KR101851921B1 - The Solar Power Grid-connected Power Supply - Google Patents

Abstract

In the present invention, in a solar power system-connected power conversion apparatus, a solar cell 100 that receives sunlight to generate electricity energy; A step-up type converter 10 that receives a voltage generated from the solar cell 100 and boosts the DC voltage to 300 [V] to 400 [V]; (AC) 220 [V] is supplied to an AC load (Load) on the basis of outputs of DC [DC] 300 [V] to 400 [V] of the step- An inverter 30; (DC) 400 [V] to the first lithium ion battery 200 on the basis of outputs of DC [DC] 300 [V] to 400 [V] of the step-up type converter 10. [ (20); If the state of charge (SOC) of the first lithium ion battery 200 of the direct current (DC) 400 [V] exceeds 80 to 85%, the second lithium ion battery 300 is charged with a direct current A second bidirectional converter 50 supplying 800 [V] to 2000 [V]; A first relay 31 for determining that the output of the half bridge grid inverter 30 is transmitted to the first and second AC output terminals AC1 and AC2; A second relay (35) for determining that the output of the first bidirectional converter (20) is to be supplied to the first lithium ion battery (200); A step-down type converter 60 for supplying a desired voltage from a DC load based on a voltage charged in the first lithium-ion battery 200; When the magnitude of the capacitance [F] of the capacitor of the first lithium ion battery 200 is equal to the magnitude of the capacitance F of the capacitor of the second lithium ion battery 300, Wherein the state of charge of the battery 300 is at most 25 times greater than the state of charge of the first lithium ion battery 200. The solar- Lt; / RTI >

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a solar power grid-

There is a growing demand for pollution-free power generation globally or nationally, and there is growing interest in photovoltaic power generation as a substitute for nuclear power and thermal power generation. The present invention stores electricity generated by a solar cell in a first lithium-ion battery of a low voltage and a second lithium-ion battery of a high voltage, supplies AC power through a grid-connected inverter, And more particularly, to a solar power grid-connected power converter that supplies DC power through a converter.

In recent years, interest in renewable energy has increased, and a solar panel is a device that functions to convert sunlight into electrical energy.

Fig. 1 shows the principle of solar power generation. A solar panel refers to a semiconductor device that converts sunlight into electrical energy using photoelectric effect. When the photovoltaic effect receives solar light on the contact surface of the metal and the semiconductor or the p-n junction of the semiconductor, electrons and holes are formed in the semiconductor. The electrons move to the front electrode, and the holes move to the rear electrode. Thereby, a voltage difference is generated between the front electrode and the rear electrode, and the electrons and the electrons move to the electric load. Generally, since the current flow is defined as the direction of the hole movement, the (+) voltage is generated electrically at the back electrode and the (-) voltage is generated at the front electrode.

In order to use electric energy generated from the solar panel, various inventions have been conventionally performed.

As a related prior art, Korean Utility Model Registration No. 10-1776160, Publication Date 2017. 09. 08 (hereinafter referred to as "Patent Document 1") proposed a grid-connected solar / ESS power conversion device. Patent Document 1 discloses a grid-type solar cell / ESS power conversion apparatus composed of a power conversion device, a filter, a circuit breaker, and a load based on a DC power generated in a solar panel or the like. And a controller is disposed between the filter and the breaker to control electricity used in the load.

As another prior art, Korean Patent Registration No. 10-1245647, Publication Date 2013. 03. 20. (hereinafter referred to as "Patent Document 2") discloses a battery rapid charging system in connection with a solar power generation system . In the above-described Patent Document 2, a DC / DC converter unit that boosts a DC voltage input to the solar cell to a predetermined DC output voltage in accordance with a maximum power point corresponding to a solar radiation amount and a temperature of the solar cell; DC link portion; An inverter for supplying a three-phase AC voltage to the system; Three Phase Bidirectional PWM Converter; And an isolated DC / DC converter unit controlling the constant voltage constant current mode. There is a technical feature that it is possible to quickly charge the battery by charging the battery and charge the battery within about 20 minutes up to 80% of the state of charge (SOC).

In the above conventional [Patent Document 1] and [Patent Document 2], a system for supplying energy generated from a solar panel to a load has been proposed, but there has been a limit in storing power in a battery rationally.

[Patent Document 1] Korean Registered Patent No. 10-1776160, Published Date 2017. 09. 08. [Patent Document 2] Korean Registered Patent No. 10-1245647, Published on March 20, 2013. [Patent Document 3] Korean Registered Patent No. 10-1766433, Published on Aug. 2017.

The present invention provides the most reasonable power conversion apparatus for storing the electric energy generated in the solar cell 100 in the first and second lithium-ion batteries 200 and 300 having a large capacity. In order to store electric energy produced by a solar panel, a grid-connected inverter (30,90) and a first lithium-ion battery 200 (200) of low voltage that can be used immediately by the step-down type converter (60) And the battery capacity of the first lithium-ion battery 200 is exceeded due to the production of considerable electric energy in the solar cell 100, the second lithium-ion battery 300 having a high voltage is rationally To provide a solar-grid-connected power conversion apparatus that stores energy of the solar cell (100) and provides it to an alternating current (AC) load and a direct current (DC) load.

The present invention provides a solar-power-based power conversion apparatus comprising a step-up type converter (10) for boosting an output voltage of a solar cell (100) Way converter (20 or 70) for transmitting power to the first lithium-ion battery (200), the first lithium-ion battery (200) is a low voltage, the second lithium-ion battery (300) is a high voltage, A second bidirectional converter 20 or 70 for charging the first lithium-ion battery 200 with a low voltage when the first lithium-ion battery 200 is overcharged by the second lithium-ion battery 300 having a high voltage, (30) for supplying energy stored in a first lithium ion battery (200) of a low voltage to an alternating current (AC) load, a second lithium ion battery (AC) load (Load) stored in the power storage unit 200 And a step-down converter 60 in the technical characteristics.

In the present invention, when the electric energy produced by the solar cell 100 is insufficient, it is stored in the first lithium-ion battery 200 having a low voltage through the solar- When the battery 100 has sufficient electric energy, it is stored in the second lithium-ion battery 300 having a high voltage, so that it can be rationally distributed in the energy storage. Second, the lithium-ion battery 200, The energy storage density can be adjusted by changing the voltage stored in the second lithium-ion battery 300 of the high voltage rather than storing energy by specifically expanding the capacity. Third, energy can be supplied to an AC load and a DC load based on the energy stored in the first lithium-ion battery 200 of a low voltage. Fourth, Since the controller of the boost converter, the grid inverter, the bidirectional converter and the step-down converter is proposed for comprehensive control of the energy, the energy control can be effectively performed.

Fig. 1 is a view showing a solar power generation principle
FIG. 2 is a view showing a solar-system-connected power conversion apparatus (first embodiment)
Fig. 3 is a diagram showing a solar-power-linked power conversion apparatus (second embodiment)
FIG. 4 is a block diagram of the controller of the step-
5 is a block diagram of the grid-
Figure 6 is a block diagram of the controller of the second bidirectional converter
FIG. 7 is a circuit diagram of a step-

W : 배터리에 저장된 에너지[W]
C : 배터리의 용량[F]
V : 배터리에 공급되는 전압[V]

