CN-121749697-B - Control method of energy storage bidirectional resonant converter

Abstract

The invention discloses a control method of an energy storage bidirectional resonant converter, which consists of two direct current power supplies (DC 1 、DC 2 ), a transformer (T), a first bridge type switch unit (10), a second bridge type switch unit (30) and a resonant unit (20), wherein the control method can realize the wide voltage range regulation of the converter, can realize the bidirectional regulation and control of energy only by regulating the duty ratio of the bridge type switch unit, the switches S 1 ~S 4 and S 5 ~S 8 included in the first bridge switch unit (10) and the second bridge switch unit (30) of the converter can respectively realize uniform distribution of heat, solve the problem of thermal stress caused by uneven heat distribution, the control method of the invention enables the resonant converter to have wide-range voltage regulation and bidirectional power rapid regulation and control capability, and simultaneously can realize the uniform heat distribution of the switch tube of the bridge switch unit, thereby being particularly suitable for the technical field of high-performance bidirectional electric energy conversion of energy storage, electric vehicles, new energy sources and the like.

Inventors

• PENG ZHENGXIONG
• LI ZHEN

Assignees

• 江苏金帆电源科技有限公司

Dates

Publication Date

20260512

Application Date

20260227

Claims (2)

1. 1. A control method of an energy storage bidirectional resonant converter is characterized by comprising the following steps: The bidirectional resonant converter is composed of a first direct current power supply (DC 1 ), a first bridge type switch unit (10), a second bridge type switch unit (30), a resonant unit (20), a transformer (T) and a second direct current power supply (DC 2 ); The transformer (T) is composed of a primary winding (N p ) and a secondary winding (N s ); The first bridge type switch unit (10) is composed of a switch tube S 1 ~S 4 , the drain electrode of the first switch tube (S 1 ) is connected with the positive electrode of a first direct current power supply (DC 1 ) and the drain electrode of a third switch tube (S 3 ), the source electrode of the second switch tube (S 2 ) is connected with the negative electrode of the first direct current power supply (DC 1 ) and the source electrode of the fourth switch tube (S 4 ), the source electrode of the first switch tube (S 1 ) is connected with the drain electrode of the second switch tube (S 2 ), the source electrode of the third switch tube (S 3 ) is connected with the drain electrode of the fourth switch tube (S 4 ), the source electrode of the first switch tube (S 1 ) is connected with the same-name end of a primary winding (N p ) of a transformer (T), and the source electrode of the third switch tube (S 3 ) is connected with the non-same-name end of a primary winding (N p ) of the transformer (T); The resonance unit (20) is composed of a resonance inductor (L r ) and a resonance capacitor (C r ), one end of the resonance inductor (L r ) is connected with the homonymous end of a secondary winding (N s ) of the transformer (T), and the other end of the resonance inductor is connected with one end of the resonance capacitor (C r ); The second bridge type switching unit (30) is composed of a switching tube S 5 ~S 8 , a fifth switching tube (S 5 ) is connected with the drain electrode of a seventh switching tube (S 7 ) and the positive electrode of a second direct current power supply (DC 2 ), the source electrode of the sixth switching tube (S 6 ) is connected with the negative electrode of the second direct current power supply (DC 2 ) and the source electrode of the eighth switching tube (S 8 ), the source electrode of the fifth switching tube (S 5 ) is connected with the drain electrode of the sixth switching tube (S 6 ), the source electrode of the seventh switching tube (S 7 ) is connected with the drain electrode of the eighth switching tube (S 8 ), the source electrode of the fifth switching tube (S 5 ) is connected with one end of a resonant capacitor (C r ) of the resonant unit (20), and the source electrode of the seventh switching tube (S 7 ) is connected with the non-homonymous end of a secondary winding (N s ) of the transformer (T); the control method of the switching tube in the first bridge type switching unit (10) comprises the following steps: The first switching tube (S 1 ) is complementarily conducted with the second switching tube (S 2 ), the third switching tube (S 3 ) is complementarily conducted with the fourth switching tube (S 4 ), the switching frequencies of the first switching tube (S 1 ), the second switching tube (S 2 ), the third switching tube (S 3 ) and the fourth switching tube (S 4 ) are equal to or more than the resonant frequency of the resonant inductor (L r ) and the resonant capacitor (C r ) in the resonant unit (20); The control method of the switching tube in the second bridge type switching unit (30) comprises the following steps: The fifth switching tube (S 5 ) is in complementary conduction with the sixth switching tube (S 6 ), the seventh switching tube (S 7 ) is in complementary conduction with the eighth