Yudai Furukawa

Digital Fast P Slow ID Control DC–DC Converter Using A–D Converters in Different Resolutions

The purpose of this paper is to present a digital fast P and slow ID control dc-dc converter using A-D converters in different resolutions. In the proposed method, the operation parts are divided into the P control and the ID control. Moreover, the high-speed and low resolution A-D converter is set for the P control, and the very low-speed and high resolution one is set for the ID control. In the transient response experiment, the convergence time is improved by about 77% compared with the conventional PID control method. As a result, it is possible to achieve the low cost design with keeping the superior transient response.

High performance digital control switching power supply

The purpose of this paper is to present a digital control method which suppresses the delay-time for the switching power supply. Generally, there is the delay-time caused by the A/D conversion time and the calculation time in the digital control. It causes the worsening of the transient response and brings the instability of the system. The proposed method can suppress the delay-time and improve the transient response. Results show that the proposed method can improve the transient response compared with the conventional PID control method and existing proposed method. Thus, the proposed method can contribute to the improvement of the transient response effectively.

Analysis of digital peak current control DC-DC converter

The purpose of this paper is to present control characteristics of digital peak current mode dc-dc converter. It is difficult to implement the digital current control. An expensive A-D converter is required in order to sample a current. Furthermore, even if an A-D converter can sample the current, it is also needed the high-performance processor to process the sampling data. The peak current can be detected by using an inexpensive voltage controlled oscillator (VCO) and a programmable delay circuit in the proposed method. In this paper, control characteristics of the proposed method are described by analytic expression. Also, we confirm that the stable region of the system of the dc-dc converter used by the proposed method is expanded than the conventional voltage mode by using the simulation.

Dynamic PID gain changing control for DC-DC converter

This paper presents a digital control method where changes PID parameter setting dynamically to improve transient characteristics of dc-dc converters. In the conventional PID control, those control parameters are selected as suitable values to satisfy stable characteristics both in transient state and steady state and keep the stability of system. Therefore, the value of control parameter tends to be a small one. In this paper, we propose the method where the PID parameter setting is changed to the suitable one in the transient state, where the value of control parameter is designed just to improve the transient response and takes larger one compared to the conventional PID control method. Using the proposed method, the transient response can be improved without the loss of stability of dc-dc converter.

Digital fast-P slow-ID control DC-DC converter

This paper presents a new digital control method for dc-dc converter which consists of two A-D converters with different sampling frequencies. In the presented method, the calculation process of P and ID controls are parallel. The sampling frequency for the P control is higher than the switching frequency and one for ID control is lower than the switching frequency. Therefore, the P control and ID control have different sampling frequency each other. Even in such different setting compared with the conventional PID control method, our presented method can realize the superior transient response. The presented method also contributes the low-cost design of A-D converters. In the experiments, it is obtained that the undershoot of the output voltage and the convergence time are improved by 44% and 78% respectively in the transient response. From the results, it is confirmed that our presented method can provide superior transient characteristics and the low cost implementation simultaneously.

Digital fast-P slow-ID control DC-DC converter using A-D converters in different resolutions

The purpose of this paper is to present a digital fast-P and slow-ID control dc-dc converter using A-D converters in different resolutions. In the proposed method, the operation parts are divided into the P control and the ID control. Moreover, the high-speed and low resolution A-D converter is set for the P control, and the very low-speed and high resolution one is set for the ID control. In the transient response experiment, the convergence time is improved by about 77% compared with the conventional PID control method. As a result, it is possible to achieve the low cost design with keeping the superior transient response.

A new quick response digital control dc-dc converter with dynamic unstable gain

In this paper, we present a new quick response digital control dc-dc converter based on a dynamic unstable gain to improve transient response. In the proposed method, the proportional gain is set to the small value in the steady state and the large value over the stability limit for only a short time in the transient state. Compared with the conventional PID, the undershoot, the overshoot and convergence time are improved by 48%, 71% and 84%, respectively. Generally, when the control gain is set to very large value, the capacitance of output smoothing capacitor must be set to large value simultaneously to maintain the stability of system. That can be reduced and the miniaturization of main circuit can be expected because the very large gain is set for only a short time to improve the transient response in the proposed method.

Transient response of feedback gain changing dc-dc converter for line variation

In this paper, we present a feedback gain changing dc-dc converter. The proposed method corresponds to the input voltage variation because the integral gain is determined in consideration of it. Generally, a quick transient response cannot be obtained when the proportional gain is small. On the other hand, when the proportional gain is set to a large value, the transient response is improved. However, the capacitance of output smoothing capacitor must be set to a large value to maintain the stability of the system when the proportional gain is set to such a large value. In the proposed method, the proportional gain is changed from a small value to a large value in the transient state to improve the transient response. Compared with the conventional PID, the undershoot, the overshoot and the convergence times are improved by 72%, 68% and 79% respectively. Therefore, the proposed method can keep up both the miniaturization of main circuit and the fast transient response even when the input voltage variation occurs.

A consideration of transient response for sensorless model control DC-DC converter

The purpose of this paper is to discuss a current prediction algorithm for sensorless model control dc-dc converter. In the proposed method, the sensing resistor for the current detection is eliminated by predicting the output current. The output current is predicted from the equation of the relationship between the output and input voltage in the static state using the duty ratio and the output voltage. The predicted output current is substituted the static model. Two different equations according to the operation mode of the dc-dc converter are used for the current presumption. They should be switched smooth and seamless for the output current prediction.

Performance characteristic of digital peak current mode control switching power supply

The purpose of this paper is to discuss performance characteristic of digital peak current mode control switching power supply. The proposed method can capture the peak current value in real time by using the voltage controlled oscillator (VCO), the programmable delay circuit and the signal frequency detector. Its transfer function is derived analytically. Also, the frequency characteristics are revealed using the loop transfer function in the case of different voltage control loop gains. In addition, its gain margin and phase margin are discussed. Furthermore, the transient responses of proposed method are compared with the conventional voltage mode control in the simulation and the experiment.