따라서 리튬이온 배터리(200,300)에 저장된 에너지(W)는 배터리의 전압[V]에 제곱에 비례한다. 따라서 상기 리튬이온 배터리(200,300)에서 전압이 2배가 되면, 에너지 저장밀도가 4배가 되며, 전압이 3배가 되면, 에너지 저장밀도가 9배가 되는 특징이 있다.
본 발명에서는 직류(DC) 400[V]로 고정전압 충전을 수행하는 제1 리튬이온 배터리(200)와 직류(DC) 800[V] 내지 2000[V]로 가변전압 충전을 수행하는 제2 리튬이온 배터리(300)가 있는 것이 가장 큰 기술적 특징이며, 태양전지(100)에서 생산된 전기에너지가 충분하지 않는 경우, 저전압(低電壓)의 제1 리튬이온 배터리(200)에 저장시키며, 상기 태양전지(100)에서 생산된 전기에너지가 충분한 경우, 고전압(高電壓)의 제2 리튬이온 배터리(300)에 저장시키는 것을 기술적 특징으로 한다.
즉 태양전지(100)에서 생산된 전기에너지가 저전압(低電壓)의 제1 리튬이온 배터리(200)의 충전용량을 모두 채우기 어려운 경우, 단지 제1 리튬이온 배터리(200)에만 에너지를 저장시킨다. 하지만, 태양전지(100)에서 생산된 전기에너지가 충분한 경우, 상기 제1 리튬이온 배터리(200)의 충전용량을 모두 채우게 되며, 이 경우 제2 리튬이온 배터리(300)으로 상기 제1 리튬이온 배터리(200)의 에너지를 변환하게 된다.
상기 제2 리튬이온 배터리(300)의 전압은 직류(DC) 800[V] 내지 2000[V]로 가변전압 충전을 수행하게 된다. 기존까지 배터리 충전은 일반적으로 고정전압을 충전시킨다.
하지만 본 발명에서는 직류(DC) 800[V] 내지 2000[V]로 가변전압 충전을 수행하기 때문에 상기 제2 리튬이온 배터리(300)의 충전 전압을 제어함을 통하여 에너지 저장밀도를 조절시킬 수 있는 상승된 효과가 있다.
본 발명에서는 제1 리튬이온 배터리(200)의 충전용량(SOC: State of Charge)이 80 내지 85[%]를 초과한 경우 제2 리튬이온 배터리(300)로 전력을 저장시킬 수 있다.
상기 제2 양방향 컨버터(50)는 상기 제1 리튬이온 배터리(200)의 에너지를 상기 제2 리튬이온 배터리(300)로 전달시키는 기능을 수행하며, 직류(DC) 400[V]로 고정전압 충전하는 상기 제1 리튬이온 배터리(200)에서 직류(DC) 800[V] 내지 2000[V]로 가변전압 충전이 가능한 제2 리튬이온 배터리(300)로 에너지 전달을 수행하는 것을 기술적 특징으로 한다.
예로서 상기 제1 리튬이온 배터리(200)와 상기 제2 리튬이온 배터리(300)의 커패시터(Capacitor)의 크기가 동일하다면, 상기 직류(DC) 400[V]의 제1 리튬이온 배터리(200)보다 최대 5배 큰 직류(DC) 2000[V]의 상기 제2 리튬이온 배터리(300)의 경우 에너지 저장 밀도가 5의 제곱인 25배 큰 충전용량(SOC: State of Charge)을 보유시킬 수 있다.
즉 비록 제1 리튬이온 배터리(200)와 제2 리튬이온 배터리(300)의 커패시터(Capacitor)의 크기가 동일하지만, 상기 제2 리튬이온 배터리(300)의 충전전압을 최대 5배로 더 크게 할 수 있기 때문에 충전용량(SOC: State of Charge)을 최대 25배(5의 제곱)로 할 수 있는 것을 가장 큰 기술적 특징으로 한다.
이로 인하여 상기 제2 리튬이온 배터리(300)의 크기를 최대한 저감시키면서, 제2 리튬이온 배터리(300)의 충전용량(SOC: State of Charge)을 최대 25배(5의 제곱)로 상승할 수 있는 매우 상승된 효과가 있다.
본 발명에서는 직류(DC) 부하(Load)에서 전기에너지를 요구하는 경우 상기 직류(DC) 400[V]의 제1 리튬이온 배터리(200)에 저장된 전기에너지를 강압형 컨버터(60)를 통하여 상기 직류(DC) 부하(Load)에서 원하는 전압으로 강압시키면서 공급할 수 있다.
도 3은 태양광 계통연계 전력변환장치(제2 실시예)를 나타낸다.
상기 태양광 계통연계 전력변환장치(제2 실시예)는 태양전지(100)에서 생산된 전기에너지가 승압형 컨버터(10)를 통하여 직류(DC) 300[V] 내지 400[V]로 승압하게 된다. 더불어 상기 직류(DC) 300[V] 내지 400[V]로 승압된 전기에너지는 (1)하프브리지 계통연계 인버터(30)를 통하여 교류(AC) 부하(Load)에 교류(AC) 220[V]를 공급될 수 있으며, (2)제11 양방향 컨버터(70)을 통하여 제1 리튬이온 배터리(200)에 공급될 수 있다. 상기 직류(DC) 300[V] 내지 400[V]로 승압된 전기에너지를 상기 교류(AC) 부하(Load)에 공급할 것인지 아니면, 상기 제1 리튬이온 배터리(200)에 공급할 것인지 여부는 제1,2 릴레이(31,35)에 의해서 결정이 된다.
도 2(제1 실시예)에서는 하프브리지 계통연계 인버터(30)를 사용하며 도 3(제2 실시예)에서는 풀브리지 계통연계 인버터(90)를 사용한 것이 차이이며, 상기 교류(AC) 부하(Load)에서 요구하는 전력량이 적은 경우 상기 하프브리지 계통연계 인버터(30)가 사용되며 상기 교류(AC) 부하(Load)에서 요구하는 전력량이 상대적으로 큰 경우 상기 풀브리지 계통연계 인버터(90)를 사용하는 것을 기술적 특징으로 한다.
상기 승압형 컨버터(10)를 통하여 상기 직류(DC) 300[V] 내지 400[V]로 승압된 전기에너지는 상기 제11 양방향 컨버터(70)에서 직류(DC) 400[V]로 상기 제1 리튬이온 배터리(200)에 충전하게 된다. 상기 제1 리튬이온 배터리(200)를 본 발명에서는 저전압(低電壓) 리튬이온 배터리라고 정의하며 이는 제2 리튬이온 배터리(300)의 충전 전압이 직류(DC) 800[V] 내지 2000[V]이기 때문이다. 따라서 상기 제2 리튬이온 배터리(300)를 고전압(高電壓) 리튬이온 배터리라고 정의하고 있다.

- 제1 리튬이온 배터리(200)[저전압(低電壓) 리튬이온 배터리] : 직류(DC) 400[V]로 고정전압 충전
- 제2 리튬이온 배터리(300)[고전압(高電壓) 리튬이온 배터리] : 직류(DC) 800[V] 내지 2000[V]로 가변전압 충전

