Abstract: A low-heat-loss operation method of a line-focusing heat collection system and the line-focusing heat collection system are provided. The method includes the following steps. Solar energy is utilized to preheat a collector tube in an empty tube state, so that the collector tube is in a preheating mode. After a set preheating temperature is reached, a heat transfer working medium is injected into the collector tube. In the injection process of the heat transfer working medium, an injection section of the collector tube is converted into a focusing mode from a preheating mode. After heat collection is finished, the circulation of the heat transfer working medium is stopped, and the focusing mode of the collector tube is kept. In the drainage process of the heat transfer working medium, an emptying section of the collector tube is converted into a light heat-tracing mode from a focusing mode.

Abstract: System and method for controlling a bleeder current to increase a power factor of an LED lighting system without any TRIAC dimmer. For example, the system for controlling a bleeder current to increase a power factor of an LED lighting system without any TRIAC dimmer includes: a first current controller configured to receive a rectified voltage generated by a rectifier that directly receives an AC input voltage without through any TRIAC dimmer; and a second current controller configured to: control a light emitting diode current flowing through one or more light emitting diodes that receive the rectified voltage not clipped by any TRIAC dimmer; and generate a sensing voltage based at least in part upon the light emitting diode current, the sensing voltage representing the light emitting diode current in magnitude.

Abstract: System and method for controlling a bleeder current to increase a power factor of an LED lighting system without any TRIAC dimmer. For example, the system for controlling a bleeder current to increase a power factor of an LED lighting system without any TRIAC dimmer includes: a first current controller configured to receive a rectified voltage generated by a rectifier that directly receives an AC input voltage without through any TRIAC dimmer; and a second current controller configured to: control a light emitting diode current flowing through one or more light emitting diodes that receive the rectified voltage not clipped by any TRIAC dimmer; and generate a sensing voltage based at least in part upon the light emitting diode current, the sensing voltage representing the light emitting diode current in magnitude.

Abstract: System and method for controlling a bleeder current to increase a power factor of an LED lighting system without any TRIAC dimmer. For example, the system for controlling a bleeder current to increase a power factor of an LED lighting system without any TRIAC dimmer includes: a first current controller configured to receive a rectified voltage generated by a rectifier that directly receives an AC input voltage without through any TRIAC dimmer; and a second current controller configured to: control a light emitting diode current flowing through one or more light emitting diodes that receive the rectified voltage not clipped by any TRIAC dimmer; and generate a sensing voltage based at least in part upon the light emitting diode current, the sensing voltage representing the light emitting diode current in magnitude.