Practical issues in the design of active rectifiers for AC drives with reduced DC-link capacitance

Tallam, R.M.; Naik, R.; Gasperi, Michael; Nondahl, Thomas A.; Lu, Hai Hui; Yin, Qiang

doi:10.1109/ias.2003.1257760

Cited by 20 publications

(10 citation statements)

References 10 publications

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“…6, wherei L is the observed inverter load current on the DC link. (13) It is a second order low pass transfer function with unity gain at low frequency under the ideal capacitor condition (C = C). The observer gains, K and K., are easily solved to p achieve the desired command tracking bandwidth and damping ratio in the form of c.e.…”

Section: DC Link Current Observer Performance Analysismentioning

confidence: 99%

“…Numerous methods to control the active front end have been proposed to achieve a broad range of goals such as maximizing DC link control bandwidth [3][4][5][6], minimizing the DC link capacitance [7][8][9], or maximizing the converter robustness to utility disturbances [10][11]. Dominant in these control schemes is the use of DC link current or load power feedforward terms [12][13][14][15]. The DC link current is often derived via a band limited observer that can significantly impact the control performance if not fully understood.…”

Section: Introductionmentioning

confidence: 99%

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Design Oriented Analysis of DC Link Current Observer of a Three-phase Double Conversion Uninterruptable Power System or Adjustable Speed Drive

Lee

Wallace

Bhadkamkar

2007

APEC 07 - Twenty-Second Annual IEEE Applied Power Electronics Conference and Exposition

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In this paper, a high performance dc link current observer is described and analyzed for a double conversion uninterruptible power system (UPS) or an adjustable speed drive (ASD). This second order observer identifies the dc link current drawn by the output inverter section. The observed load current is then used as a feedforward signal to input converter current regulator section for improving its dynamic response. The new contributions include the analysis on the system observability, observer sensitivity to system parameters, its command tracking performance, dc link voltage and load current dynamic disturbance rejection capabilities, all of which are not found in present literatures. In conjunction with the dc link current observer analysis, the current regulator bandwidth performance of the input ac-dc converter stage is characterized for both single and double update pulse width modulation (PWM) methods. The high performance resides in its fast dynamic response to the load power requirements resulting in dc link voltage variation, without using dc link current sensor or any communication channels. The solution is not only ideal for a stand alone UPS or ASD for low cost and high dynamic performance, but is particularly attractive for ac-dc converters suitable for common dc link systems. The analytical results are verified through the state-of-the-art simulation. All control algorithms are implemented in a Texas Instruments (TI) digital signal processor (DSP) and Xilinx field programmable gate array (FPGA) environment. The experimental setup of a 3-phase, 480V, 60Hz, 15 hp (11.19 kW) active front end (AFE) rectifier system is used for analytical and simulation verifications.

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Section: DC Link Current Observer Performance Analysismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Design Oriented Analysis of DC Link Current Observer of a Three-phase Double Conversion Uninterruptable Power System or Adjustable Speed Drive

Lee

Wallace

Bhadkamkar

2007

APEC 07 - Twenty-Second Annual IEEE Applied Power Electronics Conference and Exposition

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“…However, they cannot solved this question which achieve fast dc bus voltage regulation with the objective of the power feed forward technique. The output power feed forward technique is not included as a part of the solution of the control problem raised in this research due to the following two considerations [5,6] . One is that independent control of the rectifier and inverter leads to lower cost and higher reliability and the other, which is more critical, is that the objective of the power feed forward technique is to achieve fast dc bus voltage regulation, which is inherently against the control goal in this research.…”

Section: System Analysismentioning

confidence: 99%

“…However, their control goal was not improving the input power quality but to minimize the dc link voltage ripple. Some other researches focused on improving instantaneous power balance between the input and output of a rectifier-inverter system and minimizing the dc coupling capacitance to reduce the cost [5,6] . They all considered the less the dc coupling capacitance the better instantaneous power balance the system could yield.…”

Section: Introductionmentioning

confidence: 99%

A novel PWM rectifier control technique for on-line UPS under unbalanced load based on DSP

