KR20100037098A - Power converter and power combiner for power-limited power sources - Google Patents

Abstract

This invention relates to a hysteretic input-regulating high-output impedance power converter for converting the energy output of power-limited power sources such as solar cells to provide output current at voltages useful to operate electronics or charge batteries. This invention also relates to a power combiner that combines the output of multiple power sources into a single output. The power combiner is comprised of multiple circuits, one for each power source. These circuits are either complete input-regulating high-output impedance power converter circuits or, when connected to shared elements, form complete input-regulating high-output impedance power converter circuits. The power combiner can be used to combine the power from power sources that are alike or different.

Description

POWER CONVERTER AND POWER COMBINER FOR POWER-LIMITED POWER SOURCES

The present invention has been made with government support under Agreement W911NF-05-9-0005 issued by the government. The government has certain rights in the present invention.

The present invention relates to a power combiner and a power combiner that combines the output power of a plurality of power supplies into one output.

Photovoltaic cells, and in particular small power sources such as solar cells, are being used to power portable devices or charge battery packs. The well known boost chopper power converter circuit has been used with such power supplies in portable applications. This type of power converter can be used to take input current at low voltages (eg, one silicon solar cell has an output of about 0.5 volts), and to operate handheld electronic devices or to charge a battery pack. Produces an output current at a higher voltage.

If it is desired to use the power of multiple power supplies, the outputs of the individual power supplies must be combined. Traditionally, power supplies, such as silicon solar cells of the same type, have been connected in some series-parallel combination to provide the voltage and current outputs required for a particular application. For example, one type of solar cell battery charger connects the solar cells in series to approach the battery voltage. The output is then supplied to the battery via a diode. However, this architecture causes inefficient and rechargeable batteries to wear out quickly. Another approach is a solar cell powered equivalent that simulates an AC outlet that users can plug in. This architecture is inherently inefficient because battery chargers integrated in most consumer electronic devices are not designed to operate efficiently with limited power sources.

Recent solar cell architectures utilize multiple cells that efficiently absorb different portions of the solar spectrum, thereby achieving higher overall conversion efficiency than traditional solar cells using one type of cell. The voltages of the different cells are regulated at specific temperature compensated values to achieve maximum efficiency. Since the cells and their characteristics are not identical, the traditional approach of combining their outputs by connecting the cells in some series-parallel combination will not work well and different types of power combiners are required.

There is therefore a continuing need for efficient power converters and efficient power combiners, especially power combiners that can combine the outputs of different types of photovoltaic cells. There is a particular need for such power converters and power combiners for operating portable electronic devices and for charging batteries for such devices.

[Overview of invention]

The present invention provides a hysteretic input-regulating boost power converter for converting power provided by a power source, the power converter comprising a hysteretic voltage comparator, The power converter provides the output current at an output voltage that is greater than the input voltage and does not depend on the input voltage.

In one embodiment, the power converter,

(Iii) first and second input terminals for connecting to a power supply providing an input voltage;

(Ii) a capacitor having a first terminal connected to the first input terminal and a second terminal connected to the second input terminal;

(Iii) a hysteresis voltage comparator having at least three terminals, the first of which terminals being an input terminal connected to the first terminal of the capacitor, the second terminal being an input terminal for inputting a reference voltage, and a third The terminal is an output terminal;

(Iii) a switch having a first terminal connected to a third terminal of the hysteresis voltage comparator for receiving an output signal from the hysteresis voltage comparator, a second terminal and a third terminal connected to the second terminal of the capacitor; The output signal from the hysteresis voltage comparator is closed when the voltage on the capacitor exceeds the high threshold voltage of the hysteresis voltage comparator and the voltage on the capacitor is the low threshold of the hysteresis voltage comparator. opening and closing the switch to open the switch when the voltage decreases;

(Iii) an inductor having a first terminal connected to the first terminal of the capacitor and a second terminal connected to the third terminal of the switch;

(Iii) an output rectifier having a first terminal and a second terminal connected to a second terminal of the inductor; And

(Iii) first and second output terminals, wherein the first output terminal is connected to a second terminal of the output rectifier and the second output terminal is connected to a second terminal of the switch;

It has a circuit comprising a.

