Relay Driving Circuit Using Capacitor Boost for Heat Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing relay driving circuits face challenges in reducing relay driving current and heat generation while maintaining reliable operation, often resulting in increased energy losses and circuit complexity due to the use of series resistors, Zener diodes, and multiple constant-voltage power supplies, as well as radiation noise from pulse-shaped on/off control.
Innovation Solution
A relay driving circuit that incorporates a capacitor and switching elements to charge and series-connect the power supply and capacitor voltage with the relay coil, increasing the initial operating voltage and subsequently reducing the voltage to minimize current and heat generation, eliminating the need for multiple power supplies and resistors, and reducing radiation noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a constant voltage is applied to the relay coil to maintain contact closure, then the relay contact remains closed, but heat generation increases due to coil resistance increase from temperature rise
Solution Approach 1:
The patent applies dynamic voltage control by switching between high voltage (for relay operation) and low voltage (for contact maintenance). The control unit dynamically adjusts the driving voltage based on relay state, initially applying high voltage to ensure reliable contact closure, then switching to low voltage to minimize heat generation while maintaining the closed contact state.
Solution Approach 2:
The patent employs periodic voltage application through pulse-width modulation (PWM), where the driving voltage is applied in periodic pulses rather than continuously. This periodic action allows the relay contact to remain closed while reducing average power consumption and heat generation in the coil.
2Reliability
If the driving voltage is increased to compensate for counter-electromotive force during relay operation, then reliable relay operation is achieved, but heat generation increases
Solution Approach 1:
The patent applies preliminary high voltage to the relay coil before and during the initial operation phase to overcome the counter-electromotive force and ensure reliable contact closure. Once the relay is activated, the control unit switches to low voltage maintenance mode, applying voltage only periodically to maintain the closed contact state without generating excessive heat.
Solution Approach 2:
The control unit dynamically adjusts the driving voltage level based on the relay's operational state. During the transition phase, high voltage is applied to ensure reliable operation; once stabilized, the voltage is reduced to minimal levels necessary for maintaining contact closure, thereby reducing heat generation while preserving reliability.
3Reliability
If multiple constant-voltage power supplies are used to provide high voltage for operation and low voltage for maintenance, then relay reliability improves, but circuit complexity increases
Solution Approach 1:
The patent merges the functions of multiple power supplies into a single power supply unit combined with an active control unit. Instead of using separate high-voltage and low-voltage power supplies, the invention uses one power supply that dynamically adjusts its output voltage under control of the control unit, thereby achieving the same reliability benefits while reducing circuit complexity and component count.
Solution Approach 2:
The control unit serves multiple functions: it regulates voltage output, switches between high and low voltage modes, monitors relay state, and manages power distribution. This multi-functional control unit replaces what would otherwise require multiple dedicated power supply circuits, reducing overall system complexity while maintaining the ability to provide appropriate voltage levels for both relay operation and contact maintenance.
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 configuration enhances the reliability of relay operation at initiation, reduces driving current and heat generation, simplifies the circuit, and minimizes energy losses and radiation noise, thereby improving the overall performance and efficiency of the relay driving circuit.
Implementation Method 1
a capacitor (16), a switching portion (13, 14) which switches between the coil (20) of the relay, the capacitor (16) and the first terminal (111)
Implementation Method 2
a relay contact (19) is held closed by the magnetomotive force arising in the relay coil (20) within the relay due to current flowing in the relay coil
Implementation Method 3
the relay coil generates heat due to losses which are the product of the resistance and the flowing current
Data Source
AI summary
A capacitor 16 is charged by turning on a switching element 12, and when a relay 18 is operated, by turning off the switching element 12 and turning on a switching element 13, a constant-voltage power supply 11 and the capacitor 16 are series-connected, and a switching element 14 is turned on to cause the series circuit of the constant-voltage power supply 11 and the capacitor 16 to be connected to a relay coil 20, so that the voltage resulting from addition of the output voltage of the constant-voltage power supply 11 and the charging voltage of the capacitor 16 is supplied to the relay coil 20, whereby causing the relay 18 to be turned on, after which the capacitor 16 is gradually discharged by means of the relay coil 20.