical resonances to optimize the switching scheme of the inverter to reduce the noise emission. Measuring the resonance frequencies is normally a laborious process. This paper introduces a new method for estimating the mechanical resonances from acoustic noise measurements. Employing random modulation of the output voltage of the inverter, the voltage spectrum can be spread over a wide frequency range. Using the spectrum analysis of the measured acoustic noise, the resonances can easily be estimated as the dominant frequencies of the acoustic noise spectrum. The method was tested on a 2.2 kW induction motor at no load and full load. Some of the mechanical resonances of the motor at no load were calculated by the Holzer method. The calculations showed good agreement with the sound measurements. The influence of the fan cowl was investigated and it is concluded that this is an important factor in the acoustic noise emission. Finally, it was observed that new mechanical resonances appeared when the induction motor was loaded by a pump drive system, and they were estimated by the measurement technique.< >

This paper describes a new and machine-independent method to minimize the energy consumption of a speed controlled switched reluctance motor (SRM). The control strategy is to vary the duty cycle of the applied DC-voltage in order to obtain the desired speed quickly and when operating in steady-state vary the turn-on angle (/spl alphasub on/) of the phase-voltage to minimize the energy consumption. The power flow is measured in the DC-link and used to control the turn-on angle. Simulations carried out on a 6/4 pole SRM justify the algorithm and the physical implementation in a Siemens SAB 80C517A microcontroller is described. Measurements on two different load systems show it is possible to minimize the energy consumption on-line in a speed controlled switched reluctance motor without losing the dynamic performance. A comparison with an ordinary mode-shift controlled SRM shows more than 8% increase in overall efficiency for some operation points. The algorithm is fully applicable to other switched reluctance motors at other power levels or with other pole configurations.<>

A new input current modulation strategy for a matrix power converter is presented. The performance of the new strategy during input voltage unbalance is compared to two other strategies. The difference of the three modulations only concerns the detection of the reference angle for the input current vector. The input current quality is evaluated using four different criteria. It is concluded that depending upon the modulation strategy, the distortion of the input current may appear either as a series of positive sequence harmonics or a negative sequence fundamental component or a positive and a negative series of harmonic components with reduced amplitudes. Good accordance is found between the analytical solutions and numerical simulations.