1 Foreword
as electricity, telecommunications, aviation, and large-scale information, data core industry of high-end equipment for increasing the capacity and quality of power supply system requests, including "large capacity", "high solid" and "uninterrupted "powered features, epitomizes high-end equipment is unique in its energy system and basic requirements. This paper examines the parallel DSP-based power inverter control system. The refurbishment of the article is the robustness requirements of parallel power supply system, to achieve a plurality of inverter module to contentment different load power and power. Inverter Parallel control skills seminars there are far-reaching social impact and social benefits.
2 DSP-based contact system analysis and design
analysis and hardware design of 21 single inverter power module
parallel scattered power system, first it is necessary to try to safeguard the consistency between the modules each module load characteristics and solid; satisfied with this request, the inverter main circuit structure change has been updated, high-frequency soft switching techniques also generally use DC / AC power inverter.
The high-frequency pulses DC link inverter in
is a new structure based on the principle of the resonant DC link inverter. The inverter both may achieve electrical isolation between the input and output, and can achieve zero voltage switching bridge power tube. http://www.gridtieinverter.de/
Figure 1 the main circuit of the inverter
1 inverter main circuit
inverter main circuit is shown in Figure 1. The main circuit consists of three local interwoven parallel forward conversion circuit, receiving circuit and full-bridge inverter circuit.
cover of the circuit, and output filter design
the present system, the filter inductor is taken as the overcurrent maintenance, shown in Figure 1 composed filter circuit Lr1, Lr2, and Cr. Filter inductor in series the straight converter with the receiver circuit between Lr1 with a smaller capacitor Cr at the output end of the inverter bridge Also in the series with another small inductance Lr2. Voltage feedback detection points to take to the inductor Lr1 front,this can play a limiting role. Filter inductor in the the current hysteresis dominated, on the one hand from the ripple effect from the role of the integrator, on the other hand, in the current loop. If Lr1 value is too large,Grid tie inverter, it will affect the the ① current tracking speed, slow the system dynamic response speed; ② steady precision of the output voltage is decreased; ③ The add to the volume of the system, components and capital. Inductor current change rate must be greater than the rate of change given current caliber protection given the current in the inductor current track, pursuant to push under
Lr1
Ubmax - the pulse voltage Uab of maximum peak
Uomax - peak output voltage
If Lr1 value is too small, the amount of the inductor current ripple increases, the quality of the output voltage will be affected, so the necessary level of the inductor current change amount. Through the calculations and the experimental circuit parameter choices are as follows Lr1 = 15mH Lr2 = 3 mH, Cr = 220 nF.
22 temperance sector circuit design and parsing
control important part of the circuit by a dedicated digital signal processor TMS320LF2407A and pulse width modulation integrated chip UC3524 formed,power inverter.
1 digital signal disposal TMS320LF2407A first volume
each inverter module
This system uses TI's digital signal processor MS320F2407A, are TI's TMS320C2XX series. From pre dispose of real-time data transmission, moving rapidly, as well as function of the price than other aspects discretion, The system selected TMS320F2407A.
the
2SPWM waveform generation
is still used in the design of dedicated pulse width modulation chip UC3524 SPWM waveform.
Figure 2 inverter module control schematic
by the figure 2 the DSP through high-speed D / A converter, sent to the UC3524 scale semi-sinusoidal modulation wave reference signals, the current limit reference signal and a carrier synchronization control amount of the control signal, etc.. In order to adjust the the SPW modulation waveform; localized in the left, straight conversion circuit and pulse width modulation chip UC3524 formed a double closed-loop system voltage and current feedback, which is the single inverter SPWM born and regulator control strategy center. This will ensure that the DSP as well as a large number of system resources system time various control algorithms and data transmission between modules, and machine effect.
23 between modules in parallel control department design
Distributed Logic parallel control method allows each inverter power supply module is not attached to the central control unit or one of the main module, can alone break detection and control of the working conditions of the modules in the system module output power between justice deployment and circulation between good restraint module, modular power inverter in order to achieve independence-breaking run in parallel with the power system control.
basis over the evacuation logic control practice analysis, taken in the design of evacuation control parallel redundant inverter dominated system. CAN bus between the modules in the system design as current interconnection, while the discretion of the practical use from the engineering point of the introduction of a set of synchronous bus in the system in, because the synchronous bus and the corresponding synchronized restraint strategy greatly simplifies Distributed Logic master parallel the redundant master plan to achieve.
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