특히 리튬이온 배터리(200,300)에 저장된 에너지(W)는 위의 식(1)과 같다.
따라서 리튬이온 배터리(200,300)에 저장된 에너지(W)는 배터리의 전압[V]에 제곱에 비례한다. 따라서 상기 리튬이온 배터리(200,300)에서 전압이 2배가 되면, 에너지 저장밀도가 4배가 되며, 전압이 3배가 되면, 에너지 저장밀도가 9배가 되는 특징이 있다.
본 발명에서는 직류(DC) 400[V]로 고정전압 충전을 수행하는 제1 리튬이온 배터리(200)와 직류(DC) 800[V] 내지 2000[V]로 가변전압 충전을 수행하는 제2 리튬이온 배터리(300)가 있는 것이 가장 큰 기술적 특징이며, 태양전지(100)에서 생산된 전기에너지가 충분하지 않는 경우, 저전압(低電壓)의 제1 리튬이온 배터리(200)에 저장시키며, 상기 태양전지(100)에서 생산된 전기에너지가 충분한 경우, 고전압(高電壓)의 제2 리튬이온 배터리(300)에 저장시키는 것을 기술적 특징으로 한다.
즉 태양전지(100)에서 생산된 전기에너지가 저전압(低電壓)의 제1 리튬이온 배터리(200)의 충전용량을 모두 채우기 어려운 경우, 단지 제1 리튬이온 배터리(200)에만 에너지를 저장시킨다. 하지만, 태양전지(100)에서 생산된 전기에너지가 충분한 경우, 상기 제1 리튬이온 배터리(200)의 충전용량을 모두 채우게 되며, 이 경우 제2 리튬이온 배터리(300)으로 상기 제1 리튬이온 배터리(200)의 에너지를 변환하게 된다.
상기 제2 리튬이온 배터리(300)의 전압은 직류(DC) 800[V] 내지 2000[V]로 가변전압 충전을 수행하게 된다. 기존까지 배터리 충전은 일반적으로 고정전압을 충전시킨다.
하지만 본 발명에서는 직류(DC) 800[V] 내지 2000[V]로 가변전압 충전을 수행하기 때문에 상기 제2 리튬이온 배터리(300)의 충전 전압을 제어함을 통하여 에너지 저장밀도를 조절시킬 수 있는 상승된 효과가 있다.
본 발명에서는 제1 리튬이온 배터리(200)의 충전용량(SOC: State of Charge)이 80 내지 85[%]를 초과한 경우 제2 리튬이온 배터리(300)로 전력을 저장시킬 수 있다.
상기 제2 양방향 컨버터(50)는 상기 제1 리튬이온 배터리(200)의 에너지를 상기 제2 리튬이온 배터리(300)로 전달시키는 기능을 수행하며, 직류(DC) 400[V]로 고정전압 충전하는 상기 제1 리튬이온 배터리(200)에서 직류(DC) 800[V] 내지 2000[V]로 가변전압 충전이 가능한 제2 리튬이온 배터리(300)로 에너지 전달을 수행하는 것을 기술적 특징으로 한다.
예로서 상기 제1 리튬이온 배터리(200)와 상기 제2 리튬이온 배터리(300)의 커패시터(Capacitor)의 크기가 동일하다면, 상기 직류(DC) 400[V]의 제1 리튬이온 배터리(200)보다 최대 5배 큰 직류(DC) 2000[V]의 상기 제2 리튬이온 배터리(300)의 경우 에너지 저장 밀도가 5의 제곱인 25배 큰 충전용량(SOC: State of Charge)을 보유시킬 수 있다.
즉 비록 제1 리튬이온 배터리(200)와 제2 리튬이온 배터리(300)의 커패시터(Capacitor)의 크기가 동일하지만, 상기 제2 리튬이온 배터리(300)의 충전전압을 최대 5배로 더 크게 할 수 있기 때문에 충전용량(SOC: State of Charge)을 최대 25배(5의 제곱)로 할 수 있는 것을 가장 큰 기술적 특징으로 한다.
이로 인하여 상기 제2 리튬이온 배터리(300)의 크기를 최대한 저감시키면서, 제2 리튬이온 배터리(300)의 충전용량(SOC: State of Charge)을 최대 25배(5의 제곱)로 상승할 수 있는 매우 상승된 효과가 있다.
본 발명에서는 직류(DC) 부하(Load)에서 전기에너지를 요구하는 경우 상기 직류(DC) 400[V]의 제1 리튬이온 배터리(200)에 저장된 전기에너지를 강압형 컨버터(60)를 통하여 상기 직류(DC) 부하(Load)에서 원하는 전압으로 강압시키면서 공급할 수 있다.
도 4는 승압형 컨버터(10)의 제어기를 나타낸다.
상기 승압형 컨버터(10)는 태양전지(100)에서 생산된 전기에너지를 직류(DC) 300 내지 400[V]로 승압시키는 것을 기술적 특징으로 한다. 이의 제어를 위하여 제1 덧셈기(401)에서는 승압형 컨버터의 출력 커패시터의 실제전압(Vdclink)과 승압형 컨버터의 출력 커패시터의 기준전압(Vdcref)의 오차를 검출한다. 그 후에 제1 PI 제어기(402)에서는 비례-적분 제어를 수행하며, 상기 출력 커패시터의 실제전압(Vdclink)과 승압형 컨버터의 출력 커패시터의 기준전압(Vdcref)의 오차를 저감하는 방향으로 제1 리튬이온 배터리 기준전류(Ibatref)를 생성하게 된다. 제2 덧셈기에서는 제1 리튬이온 배터리 실제전류(Ibat)와 상기 제1 리튬이온 배터리 기준전류(Ibatref)의 오차를 검출하며, 제2 PI 제어기(404)에서는 상기 제1 리튬이온 배터리 실제전류(Ibat)와 상기 제1 리튬이온 배터리 기준전류(Ibatref)의 오차를 저감하는 방향으로 승압형 컨버터(10)의 주 스위치의 게이트 듀티(Duty1)를 생성하는 것을 기술적 특징으로 한다.
상기 승압형 컨버터(10)의 제어기(도 4)는 태양전지(100)에서 생산된 전기에너지를 직류(DC) 300 내지 400[V]로 승압시키면서, (1)승압형 컨버터의 출력 커패시터의 실제전압(Vdclink)와 승압형 컨버터의 출력 커패시터의 기준전압(Vdcref)의 오차의 저감을 시키며, (2)배터리 제1 리튬이온 실제전류(Ibat)와 상기 제1 리튬이온 배터리 기준전류(Ibatref)의 오차를 저감하는 방향으로 제어하는 것을 가장 큰 기술적 특징으로 한다. 따라서 상기 승압형 컨버터(10)의 제어기는 제1 리튬이온 배터리 기준전류(Ibatref)를 변경하기 때문에 교류(AC) 부하(Load)에서 요구하는 전력량을 맞추기 위하여 필요한 경우 양방향 컨버터(20,70)를 동작시켜 상기 제1 리튬이온 배터리(200)에 저장된 에너지를 승압형 컨버터의 출력 커패시터(15)로 공급하는 것을 가장 큰 기술적 특징으로 한다.
도 5는 계통연계 인버터 제어기를 나타낸다.
상기 계통연계 인버터 제어기(도 5)에서는 제11 덧셈기(411)를 통하여 승압형 컨버터의 출력 커패시터의 실제전압(Vdclink)과 승압형 컨버터의 출력 커패시터의 기준전압(Vdcref)의 오차를 검출한다. 그 후에 제11 PI 제어기(412)에서는 비례-적분 제어를 수행하여 제1 계통연계 인버터 기준 전류(Iref)를 생성하게 된다. 제1,2 교류출력 단자(AC1,AC2)에서 최종적으로 출력하고자 하는 사인파(Sine Wave) 교류전압(Vsinwt)을 검출하여 위상동기화루프(PLL: Phase Locked Loop)(415)를 통하여 위상을 동기화시키며, 사인파(Sine Wave) 생성부(414)에서 생성된 상기 사인파(Sine Wave)와 제1 계통연계 인버터 기준 전류(Iref)가 제11 곱셈기(413)에 의해 곱해져서 제2 계통연계 인버터 기준 전류(Isref)를 생성하며, 제12 덧셈기(416)를 통하여 계통연계 인버터 실제 전류(Iinv)와 제2 계통연계 인버터 기준 전류(Isref)의 오차를 검출한다. 그 후에 제12 PI 제어기(417)를 통하여 계통연계 인버터 제어를 위한 제1 게이트 듀티(D1)를 생성한다. 또한, 계통연계 인버터 전압(Vs)과 승압형 컨버터의 출력 커패시터의 실제전압(Vdclink)의 비율이 사인파(Sine Wave) 생성부(414)에서 생성된 상기 사인파(Sine Wave)와 제12 곱셈기(419)를 통하여 곱해짐을 통하여 계통연계 인버터 제어를 위한 제2 게이트 듀티(D2)를 형성하게 된다. 제13 덧셈기(418)를 통하여 계통연계 인버터 제어를 위한 제1 게이트 듀티(D1)와 계통연계 인버터 제어를 위한 제2 게이트 듀티(D2)를 더함을 통하여 최종적으로 계통연계 인버터(30,90)를 제어하기 위한 게이트 신호의 생성이 가능하게 된다.
본 발명에서 계통연계 인버터(30,90)의 안정적인 제어를 위하여 제1,2 교류출력 단자(AC1,AC2)로부터 사인파(Sine Wave) 교류전압(Vsinwt)을 검출하여 위상동기화루프(PLL: Phase Locked Loop)(415)를 통하여 위상을 동기화시키는 제어가 수행되며, 상기 계통연계 인버터(30,90)의 입력단 출력 커패시터의 실제전압(Vdclink)과 승압형 컨버터의 출력 커패시터의 기준전압(Vdcref)의 오차를 바탕으로 상기 계통연계 인버터(30,90)의 제1,2 계통연계 인버터 기준 전류(Iref,Isref)를 생성하며, 이를 바탕으로 상기 계통연계 인버터(30,90)의 주 스위치를 제어하는 것을 가장 큰 기술적 특징으로 한다.
이를 통하여 안정적으로 상기 계통연계 인버터(30,90)를 통하여 교류(AC) 부하(Load)에 교류(AC) 220[V]를 공급할 수 있는 상승된 효과가 나타나게 된다.
도 6은 제2 양방향 컨버터의 제어기를 나타낸다.
상기 제2 양방향 컨버터(50)는 제1 리튬이온 배터리(200)와 제2 리튬이온 배터리(300) 사이에 위치하며, 상기 제1 리튬이온 배터리(200)의 에너지를 상기 제2 리튬이온 배터리(300)로 전달시키는 기능을 수행한다. 상기 제2 양방향 컨버터(50)의 제어기는 제21 덧셈기(421)를 통하여 제1 리튬이온 배터리 실제전류(Ibat)와 제1 리튬이온 배터리 기준전류(Ibatref)의 오차를 검출한다. 그 후에 제22 PI 제어기(422)에서는 비례-적분 제어를 수행하며, 상기 제1 리튬이온 배터리 실제전류(Ibat)와 제1 리튬이온 배터리 기준전류(Ibatref)의 오차를 저감하는 방향으로 상기 제2 양방향 컨버터(50)의 상부 및 하부 양방향 스위치(52,53)의 게이트 듀티를 형성하게 된다. 상기 제2 양방향 컨버터(50)의 상부 및 하부 양방향 스위치(52,53)는 서로 상보적(相補的)으로 동작하며, 상기 상부 양방향 스위치(52) 제어를 위한 게이트 듀티는 Db1이며, 상기 하부 양방향 스위치(53) 제어를 위한 게이트 듀티는 Db2이다. 상기 제22 PI 제어기(422)의 출력은 버퍼(Buffer)(423)를 통하여 상기 상부 양방향 스위치(52) 제어를 위한 게이트 듀티는 Db1이 생성되며, 상기 제22 PI 제어기(422)의 출력은 인버터(Inverter)(424)를 통하여 상기 하부 양방향 스위치(53) 제어를 위한 게이트 듀티는 Db2가 생성되는 것을 가장 큰 기술적 특징으로 한다.
출력 커패시터의 실제전압(Vdclink)과 승압형 컨버터의 출력 커패시터의 기준전압(Vdcref)의 오차를 저감하는 방향으로 제1 리튬이온 배터리 기준전류(Ibatref)를 생성하게 된다.
본 발명에서는 제1 리튬이온 배터리(200)의 충전용량(SOC: State of Charge)가 80 내지 85[%]를 초과한 경우 제2 리튬이온 배터리(300)로 전력을 저장시킬 수 있다.
상기 제2 양방향 컨버터(50)는 상기 제1 리튬이온 배터리(200)의 에너지를 상기 제2 리튬이온 배터리(300)로 전달시키는 기능을 수행하며, 직류(DC) 400[V]로 고정전압 충전하는 상기 제1 리튬이온 배터리(200)에서 직류(DC) 800[V] 내지 2000[V]로 가변전압 충전이 가능한 제2 리튬이온 배터리(300)로 에너지 전달을 수행하는 것을 기술적 특징으로 한다.
예로서 상기 제1 리튬이온 배터리(200)와 상기 제2 리튬이온 배터리(300)의 커패시터(Capacitor)의 크기가 동일하다면, 상기 직류(DC) 400[V]의 제1 리튬이온 배터리(200)보다 최대 5배 큰 직류(DC) 2000[V]의 상기 제2 리튬이온 배터리(300)의 경우 에너지 저장 밀도가 5의 제곱인 25배 큰 충전용량(SOC: State of Charge)을 보유시킬 수 있다.
즉 비록 제1 리튬이온 배터리(200)와 제2 리튬이온 배터리(300)의 커패시터(Capacitor)의 크기가 동일하지만, 상기 제2 리튬이온 배터리(300)의 충전전압을 최대 5배로 더 크게 할 수 있기 때문에 충전용량(SOC: State of Charge)을 최대 25배(5의 제곱)로 할 수 있는 것을 가장 큰 기술적 특징으로 한다.
이로 인하여 상기 제2 리튬이온 배터리(300)의 크기를 최대한 저감시키면서, 제2 리튬이온 배터리(300)의 충전용량(SOC: State of Charge)을 최대 25배(5의 제곱)로 상승할 수 있는 매우 상승된 효과가 있다.
도 7은 강압형 컨버터의 제어기를 나타낸다.
상기 강압형 컨버터(60)의 제어기(도 7)는 제31 덧셈기(431)를 통하여 강압형 컨버터의 출력 커패시터의 실제전압(Vdc1)과 강압형 컨버터의 출력 커패시터의 기준전압(Vdcref1)의 오차를 검출한다. 그 후에 제31 PI 제어기(432)에서는 비례-적분 제어를 수행하여 강압형 컨버터의 기준전류(Idcref1)를 생성하게 된다. 또한, 제32 덧셈기(433)를 통하여 강압형 컨버터의 실제전류(Idc1)와 강압형 컨버터의 기준전류(Idcref1)의 오차를 검출한다. 그 후에 제32 PI 제어기(434)에서 비례-적분 제어를 수행하여 강압형 컨버터(60)의 주 스위치의 게이트 듀티(Duty2)를 생성하는 것을 가장 큰 기술적 특징으로 한다.
본 발명에서는 강압형 컨버터(60)에서 전압제어 및 전류제어를 동시에 수행하고 있기 때문에 더욱 안정적으로 상기 강압형 컨버터(60)를 제어하는 상승된 효과가 나타난다.