In another embodiment, the power converter,

(Iii) first and second input terminals for connecting to a power supply providing an input voltage;

(Ii) a capacitor having a first terminal connected to the first input terminal and a second terminal connected to the second input terminal;

(Iii) a hysteresis voltage comparator having at least three terminals, the first of which terminals being an input terminal connected to the first terminal of the capacitor, the second terminal being an input terminal for inputting a reference voltage, and a third The terminal is an output terminal;

(Iii) a switch having a first terminal connected to a third terminal of the hysteresis voltage comparator for receiving an output signal from the hysteresis voltage comparator, a second terminal and a third terminal connected to the second terminal of the capacitor; The output signal from the hysteresis voltage comparator is closed when the voltage on the capacitor exceeds the high threshold voltage of the hysteresis voltage comparator and the switch is opened when the voltage on the capacitor decreases to the low threshold voltage of the hysteresis voltage comparator. To open and close the switch;

(Iii) a primary winding having a first terminal connected to the first terminal of the capacitor and a second terminal connected to the third terminal of the switch and a secondary winding having the first terminal and the second terminal a transformer having a secondary winding;

(Iii) an output rectifier having a first terminal and a second terminal connected to the first terminal of the transformer secondary winding; And

(Iii) first and second output terminals, wherein the first output terminal is connected to a second terminal of the output rectifier and the second output terminal is connected to a second terminal of the transformer secondary winding;

It has a circuit comprising a.

The invention also provides a power combiner that combines the output power of a plurality of power supplies into one output. This power combiner includes a parallel arrangement of circuits, different circuits of which are assigned to each of the plurality of power sources. Each of these circuits is a fully input-regulated high output impedance power converter circuit or forms a complete input-regulated high output impedance power converter circuit when connected to one or more elements shared by these circuits. When elements are shared, only one circuit is connected to those shared elements at any given time. The output power of these circuits is supplied to one output.

In the same embodiment where the circuits assigned to the various power sources are complete power converter circuits, the power combiner uses one embodiment of the power converter circuit of the present invention, and the power combiner

(a) a power converter circuit assigned to each of said power sources, each power converter circuit comprising:

(Iii) first and second input terminals for connecting to a power source designated for the power converter circuit;

(Ii) a capacitor having a first terminal connected to the first input terminal and a second terminal connected to the second input terminal;

(Iii) a hysteresis voltage comparator having at least three terminals, the first of which terminals being an input terminal connected to the first terminal of the capacitor, the second terminal being an input terminal for inputting a reference voltage, and a third The terminal is an output terminal;

(Iii) a switch having a first terminal connected to a third terminal of the hysteresis voltage comparator for receiving an output signal from the hysteresis voltage comparator, a second terminal and a third terminal connected to the second terminal of the capacitor; The output signal from the hysteresis voltage comparator is closed when the voltage on the capacitor exceeds the high threshold voltage of the hysteresis voltage comparator and the switch is opened when the voltage on the capacitor decreases to the low threshold voltage of the hysteresis voltage comparator. To open and close the switch;

(Iii) an inductor having a first terminal connected to the first terminal of the capacitor and a second terminal connected to the third terminal of the switch; And

(Iii) an output rectifier having a first terminal and a second terminal connected to a second terminal of the inductor; And

(b) an output having a first terminal connected to the second terminal of the output rectifier of each power converter circuit and a second terminal connected to the second terminal of the switch of each power converter circuit.

.

