US 11,658,584 B2
LLC resonance converter and method of controlling the same
Shang-Kay Yang, Taoyuan (TW); Hsien-Kai Wang, Taoyuan (TW); and Yen-Wei Lin, Taoyuan (TW)
Assigned to DELTA ELECTRONICS, INC., Taoyuan (TW)
Filed by DELTA ELECTRONICS, INC., Taoyuan (TW)
Filed on Nov. 24, 2021, as Appl. No. 17/534,846.
Claims priority of application No. 202110711031.8 (CN), filed on Jun. 25, 2021.
Prior Publication US 2022/0416677 A1, Dec. 29, 2022
Int. Cl. H02M 3/335 (2006.01); H02M 3/00 (2006.01)
CPC H02M 3/33592 (2013.01) [H02M 3/01 (2021.05); H02M 3/33571 (2021.05); H02M 3/33573 (2021.05)] 16 Claims
OG exemplary drawing
 
8. An LLC resonance converter, comprising:
a switching circuit, comprising a first switch and a second switch,
a resonance tank, coupled to the switching circuit,
a transformer, comprising a primary winding and a secondary winding, and the primary winding coupled to the resonance tank,
a synchronous rectification unit, coupled to the secondary winding, comprising a first synchronous rectification switch and a second synchronous rectification switch, and
a control unit, configured to provide a first control signal to control the first switch, a second control signal to control the second switch, a first rectification control signal to control the first synchronous rectification switch, and a second rectification control signal to control the second synchronous rectification switch according to an output voltage of the resonance converter; the first control signal and the first rectification control signal having an operation frequency and a phase shift amount, and the second control signal and the second rectification control signal having the operation frequency and the phase shift amount,
the control unit comprising:
a comparison unit, configured to receive an output voltage feedback value corresponding to the output voltage and an output voltage reference value, and compare the output voltage feedback value to the output voltage reference value to generate a voltage error value,
a voltage controller, configured to receive the voltage error value, and calculate the voltage error value to acquire a frequency control command corresponding to the operation frequency, and
a signal modulation unit, configured to modulate the first control signal and the second control signal interleaved to the first control signal according to the frequency control command, modulate the first rectification control signal corresponding to the first control signal according to the frequency control command, and modulate the second rectification control signal corresponding to the second control signal according to the frequency control command,
wherein the control unit controls the operation frequency to be variable frequency and adjusts the phase shift amount when the operation frequency is lower than a phase shift frequency, and controls the phase shift amount to be equal to a phase shift threshold and controls the operation frequency to be variable frequency when the phase shift amount is higher than the phase shift threshold, and
wherein the control unit controls a phase of the first rectification control signal to lead a phase of the first control signal, and controls a phase of the second rectification control signal to lead a phase of the second control signal when the operation frequency is lower than a frequency threshold.