switching tube (S 8 ), the switching frequencies of the fifth switching tube (S 5 ), the sixth switching tube (S 6 ), the seventh switching tube (S 7 ) and the eighth switching tube (S 8 ) are equal to or more than the resonant frequency of the resonant inductor (L r ) and the resonant capacitor (C r ) in the resonant unit (20); All switching tube driving signals of the first bridge type switching unit (10) and the second bridge type switching unit (30) are realized by the following method: The driving signals of the first switching tube (S 1 ), the fourth switching tube (S 4 ), the fifth switching tube (S 5 ) and the eighth switching tube (S 8 ) pass through a first modulation wave (V m1 ), A second modulated wave (V m2 ), a third modulated wave (V m3 ), The fourth modulated wave (V m4 ) is obtained by cutting off the carrier wave (V c ), the carrier wave (V c ) is a triangular wave with central symmetry, the amplitude ranges of the modulated wave and the carrier wave are 0 to V cpk , the sum of the first modulated wave (V m1 ) and the second modulated wave (V m2 ) is equal to the peak value of the carrier wave (V c ) (V m1 +V m2 =V cpk ), the sum of the third modulated wave (V m3 ) and the fourth modulated wave (V m4 ) is equal to the peak value of the carrier wave (V c ) (V m3 +V m4 =V cpk ), the driving signal of the second switching tube (S 2 ) is generated by being complementary to the driving signal of the first switching tube (S 1 ), the driving signal of the third switching tube (S 3 ) is generated by being complementary to the driving signal of the fourth switching tube (S 4 ), the driving signal of the sixth switching tube (S 6 ) is generated by being complementary to the driving signal of the fifth switching tube (S 5 ), the driving signal of the seventh switching tube (S 7 ) is generated by being complementary to the driving signal of the eighth switching tube (S 8 ), and the two switching units are cyclically cycled with one time and the two switching units.
2. 2. The energy storage bidirectional resonant converter control method based on claim 1, characterized by comprising the following steps: The control method for the bidirectional resonant converter working in the buck mode comprises the following steps: Adjusting the output power of the bidirectional resonant converter by adjusting the first modulation wave (V m1 ) and the second modulation wave (V m2 ), wherein the third modulation wave (V m3 ) is equal to the fourth modulation wave (V m4 ) and is equal to half of the peak value of the triangular carrier wave (V c ), the duty cycle of the fifth switching tube (S 5 ) is generated by the intersection of the third modulation wave (V m3 ) and the carrier wave, and the duty cycle of the eighth switching tube (S 8 ) is generated by the intersection of the fourth modulation wave (V m4 ) and the carrier wave (V c ); Any two adjacent switching periods, wherein in one switching period, the duty cycle of a first switching tube (S 1 ) of the first bridge switching unit (10) is generated by the intersection of a first modulation wave (V m1 ) and a triangular carrier wave (V c ), the duty cycle of a fourth switching tube (S 4 ) is generated by the intersection of a second modulation wave (V m2 ) and the triangular carrier wave (V c ), and in the other switching period, the duty cycle of a first switching tube (S 1 ) of the first bridge switching unit (10) is generated by the intersection of a second modulation wave (V m2 ) and the triangular carrier wave (V c ), and the duty cycle of a fourth switching tube (S 4 ) is generated by the intersection of the first modulation wave (V m1 ) and the triangular carrier wave (V c ); the control method for the bidirectional resonant converter working in the boost mode comprises the following steps: Adjusting the output power of the bidirectional resonant converter by adjusting a third modulation wave (V m3 ) and a fourth modulation wave (V m4 ), wherein the first modulation wave (V m1 ) is equal to the second modulation wave (V m2 ) and is equal to half of the peak value of a triangular carrier wave (V c ), the duty cycle of a first switching tube (S 1 ) is generated by the intersection of the first modulation wave (V m1 ) and the carrier wave (V c ), and the duty cycle of a fourth switching tube (S 4 ) is generated by the intersection of the second modulation wave (V m2 ) and the carrier wave (V c ); Any two adjacent switching periods, wherein in one switching period, the duty cycle of the fifth switching tube (S 5 ) of the second bridge switching unit (30) is generated by the intersection of the third modulation wave (V m3 ) and the triangular carrier wave (V c ), the duty cycle of the eighth switching tube (S 8 ) is generated by the intersection of the fourth modulation wave (V m4 ) and the triangular carrier wave (V c ), and in the other switching period, the duty cycle of the fifth switching tube (S 5 ) of the second bridge switching unit (30) is generated by the intersection of the fourth modulation wave (V m4 ) and the triangular carrier wave (V c ), and the duty cycle of the eighth switching tube (S 8 ) is generated by the intersection of the third modulation wave (V m3 ) and the triangular carrier wave (V c ).

