To design the control system of PMSM, the state equation by the d-q coordinate system which set d-axis as the direction of the magnet of PMSM is used. Because, by the current of d-axis and q-axis is controlled appropriately, various control systems can be constituted and this coordinate system is convenient. Moreover, since inductance does not change with rotation angles, there is also an advantage that a formula becomes simple. The state equation by other coordinate systems is hardly discussed. In this paper, while summarizing the difference among these coordinate systems, the state equation of the three phase coordinate system in PMSM is proposed. And, the simulation results of the above vector control system using the three phase coordinate and the γ - δ coordinate will be presented.
This paper proposes a novel reactive power control algorithm without load-side active power calculation for the previously proposed smart charger of Electric Vehicles (EVs) on single-phase three-wire distribution feeders. The basic principle of the proposed reactive power control algorithm is discussed in detail and then confirmed by digital computer simulation using PSIM software. A prototype experimental model is constructed and tested. Experimental results demonstrate that balanced source currents with a power factor of 0.9, which is acceptable value in Japanese regulation, are obtained on the secondary side of the pole-mounted distribution transformer during the battery charging operation.
In this paper, an auto tuning method is reported for interior permanent magnetic synchronous motor drives. The method is proposed for obtaining the position angles, the accuracy of which affect the operation of the switching devices of the inverter that drives the motor. First, the method for estimating the motor parameters is proposed. Secondly, the accuracy and the robustness of the method are studied. The experimental results show that the estimated motor parameters are obtained precisely.
This paper describes whether a method to connect an external SiC SBD with SiC MOSFET is truly effective or not. Wide gap characteristic makes SiC devices have excellent characteristics; high breakdown voltage, low on-resistance, high heat-conductivity etc. In contrast, the characteristic leads to large forward voltage drop in case of diode application. It means that conduction loss becomes large. SBD has lower conduction loss than PN diode. That is why SiC SBDs are connected with SiC MOSFETs especially in inverter circuits in order to suppress recovery loss. However, the technique is effective for silicon devices but it is not clarified for SiC devices. We confirmed that the recovery suppression method has effective range.
The DC-DC converter using integrated magnetic components that may achieve high power density has gained attention in environmentally-friendly cars such as electric vehicles (EV) and plug-in hybrid electric vehicle (PHEV). This paper focused on this circuit types using coupled indictors and close-coupled inductors that are the integrated magnetic components. In order to realize further high power density, calculation methods for the allowable power of the coupled indictors and close-coupled inductors are presented. The calculation method is based on detailed analysis of the characteristics of ripple current and magnetic flux. From the allowable power viewpoint, the volumes of the inductors are compared to a conventional interleaved boost chopper circuit in the same conditions. As a result, CCM operation is effective for downsizing of the magnetic components in case of the interleaved boost chopper circuit using coupled inductors. On the other hand, the interleaved boost converter using close-coupled inductors is effective for downsizing of the magnetic components with CRM operation.
In order to downsize the storage unit of Hybrid Electric Vehicles, a novel high step-up interleaved boost converter has been proposed. This converter is suitable for automotive applications due to its expected high voltage gain. However, the actual voltage conversion ratio may be significantly reduced by the parasitic resistance effect of the circuit because the input current tends to be large at a high step-up operation and therefore the voltage drop at the parasitic resistance may not be ignorable. This paper analyzes the effect of the parasitic resistance on the voltage gain and evaluates the result experimentally. Consequently, it is found that parasitic resistance affects the voltage gain largely as the ratio of the number of turns in the integrated magnetic component of the proposed converter increases and particularly when the duty cycle is larger than 0.5.
Wind energy is a clean and renewable energy source. The wind generator using the PMSG with grid interface inverter can control its active and reactive power output independently. In addition, it has high performances for fault ride through (FRT) capability, and voltage regulations. Usually, the generator in the grid system has a synchronizing power. On the other hand, the grid interfaced inverter and converter controlled PMSG does not have it. This paper presents a numerical simulation analysis about controlling of the discrete-time model following controlled PWM inverter in grid connected wind generator in order for the generator to develop synchronizing power.
Nowadays, cooking equipment using induction heating is increasing for safety, high efficiency, and low cost. In this paper, a thermal control of large pot for ODEN warming using induction heating is studied. Many of the current products are heated by one induction coil in whole of a pot. However a fine thermal control of segmental area in pot might be difficult because of warming its whole. In this study, we proposed a thermal control of pot water in six segmental areas with six induction coils. Thus an appropriate thermal control of pot for ODEN warming was realized.
This paper describes the boost-type matrix converter for three-phase four wire system. This system is intended for use in a stand-alone power source with constant voltage and frequency. Steady state characteristics of boost-type matrix converter is changed by filter value. In this paper, we show relationship between steady state characteristics of boost-type matrix converter and filter value.
