kind of LLC resonant converter for full voltage range and its control method

• US 20110310640A1
• Filed: 07/09/2010
• Published: 12/22/2011
• Est. Priority Date: 06/18/2010
• Status: Active Grant

• Current Assignee: Shunzhu Tao
• Original Assignee: Shunzhu Tao
• Inventors: Tao, Shunzhu
• Granted Patent: US 8,681,520 B2
• Time in Patent Office: Days
• US Class Current: 363/34
• CPC Class Codes: H02M 1/0058 by employing soft switching techniques, i.e. commutation of transistors when applied voltage is zero or when current flow is zero using an auxiliary actively switched resonant commutation circuit connected to an intermediate DC voltage or between two push-pull branches of an inverter bridge H02M7/4811; in resonant inverters H02M7/4815; in inverters operating from a resonant DC source H02M7/4826
• CPC Class Codes: H02M 3/3376 with automatic control of output voltage or current
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

This invention relates to a kind of LLC resonant converter for full input voltage range and its control method, and belongs to LLC resonant power conversion field.

The technical solution: the current type main tank current sampler test the main tank current signal of the LLC resonant conversion circuit, and its output signal passes a rectifier then to be sent into the main tank energy quantifier connected to it. In the bus voltage range from 5% Vmax to Vmax, the main tank energy quantifier can count the remained LLC resonant main tank energy corresponding to measuring the bus transient voltage, and output a stable energy wave Vo, and if the remained LLC resonant energy falls down to a given energy value, the energy comparator output control signal and the controller controls the electronic switch device turning off, and the corresponding electronic switch gains a ZVS in the next half working period of LLC resonant converter.

This invention realizes the full voltage working range of LLC resonant converter whose reliability can get a fundamental guarantee. And it becomes true to design a LLC converter to be a solid state converter. The lifetime of LLC converter would be equivalent to the lifetime of semi permanent devices used in LLC converter. It can be widely applied into some domains such as non-contact charging stations for electric vehicle, electromagnetic inductance heating and switch power, etc.

Claims

1. A kind of full voltage range of LLC resonant converter includes the LLC resonant converter circuit (1), current type main tank current sampler (21), rectifier (22), the main tank energy quantifier (23), the energy comparator (24), returntozero pulse generator (25), oscillator (12), split phase controller (11), and the current type main tank current sampler, the rectifier, the main tank energy quantifier, energy comparator, back-to-zero pulse generator, oscillator, and split phase controller are connected together one after another. The bus supply voltage of LLC resonant converter can either be DC voltage or the full-wave rectified sine waveform voltage gained only from a line-in AC voltage without capacitor energy storage and inductor freewheeling. The current type main tank current sampler collects the main tank current signal of the LLC resonant converter main tank, and sends the collection to the connected main tank energy quantifier by passing through a rectifier. In the bus voltage amplitude value range changing from 5% Vmax to Vmax, the main tank energy quantifier can measure the transient bus voltage to gain the remained energy of the LLC resonant main tank, and can output a stable energy waveform Vo. If the value of the remained LLC resonant main tank energy is lower than the given energy value Vf, the energy comparator will output control signal to returntozero pulse generator, and the returntozero pulse generator will output returntozero pulse to the oscillator to make it back to zero. And then the split phase controller will turn off the corresponding electric switches of the LLC resonant conversion circuit. The remained energy of the LLC main resonant tank can ensure the corresponding electric switch to work at ZVS states in the next half working period of the LLC resonant converter.

2. The full voltage range of LLC resonant converter according to claim 1, the wherein said LLC resonant conversion circuit has been made up of electric switches S1 and S2, half bridge or full bridge or push pull structure output port, with elements as resonant inductor Lr and resonant capacitor Cr and the primary side of transformer or electromagnetic induction coil Tr in serial connection.

3. The full voltage range of LLC resonant converter according to claim 1 or claim 2, the wherein said current type main tank current sampler in LLC resonant conversion circuit adopts current type current signal sampling devices such as Hall element or current transformer. The rectifier is a full-wave rectifier;

the main tank energy quantifier is constituted of amplitude value limiting and converting circuit. The returntozero pulse generator is a kind of differential circuit.

4. The full voltage range of LLC resonant converter according to claim 1 or claim 2, the wherein said current type main tank current sampler can output signals and pass them through a rectifier connected with the current sampler output port, and the signal from the rectifier is a kind of high frequency semi sine wave or a kind of high frequency semi-sine wave current signal with line wave modulated in line frequency. When the bus voltage amplitude value is changing from 5% Vmax to Vmax, the main tank energy quantifier measures the transient bus voltage that is corresponding to the remained LLC resonant main tank energy in real-time, and the main tank energy quantifier will output a stable energy wave Vo into energy comparator to be taken a comparison.

5. A kind of full voltage range control method for LLC resonant converter has the following steps:

the bus voltage of LLC resonant converter can be a DC voltage or a kind of full-wave rectified sine waveform voltage which is gained from a rectifier connected to the lined in AC voltage, and there are no energy storage capacitor or freewheeling inductor at the rectifier output port. The current type main tank current sampler samples the current signals from LLC resonant conversion circuit, and its result passes through a rectifier into the connected main tank energy quantifier, then when the bus voltage amplitude value is changing from 5% Vmax to Vmax, the main tank energy quantifier count the remained main tank energy of LLC resonant converter from measure the transient bus voltage, the quantifier can output a stable energy waveform Vo. When the remained resonant energy is falling down to the given energy value Vf the energy comparator will output control signal to turn off the corresponding electric switch of the LLC resonant converter. The remained energy of the LLC resonant main tank can make the corresponding electronic switch ZVS turning on in the next half working period of LLC resonant converter.

6. The kind of full voltage range control method for LLC resonant converter according to claim 5, the wherein said output control signal can control to generate returntozero pulse firstly, and the returntozero pulse let the oscillator cut-off, and split phase controller turns off the corresponding electric device of the LLC resonant.