Common-mode voltage (CMV) is responsible for overvoltage stress to the winding insulation and bearing damage of an ac motor. High dv/dt of CMV raises leakage currents, which can cause serious problems such as motor damage and electromagnetic noise to the equipment installed near the converter. This paper proposes two modulation strategies for indirect matrix converters that substantially eliminate CMV. The first method is developed by using the suitable couple of nonzero space vectors instead of zero space vectors in the inverter stage. The maximum voltage transfer ratio of this method is unaffected and remains 0.866. The second one, which is useful for low-voltage operation, is approached by choosing the medium and the lowest positive line-to-line input voltages in the rectifier stage to generate the dc-link voltage and by placing suitable zero space vectors in the inverter stage. In the second method, the maximum voltage transfer ratio is 0.5. Both methods can mitigate the peak value to 42%. In addition, while the first method provides the same performance to the conventional method, the second method can reduce significantly the harmonic components of line-to-line output voltage. Simulation and experimental results are shown to verify the effectiveness of the proposed methods.

A new space vector modulation (SVM) process for use in an indirect matrix converter (IMC) has been proposed in this paper to reduce the common-mode voltage (CMV) in a high voltage transfer ratio. The principles of selecting suitable active vectors and then properly arranging the switching sequence in the inverter stage of the IMC are described. The IMC with the new SVM method significantly reduces the peak-to-peak voltage of the CMV without any extra hardware. The new SVM method has some other advantages such as a lower total harmonic distortion of line-to-line output voltage and a reduced switching loss at the inverter stage through a minimum number of switching commutations as compared to the conventional reduced CMV-SVM method. The proposed modulation can be easily implemented in software without any additional hardware modifications. Both simulation and experimental results are shown to demonstrate that the new SVM method can generate good performance of the input/output waveforms and provide CMV reduction.

This paper proposes an indirect matrix converter (IMC) topology with dual three-phase outputs and its effective carrier-based pulse width modulation (PWM) method. The proposed IMC topology can independently supply ac power for two three-phase loads from a single three-phase ac power source. This converter consists of a rectifier stage used in traditional three-phase IMC and a five-leg inverter. Besides a proposed IMC topology, the carrier-based PWM method suitable for this converter is also introduced. The proposed PWM method is easily implemented by using only one symmetrical triangular carrier signal to generate the PWM signals for a rectifier and five-leg inverter. Proposed IMC topology features the advantages of conventional three-phase IMC, such as sinusoidal input/output current waveforms, controllable input power factor, and simple commutation at the rectifier stage. Analysis, simulation, and experimental results are provided to demonstrate the advantages of the proposed IMC topology with dual three-phase outputs and to validate the effectiveness of the applied modulation strategy.

This paper proposes an indirect matrix converter (IMC) topology to supply a five-phase load directly from three-phase ac power sources without bulky electrolytic capacitors and explains its operating principle. Using the emerging topology, which combines the five-leg inverter into the rectifier stage of the conventional IMC, the three-to-five-phase IMC topology reduces the number of power switches and results in a simpler commutation compared with the conventional three-to-five-phase direct matrix converter. In addition, a simple approach to realize the carrier-based pulsewidth modulation (CBPWM) method for a three-to-five-phase IMC is presented, and the proposed CBPWM method is analyzed based on the space-vector approach. As a result, the IMC with the proposed CBPWM method can be more easily implemented compared with IMCs with the space-vector PWM method. A three-to-five-phase IMC control platform is realized by coordinating a TMS320F28335 DSP (Texas Instruments) with an EPM7128SLC84-15 field-programmable gate array (Altera). The simulation and experimental results are provided to verify the effectiveness of the CBPWM strategy.

Continuous glucose monitoring systems that do not require blood to be drawn are crucial for enhancing the comfort and quality of life of diabetic patients. This paper introduces a novel, non-invasive approach using a textile-based wearable microwave sensor that utilizes real-time sweat for glucose monitoring. Operating at a resonance frequency of 4.87 GHz, the sensor enables high sensitivity to small variations in the dielectric properties of the skin tissues. The sensor’s performance was validated through extensive glucose solution-based tests and trials involving volunteers of various ages, and the results were compared with those from a commercial invasive glucose monitoring device. The wearable sensor demonstrated a measurement error of just 3.1%. Moreover, the sensitivity of the sensor was 0.092 (1/(mg/dL)) with a high Q factor of 240, highlighting its effectiveness in detecting glucose with minimal interference from other physiological variables. In addition to its high-performance metrics, the integration of the sensor into a wearable textile enables user-friendly and unobtrusive glucose monitoring. The proposed wearable sensor can continuously track patient glucose levels, thus enabling timely medical intervention and improving treatment outcomes. Moreover, this study paves the way for customizable and personalized biosensors, potentially transforming patient care.

This paper proposes an adaptive carrier-based pulse width modulation (PWM) for four-switch three-phase inverter. The balanced output currents are guaranteed by this proposed method instead of voltage oscillations across two DC-link capacitors. The linear over-modulation can be easily obtained with this new approach. Simulation and experimental results are shown to validate the feasibility of the proposed method.