In another embodiment where the circuits assigned to the various power sources are complete power converter circuits and in the same embodiment, the power combiner utilizes another embodiment of the power converter circuit of the present invention, wherein the power combiner

(a) a power converter circuit assigned to each of said power sources, each power converter circuit comprising:

(Iii) first and second input terminals for connecting to a power source designated for the power converter circuit;

(Ii) a capacitor having a first terminal connected to the first input terminal and a second terminal connected to the second input terminal;

(Iii) a hysteresis voltage comparator having at least three terminals, the first of which terminals being an input terminal connected to the first terminal of the capacitor, the second terminal being an input terminal for inputting a reference voltage, and a third The terminal is an output terminal;

(Iii) a switch having a first terminal connected to a third terminal of the hysteresis voltage comparator for receiving an output signal from the hysteresis voltage comparator, a second terminal and a third terminal connected to the second terminal of the capacitor; The output signal from the hysteresis voltage comparator is closed when the voltage on the capacitor exceeds the high threshold voltage of the hysteresis voltage comparator and the switch is opened when the voltage on the capacitor decreases to the low threshold voltage of the hysteresis voltage comparator. To open and close the switch;

(Iii) a transformer having a primary winding having a first terminal connected to the first terminal of the capacitor and a second terminal connected to the third terminal of the switch and a secondary winding having the first terminal and the second terminal; And

(Iii) an output rectifier having a first terminal and a second terminal connected to a second terminal of the inductor; And

(b) an output having a first terminal connected to the second terminal of the output rectifier of each power converter circuit and a second terminal connected to the second terminal of the transformer secondary winding of each power converter circuit.

.

In an embodiment in which circuits assigned to various power sources share one or more elements to form power converter circuits, the power combiner is:

(a) a parallel arrangement of circuits, wherein a different one of said circuits is assigned to each of said plurality of power sources;

(b) one or more shared elements shared by the circuits, when the circuit and the shared elements form a complete input-regulating high output impedance power converter circuit when the circuit is connected to the one or more shared elements; And

(c) one output

.

In one such embodiment in which circuits assigned to various power sources share one or more elements to form power converter circuits, the power combiner is:

(a) a parallel arrangement of circuits, wherein a different one of said circuits is assigned to each of said plurality of power sources, each said circuit being:

(Iii) a first input terminal and a second input terminal for connecting to a power supply designated for the circuit;

(Ii) a capacitor having a first terminal connected to the first input terminal and a second terminal connected to the second input terminal;

(Iii) a switch having a first terminal and a second terminal connected to the first terminal of the capacitor;

(b) an inductor having a first terminal connected to a second terminal of a switch of each said circuit and a second terminal connected to a second terminal of a capacitor of each said circuit;

(c) an output rectifier having a first terminal and a second terminal connected to the second terminal of the inductor;

(d) an output having a first terminal connected to the second terminal of the output rectifier and a second terminal connected to the first terminal of the inductor; And

(e) a controller that periodically cycles through all the switches to open and close all the switches and process each of the power sources, with only one switch closed at any given time.

It includes.

The present power converter and power combiner are useful in power sources such as fuel cells and photovoltaic cells, in particular solar cells, ie in power sources with power limited outputs. The present power combiner is useful when the solar cell unit consists of a plurality of cells and especially when the plurality of cells are of different types.

1 is a schematic diagram of one embodiment of a power converter of the present invention.
2 is a schematic diagram of another embodiment of a power converter of the present invention.
3 is a circuit diagram of an embodiment of a power converter used in Example 1. FIG.
4 is a schematic diagram of an embodiment of the power combiner of the present invention wherein the circuits assigned to each of the power supplies are complete hysteresis input-regulated high output impedance power converter circuits.
5 is a schematic diagram of an embodiment of the power combiner of the present invention that forms complete input-regulated high output impedance power converter circuits when circuits assigned to each of the power supplies share elements and are connected to the shared elements.
6 is a circuit diagram of an embodiment of a power converter used in Example 2. FIG.
7 is a circuit diagram of an embodiment of a power converter of the present invention used in Example 3. FIG. The circuits assigned to each of the power supplies are fully hysteretic input-regulated high output impedance power converter circuits.
8 is a circuit diagram of one embodiment of a power converter of the present invention used in Example 4. FIG. Circuits assigned to each of the power supplies share elements and each form a complete input-regulated high output impedance power converter circuit when each is connected to the shared elements.
FIG. 9 shows the charging characteristics obtained by the simulation of the circuit shown in FIG. 8.
10 is a circuit diagram of another embodiment of a power converter of the present invention used in Example 5. FIG. Circuits assigned to each of the power supplies share the elements and form a complete input-regulated high output impedance power converter circuit when connected to the shared elements.

