Recently, the design procedure of a power electronics circuit structure is discussed for high power density circuits or thin structure converters. Control circuits of the converter circuit may connect close to the power circuit. When the pulse current flows into the power circuit, it radiates the magnetic field and may generate near field noise voltage to the control circuit. Therefore, it is important for the power electronics circuits to evaluate the near field noise voltage by experiment. This paper shows the measurement results of the near field noise voltage and the electromagnetic force voltage of a small area loop antenna from the 15A, 100kHz buck chopper circuit. Moreover, this paper discusses that the noise voltage may affect the control circuits in the high power density circuits.
A high response field weakening control has been developed for the torque control drives of permanent magnet synchronous motors (PMSMs). Compared to the conventional method, the torque response and the output torque of PMSMs in the voltage saturation region becomes higher when using the proposed method. In this paper, the field weakening control, which is generated for a voltage phase operation command, is described. The principle of operating the proposed method and the design approach of the feedback gains are clarified. The validity of the proposed method is checked by the frequency domain analysis and the time domain simulations. The torque step response between conventional and proposed methods was determined by simulation and experiment.
This paper describes a stabilization control method of a two-wheels driven mobile manipulator by ground reaction torque feedback. As the population ages and birthrates decline, many people are expecting robots to assist them in their daily lives, such as in homes, offices, and hospitals. However, there are some issues in robot development. Human environment is complex and dynamic, such as the presence of steps, slopes, narrow paths, and unknown obstacles. Therefore, the future robots will be required to have high mobility. The two-wheels driven mobile manipulator has excellent mobility and can realize rapid and smooth motion such as turning instantly. However, since it does not have any casters, its attitude is unstable and some attitude control is required. In addition, even if attitude control is implemented, there is a risk of falling down on rough terrains. Hence, in this paper, a stabilization control considering rough terrains is proposed. The validity of the proposed method is confirmed by simulation and experimental results.
This paper describes a method for adapting to rough terrain for biped robots. The robots obtain information of reaction force from the ground by sensors located at each corner of rectangular soles. From the sensor information, environmental modes are extracted. The environmental modes consist of four modes: heaving, rolling, pitching, and twisting, which represent contact states between the ground and the soles. On the basis of the twisting mode, the robot detects the unevenness of the ground, makes contact with the uneven ground stably with three corners of the sole, and modifies the trajectory to continue stable walking. The validity of the proposed method is confirmed by experimental results.
This paper proposes a new robust position sensorless control of interior permanent magnet synchronous motors (IPMSMs) for inductance variation using an unknown input observer. In position sensorless control of IPMSMs, accurate motor parameters are required for position estimation. However, inductance variation due to magnetic saturation is known to heavily deteriorate the performance of sensorless control. The authors have already proposed the unknown input observer for position sensorless control of IPMSMs. This paper shows that the proposed observer possesses high robustness for magnetic saturation by analyses and experiments.
This paper presents a transformerless hybrid active filter that is integrated into medium-voltage adjustable-speed motor drives for fans, pumps, and compressors without regenerative braking. The authors have designed and constructed a three-phase experimental system rated at 400V and 15kW, which is a downscaled model from a feasible 6.6-kV 1-MW motor drive system. This system consists of the hybrid filter connecting a passive filter tuned to the 7th harmonic filter in series with an active filter that is based on a three-level diode-clamped PWM converter, as well as an adjustable-speed motor drive in which a diode rectifier is used as the front end. The hybrid filter is installed on the ac side of the diode rectifier with no line-frequency transformer. The downscaled system has been exclusively tested so as to confirm the overall compensating performance of the hybrid filter and the filtering performance of a switching-ripple filter for mitigating switching-ripple voltages produced by the active filter. Experimental results verify that the hybrid filter achieves harmonic compensation of the source current in all the operating regions from no-load to the rated-load conditions, and that the switching-ripple filter reduces the switching-ripple voltages as expected.
