Switching Transformer Drive Circuit for Low-Loss Bipolar Current Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
H-bridge circuits for bipolar current control of inductive loads suffer from high noise and losses, especially when using pulse width modulation, and require complex configurations to prevent short circuits, limiting efficient control and increasing power losses.
Innovation Solution
A bipolar current control drive circuit using a switching transformer with one shared switching element for amplitude control and two secondary switching elements for polarity control, eliminating the need for an H-bridge configuration, reduces noise and losses by supplying rectified and smoothed voltage directly to the load without switching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If PWM control is used in H-bridge configuration for bipolar current control, then control efficiency is improved, but noise and losses increase
Solution Approach 1:
The patent divides the bipolar current control function into two separate circuits: a positive current supply circuit and a negative current supply circuit. Each circuit independently controls current in one direction, eliminating the need for high-frequency switching between directions. This segmentation allows PWM control to be applied separately to each polarity without generating the noise and losses associated with rapid bidirectional switching in traditional H-bridge configurations.
2Speed
If power supply voltage is increased to accelerate load operation, then operation speed is improved, but noise and losses further increase
Solution Approach 1:
The patent changes the control parameter from voltage-based control to current-based control. By directly controlling the current amplitude and polarity through separate positive and negative current circuits, the system can accelerate the load more effectively without relying on increased voltage. This parameter change allows for optimized current waveforms that reduce noise and losses while maintaining high operation speed.
3Adaptability or versatility
If H-bridge circuit is used for bipolar current control, then current direction control is achieved, but circuit configuration becomes complicated
Solution Approach 1:
Instead of using a single H-bridge circuit to handle both positive and negative current directions, the patent segments the control into two independent circuits: one dedicated to positive current supply and another to negative current supply. Each circuit contains simplified switching elements and control logic for its specific direction, eliminating the complexity of coordinating multiple switches in an H-bridge configuration while maintaining full bipolar control capability.
4Adaptability or versatility
If H-bridge circuit elements are controlled to reverse current direction, then bipolar control is achieved, but risk of short circuit increases
Solution Approach 1:
The patent eliminates the short circuit risk inherent in H-bridge configurations by completely separating the positive and negative current paths into independent circuits. Since each circuit only handles current in one direction, there is no possibility of simultaneous conduction of opposing switches that would cause a short circuit. This segmentation inherently prevents the reliability issues associated with complex switching coordination.
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 simplifies the circuit, reduces noise and losses, and allows for efficient bipolar current control of inductive loads with increased accuracy and safety, enabling accelerated operation without voltage dependence on the power supply.
Implementation Method 1
a switching transformer configured to transform a pulse wave alternating current at a predetermined alternating voltage
Implementation Method 2
a rectifier bridge diode configured to rectify an alternating current from a power supply
Data Source
Figure 1~2
Figure 3~4
AI summary
A bipolar current control drive circuit for an inductive load includes a switching power supply circuit in which an alternating current from a power supply is formed to a direct current smoothed through a rectifier bridge diode and a primary smoothing capacitor, this direct current is formed to a pulse wave alternating current using a switching element switched in response to a pulse signal from a pulse signal generator, the current is transmitted to a secondary side using a switching transformer, and the current is formed to a direct current smoothed through a secondary diode and a secondary capacitor. The switching transformer includes a first secondary coil and a second secondary coil for one primary coil. A first secondary circuit and a second secondary circuit are provided to form alternating currents from the secondary coils to direct currents in reverse orientations and output the currents to an inductive load. A polarity control circuit controls switching between closing and opening of a first secondary switching element and a second secondary switching element placed on the respective secondary circuits and controls the polarity of an electric current by selectably outputting, to the inductive load, an electric current from the first secondary circuit and an electric current from the second secondary circuit. circuit