Description

Control method of energy storage bidirectional resonant converter Technical Field The invention relates to a control method of an energy storage bidirectional resonant converter, belongs to the technical field of power electronic converters, and particularly belongs to the technical field of bidirectional direct current-direct current electric energy conversion. Background In the field of new energy and electric energy management such as electric automobiles and energy storage systems, the bidirectional converter plays an indispensable role as a core device for energy interconnection and efficient management and control, and the application of the bidirectional converter can effectively reduce the whole volume, weight and manufacturing cost of the system and provide key support for miniaturization and economical improvement of related equipment. Meanwhile, with the large-scale popularization and industrialization application of the solar photovoltaic power generation system, the direct-current bidirectional converter continuously expands market demands by virtue of the core characteristics of high efficiency, stability and reliability, and has important values in the aspects of improving the energy conversion efficiency of the photovoltaic power generation system and guaranteeing the operation stability and reliability of the system. At present, how to further improve the power transmission efficiency of the bidirectional converter, develop a control strategy with excellent performance, smooth output and running stability, and become the focus of core research direction and industry attention in the technical field. The traditional LLC variable frequency resonant converter has the advantages of low switching loss, high efficiency and high reliability, but in a new energy occasion, how to realize wide-range voltage regulation is an important difficult problem, the traditional LLC variable frequency resonant converter needs to be designed to be small in order to widen the voltage regulation range, so that the reactive circulation loss of a resonant cavity of a transformer becomes large and the efficiency is reduced, the wide voltage regulation range and the high efficiency cannot be realized at the same time, and the forward and reverse power transmission smooth switching cannot be realized due to the fact that the forward and reverse transmission characteristics are inconsistent, meanwhile, the traditional direct current bidirectional converter is mainly of a two-stage type framework, and the single-stage framework is more advantageous in terms of inherent high efficiency and high density in order to realize the direct current bidirectional converter with high efficiency and high density. In order to enable the resonant converter to have wide-range voltage regulation capability, reduce the frequency variation range of the resonant converter and improve the efficiency and the power density, a patent CN106026645A (publication day: 2016-10-12) proposes a small bidirectional resonant converter which can be applied to an energy storage system and photovoltaic power generation, the converter has the capability of boosting and reducing voltage by utilizing a constant-frequency pulse width modulation strategy, the forward transmission and the reverse transmission have the same characteristics, the gain is only related to the duty ratio of an original secondary side, the gain is irrelevant to the load, the power transmission direction can be quickly and smoothly switched, and the gain range from 0 to infinity can be theoretically realized. Disclosure of Invention The invention aims at overcoming the defects of the prior art, and provides a control method of an energy storage bidirectional resonant converter, which enables the converter to work around a series resonance point all the time, realizes energy bidirectional regulation by adjusting the duty ratio of a bridge type switching unit, has the capability of smoothly realizing the fast switching of bidirectional power transmission independent of the size and the direction of the transmitted power, and simultaneously can realize the uniform distribution of heat of switching tubes of the bridge type switching unit in a boosting mode and a buck mode and effectively reduce the local highest thermal stress by taking two switching periods as a cycle to rotate the switching time sequence of the bridge type switching unit at the voltage regulation side. The bidirectional resonant converter is realized by the following technical scheme that the bidirectional resonant converter consists of a first direct current power supply (DC 1), a first bridge type switch unit (10), a second bridge type switch unit (30), a resonant unit (20), a transformer (T) and a second direct current power supply (DC 2). The transformer (T) is composed of a primary winding (N p) and a secondary winding (N s). The first bridge type switch unit (10) is composed of a switch tube S 1~S4, a drain electrod