본 발명에서는 태양광 계통연계 전력변환장치에 있어서 태양광을 받아서 전기(電氣)에너지를 발생시키는 태양전지(100); 상기 태양전지(100)로부터 발생된 전압을 공급받아 직류(DC) 300[V] 내지 400[V]로 승압시키는 승압형 컨버터(10); 상기 승압형 컨버터(10)의 직류(DC) 300[V] 내지 400[V]의 출력을 바탕으로 교류(AC) 부하(Load)에 교류(AC) 220[V]를 공급하는 하프브리지 계통연계 인버터(30); 상기 승압형 컨버터(10)의 직류(DC) 300[V] 내지 400[V]의 출력을 바탕으로 제1 리튬이온 배터리(200)에 직류(DC) 400[V]를 공급하는 제1 양방향 컨버터(20); 상기 직류(DC) 400[V]의 제1 리튬이온 배터리(200)의 충전용량(SOC: State of Charge)이 80 내지 85[%]를 초과한 경우, 제2 리튬이온 배터리(300)에 직류(DC) 800[V] 내지 2000[V]를 공급하는 제2 양방향 컨버터(50); 상기 하프브리지 계통연계 인버터(30)의 출력이 제1,2 교류출력 단자(AC1,AC2)로 전달하도록 결정하는 제1 릴레이(31); 상기 제1 양방향 컨버터(20)의 출력이 상기 제1 리튬이온 배터리(200)에 공급되도록 결정하는 제2 릴레이(35); 상기 제1 리튬이온 배터리(200)에 충전된 전압을 바탕으로 직류(DC) 부하(Load)에서 원하는 전압을 공급하는 강압형 컨버터(60); 상기 제1 리튬이온 배터리(200)의 커패시터의 정전용량[F] 크기와 상기 제2 리튬이온 배터리(300)의 커패시터의 정전용량[F] 크기가 동일(同一)한 경우, 상기 제2 리튬이온 배터리(300)의 충전용량(SOC: State of Charge)은 상기 제1 리튬이온 배터리(200)의 충전용량(SOC: State of Charge) 보다 최대 25배 큰 것을 특징으로 하는 태양광 계통연계 전력변환장치를 제안하고자 한다.

또한, 본 발명에서는 태양광 계통연계 전력변환장치에 있어서 태양광을 받아서 전기(電氣)에너지를 발생시키는 태양전지(100); 상기 태양전지(100)로부터 발생된 전압을 공급받아 직류(DC) 300[V] 내지 400[V]로 승압시키는 승압형 컨버터(10); 상기 승압형 컨버터(10)의 직류(DC) 300[V] 내지 400[V]의 출력을 바탕으로 교류(AC) 부하(Load)에 교류(AC) 220[V]를 공급하는 하프브리지 계통연계 인버터(30); 상기 승압형 컨버터(10)의 직류(DC) 300[V] 내지 400[V]의 출력을 바탕으로 제1 리튬이온 배터리(200)에 직류(DC) 400[V]를 공급하는 제1 양방향 컨버터(20); 상기 직류(DC) 400[V]의 제1 리튬이온 배터리(200)의 충전용량(SOC: State of Charge)이 80 내지 85[%]를 초과한 경우, 제2 리튬이온 배터리(300)에 직류(DC) 800[V] 내지 2000[V]를 공급하는 제2 양방향 컨버터(50); 상기 하프브리지 계통연계 인버터(30)의 출력이 제1,2 교류출력 단자(AC1,AC2)로 전달하도록 결정하는 제1 릴레이(31); 상기 제1 양방향 컨버터(20)의 출력이 상기 제1 리튬이온 배터리(200)에 공급되도록 결정하는 제2 릴레이(35); 상기 제1 리튬이온 배터리(200)에 충전된 전압을 바탕으로 직류(DC) 부하(Load)에서 원하는 전압을 공급하는 강압형 컨버터(60)를 포함하는 것을 특징으로 하는 태양광 계통연계 전력변환장치를 제안하고자 한다.

또한, 본 발명에서는 태양광 계통연계 전력변환장치에 있어서, 태양광을 받아서 전기(電氣)에너지를 발생시키는 태양전지(100); 상기 태양전지(100)로부터 발생된 전압을 공급받아 제1 직류전압으로 승압시키는 승압형 컨버터(10); 상기 승압형 컨버터(10)의 제1 직류전압의 출력을 바탕으로 교류(AC) 부하(Load)에 교류(AC) 전압을 공급하는 계통연계 인버터(30 또는 90); 상기 승압형 컨버터(10)의 직류(DC) 300[V] 내지 400[V]의 출력을 바탕으로 제1 리튬이온 배터리(200)에 제2 직류전압을 공급하는 제1 양방향 컨버터(20); 상기 제2 직류전압의 제1 리튬이온 배터리(200)의 충전용량(SOC: State of Charge)이 특정(特定) 충전용량을 초과한 경우, 제2 리튬이온 배터리(300)에 제3 직류전압을 공급하는 제2 양방향 컨버터(50)를 포함하는 것을 특징으로 하는 태양광 계통연계 전력변환장치를 제안하고자 한다.

