A carrier-based pwm method with the double frequency voltage injection for three-level neutral-point clamped (NPC) converters

DC-Link Capacitor Voltage Imbalance Compensation Method Based Injecting Harmonic Voltage for Cascaded Multi-Module Neutral Point Clamped Inverter

“…This voltage imbalance is considered a system imperfection, which is caused by the difference in hardware components or switching operations of the NPC inverter [10,11]. Many strategies have been proposed to solve the capacitor voltage imbalance problem, and these strategies have achieved successful results [12][13][14][15][16][17][18][19][20][21][22][23][24][25].…”

A Harmonic Voltage Injection Based DC-Link Imbalance Compensation Technique for Single-Phase Three-Level Neutral-Point-Clamped (NPC) Inverters

“…This voltage imbalance harms the stability of the system, and limits the switching operation of the power stage [8][9][10][11]. In order to mitigate the voltage imbalance, many strategies that are based on additional hardware configurations or control algorithms have been proposed, hardware configurations or control algorithms have been proposed, and have been successfully adapted in some applications [12][13][14][15][16][17][18][19][20][21][22][23][24][25]. In [12,13], additional circuits for dc-link balancing were proposed.…”

“…Although these methods achieved the dc-link voltage balancing successfully, the increase in the cost and the losses were major defects. To avoid these disadvantages, several modulation techniques for single-phase three-level NPC inverters have been presented in [14][15][16][17][18][19][20][21]. Among these modulation techniques, the carrier-based pulse width modulation (CB-PWM) approaches have been extensively preferred due to their simplicity of implementation.…”

“…Additionally, the exact parameter information is essential to implement these methods as the algorithms are highly dependent on the system parameters. In [16], a simple signal injection method was proposed to balance out the dc-link capacitor voltages by utilizing the harmonic signal consisting of the dc-link voltage difference and the double frequency of the utility grid. The method can easily be implemented as well as reducing the harmonic distortion in the input current of the NPC inverter.…”

“…In this paper, the method proposed in [16] was further extended and detailed. In the proposed method, an even harmonic signal was added to the reference signal, which is generated by the current controller.…”