Lamp Ballast Filament Heating Circuit for Gas Discharge Lamps
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Solution Overview
Problem
Conventional lamp ballasts for gas discharge lamps face inefficiencies due to high power loss from difficulty in removing heating power after pre-heating, leading to increased power consumption and reduced efficiency.
Innovation Solution
A lamp ballast with a power factor correction converter, an inverter, and a filament heating apparatus that includes an auxiliary heating circuit and control circuit to pre-heat the filaments for a predetermined time before disabling the heating circuit and starting the inverter, allowing efficient ignition and operation of gas discharge lamps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If heating windings are coupled to the inverter transformer to pre-heat filaments, then the filaments can be pre-heated before ignition, but heating power cannot be removed after ignition causing increased power loss
Solution Approach 1:
The heating function is segmented from the inverter circuit by using a separate auxiliary heating circuit connected to the PFC converter output. This allows independent control of heating power, enabling the heating windings to be deactivated after filament pre-heating while the inverter continues to operate, thus eliminating continuous power loss.
Solution Approach 2:
The auxiliary heating circuit performs the filament pre-heating action before the inverter is activated. By completing the heating function in advance through a dedicated circuit, the system avoids the need to maintain heating power during normal inverter operation, thereby reducing energy loss.
2Reliability
If high voltage is applied to pre-heat filaments before ignition, then the gas discharge lamp can be ignited successfully, but the heating power increases the overall power consumption
Solution Approach 1:
The power consumption is segmented into two distinct phases: a high-power heating phase handled by the auxiliary heating circuit for reliable filament pre-heating, and a normal operation phase handled by the inverter. This segmentation allows the system to accept high power consumption only when necessary for ignition, while maintaining low power consumption during steady-state operation.
Solution Approach 2:
The auxiliary heating circuit performs the energy-intensive filament pre-heating as a preliminary action before inverter startup. This ensures that the high voltage required for reliable ignition is delivered only when needed, rather than being continuously supplied, thus reducing overall power consumption.
3Ease of operation
If heating windings are used for filament pre-heating, then the ignition process can be completed, but the heating mechanism cannot be turned off leading to continuous power loss
Solution Approach 1:
The heating function is segmented into a dedicated auxiliary heating circuit with independent on/off control, separate from the inverter circuit. This segmentation enables the heating windings to be activated only during the pre-heating phase and then deactivated, allowing the ignition process to be completed while eliminating continuous power loss during normal operation.
4Loss of energy
If the inverter is started immediately without pre-heating, then the power loss from heating can be avoided, but the filament heating is insufficient leading to poor ignition
Solution Approach 1:
The auxiliary heating circuit performs preliminary filament heating before inverter startup by drawing power from the PFC converter output. This preliminary action ensures sufficient filament temperature for good ignition, while the heating is confined to a specific time window before inversion, avoiding continuous power loss during normal operation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution improves the efficiency of gas discharge lamps by stabilizing filament pre-heating and removing heating power after ignition, reducing power loss and enhancing operational efficiency.
Implementation Method 1
The heating windings will generate heat by way of electromagnetic effect in order to pre-heat the filaments of the gas discharge lamps
Implementation Method 2
an inverter connected to an output end of the power factor correction converter for converting the DC bus voltage into an AC output voltage
Data Source
AI summary
Provided is a lamp ballast having a filament heating apparatus for gas discharge lamp, including a PFC converter for receiving an AC input voltage and converting the AC input voltage into a DC bus voltage; an inverter connected to an output end of the PFC converter for converting the DC bus voltage into an AC output voltage for driving gas discharge lamps; and a filament heating apparatus connected to the output end of the PFC converter. The filament heating apparatus includes an auxiliary heating circuit for converting the DC bus voltage into a heating power for pre-heating the filaments of the gas discharge lamps; and a control circuit connected to the inverter and the auxiliary heating circuit for generating an auxiliary voltage according to the heating power to activate the PFC converter. After the auxiliary heating circuit has been operating for a predetermined period of time, the auxiliary heating circuit is turned off first and then the inverter is turned on; or otherwise the inverter is turned on first and then the auxiliary heating circuit is turned off.