상기 제1 직류전압은 직류(DC) 300 내지 400[V]가 적절하며, 상기 제2 직류전압은 직류(DC) 400[V]가 적절하며, 상기 제3 직류전압은 직류(DC) 800[V] 내지 2000[V]가 적절하지만, 이 기술의 통상의 지식을 가진자(당업자)가 일정한 전압의 범위 이내에서 적절하게 가변적으로 선택할 수 있다. 다만, 상기 제1,2,3 직류전압은 아래의 관계가 있다.
“제1 직류전압 ≤ 제2 직류전압 ≤ 제3 직류전압”인 것을 기술적 특징으로 한다.

본 발명은 이 분야의 통상의 지식을 가진자가 다양한 변형에 의하여 태양광 계통연계 전력변환장치에 적용시킬 수 있으며, 기술적으로 용이하게 변형시키는 기술의 범주도 본 특허의 권리범위에 속하는 것으로 인정해야 할 것이다.The present invention will now be described in detail with reference to the accompanying drawings.
2 shows a solar-system-connected power conversion apparatus (first embodiment).
The solar cell-based power conversion apparatus (first embodiment) is configured such that the electric energy produced by the solar cell 100 is boosted to DC (DC) from 300 [V] to 400 [V] through the boost converter 10 do. In addition, the electric energy boosted to the DC (DC) of 300 [V] to 400 [V] is supplied to the AC load 220 through the half bridge grid inverter 30, , And (2) can be supplied to the first lithium ion battery 200 through the first bidirectional converter 20. Whether to supply the alternating current (AC) load or the first lithium ion battery 200 with the electric energy boosted to the direct current (DC) of 300 [V] to 400 [V] , And 2 relays (31, 35).
The electric energy that has been boosted to DC (DC) from 300 [V] to 400 [V] through the boost converter 10 is converted into DC (DC) 400 [V] from the first bidirectional converter 20, The lithium ion battery 200 is charged. The first lithium-ion battery 200 is defined as a low-voltage lithium-ion battery in the present invention, and the charging voltage of the second lithium-ion battery 300 is 800 [V] to 2000 [ . Therefore, the second lithium-ion battery 300 is defined as a high-voltage lithium-ion battery.

- First Lithium Ion Battery (200) [Low Voltage Lithium Ion Battery]: Fixed voltage with DC (DC) 400 [V]
- Second Lithium Ion Battery (300) [High Voltage Lithium Ion Battery]: Variable voltage charging from DC (DC) 800 [V] to 2000 [V]

In particular, the energy W stored in the lithium ion batteries 200 and 300 is expressed by the following equation (1).

W: Energy stored in the battery [W]
C: Capacity of the battery [F]
V: Voltage supplied to the battery [V]

Therefore, the energy W stored in the lithium ion batteries 200 and 300 is proportional to the voltage [V] of the battery. Therefore, when the voltage is doubled in the lithium ion batteries 200 and 300, the energy storage density is quadrupled, and when the voltage is tripled, the energy storage density is increased 9 times.
In the present invention, a first lithium ion battery 200 for performing a fixed voltage charging with a direct current (DC) voltage of 400 [V] and a second lithium ion battery 200 performing variable voltage charging with a direct current (DC) voltage of 800 [V] Ion battery 300 is the most important technical feature. When the electric energy produced by the solar cell 100 is insufficient, it is stored in the first lithium-ion battery 200 of a low voltage, And is stored in the second lithium ion battery 300 having a high voltage when the electric energy produced by the battery 100 is sufficient.
That is, when the electric energy produced by the solar cell 100 is difficult to fill all of the charging capacity of the first lithium-ion battery 200 with a low voltage, only the first lithium-ion battery 200 stores energy. However, when the electric energy produced by the solar cell 100 is sufficient, the charging capacity of the first lithium-ion battery 200 is fully satisfied. In this case, the second lithium- (200).
The voltage of the second lithium ion battery 300 is variable voltage charged to DC (DC) from 800 [V] to 2000 [V]. Until now, battery charging usually charges a fixed voltage.
However, according to the present invention, since variable voltage charging is performed from 800 [V] to 2000 [V] in direct current (DC), the energy storage density can be controlled by controlling the charging voltage of the second lithium- There is an increased effect.
In the present invention, power can be stored in the second lithium ion battery 300 when the state of charge (SOC) of the first lithium ion battery 200 exceeds 80 to 85%.
The second bidirectional converter 50 functions to transfer the energy of the first lithium ion battery 200 to the second lithium ion battery 300. The second bidirectional converter 50 is charged with a fixed voltage The energy transfer from the first lithium ion battery 200 to the second lithium ion battery 300 capable of variable voltage charging from 800 [V] to 2000 [V] is performed.
For example, if the capacities of the first lithium ion battery 200 and the second lithium ion battery 300 are the same, the first lithium ion battery 200 of the direct current (DC) 400 [V] The second lithium ion battery 300 having a direct current (DC) of 2000 [V], which is five times larger than the lithium secondary battery 300, can hold a charge capacity (SOC) of 25 times the energy storage density of 5 .
That is, although the size of the capacitors of the first lithium ion battery 200 and the second lithium ion battery 300 is the same, the charging voltage of the second lithium ion battery 300 can be increased up to five times The biggest technical feature is that the charge capacity (SOC: State of Charge) can be increased up to 25 times (the square of 5).
The state of charge of the second lithium ion battery 300 can be increased up to 25 times (the square of 5) while reducing the size of the second lithium ion battery 300 as much as possible There is a very elevated effect.
In the present invention, when electric energy is required in a direct current (DC) load, the electric energy stored in the first lithium ion battery 200 of the direct current (DC) 400 [V] It can be supplied while reducing the voltage to the desired voltage from the DC (DC) load (Load).
Fig. 3 shows a solar-system-connected power converter (second embodiment).
The solar-energy-linked power conversion apparatus (the second embodiment) increases the electric energy produced by the solar cell 100 from DC [DC] to 400 [V] through the boost converter 10 do. In addition, the electric energy boosted to the DC (DC) of 300 [V] to 400 [V] is supplied to the AC load 220 through the half bridge grid inverter 30, , And (2) can be supplied to the first lithium ion battery 200 through the eleventh bidirectional converter 70. [ Whether to supply the alternating current (AC) load or the first lithium ion battery 200 with the electric energy boosted to the direct current (DC) of 300 [V] to 400 [V] , And 2 relays (31, 35).
3 (second embodiment) uses a full-bridge system grid inverter 90, and the AC load (AC load) is used in the case of using the half bridge system grid inverter 30 in the first embodiment Bridge system link inverter 30 is used when the amount of power required by the AC link load is small and the full bridge system link inverter 90 is used when the amount of power required by the AC load is relatively large. As a technical feature.
The electric energy that is boosted to DC (DC) 300 [V] to 400 [V] through the step-up type converter 10 is converted into DC [DC] 400 [V] from the eleventh bidirectional converter 70, The lithium ion battery 200 is charged. The first lithium-ion battery 200 is defined as a low-voltage lithium-ion battery in the present invention, and the charging voltage of the second lithium-ion battery 300 is 800 [V] to 2000 [ . Therefore, the second lithium-ion battery 300 is defined as a high-voltage lithium-ion battery.

- First Lithium Ion Battery (200) [Low Voltage Lithium Ion Battery]: Fixed voltage with DC (DC) 400 [V]
- Second Lithium Ion Battery (300) [High Voltage Lithium Ion Battery]: Variable voltage charging from DC (DC) 800 [V] to 2000 [V]

