Digital generators are a relatively new product category that has emerged in recent years. Their widespread adoption is primarily focused on small generator systems under 5 kilowatts. Traditional generators mainly use a low-speed motor to drive a mains frequency output generator for normal operation, directly outputting the required power. This type of system, due to the low speed of the motor, results in a relatively large size. Furthermore, the low speed of the generator itself makes it difficult to reduce its size, hindering the overall miniaturization and portability of the system. The quality of the output power also suffers from limitations.
Digital generators are a new product category that has emerged in recent years, and their widespread adoption is mainly concentrated in small generator systems below 5 kilowatts.
Traditional generator products mainly use a low-speed engine to drive a power frequency output generator to work normally and directly output the required power. Because the engine operates at a low speed, this type of system is relatively large. At the same time, it is also difficult to reduce the size of the generator due to the low speed. Therefore, it is difficult to achieve miniaturization and portability of the entire system.
Regarding the quality of the output power supply, since the voltage and frequency of the output power supply are directly proportional to the engine speed, the fluctuation of the system speed under different load conditions will directly affect the stability of the output power supply voltage and frequency. The waveform of the output power supply is directly affected by the generator. Generally, the TDH of the output waveform of this type of generator with low power is not ideal.
The emergence of digital generator solutions has effectively solved these problems.
Digital Generator Controller Product Description
This controller product combines advanced power inverter technology with control technology, and its output waveform is a standard sine wave, as shown below:
The system power output adopts software closed-loop control technology, which has a higher utilization efficiency of engine output power compared with conventional hardware control methods, thus enabling the same engine system to have a higher system output utilization efficiency.
Compared with traditional generator systems, this control system produces a sine wave output during the full power output phase, resulting in high-quality and stable power output.
This system offers a high degree of flexibility in terms of output power type, allowing it to output power at different frequencies and voltages according to the specific requirements of different customers. Currently, the output power types are as follows:
A. 220V/50Hz standard sinusoidal voltage output;
B. 230V/50Hz standard sinusoidal voltage output;
C. 110V/60Hz standard sinusoidal voltage output;
D. 115V/60Hz standard sine voltage output.
In terms of system control, we adopt an advanced dynamic intelligent applicable control scheme. Due to the special nature of this product system, if the engine system, carburetor, and throttle adjustment mechanism have a certain degree of discreteness, traditional system control schemes cannot accurately and stably achieve effective adjustment of the system under variable load conditions, or even if they achieve effective adjustment, they cannot achieve dynamic energy-saving effects during the adjustment process. Our system, by adopting a control scheme with its own technical characteristics, achieves effective and accurate control of the system. At the same time, our control system has strong system adaptability.
In the development process of system control design, we adopted a development approach that combines controller and PC monitoring and analysis using self-developed PC software.
By leveraging the powerful monitoring and analysis capabilities of PCs, we can achieve dynamic monitoring and analysis of the system, thereby ensuring that we can develop high-quality system control in a relatively short period of time.
Because all the core technologies of this product were developed independently by us, and because we possess advanced development methods, we can guarantee a rapid response speed and strong adaptability to meet the needs of different customers. We guarantee that, within our product series, provided the customer's system prototype is completed, we can cooperate to complete the development of a full-featured prototype within four weeks.
In terms of system adaptability, our controller system has a wide range of compatible applications.
Our controllers are compatible with oil engine systems for high-speed engines as well as medium- and low-speed engines.
In the actual system, we make corresponding adjustments to the control parameters of the controller, so as to enable our controller to support engine systems with different characteristics without making corresponding changes to the hardware.
Our controllers can achieve equally high-quality system control and power output quality across engine systems with different characteristics.
Regarding the product's functions, features, and advantages, our overall functionality is as follows:
1. Standard sinusoidal voltage output function;
2. Electronic throttle speed control function;
3. Power usage status management and monitoring functions;
4. Comprehensive system anomaly adjustment and protection functions;
5. System output indication and fault indication (LED display) functions;
Our product design incorporates robust software monitoring and processing, maximizing software integration to replace hardware design and significantly improve system reliability. For output waveform processing, we employ a purely software-controlled waveform generation method, offering superior reliability and flexibility in output power supply. We utilize a direct dynamic compensation method for the inverter system, resulting in higher inverter efficiency. This improves engine output power utilization while significantly reducing controller system temperature rise. Our unique soft-start function during the system's power output phase ensures excellent inrush current suppression for the entire system integrated with our controller. Furthermore, our controller design includes a unique engine shutdown control function for extreme system anomalies, forcibly shutting down the engine to ensure system safety. Additionally, our controller system has a built-in temperature detection function, enabling appropriate responses to internal temperature anomalies, thus guaranteeing the absolute safety of the entire system.
A Brief Analysis of System Throttle Control
The digital generator inverter controller consists of several parts, among which inverter control and system throttle control are the core components. I will now introduce some personal experiences regarding the throttle control part. Due to the involvement of some specific technologies, I cannot go into too much detail. I can only give a brief introduction for discussion.
Throttle control primarily aims to effectively control engine output power and DC voltage during the dynamic operation of the system. There are numerous methods for achieving throttle control during dynamic system operation, based on different underlying principles.
From the perspective of automation control, the throttle control model should be considered a system with hysteresis. Furthermore, due to the inconsistency of machining processes and the relative changes in characteristics after long-term operation, the degree of hysteresis becomes uncertain, ultimately increasing the control difficulty of the system. A good throttle control scheme in this system should possess the following characteristics:
1. Achieve static stability control at different speeds;
2. To achieve effective and stable control during sudden increases and decreases in maximum rated load during system operation;
3. Achieve stable control during variable load processes;
4. It can still effectively control the system even after certain changes in system status (such as a decrease in engine output power or micro-clogging of the carburetor);
5. Enables rapid and accurate throttle response in abnormal situations.
From the perspective of automation control, before we can effectively control a system, we must conduct a specific analysis of the system. The first step is to analyze the input and output parameters and determine their causal relationships. In this system, to control the throttle, we can use the following inputs: system speed, DC voltage, output current, and output power. Changes in speed lead to changes in DC voltage (assuming constant output power), and changes in output power lead to changes in system speed (assuming the throttle is fixed). It is evident that changes in load are the internal cause of large changes in the system (of course, the output current also reflects the load size). Therefore, to achieve optimal results and effective system control, load changes must be considered as an important parameter (although other parameters are also essential). Whether you ultimately aim to stabilize a specified speed or a specified voltage, load changes are a crucial parameter.
Relative to the engine system, if we expect the system speed to be dynamically stable, we can treat the system speed and the load as physical variables. Then we can consider the load as a variable that can change abruptly (relative to the system speed) and the system speed as a gradual variable. The advantage of this analysis is that in the process of system control, in order to achieve fast and effective control of the system speed, we can use the load to perform relative system feedforward control.
Of course, to achieve effective system control, the details must be well done, and the design of local functions cannot be divorced from the larger system framework. For example, a good system throttle control must also cooperate with the inverter section in some way.
Specifically, for specific products, such as the throttle control of a digital generator system, this product does not require the same high precision control as servo systems or motion control systems. In the design of this system, after the initial precision of control is achieved, the focus should be on the adaptability and stability of the control design.
