The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
DC-DC converters with wide-bandgap semiconductors facilitate the operation at higher switching frequencies. Thus, inductors can be reduced in size which is beneficial in regard to power density and weight of the converter. As a drawback, high frequency inductors suffer from considerably large winding losses caused by skin and proximity effects. Litz wire is a possible solution but it results in a...
When using model predictive torque control (MPTC) for controlling permanent magnet synchronous motors (PMSM), often more than one objective is considered. A common approach is to combine different objectives with weighting factors into one cost function. Due to conflicts between the objectives, a deviation from the commanded reference for each objective results. For a PMSM, the tracking of a torque...
Temperature monitoring and derating of electric vehicle (EV) drive trains is of key importance to increase power and torque utilization while preventing thermal damages. Derating by static regulations and standard closed-loop controllers (e.g. PI-type) is not optimal since conservative safety margins have to be chosen to prevent temperature constraint violations. In contrast, model predictive control...
This contribution deals with the design of a water-cooled on-board charger for electric vehicles. The charger consists of two power stages: a bridgeless power factor correction boost rectifier and an isolating resonant converter. Though wide-bandgap semiconductors with excellent reverse recovery behavior exist, the comparably high cost still advices the use of traditional silicon semiconductors. However,...
Measuring the dissipated power of fast switching semiconductors or magnetic components with low power factor makes high demands on the accuracy of the measurement equipment. Calorimetric measurement methods represent a possible solution for this problem but are considered as being too time demanding. A compensating temperature control facilitates to reduce the time demand for a single measurement...
Like all industrially manufactured products, interior permanent magnet synchronous machines are subject to deviations due to production tolerances. In particular, deviations in the permanent magnet flux and the air gap thickness cause considerably high torque errors and influence efficiency. Especially for traction drives in hybrid or electric vehicles this is not acceptable. In this paper, the impact...
Electrical fundamental frequencies of high-speed drives typically range between 1 and 2 kHz. In order to ensure low-loss operation of the drive, the switching frequency has to be kept as low as possible, resulting in pulse numbers smaller than 15. To avoid subharmonics of the modulated voltages, it is highly recommended to synchronize the PWM with the fundamental voltage. In addition to that, the...
Permanent magnet synchronous motors (PMSM) are widely used in many industry fields. Maximizing their degree of thermal utilization reduces the motor's weight, volume and cost. For this reason, real-time temperature information is required. However, this cannot be solely obtained from measurement sensors due to costs and constructional drawbacks. Thus, several direct temperature modeling techniques,...
The main goal of an industrial microgrid during grid-connected operation is maximal cost saving for the microgrid owner. Many industrial companies do not only pay for the amount of electrical energy, but also for the maximum electrical power, which they have drawn from the distribution grid within the billing period. Under these conditions two basic options of cost saving exists utilizing the local...
Monitoring critical temperatures in permanent magnet synchronous motors (PMSMs) is crucial to ensure safe operation and maximum device utilization as well. In this work, the application of recurrent neural networks featuring memory blocks (LSTMs/GRUs) are investigated upon their suitability to accurate temperature time series prediction inside PMSMs or similar motor types, which is the first time...
Estimating the magnet temperature of permanent-magnet synchronous motors on a model basis is the key for both the highest device utilization and preventing irreversible demagnetization. Using an exact flux linkage observer in the fundamental wave domain is an elegant way to indirectly retrieve the magnet temperature without requiring any additional sensors or signal injection. This contribution addresses...
In modern resistance spot welding applications dynamic current control is essential, but at the same time, the current drawn from the mains should be as low and consistent as possible, making an energy storage mandatory. As the type of storage is extremely important for the total system performance, it must be selected carefully focusing primarily on size, efficiency, dynamics and lifetime. At first...
Due to their low switching and conduction losses, Gallium Nitride (GaN) transistors are inherent candidates in hard-switched power converter topologies. The performance of five different GaN transistors in a Totem-Pole Power Factor Controlled (PFC) rectifier is compared by circuit simulation using transistor models parameterized by measurements with the double-pulse test. This is supplemented by calorimetric...
The differential mode and common mode inductance of two windings located on a magnetic material of toroidal shape are investigated. The field problem is solved by the method of separation and the use of Fourier approximation for fitting the solutions to the boundary conditions. The solution is discussed by means of numerical evaluation for different parameters like magnetic material, width of the...
In this contribution, a uni-directional converter is proposed which supplies the EV's safety-low voltage grid of 14 V DC directly from the drive battery voltage level of Vbatt = 250…370 V. The converter consists of two power stages which are a hard-switching SiC boost converter and a softswitching resonant converter. Special attention is paid to the accurate loss modelling of the converter, where...
Production tolerances in electric drive systems with interior permanent magnet synchronus machines (IPMSM) lead to unavoidable deviations in torque and power. This paper presents an investigation of the underlying effects utilizing simulations and measurements as well as methods for detection. In particular, deviations of the sensors and of the machine are studied. For the machine, the permanent magnet...
A 27-to-3-phase thyristor matrix converter using a model predictive control (MPC) is considered. Compared to the standard method the MPC considers the coupled overall system. Due to this, all 273 = 19683 switching states are to be considered. The result of the MPC strategy is, compared to classical control, a drastic reduction of the commutation frequency and respectively the converter losses. However,...
Some domestic appliances can shift their load by a least-cost optimization in a variable-tariff environment. As decisions of all appliances are highly correlated, high load peak arise. With the presented coordination in an optimization hierarchy, load peak is significantly lowered by load distribution in time.
Constant velocity high-speed drives which are typically used in pumps, compressors or fans are supposed to be operated with high efficiency whereas dynamic behavior of the controlled drive system is of secondary priority. To ensure low-loss operation, the switching frequency has to be chosen as low as acceptable to guarantee stable operation without thermal overload of the PM-synchronous machine due...
This paper presents a method how to simply determine the losses of an energy storage depending on state of charge and actual power. The proposed method only requires the measurement of electrical quantities to determine the characteristic map and therefore can be implemented without need to modify of an existing electrical storage system. Exemplary results are shown of lithium-ion and lead-acid battery...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.