In particular, the energy W stored in the lithium ion batteries 200 and 300 is expressed by the above equation (1).
Therefore, the energy W stored in the lithium ion batteries 200 and 300 is proportional to the voltage [V] of the battery. Therefore, when the voltage is doubled in the lithium ion batteries 200 and 300, the energy storage density is quadrupled, and when the voltage is tripled, the energy storage density is increased 9 times.
In the present invention, a first lithium ion battery 200 for performing a fixed voltage charging with a direct current (DC) voltage of 400 [V] and a second lithium ion battery 200 performing variable voltage charging with a direct current (DC) voltage of 800 [V] Ion battery 300 is the most important technical feature. When the electric energy produced by the solar cell 100 is insufficient, it is stored in the first lithium-ion battery 200 of a low voltage, And is stored in the second lithium ion battery 300 having a high voltage when the electric energy produced by the battery 100 is sufficient.
That is, when the electric energy produced by the solar cell 100 is difficult to fill all of the charging capacity of the first lithium-ion battery 200 with a low voltage, only the first lithium-ion battery 200 stores energy. However, when the electric energy produced by the solar cell 100 is sufficient, the charging capacity of the first lithium-ion battery 200 is fully satisfied. In this case, the second lithium- (200).
The voltage of the second lithium ion battery 300 is variable voltage charged to DC (DC) from 800 [V] to 2000 [V]. Until now, battery charging usually charges a fixed voltage.
However, according to the present invention, since variable voltage charging is performed from 800 [V] to 2000 [V] in direct current (DC), the energy storage density can be controlled by controlling the charging voltage of the second lithium- There is an increased effect.
In the present invention, power can be stored in the second lithium ion battery 300 when the state of charge (SOC) of the first lithium ion battery 200 exceeds 80 to 85%.
The second bidirectional converter 50 functions to transfer the energy of the first lithium ion battery 200 to the second lithium ion battery 300. The second bidirectional converter 50 is charged with a fixed voltage The energy transfer from the first lithium ion battery 200 to the second lithium ion battery 300 capable of variable voltage charging from 800 [V] to 2000 [V] is performed.
For example, if the capacities of the first lithium ion battery 200 and the second lithium ion battery 300 are the same, the first lithium ion battery 200 of the direct current (DC) 400 [V] The second lithium ion battery 300 having a direct current (DC) of 2000 [V], which is five times larger than the lithium secondary battery 300, can hold a charge capacity (SOC) of 25 times the energy storage density of 5 .
That is, although the size of the capacitors of the first lithium ion battery 200 and the second lithium ion battery 300 is the same, the charging voltage of the second lithium ion battery 300 can be increased up to five times The biggest technical feature is that the charge capacity (SOC: State of Charge) can be increased up to 25 times (the square of 5).
The state of charge of the second lithium ion battery 300 can be increased up to 25 times (the square of 5) while reducing the size of the second lithium ion battery 300 as much as possible There is a very elevated effect.
In the present invention, when electric energy is required in a direct current (DC) load, the electric energy stored in the first lithium ion battery 200 of the direct current (DC) 400 [V] It can be supplied while reducing the voltage to the desired voltage from the DC (DC) load (Load).
Fig. 4 shows the controller of the step-up converter 10. Fig.
The boost converter 10 has a technical feature of boosting the electric energy produced by the solar cell 100 to a direct current (DC) of 300 to 400 [V]. For this purpose, the first adder 401 detects an error between the actual voltage (Vdclink) of the output capacitor of the step-up converter and the reference voltage (Vdcref) of the output capacitor of the step-up converter. Thereafter, the first PI controller 402 performs proportional-integral control, and performs a proportional-integral control in the direction of reducing the error between the actual voltage Vdclink of the output capacitor and the reference voltage Vdcref of the output capacitor of the step- Ion battery reference current Ibatref. In the second adder, an error between the first lithium-ion battery actual current Ibat and the first lithium-ion battery reference current Ibatref is detected. In the second PI controller 404, the first lithium-ion battery actual current Ibat And the gate duty (Duty1) of the main switch of the step-up type converter (10) in the direction of reducing the error between the reference current (Ibatref) and the first lithium ion battery reference current (Ibatref).
4) of the step-up converter 10 boosts the electric energy produced by the solar cell 100 to DC (DC) 300 to 400 [V], and (1) realizes the output capacitor of the step- The difference between the voltage Vdclink and the reference voltage Vdcref of the output capacitor of the step-up converter is reduced, and (2) the difference between the battery first lithium ion actual current Ibat and the first lithium ion battery reference current Ibatref And the control is performed in the direction of reducing the error. Therefore, since the controller of the step-up type converter 10 changes the first lithium-ion battery reference current Ibatref, the bidirectional converters 20 and 70 are required to adjust the amount of power required in the AC load. And the energy stored in the first lithium ion battery 200 is supplied to the output capacitor 15 of the step-up type converter.
5 shows a grid-connected inverter controller.
5), an error between the actual voltage (Vdclink) of the output capacitor of the step-up converter and the reference voltage (Vdcref) of the output capacitor of the step-up converter is detected through the eleventh adder (411). Thereafter, the eleventh PI controller 412 performs proportional-integral control to generate the first grid-connected inverter reference current Iref. The sine wave AC voltage Vsinwt to be finally outputted is detected at the first and second AC output terminals AC1 and AC2 and the phases are synchronized through a phase locked loop (PLL) The sine wave generated by the sine wave generator 414 and the first grid link inverter reference current Iref are multiplied by an eleventh multiplier 413 to generate a second grid link inverter reference current And the error between the grid link inverter actual current Iinv and the second grid link inverter reference current Isref is detected through the twelfth adder 416. [ And then generates a first gate duty (D1) for the grid-connected inverter control through the twelfth PI controller (417). The ratio of the grid link inverter voltage Vs to the actual voltage Vdclink of the output capacitor of the step-up converter is the sum of the sine wave generated by the sine wave generator 414 and the twelfth multiplier 419 To form a second gate duty D2 for the grid-connected inverter control. Connected inverter 30 and 90 through a thirteenth adder 418 to add a first gate duty D1 for controlling the grid-connected inverter and a second gate duty D2 for controlling the grid-connected inverter through the thirteenth adder 418 It is possible to generate a gate signal for control.
In the present invention, a sinusoidal AC voltage Vsinwt is detected from the first and second AC output terminals AC1 and AC2 for stable control of the grid-connected inverters 30 and 90 and a phase locked loop (PLL) (Vdclink) of the input stage output capacitor of the system link inverter (30, 90) and the reference voltage (Vdcref) of the output capacitor of the step-up converter Based inverter based reference currents (Iref, Isref) of the grid-connected inverters 30 and 90 and controlling the main switches of the grid-connected inverters 30 and 90 based on the generated first and second grid- It is the biggest technical feature.
The AC voltage 220 [V] can be stably supplied to the AC load through the grid-connected inverters 30 and 90. [0052]
6 shows a controller of a second bidirectional converter.
The second bidirectional converter 50 is disposed between the first lithium ion battery 200 and the second lithium ion battery 300 and supplies energy of the first lithium ion battery 200 to the second lithium ion battery 300). The controller of the second bidirectional converter 50 detects an error between the first lithium ion battery actual current Ibat and the first lithium ion battery reference current Ibatref through the twenty first adder 421. Thereafter, the 22nd PI controller 422 carries out the proportional-integral control, and the 22nd PI controller 422 performs the proportional-integral control on the 2 nd PI controller 422 in the direction of reducing the error between the first lithium ion battery actual current Ibat and the first lithium ion battery reference current Ibatref. Thereby forming the gate duty of the upper and lower bidirectional switches 52 and 53 of the bidirectional converter 50. The upper and lower bidirectional switches 52 and 53 of the second bidirectional converter 50 operate complementary to each other and the gate duty for controlling the upper bidirectional switch 52 is Db1, The gate duty for controlling the switch 53 is Db2. The output of the twenty-second PI controller 422 is generated through a buffer 423 to generate a gate duty Db1 for controlling the upper bidirectional switch 52. The output of the twenty- The gate duty for controlling the lower bidirectional switch 53 through the inverter 424 is the most technical feature that Db2 is generated.
The first lithium-ion battery reference current Ibatref is generated in a direction to reduce the error between the actual voltage Vdclink of the output capacitor and the reference voltage Vdcref of the output capacitor of the step-up type converter.
In the present invention, power can be stored in the second lithium-ion battery 300 when the state-of-charge (SOC) of the first lithium-ion battery 200 exceeds 80 to 85%.
The second bidirectional converter 50 functions to transfer the energy of the first lithium ion battery 200 to the second lithium ion battery 300. The second bidirectional converter 50 is charged with a fixed voltage The energy transfer from the first lithium ion battery 200 to the second lithium ion battery 300 capable of variable voltage charging from 800 [V] to 2000 [V] is performed.
For example, if the capacities of the first lithium ion battery 200 and the second lithium ion battery 300 are the same, the first lithium ion battery 200 of the direct current (DC) 400 [V] The second lithium ion battery 300 having a direct current (DC) of 2000 [V], which is five times larger than the lithium secondary battery 300, can hold a charge capacity (SOC) of 25 times the energy storage density of 5 .
That is, although the size of the capacitors of the first lithium ion battery 200 and the second lithium ion battery 300 is the same, the charging voltage of the second lithium ion battery 300 can be increased up to five times The biggest technical feature is that the charge capacity (SOC: State of Charge) can be increased up to 25 times (the square of 5).
The state of charge of the second lithium ion battery 300 can be increased up to 25 times (the square of 5) while reducing the size of the second lithium ion battery 300 as much as possible There is a very elevated effect.
7 shows the controller of the step-down type converter.
7) of the step-down type converter 60 receives the error between the actual voltage Vdc1 of the output capacitor of the step-down type converter and the reference voltage Vdcref1 of the output capacitor of the step-down type converter through the 31st adder 431 . Thereafter, the 31st PI controller 432 performs proportional-integral control to generate the reference current Idcref1 of the step-down converter. An error between the actual current Idc1 of the step-down type converter and the reference current Idcref1 of the step-down converter is detected through the 32nd adder 433. And then the 32 PI controller 434 performs proportional-integral control to generate the gate duty (Duty2) of the main switch of the step-down type converter 60 as the biggest technical feature.
In the present invention, since the voltage control and the current control are simultaneously performed in the step-down type converter 60, the effect of controlling the step-down type converter 60 more stably appears.

