Optimal PWM method for electric and electro-hydraulic power steering applications

This research demonstrates modular battery storage systems' voltage balancing using cascaded H‐bridge (CHB) converters. The main principle is to maintain AC‐side high‐quality power absorption or injection, while on the DC‐side independent battery units' voltages get balanced. The CHB converter operates in inversion or rectification modes to discharge the storage system to an AC load/grid, or to charge it from an AC source, respectively. To achieve this goal, several challenges as high‐differential mode normaldv/normaldt, and dealing with semiconductors voltage drop also arise which should get tackled through feasible controller design. Model predictive control (MPC), as a flexible technique capable of multi‐parameter controlling, is used to achieve the beforementioned system objectives in a simple, efficient, and scalable manner. The proposed MPC‐based algorithm is an AC current controller, which handles DC‐side voltage equalisation and introduces adjacent CHB voltage levels to reduce normaldv/normaldt and performs switches voltage loss modelling all in a single control block. An additional linear controller based on multi‐carrier pulse width modulation is also implemented for comparison with the MPC‐based design. Experimental prototyping and simulation results validate the feasibility of this approach.

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“…3. As current flows through each FET, the switch acts as a resistor with

R_{DSon}

resistance extracted from its datasheet [30] and causes a drain to the source voltage drop of

v_{DS} = i_{D S} . R_{DSon}

. Body diodes also cause a voltage drop equal to their forward voltage

V_{Df}

while conducting current.…”

Section: System Model and Configurationmentioning

confidence: 99%

Battery voltage equalisation using single‐phase cascaded H‐bridge converters

Pirooz

Firouz

Berecibar

et al. 2020

IET power electron.

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“…As it can be seen in Figure 13, ripple. Both of these parameters, as discussed in (Bianchi et al, 2005, Graovac et al, 2008, are key to satisfactory system performance within a vehicle application.…”

Section: Iii23 Validation Of the Epasmentioning

confidence: 99%

Feasibility of High-Frequency Alternating Current Power for Motor Auxiliary Loads in Vehicles

Antaloae

Marco

Vaughan

2011

IEEE Trans. Veh. Technol.

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This paper presents a feasibility study into the application of a 100V, 50kHz high frequency alternating current (HFAC) network for powering automotive electrical auxiliaries. The study is focused on motoractuated loads, and is divided into two sections. First, the investigation indicates the benefits of replacing low-torque DC motors with lighter and more efficient 400Hz AC machines for applications such as electric fans, fuel pumps or blower motors. A comparative examination of commercially available machines indicates space and weight reduction of more than 60%, and efficiency savings between 25% and 100% are possible. Second, the inquiry evaluates the viability of replacing existing DC/AC inverters with HFAC/AC converters for high-torque AC machines as employed for example in the electric power assisted steering (EPAS) or the heating, ventilation and air conditioning (HVAC) systems. Based on experimental and simulation results for a column-assist EPAS application, employing a three-phase permanent magnet synchronous motor, this study shows that a HFAC drive is expected to reduce the voltage harmonic content below 50kHz by at least 10% compared to the DC/AC inverter. However, the disadvantages of the former drive make it less attractive than the existing DC/AC circuit. Specifically, the EPAS motor torque ripple is expected to be approximately 2% higher compared to the DC counterpart drive. Further drawbacks of the HFAC/AC drive include high MOSFET conduction losses, higher voltage harmonics above 50kHz and complex control requirements of the inverter. Conclusively, significant HFAC advantages for motor loads can be attributed only to machines with a nominal torque capability that is limited to 2Nm. However, given the number of such devices within a typical vehicle, this translates into a possible vehicle mass saving of 30kg and a potential reduction in fuel consumption by 0.8L/100km.

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“…Therefore, electro-hydraulic power steering systems (EHPSSs) are wildly used in multi-axle vehicles, combining hydraulic power steering and electronic control systems. 4–7…”

Section: Introductionmentioning

confidence: 99%

“…Therefore, electro-hydraulic power steering systems (EHPSSs) are wildly used in multi-axle vehicles, combining hydraulic power steering and electronic control systems. [4][5][6][7] It is difficult to establish an accurate EHPSS model because of its complex structure, including steering mechanisms, valve controlled dual hydraulic actuators, and heavy duty tires. The coupling relationships among these three parts further increase the difficulty of accurate modeling.…”

Section: Introductionmentioning

confidence: 99%

Modeling, simulation, and experimental validation of electro-hydraulic power steering system in multi-axle vehicles

Zhang

Chen

et al. 2017

Proceedings of the Institution of Mechanical Engineers, Part D:

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An accurate electro-hydraulic power steering system (EHPSS) model is essential to analyze dynamic steering performance and advanced nonlinear control. The main obstacle to establish an accurate model is the complex structure, including steering mechanism, valve controlled dual hydraulic-actuator, and heavy duty tires. This paper constructs a suitable model incorporating these parts, based on a Lagrange equation describing the steering trapezoid mechanism and dual cylinder hydraulic dynamics, regarding steering resisting moment as an external load. A simplified tire model is used to represent the tire basic steering load characteristics. Due to the complexity of the kinematic relationship in the model, several expressions are fitted using back propagation neural networks to significantly reduce calculation difficulty. Experimental measurements and simulation using Matlab/Simulink and experiment are realized for the case of in situ steering, and the results validate the proposed model accuracy. Thus, the proposed model is suitable to analyze the system and design advanced controllers.

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Optimal PWM method for electric and electro-hydraulic power steering applications

Cited by 9 publications

References 5 publications

Battery voltage equalisation using single‐phase cascaded H‐bridge converters

Battery voltage equalisation using single‐phase cascaded H‐bridge converters

Feasibility of High-Frequency Alternating Current Power for Motor Auxiliary Loads in Vehicles

Modeling, simulation, and experimental validation of electro-hydraulic power steering system in multi-axle vehicles

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