The power converter of the present invention may be used with a power limited power source to provide an output voltage sufficient to operate a handheld electronic device or charge a battery pack. Power converters use hysteresis, input-side regulation and self-induced oscillation to reduce parts count and power consumption. hysteretic input-regulating high-output impedance power converter.

One embodiment of a power converter circuit is shown in the schematic diagram of FIG. 1. The power converter has a circuit 10 that includes the following elements. The first input terminal 11 and the second input terminal 12 provide a connection to the power source PS. The capacitor 13 has a first terminal connected to the first input terminal and a second terminal connected to the second input terminal. The hysteresis voltage comparator 14 has a first terminal connected to the first terminal of the capacitor, a second terminal for inputting a reference voltage, and a third terminal which is an output terminal. The switch 16 is connected to a third terminal of the hysteresis voltage comparator 14 and has a first terminal for receiving an output signal from the hysteresis voltage comparator 14. The output signal serves to open and close the switch 16. The switch 16 also has a second terminal and a third terminal connected to the second terminal of the capacitor. The inductor 17 has a first terminal connected to the first terminal of the capacitor 13 and a second terminal connected to the third terminal of the switch 16. The output rectifier 18 has a first terminal connected to the second terminal of the inductor 17 and a second terminal connected to the first output terminal 19. The second output terminal 20 is connected to the second terminal of the switch 16. Preferably, the second input terminal, the second terminal of the capacitor, the second terminal of the switch and the second output terminal are all connected to ground.

The power converter operates as follows. The power supply PS charges the capacitor 13 until the voltage on the capacitor 13 exceeds the high threshold voltage of the hysteresis voltage comparator 14. This causes the hysteresis voltage comparator 14 to close the switch 16. Increasing current flows from the capacitor 13 through the inductor 17 and the switch 16 to ground, discharging energy from the capacitor 13 and storing it in the magnetic field of the inductor 17. When the voltage on capacitor 13 drops to the low threshold voltage of hysteresis voltage comparator 14, switch 16 is opened. The energy stored in the inductor 17 acts as a power source and raises the voltage until the voltage at the output rectifier 18 exceeds the level at the output terminal 19. Current flows through the output rectifier 18 and out of the converter via the output terminal 19. When the energy stored in the inductor 17 is exhausted, the rectifier stops conducting and the power converter returns to its original state. This cycle repeats when the capacitor 13 is again charged to a sufficient level. The voltage at the output terminal is greater than the voltage of the power supply at the input terminal.

Another embodiment of a power converter circuit is shown in the schematic diagram of FIG. 2. Comparable elements are indicated by the same numbers used for the schematic diagram of FIG. 1. The elements 11-16 are all of the same configuration as shown in FIG. 1. However, in this embodiment a flyback converter is used. Transformer 17F has a primary winding having a first terminal connected to the first terminal of the capacitor and a second terminal connected to the third terminal of the switch. The secondary winding has a first terminal connected to the first terminal of the output rectifier 18 and a second terminal connected to the output terminal 20. The second terminal of the output rectifier is connected to the first output terminal 19. If the output rectifier is a diode as shown in FIG. 2, the diode can be “flipped”. That is, the diode may have its N side connected to the terminal.