This paper proposes a new control method for reducing the capacity of an active power quality compensator with a three-leg inverter used in electrified railways. In the proposed control method, the fundamental reactive and unbalanced-active components of the load currents are detected. The non-active and unbalanced-active components are compensated on the source side with the fundamental reactive power control. This reactive power control reduces the capacity of the three-leg inverter, which performs the active power quality compensator. The basic principle of the proposed control method is discussed in detail, and then confirmed by digital computer simulation using the PSIM software. A reduced-scale experimental model is constructed and tested. Experimental results demonstrate that the balanced sinusoidal source currents with the power factor of 0.9 are obtained, reducing the capacity of the three-leg inverter by 13% as compared to the already proposed control method.
This paper presents a motor surge voltage suppression system that utilizes a newly developed surge suppression cable. A feature of this system is that the surge suppression cable is connected in parallel with the motor terminal; the surge suppression cable is independent from the main cable, which is connected between the inverter and the motor. The advantage of this method is that the current capacity of the surge suppression cable does not get influenced by the power capacity of the motor drive system. A mechanism of the motor surge suppression on the present system is demonstrated, and also the numerical equation for motor surge voltage is derived by taking the surge voltage transmission phenomenon on the cables into account. The calculated results are verified through the 750W ac drive experimental setup.
The speed servo system of an AC motor should always have a rapid and smooth response without current ripple. For this purpose, this paper proposes a new mixed modulation method of the PWM inverter by considering acceleration torque and voltage saturation. The rapid and robust speed servo system often has the high gain speed controller and the high gain current controller. In this case, this speed servo system often has the voltage saturation in the transient state. This paper discusses the amplitude and THD of output voltage on the condition of voltage saturation for each voltage modulation method of three phase inverter such as the carrier comparison inverter using the two phase modulation (2ph. M) and the space voltage vector modulation (SVM) inverter. The carrier comparison inverter using the 2ph. M has the large voltage with large harmonic current. The SVM inverter has the smooth voltage response with small harmonic current. The proposed method switches over the SVM and the 2ph. M methods properly by considering acceleration torque and voltage saturation. The experimental results confirm the effectiveness of the proposed mixed modulation method of the PWM inverter.
In this paper, we propose an image-based visual tracking control method of a hand-eye robot for a moving target object. The hand-eye robot is constructed from a three-DoF planar manipulator and a single CCD camera that is mounted on the end-effector. This robot is a typical example of an eye-in-hand system with a single camera. The control objective is to keep the target object around the center of the image plane. In many conventional visual servo methods, it is assumed that the target object is static. Consequently, the visual tracking delay arises in the case of a moving target object. Although we have already proposed a non-delayed visual tracking control method for a moving target object, this method is developed only for a stereo vision robot with two CCD cameras. Therefore, this paper provides such a visual tracking control method for the hand-eye robot. The validity of our control method is evaluated by an experiment.
This paper proposes a new design method of nanoscale servo control for a Galvano scanner by using FFSC (frequency-shaped final-state control) method. In the Galvano scanner, it is important to reduce the residual vibration after positioning; further, this scanner must be robust to the variation of the resonance modes of the plant. In this paper, a feedforward input is designed by using FFSC by considering not only nominal performance but also robust performance. Simulations and experimental results are shown to evaluate the effectiveness of the proposed method.
This paper proposes a method for correcting voltage errors using a disturbance observer for an induction motor controlled by speed sensor-less vector controller. The disturbance observer uses a fast-response observer, which responses ten times as fast as current controller in sensor-less vector controller. The voltage error is thus efficiently corrected using the proposed method. The proposed method is validated on the basis of the experimental results. This method can be used to decrease current distortion to less than 1/3 that observed without the correction method.
Single-phase boost rectifier with parallel-input/series-output structure is studied by the simulation. In this rectifier, the output capacitor is charged by the series connection of intermediate capacitors arranged in parallel. To improve the input current distortion just after a zero-crossing, moreover, the snubber capacitor voltage is superimposed on the supply by using the snubber energy recovery switch cell. The simulated results confirm that the low-order input current harmonics can be reduced under the operating condition with the output voltage almost twice the peak supply voltage.