In the present invention, in a solar power system-connected power conversion apparatus, a solar cell 100 that receives sunlight to generate electricity energy; A step-up type converter 10 that receives a voltage generated from the solar cell 100 and boosts the DC voltage to 300 [V] to 400 [V]; (AC) 220 [V] is supplied to an AC load (Load) on the basis of outputs of DC [DC] 300 [V] to 400 [V] of the step- An inverter 30; (DC) 400 [V] to the first lithium ion battery 200 on the basis of outputs of DC [DC] 300 [V] to 400 [V] of the step-up type converter 10. [ (20); If the state of charge (SOC) of the first lithium ion battery 200 of the direct current (DC) 400 [V] exceeds 80 to 85%, the second lithium ion battery 300 is charged with a direct current A second bidirectional converter 50 supplying 800 [V] to 2000 [V]; A first relay 31 for determining that the output of the half bridge grid inverter 30 is transmitted to the first and second AC output terminals AC1 and AC2; A second relay (35) for determining that the output of the first bidirectional converter (20) is to be supplied to the first lithium ion battery (200); A step-down converter 60 for supplying a desired voltage from a DC load based on a voltage charged in the first lithium-ion battery 200; When the magnitude of the capacitance [F] of the capacitor of the first lithium ion battery 200 is equal to the magnitude of the capacitance F of the capacitor of the second lithium ion battery 300, Wherein the state of charge of the battery 300 is at most 25 times greater than the state of charge of the first lithium ion battery 200. The solar- .

In addition, the present invention provides a solar cell-based power conversion apparatus comprising: a solar cell (100) which receives sunlight to generate electricity energy; A step-up type converter 10 that receives a voltage generated from the solar cell 100 and boosts the DC voltage to 300 [V] to 400 [V]; (AC) 220 [V] is supplied to an AC load (Load) on the basis of outputs of DC [DC] 300 [V] to 400 [V] of the step- An inverter 30; (DC) 400 [V] to the first lithium ion battery 200 on the basis of outputs of DC [DC] 300 [V] to 400 [V] of the step-up type converter 10. [ (20); If the state of charge (SOC) of the first lithium ion battery 200 of the direct current (DC) 400 [V] exceeds 80 to 85%, the second lithium ion battery 300 is charged with a direct current A second bidirectional converter 50 supplying 800 [V] to 2000 [V]; A first relay 31 for determining that the output of the half bridge grid inverter 30 is transmitted to the first and second AC output terminals AC1 and AC2; A second relay (35) for determining that the output of the first bidirectional converter (20) is to be supplied to the first lithium ion battery (200); And a step-down type converter (60) for supplying a desired voltage from a DC load based on a voltage charged in the first lithium ion battery (200) .

Further, in the present invention, in the solar power system-connected power conversion apparatus, a solar cell 100 that receives sunlight to generate electricity energy; A step-up type converter 10 for supplying a voltage generated from the solar cell 100 to a first DC voltage; A grid-connected inverter (30 or 90) for supplying an AC voltage to an AC load based on an output of a first DC voltage of the step-up type converter; A first bidirectional converter 20 for supplying a second direct current voltage to the first lithium ion battery 200 on the basis of outputs of direct current (DC) 300 [V] to 400 [V] of the step-up type converter 10; When the state of charge of the first lithium ion battery 200 of the second DC voltage exceeds the specific charge capacity, the third DC voltage is applied to the second lithium ion battery 300 And a second bidirectional converter (50) for supplying power to the photovoltaic system.

The first direct current voltage may be a direct current (DC) of 300 to 400 V, the second direct current voltage may be a direct current of 400 [V], and the third direct current voltage may be a direct current (DC) V] to 2000 [V] are suitable, but those skilled in the art (those skilled in the art) can appropriately and variably select within a certain voltage range. However, the first, second and third DC voltages have the following relationship.
Quot; first DC voltage < second DC voltage < third DC voltage ".

The present invention can be applied to a solar power grid-connected power conversion apparatus by a person skilled in the art by various modifications, and it should be admitted that the category of the technology which easily transforms technically belongs to the scope of the present patent will be.

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10: Boost converter
11: Step-up inductor
12: Rectifier diode of boost converter
13: Main switch of boost converter
14: Reflux diode of boost converter
15: Output capacitor of the step-up converter
16: smoothing capacitor
20: First bidirectional converter
21: first inductor
22: first switch
23: second switch
24: first reflux diode
25: second reflux diode
30: Half-Bridge Grid Inverter
31: First relay (RY1)
32: first divided capacitor
33: second voltage-dividing capacitor
34: Grid-connected transformer
35: second relay (RY2)
40: Battery storage unit
50: second bidirectional converter
51: Second inductor
52: Upper bidirectional switch
53: Lower bidirectional switch
54: Third reflux diode
55: fourth reflux diode
60: Step-down converter
61: Main switch of step-down converter
62: Forcing type reflux diode
63: Inductive inductor
64: Step-down type output capacitor
70: eleventh bidirectional converter
71: 11th inductor
72: eleventh switch
73: twelfth switch
74: eleventh reflux diode
75: twelfth reflux diode
80: twelfth bidirectional converter
81: twelfth inductor
82: thirteenth switch
83: Fourteenth switch
84: 13th reflux diode
85: 14th reflux diode
90: Full bridge system link inverter
100: Solar cell
200: First lithium ion battery
300: Second Lithium Ion Battery
401: first adder
402: first PI controller
403: second adder
404: second PI controller
411: eleventh adder
412: eleventh PI controller
413: Eleventh multiplier
414: Sine Wave Generator
415: Phase Locked Loop
416: Twelfth adder
417: the twelfth PI controller
418: thirteenth adder
419: Twelfth multiplier
421: the twenty-first adder
422: the twenty-first PI controller
423: Buffer
424: Inverter
431: the 31st adder
432: the 31st PI controller
433: 32nd adder
434: 32 th PI controller
AC1: First AC output terminal
AC2: Second AC output terminal
D1: First gate duty for grid-linked inverter control
D2: second gate duty for grid link inverter control
Db1: Gate duty for upper bidirectional switch control
Db2: Gate duty for lower bidirectional switch control
DC1: (+) output terminal
DC2: (-) output terminal
Duty 1: Gate duty of the main switch of boost converter
Duty 2: Gate duty of main switch of step-down converter
Ibatref: 1st Li-ion battery reference current
Ibat: 1st Li-ion battery actual current
Idc1: Actual current of the step-down converter
Idcref1: Reference current of step-down converter
Iinv: Grid-connected inverter actual current
Iref: 1st grid connection inverter reference current
Isref: 2nd grid connection inverter reference current
RY1: first relay
RY2: Second relay
Vdclink: Actual Voltage of Output Capacitor of Boost Converter
Vdcref: Reference voltage of the output capacitor of the boost converter
Vdc1: Actual voltage of the output capacitor of the step-down converter
Vdcref1: Reference voltage of the output capacitor of the step-down type converter
Vs: grid connection inverter voltage
Vsinwt: Sine wave ac voltage

Claims (12)