Circuit elements can take various forms. Capacitor 13 may be one capacitor or two or more capacitors arranged in parallel and / or series configurations. The hysteresis voltage comparator 14 may be configured as a commercially available externally referenced integrated circuit comparator or a self-referencing circuit. The switch 16 may consist of a bipolar transistor or a field effect transistor and resistors for setting the high and low switching threshold voltages. Inductor 17 may be one inductor or coupled inductors to provide more flexibility in the operating range. The output rectifier 18 can be in the form of a diode, or if pulse outputs are not desired, the pulses can be easily filtered to DC by using a capacitor with the diode. Alternatively, a synchronous rectifier structure can be used instead of the diode. Other forms of these elements will be apparent to those skilled in the art. The power converter does not require a programmed controller, but the use of such a controller is not excluded. One controller circuit may be used to operate a plurality of power converters, eg, a plurality of power converters in a power combiner.

The hysteresis input-controlled boost power converter of the present invention has many advantages. It has a wide operating range, high efficiency, simple and low cost implementation. It uses one of the largest components in the circuit, the inductor, by its inherently fixed-on-time switching, which is set by an inductor-capacitor (LC) time constant and hysteresis voltage, Use efficiently

The power consumption of the power converter is in the microwatt range, which makes the power converter efficient for use with power sources such as solar cells that generate only a few milliwatts of power. It can also optimally match its power supply by dynamically adjusting the internal or external reference voltage of the hysteresis voltage comparator to achieve maximum power point (MPP) tracking of the sun or other photovoltaic cells. MPP is that the current and voltage output of these cells are jointly maximized, ie, the cells operate at maximum efficiency. For these cells, temperature tracking of the cell voltage is very important to achieve optimal power output and can be achieved by using temperature variable resistors or diodes in the reference circuit or varying reference voltages obtained externally. have. When a controller is used to operate one or more power converters it does so that the photovoltaic power supply of each power converter essentially operates at its MPP.

The output of the power converter is flexible. There is no feedback to adjust its impedance and therefore at the output terminals it naturally looks like an inductor / diode series combination with a high impedance. As a result, it is possible to track the output voltage over a wide range without losing power. The power converter generates ideal saw current pulses for pulse charging the battery. The size and chemistry of the battery does not affect the efficiency of the power converter. Pulse charging of batteries is known to improve battery life. If it is not desired to use current pulses directly, the pulses can be easily filtered to DC by using a capacitor to allow conventional charging methods.

The components used in one embodiment of the power converter schematically shown in FIG. 1 are shown in the circuit diagram of FIG. 3. The comparable elements in FIG. 3 are indicated by the same numbers as used in FIG. 1 and the circuit components making up the elements are indicated. The capacitor 13 consists of a capacitor C5. Comparator 14 is implemented in this embodiment with a 1.8 V low power LMV7271 comparator (National Semiconductor, Santa Clara, Calif.), Resistors R11, R12 and capacitor C14. The five terminals of the LMV7271 comparator are indicated in FIG. 2 using the manufacturer's terminal numbers. The VDD input provides the power needed to operate the comparator. The high and low voltage switching thresholds are set by input voltage reference VREF applied to terminal 15 and resistors R11, R12 and R13. Switch 16 is a ZXTN23015CPH bipolar transistor BT (Zetex Semiconductor plc, Chadderton, Oldham, UK), its base-feed network consisting of capacitor C9 and resistor R10 and electromagnetic interference protection consisting of capacitor C7 and resistor R8. (anti-electromagnetic interference (EMI)) network is implemented. Inductor 17 is an inductor L4. The output rectifier is implemented with a low-leakage Schottky diode D3 and filter capacitor C15. This embodiment has only 14 or 15 components depending on whether filter capacitor C15 is used. Most of these are small resistors and capacitors.

The present invention also provides a power combiner that combines the output power of a plurality of power supplies into one output with minimal loss. The power combiner provides power from one or more power supplies to one output. Power combiners can be used to combine power from the same or different power supplies. For example, when used with a plurality of the same type of photovoltaic cells, a power combiner can be used to combine power from individual cells or from a parallel or series combination of these cells. The power combiner of the present invention is particularly useful when combining the outputs of individual power supplies that are not equal to each other, for example, when a plurality of cells of a solar cell combines power from a plurality of cells of a different type solar cell. Do. Various cells can be selected to each convert different ranges of the solar spectrum and thereby provide greater efficiency. The voltage across each cell is regulated at specific temperature compensated values to provide optimum operation of that cell. The power combiner circuit operates with the same energy conversion efficiency regardless of the number or types of cells attached to its inputs. The power combiner of the present invention is simple, efficient and inexpensive to manufacture.