Zhang

Yu-gang

Zhang³

2008

2008 27th Chinese Control Conference

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Three-phase ac-dc-ac voltage stiff systems consisting of a front-end rectifier, a dc link with a capacitor, and an inverter are widely used in on-line UPS, motor drive, and distributed generation systems. A PWM controlled front-end rectifier is desirable in three-phase ac-dc-ac systems. With the conventional PWM rectifier control technique, the input current tends to be unbalanced under unbalanced inverter load, which contaminates input power source and is therefore undesirable. In this paper, a novel PWM rectifier control technique for on-line UPS under unbalanced load is presented, the cause of the unbalancing is disclosed by evaluating the spectra of the switching functions of the full bridge three-phase inverter analytically using Bessel function under standard space vector PWM switching scheme, which relates the dc link current and voltage ripples to the inverter load balancing. First of all, three-phase on-line UPS structure based on DSP is given. secondly, the principles of this system is analyzed, which shows that the dc link voltage contains significant second order harmonic component which affects the voltage loop of the rectifier controller, especially when the control gain is high. A notch filter based voltage control loop is proposed to eliminate the second harmonic component in the dc-link voltage feedback signal and achieve balanced three-phase input currents. Finally, the effectiveness of the proposed control technique in decoupling the rectifier and the inverter under unbalanced load are presented to demonstrate through both simulation and experimental text results.

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“…1(b) it can be seen that the VSMC has a DC link between the input and output stages, although it does not use any energy storage capacitors. To better compare the physical size of the BBC and VSMC, the BBC is considered using the minimum possible DC-link capacitance for normal operation (7) . In Section 2 the basic operation of the VSMC and the BBC, including modulation strategies, and typical voltage and current waveforms are presented.…”

Section: Introductionmentioning

confidence: 99%

Comparison of Performance and Realization Effort of a Very Sparse Matrix Converter to a Voltage DC Link PWM Inverter with Active Front End

et al. 2006

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The matrix converter directly produces a variable amplitude and frequency three-phase output from a three-phase input source without any energy storage in a DC-link, draws unity power factor mains current and has bi-directional power flow. To achieve an equivalent functionality using more traditional converter topologies requires two voltage DC-link PWM converters connected in a back-to-back configuration (BBC). In the literature it is often claimed that the matrix converter is more compact and efficient than an equivalent BBC system. This paper attempts to prove this claim by undertaking a comparison of a very sparse matrix converter (VSMC) and BBC in terms of compactness, efficiency and torque rating for a typical AC motor drive application. The converters have been designed for a thermally limited output rating of 6.8 kW.Both the VSMC and BBCs have been thermally designed so that the maximum junction of any one semiconductor module is 150˚C. The power dissipation of each switch module is calculated using analytical equations and is then used as the input to a 3-D thermal simulation. The length of the heatsink is adjusted to ensure that the maximum junction temperature is not exceeded. Fig. 1 presents the efficiency, assuming an output phase angle of zero degrees, for the converters over varying modulation indexes and output current levels. It can be seen that the VSMC has an overall higher efficiency than the BBC, with the maximum efficiency at full load of the VSMC being 94.5% compared to 92% for the BBC. Fig. 2 shows the physical layout arrangement of the VSMC and the BBC, where the layout includes all power devices, gate drives, passive components, EMI filter, fan, control and power supply. The overall volume of the VSMC is 2.3 liters compared to a volume of 4.6 liters for the BBC.The complexity of the two converters is very similar in terms of Fig. 1. Efficiency comparison of the VSMC and BBC number of switches and control circuitry required. The volume of the EMI filter for the VSMC is 10% larger than the BBC. A further advantage of the VSMC is that the continuous rated output current can be increased by 25% for standstill motor operation, while for the BBC it has to be decreased by 54%. Overall the VSMC offers advantages in volume and efficiency for motor drive applications requiring switching frequencies above 10 kHz. Non-memberFrank Schafmeister * Non-memberMarcelo Heldwein * Non-memberEduardo Pereira * Non-memberLeonardo Serpa * Non-memberJohann Kolar * MemberThis paper undertakes a comparison of the very sparse matrix converter (VSMC) and the back-to-back voltage DC-link converter (BBC) for a permanent magnetic synchronous motor drive application. The VSMC has the same functionality as the conventional matrix converter but a reduced number of switches and lower control complexity. The two converters are designed, using the same IGBT power modules, with a switching frequency of 40 kHz and a thermal rating of 6.8 kW at an ambient temperature of 45 . From the design, the volume of the VSMC is 2.3 lite...

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Practical issues in the design of active rectifiers for AC drives with reduced DC-link capacitance

Cited by 20 publications

References 10 publications

Design Oriented Analysis of DC Link Current Observer of a Three-phase Double Conversion Uninterruptable Power System or Adjustable Speed Drive

Design Oriented Analysis of DC Link Current Observer of a Three-phase Double Conversion Uninterruptable Power System or Adjustable Speed Drive

A novel PWM rectifier control technique for on-line UPS under unbalanced load based on DSP

Comparison of Performance and Realization Effort of a Very Sparse Matrix Converter to a Voltage DC Link PWM Inverter with Active Front End

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