Standalone Operation of Modified Seven-Level Packed U-Cell (MPUC) Single-Phase Inverter


In this paper the standalone operation of the modified seven-level Packed U-Cell (MPUC) inverter is given and consider. The MPUC inverter has two DC sources and six switches, which cause seven voltage levels at the output. Compared to cascaded H-bridge and neutral point clamp multilevel inverters, the MPUC inverter produce a higher number of voltage levels using fewer components. The experimental results of the MPUC prototype validate the allocate operation of the multilevel inverter handle with various load types including motor, linear, and nonlinear ones. The design considerations, including output AC voltage RMS value, switching frequency, and switch voltage rating, as well as the harmonic analysis of the output voltage waveform, are taken into account to prove the advantages of the introduced multilevel inverter.


1. Multilevel inverter
2. Packed u-cell
3. Power quality
4. Multicarrier PWM
5. Renewable energy conversion



Figure 1. Single-phase seven-level MPUC inverter in standalone mode of operation


Figure 2. Seven-level MPUC inverter output voltage and current with DC source voltages. Ch1: V1,
Ch2: V2, Ch3: Vab, Ch4: il.

Figure 3. One cycle of output voltage and gate pulses of MPUC inverter switches. Ch1: Vab, Ch2: T1
gate pulses, Ch3: T2 gate pulses, Ch4: T3 gate pulses

Figure 4. MPUC inverter switches’ voltage ratings. Ch1: Vab, Ch2: T1 voltage, Ch3: T2 voltage, Ch4:
T3 voltage. and nonlinear). The step-by-step process for connecting loads is depicted in Figure 7, which show

Fig.5. Test results when a nonlinear load is connected to the MPUC inverter.Ch1 :Vab :Ch4 :il.

Figure 6. Output voltage and current waveform of MPUC inverter when different loads are added
step by step. Ch1: Vab, Ch4: il. (A) Transient state when nonlinear load is added to the RL load (left)
and after a while a motor load is added to the system (right); (B) steady state when a nonlinear load is
added to the RL load (left) and after a while a motor load is added to the system (right).

Figure 7. Voltage and current waveform of MPUC inverter with RMS calculation for 120 V system.


In this paper a redesign PUC inverter topology has been presented and studied experimentally. The proposed MPUC inverter can produce a seven-level voltage waveform at the output with low harmonic contents. The associated switching algorithm has been create and achieve on the introduced MPUC topology with reduced switching frequency aspect. Switches’ frequencies and ratings have been investigated experimentally to validate the good dynamic performance of the proposed topology. Moreover, the comparison of MPUC to the CHB multilevel inverter showed other advantages of the proposed multilevel inverter topology, including fewer components, a lower manufacturing price, and a smaller package due to reduced filter size.
Author improvement: All authors improvement equally to the work presented in this paper.
Funding: This research received no external funding.
competition of Interest: The authors declare no competition of interest.


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2. Mobarrez, M.; Bhattacharya, S.; Fregosi, D. Implementation of distributed power balancing strategy with a layer of supervision in a low-voltage DC microgrid. In Proceedings of the 2017 IEEE Applied Power Electronics Conference and Exposition (APEC), Tampa, FL, USA, 26–30 March 2017; pp. 1248–1254.
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A Switched-Capacitor Inverter Using Series/Parallel Conversion with Inductive Load


A new switched-capacitor inverter is prepared. The prepared inverter outputs larger voltage than the input voltage by change the capacitors in series and in parallel. The highest output voltage is driven by the number of the capacitors. The prepared inverter, which does not need any inductors, can be smaller than a normal two-stage unit which happen of a boost converter and an inverter bridge.


Its output frequency are decreased compared to a normal voltage source single phase full bridge inverter. In this paper, the circuit configuration, the logical operation, the simulation results with MATLAB/ SIMULINK, and the experimental results are shown. The experimental results give with the logical calculation and the simulation results.


  1. Charge pump
  2. Multicarrier PWM
  3. Multilevel Inverter
  4. Switched capacitor (SC)



Fig. 1. Circuit topology of the switched-capacitor inverter using series/ parallel conversion.




Fig. 2. Simulated voltage waveforms of the proposed inverter (n = 2) designed for high power at 4.50 [kW], switching frequency f = 40 [kHz] and reference waveform frequency fref = 1 [kHz]. (a) Bus voltage waveform vbus and (b) the output voltage waveform vout.


Fig. 3. Simulated current waveforms of the capacitor iC1 in the proposed inverter (n = 2).(a) Designed for low power at 5.76 [W] and (b) designed for high power at 4.50 [kW].


Fig. 4. Simulated spectra of the bus voltage waveform of the proposed inverters (n = 2) normalized with the fundamental component. (a) Designed for low power at 5.76 [W] and (b) designed for high power at 4.50 [kW].


Fig. 5. Simulated bus voltage waveforms vbus and the voltage waveforms of the load resistance vR of the proposed inverter (n = 2) designed for low power at 5.76 [W] with an inductive load.


In this paper, a novel boost change-capacitor inverter was prepared. The circuit topology was produce. The modulation method, the decision method of the capacitance, and the loss calculation of the proposed inverter were shown. The circuit operation of the proposed inverter was proved by the simulation results and the experimental results with a resistant load and an inductive load.


The prepared inverter outputs a larger voltage than the input voltage by change the capacitors in series and in parallel. The inverter can operate with an inductive load. The structure of the inverter is simpler than the normal change-capacitor inverters. THD of the output waveform of the inverter is reduce compared to the normal single phase full bridge inverter as the normal multilevel inverter.


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