The power combiner of the present invention combines the output power of the plurality of power sources and consists of a plurality of circuits, different ones of which are assigned to each of the plurality of power sources. For example, if there are n power supplies, there will be n circuits, one for each of those power supplies. The plurality of circuits may be different or the same. As used herein, "identical circuits" indicate that the circuits have the same components. Even if the components are identical, their values and the operation of the circuits may be different. For example, the internal or external reference voltages of the hysteresis voltage comparators may be different to achieve MPP tracking.

In one type of embodiment, each circuit is a complete input-regulated high output impedance power converter circuit. The high output impedance of the power converter of the present invention makes it possible to directly connect a plurality of power converters in parallel to add their power. The power combiner also consists of one output. In one preferred embodiment, each circuit is a complete hysteresis input-regulating high output impedance power converter circuit. One such embodiment is shown schematically in FIG. 4. It uses the same circuits, each with a hysteresis input-regulating high output impedance power converter circuit shown schematically in FIG. For simplicity, power converter 25 is shown having only two power supplies and two power converter circuits, although any number may be used. Comparable circuit elements are indicated by the same numbers used for the schematic diagram of FIG. 1. In each circuit, the second input terminal 12A or 12B, the second terminal of the capacitor and the second terminal of the switch are all connected to ground. The second output terminal 22 is therefore connected to ground. The power supply PSA is connected to the power converter circuit 10A using an input terminal 11A and a ground terminal 12A. Various Circuit Elements The capacitor 13A, the voltage comparator 14A having a terminal 15A for inputting a reference voltage, the switch 16A, the inductor 17A and the output rectifier 18A are all connected to the power converter of the present invention. Connected as described above with respect to circuit 10A operates in the manner described above. The power supply PSB is connected to the power converter circuit 10B using the input terminal 11B and the ground terminal 12B. The power converter circuit 10B has the same elements (ie, 13B to 18B) as the power converter circuit 10A. They are all also connected as described above for the power converter of the present invention and the circuit 10B operates in the manner described above. The second terminal of the output rectifier of each power converter circuit is connected to a common output terminal 21 and current flows out of the output rectifier of each of the power converter circuits and through the output terminal 21 to the outside of the power combiner. A similar preferred embodiment of this type of power combiner can be constructed using the hysteresis input-regulating high output impedance power converter circuit shown schematically in FIG. 2.

In another type of preferred power combiner circuit, the circuits assigned to the various power sources are not complete power converter circuits and share one or more elements. The circuits may be different or the same. When a circuit is connected to one or more shared elements, the circuit and the shared elements form a complete input-regulated high output impedance power converter circuit. Only one circuit is connected to the shared elements at any given time. Sharing certain elements results in a reduction in the number and number of components needed and the cost and size of the power converter. For example, an inductor is a representative element and is often the largest size component in a power converter circuit. Therefore, sharing inductors can enable the use of higher quality inductors to reduce overall size and cost while improving the efficiency of the power combiner.

The power combiner also includes a controller that periodically cycles through all the switches to open and close all the switches and process each of the power supplies, with only one switch closed at any given time.

In one such embodiment the circuits are the same and each circuit includes a capacitor and a switch and the shared elements include an inductor and an output rectifier.