1. A solar power grid-connected power converter,
A solar cell 100 that receives solar light and generates electricity energy;
A step-up type converter 10 that receives a voltage generated from the solar cell 100 and boosts the DC voltage to 300 [V] to 400 [V];
(AC) 220 [V] is supplied to an AC load (Load) on the basis of outputs of DC [DC] 300 [V] to 400 [V] of the step- An inverter 30;
(DC) 400 [V] to the first lithium ion battery 200 on the basis of outputs of DC [DC] 300 [V] to 400 [V] of the step-up type converter 10. [ (20);
If the state of charge (SOC) of the first lithium ion battery 200 of the direct current (DC) 400 [V] exceeds 80 to 85%, the second lithium ion battery 300 is charged with a direct current A second bidirectional converter 50 supplying 800 [V] to 2000 [V];
A first relay 31 for determining that the output of the half bridge grid inverter 30 is transmitted to the first and second AC output terminals AC1 and AC2;
A second relay (35) for determining that the output of the first bidirectional converter (20) is to be supplied to the first lithium ion battery (200);
A step-down converter 60 for supplying a desired voltage from a DC load based on a voltage charged in the first lithium-ion battery 200;
When the magnitude of the capacitance [F] of the capacitor of the first lithium ion battery 200 is equal to the magnitude of the capacitance F of the capacitor of the second lithium ion battery 300, Wherein the state of charge of the battery 300 is at most 25 times greater than the state of charge of the first lithium ion battery 200. The solar- 1. A solar power grid-connected power converter,
A solar cell 100 that receives solar light and generates electricity energy;
A step-up type converter 10 that receives a voltage generated from the solar cell 100 and boosts the DC voltage to 300 [V] to 400 [V];
(AC) 220 [V] is supplied to an AC load (Load) on the basis of outputs of DC [DC] 300 [V] to 400 [V] of the step- An inverter 30;
(DC) 400 [V] to the first lithium ion battery 200 on the basis of outputs of DC [DC] 300 [V] to 400 [V] of the step-up type converter 10. [ (20);
If the state of charge (SOC) of the first lithium ion battery 200 of the direct current (DC) 400 [V] exceeds 80 to 85%, the second lithium ion battery 300 is charged with a direct current A second bidirectional converter 50 supplying 800 [V] to 2000 [V];
A first relay 31 for determining that the output of the half bridge grid inverter 30 is transmitted to the first and second AC output terminals AC1 and AC2;
A second relay (35) for determining that the output of the first bidirectional converter (20) is to be supplied to the first lithium ion battery (200);
And a step-down type converter (60) for supplying a desired voltage from a DC load based on a voltage charged in the first lithium ion battery (200) 1. A solar power grid-connected power converter,
A solar cell 100 that receives solar light and generates electricity energy;
A step-up type converter 10 that receives a voltage generated from the solar cell 100 and boosts the DC voltage to 300 [V] to 400 [V];
(AC) 220 [V] is supplied to the AC load (Load) based on the DC (DC) 300 [V] to 400 [V] output of the step- An inverter 90;
(DC) 400 [V] to the first lithium ion battery 200 on the basis of outputs of DC [DC] 300 [V] to 400 [V] of the step-up type converter 10. [ (20);
If the state of charge (SOC) of the first lithium ion battery 200 of the direct current (DC) 400 [V] exceeds 80 to 85%, the second lithium ion battery 300 is charged with a direct current A second bidirectional converter 50 supplying 800 [V] to 2000 [V];
A first relay 31 for determining that the output of the full bridge system link inverter 90 is transferred to the first and second AC output terminals AC1 and AC2;
A second relay (35) for determining that the output of the first bidirectional converter (20) is to be supplied to the first lithium ion battery (200);
A step-down converter 60 for supplying a desired voltage from a DC load based on a voltage charged in the first lithium-ion battery 200;
When the magnitude of the capacitance [F] of the capacitor of the first lithium ion battery 200 is equal to the magnitude of the capacitance F of the capacitor of the second lithium ion battery 300, Wherein the state of charge of the battery 300 is at most 25 times greater than the state of charge of the first lithium ion battery 200. The solar- 1. A solar power grid-connected power converter,
A solar cell 100 that receives solar light and generates electricity energy;
A step-up type converter 10 that receives a voltage generated from the solar cell 100 and boosts the DC voltage to 300 [V] to 400 [V];
(AC) 220 [V] is supplied to the AC load (Load) based on the DC (DC) 300 [V] to 400 [V] output of the step- An inverter 90;
(DC) 400 [V] to the first lithium ion battery 200 on the basis of outputs of DC [DC] 300 [V] to 400 [V] of the step-up type converter 10. [ (20);
If the state of charge (SOC) of the first lithium ion battery 200 of the direct current (DC) 400 [V] exceeds 80 to 85%, the second lithium ion battery 300 is charged with a direct current A second bidirectional converter 50 supplying 800 [V] to 2000 [V];
A first relay 31 for determining that the output of the full bridge system link inverter 90 is transferred to the first and second AC output terminals AC1 and AC2;
A second relay (35) for determining that the output of the first bidirectional converter (20) is to be supplied to the first lithium ion battery (200);
And a step-down type converter (60) for supplying a desired voltage from a DC load based on a voltage charged in the first lithium ion battery (200) 1. A solar power grid-connected power converter,
A solar cell 100 that receives solar light and generates electricity energy;
A step-up type converter 10 that receives a voltage generated from the solar cell 100 and boosts the DC voltage to 300 [V] to 400 [V];
(AC) 220 [V] is supplied to an AC load (Load) on the basis of outputs of DC [DC] 300 [V] to 400 [V] of the step- An inverter 30;
(DC) 400 [V] to the first lithium ion battery 200 on the basis of outputs of DC [DC] 300 [V] to 400 [V] of the step-up type converter 10. [ (20);
If the state of charge (SOC) of the first lithium ion battery 200 of the direct current (DC) 400 [V] exceeds 80 to 85%, the second lithium ion battery 300 is charged with a direct current A second bidirectional converter 50 supplying 800 [V] to 2000 [V];
The first half of the half bridge grid inverter 30 is located between one side (one side) of the grid-connected transformer 43 of the first bidirectional converter 20 and the contact points of the first and second switches 22, And a first relay (31) for determining that the output is transmitted to the first and second AC output terminals (AC1, AC2) 1. A solar power grid-connected power converter,
A solar cell 100 that receives solar light and generates electricity energy;
A step-up type converter 10 that receives a voltage generated from the solar cell 100 and boosts the DC voltage to 300 [V] to 400 [V];
(AC) 220 [V] is supplied to the AC load (Load) based on the DC (DC) 300 [V] to 400 [V] output of the step- An inverter 90;
(DC) 400 [V] to the first lithium ion battery 200 on the basis of outputs of DC [DC] 300 [V] to 400 [V] of the step-up type converter 10. [ (20);
If the state of charge (SOC) of the first lithium ion battery 200 of the direct current (DC) 400 [V] exceeds 80 to 85%, the second lithium ion battery 300 is charged with a direct current A second bidirectional converter 50 supplying 800 [V] to 2000 [V];
Is connected between one side (one side) of the grid-connected transformer 43 of the first bidirectional converter 20 and the contact point of the eleventh and twelfth switches 72 and 73 and the output of the full bridge grid- To the first and second AC output terminals (AC1, AC2), the first relay (31) 1. A solar power grid-connected power converter,
A solar cell 100 that receives solar light and generates electricity energy;
A step-up type converter 10 for supplying a voltage generated from the solar cell 100 to a first DC voltage;
A grid-connected inverter (30 or 90) for supplying an AC voltage to an AC load based on an output of a first DC voltage of the step-up type converter;
A first bidirectional converter 20 for supplying a second direct current voltage to the first lithium ion battery 200 on the basis of outputs of direct current (DC) 300 [V] to 400 [V] of the step-up type converter 10;
When the state of charge of the first lithium ion battery 200 of the second DC voltage exceeds the specific charge capacity, the third DC voltage is applied to the second lithium ion battery 300 And a second bidirectional converter (50) for supplying power to the photovoltaic system The method of claim 7,
Wherein the relationship between the first, second and third DC voltages is a first DC voltage < a second DC voltage < a third DC voltage. The method according to any one of claims 1 to 6,
The controller of the step-up converter 10 controls the first adder 401 so that the actual voltage Vdclink of the output capacitor of the step-up converter 10 and the reference voltage Vdcref of the output capacitor of the step- And the first PI controller 402 performs the proportional-integral control on the detection result;
The first lithium ion battery reference current Ibatref is reduced in the direction of reducing the error between the actual voltage Vdclink of the output capacitor and the reference voltage Vdcref of the output capacitor in the step- Wherein said solar power system power converter The method according to any one of claims 1 to 6,
The half bridge system grid inverter 30 or the full bridge system grid inverter 90 detects a sine wave AC voltage Vsinwt to be finally outputted at the first and second AC output terminals AC1 and AC2 Synchronizes the phase through a phase locked loop (PLL) 415;
The sine wave and the first grid link inverter reference current Iref generated by the sine wave generator 414 are multiplied by an eleventh multiplier 413 to generate a second grid link inverter reference current Isref ) Of the photovoltaic power generation system 11. The method of claim 10,
The controller of the half bridge system grid inverter 30 or the full bridge system grid inverter 90 receives the error between the grid link inverter actual current Iinv and the second grid link inverter reference current Isref through the twelfth adder 416 And generates a first gate duty (D1) for the grid-connected inverter control through the twelfth PI controller (417);
The ratio of the voltage Vs of the half bridge system grid inverter 30 or the full bridge system grid inverter 90 to the actual voltage Vdclink of the output capacitor of the voltage step up converter is generated by the sine wave generator 414 Multiplied through the twelfth multiplier 419 to form a second gate duty D2 for the grid-connected inverter control;
The gate signal for controlling the grid interconnect inverter 30 or 90 is finally generated by adding the first gate duty Dl and the second gate duty D2 through the thirteenth adder 418 A solar power system-connected power converter The method according to any one of claims 1 to 6,
The controller of the second bidirectional converter 50 detects an error between the first lithium ion battery actual current Ibat and the first lithium ion battery reference current Ibatref through the twenty first adder 421, (422) performs proportional-integral control;
The switches of the upper and lower bidirectional switches 52 and 53 of the second bidirectional converter 50 in the direction of reducing the error between the first lithium ion battery actual current Ibat and the first lithium ion battery reference current Ibatref, Wherein the solar-power-associated power converter

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