Characteristics and controllability analysis of the motor is tested by using the M-G set which is combining the motor and generator. The test of motor of tens of kW class that is used for the electric vehicle need the suitable generator or servo system. Thus, it is impossible to avoid the high cost and the increasing size of the M-G set. In this laboratory, we have conducted productions and experiments of the motor loading test equipment for the purpose of low speed, high torque test using auto parts. The equipment makes it possible to constant torque load test by feedback the hydraulic disc brake. It can more compact and inexpensive than with the servo system and the generator. In this paper, the loading test equipment was examined in consideration of not just the motor, but also chassis dynamo. As the results, it was confirmed that the constant speed test is possible in addition to the constant torque test. Therefore, we describe the diversity and ability test, report the experimental results include of the production process.
The single-phase PFC converters are used for a lot of applications, such as air conditioners, heat pumps, etc. Its application range is expected to expand such as battery charger for EVs, PHEVs and home strages. However, the single-phase PFC converter has output voltage ripple caused by supply power ripple. It is a one of demerit of single-phase PFC converters. Thus, the authors have proposed a ripple reducing control method which can apply to buck, buck-boost and series-type buck/boost converters. However, the ripple reducing control method has not applied to the parallel-type buck/boost converter yet. Therefore the authors have applied this method to the parallel-type buck/boost converter. In this paper, the switching losses in three type converters, the Parallel type buck/boost, the buck and the series-type buck/boost, are evaluated with a simple analytical analysis and computer simulation and compared.
MPPT by the perturb and observe method (P&O) is used when the characteristic of these cells have a single maximum point. However, when PV cells are under partial shade, MPPT by particle swarm optimization (PSO) is used, which can be applied to PV characteristics with multiple maximum points. Therefore, in this study, we propose MPPT by PSO of PV cells for managing solar radiation intensity, which changes with time. Using simulation, we examine the effectiveness of this proposed method. The results show that in environmental conditions, where solar radiation intensity changes with time, it is possible to produce power efficiently through MPPT by PSO.
A practical evaluation of a new bridgeless boost half-bridge zero voltage switching (ZVS) pulse-widthmodulation(PWM)-controlled utility ac (UFAC) – high frequency ac (HFAC) converter for induction heating (IH) applications is presented in this paper. The non-smoothed dc link capacitors in the frequency converter have a great relevance with power factor correction (PFC) of the source side and voltage boost ratio in the IH load side as well as ZVS range of the active switches. Theoretical and experimental analyses on the dc-link stage are described in details and the effectiveness of the frequency converter is discussed.
Recently, applications of small induction heater are evolving into various fields for high heating efficiency, saving energy and environmental improvement. The purpose of this study is to improve heating efficiency and to get a wide uniform heating region in iron hot plate for cooking, by devising a shape and a position of plural induction coils wound on ferrite cores of induction heater. Proposed induction heater for iron hot plate was realized a high temperature rise more than 200 degree on iron hot plate, and was proved practically and economically.
This paper proposes a novel co-operational control method of LED driver, consisting of voltage and current sourced flyback converters. In the proposed method, both the flyback converters are controlled by the LED reference current to obtain wide range variable light control from 10 % to 100 %. Digital computer simulation is implemented to confirm the validity of the proposed method and demonstrate that the minimum on time of the MOSFET is longer than 1 μs even under the operation of 10 % of the LED rated current.
A three-phase voltage-fed converter operated by a two-phase PWM scheme offers relatively high ac voltage, low switching times, and low switching losses in comparison to that operated by a three-phase PWM scheme. However, the harmonics involved in the ac-side voltages and currents produced in the two-phase PWM scheme are distributed over a wide frequency range, which can be a significant drawback depending on its applications. Therefore the authors examine the problem using wavelet transform.
The phase-shift controlled series resonant high frequency inverter has attracted growing interest as an induction heating and plasma production for basic research and industrial application. In general, the phase-shift controlled series resonant inverter by using the resonant current tracking or adaptive control scheme have excellent characteristics for power regulation and soft-switching operation. However, the inverter resonant frequency fluctuation by influence of switching disturbance in a resonant state is a problem of great proportions from a practical point of view. This paper deals with a newly developed phase-shift controlled ZCS (Zero Current Switching) inverter, which consists of the duplexed series resonant circuit topology that is suitable for high-frequency operation in Megahertz (MHz) switching range. In accordance with the discussion of frequency fluctuation in phase-shift controlled resonant inverter, we explained the operation of duplexed resonant circuit topology to reduce the frequency fluctuation. Furthermore, the design method of this proposed circuit is also described. Feature of this proposed circuit topology is described by using the computer simulation and experimental results.