What are the characteristics of the inverter stage of a power inverter

The inverter stage of a power inverter is the core part of converting DC power into AC power. At this stage, switching circuits, such as transistors (IGBT), metal oxide field effect transistors (MOSFET) and other power semiconductor devices, are used to achieve precise control of the output waveform through precise control and modulation technology.

Switch circuit:

The core of the inverter is the switching circuit, which switches the DC power supply to AC power supply by turning on and off the switching device. Commonly used power semiconductor devices include transistors (usually IGBTs) and MOSFETs. These switching devices are precisely controlled in the inverter to simulate the desired output waveform.

Inverter working cycle:

The basic cycle of inverter operation includes two phases: the conduction phase and the cut-off phase. In the conduction phase, the switching device is turned on, allowing current to pass; while in the cutoff phase, the switching device is turned off, and the current is blocked. By adjusting the ratio of on and off time, the shape, frequency and voltage of the output waveform can be changed.

Pulse Width Modulation (PWM):

In order to improve the quality of the output waveform, inverters usually use pulse width modulation (PWM) technology. PWM achieves high-precision control of the output waveform by adjusting the working time of the switching device. Specifically, PWM switches the switching device at a certain frequency and simulates the required AC waveform by adjusting the conduction time within each switching cycle.

Output waveform control:

The design of the inverter allows engineers to adjust parameters of the output waveform, including frequency, amplitude and phase. This flexibility allows the inverter to be adapted to different application needs, for example, providing 50Hz power to household appliances, or 60Hz power to industrial equipment.

Inverter efficiency and losses:

The efficiency of the inverter stage is a key consideration in the design. There will be a certain amount of energy loss during the turn-on and turn-off process of the switching device, and the overall efficiency of the inverter depends on the control and minimization of these losses. Efficient inverter designs usually use advanced power semiconductor devices and optimized PWM control strategies to improve energy conversion efficiency.

Current and voltage control:

The inverter not only needs to generate a waveform of a specific shape, but also needs to ensure the stability of the output current and voltage. Therefore, the control system needs to monitor the output in real time and adjust the operation of the switching device through a feedback mechanism to maintain stable output characteristics.