A schematic diagram of one such embodiment of a power combiner architecture in which elements are shared is shown in FIG. 5. For simplicity, the power combiner 30 is shown having only two power sources PSA and PSB, but power from any number of power sources can be combined. The circuit 31A consists of input terminals 32A and 33A, a capacitor 34A and a switch 35A. The power supply PSA is connected to the circuit 31A using the first input terminal 32A and the second input terminal 33A. The capacitor 34A has a first terminal connected to the first input terminal 32A and a second terminal connected to the second input terminal 33A. The switch 35A has a first terminal and a second terminal connected to the first terminal of the capacitor 34A. The circuit 31B is composed of output terminals 32B and 33B, a capacitor 34B and a switch 35B. The power supply PSB is connected to the circuit 31B using the first input terminal 32B and the second input terminal 33B. The capacitor 34B has a first terminal connected to the first input terminal 32B and a second terminal connected to the second input terminal 33B. The switch 35B has a first terminal and a second terminal connected to the first terminal of the capacitor 34B. Also shown in FIG. 5 is an output rectifier in the form of shared elements inductor 36 and diode 37. Inductor 36 is the first terminal connected to the second terminal of switches 35A and 35B, and all capacitors, i.e., in the power combiner shown in FIG. In the power combiner, it has a second terminal connected to the second terminal of the capacitors 34A and 34B. The diode 37 has a first terminal connected to the second terminal of the inductor 36 and a second terminal connected to the first output terminal 38. The second output terminal 39 is connected to the first terminal of the inductor. The controller 40 periodically cycles through all the switches to open and close all switches and thereby process all power sources. When processing the power supply PSA, switch 35A is closed and in all other switches, i.e., the power combiner shown in FIG. 5, switch 35B is opened. The energy stored in capacitor 34A is then transferred to shared inductor 36. The switch 35A then opens and all other switches remain open. Therefore, only one switch is closed at any time. The voltage across the inductor increases until it turns on diode 37 to conduct current to a common output terminal 38. The common output terminal 38 can be connected directly to a rechargeable battery to charge it. The power combiner produces ideal saw current pulses for pulse charging the battery. If it is not desired to use current pulses directly, the pulses can be easily filtered to DC by using a capacitor to allow conventional charging methods. In one preferred embodiment, the second terminals of all switches 35A and 35B, the first terminal of inductor 36 and the second output terminal 39 are all connected to ground.

In the case of the circuit 31A, the first terminal of the capacitor 34A is connected to the first input terminal 32A and to ground and the second terminal of the capacitor 34A is connected to the second input terminal 33A and the switch ( The positions of the capacitors and the switches in the circuits can be exchanged to be connected to one terminal of 35A). The other terminal of the switch 35A is connected to the second terminal of the inductor 36. However, the configuration shown in FIG. 5 is preferred because in that configuration the switching voltages are referenced to ground.

In simple mode, the switch cycling process can be performed at a fixed frequency. In more complex modes, cycling can be performed with varying times spent at different power sources, for example in different solar cells. If the controller can sense the voltage of each storage capacitor, it can skip solar cells with little or no stored energy, which "drains" the storage capacitors of solar cells that have accumulated more stored energy. You can spend more time on it.

For n power supplies, the power combiner shown in FIG. 5 requires n storage capacitors, n switches, one inductor, one diode and one controller chip. In one embodiment the controller is implemented as one silicon chip that also includes all the switches used in the circuits. This implementation will require n storage capacitors, a controller chip with switches, one inductor and one diode to operate with n power supplies. The only component whose number is proportional to the number of power supplies is the storage capacitor. For a larger number of supplies, the shared element architecture is smaller and less expensive than a complete power converter dedicated to each supply.

Circuit elements for the power combiner may take the same various forms described above with respect to the circuit elements of the power converter.

A plurality of electronic devices utilizing the charger architecture of the power converter or power combiner of the present invention may be connected with conventional wiring to share power from the power converter or power combiner. As long as one or more of the devices are equipped with solar cells and a power converter or power combiner, all connected devices will be charged. If two or more of the devices are equipped with solar cells and power converters or power combiners, then the combined power of all the devices so equipped can be induced to charge the batteries of the devices requiring charging.

The power combiner of the present invention may be embedded in the photovoltaic generation module. For example, a power combiner is useful for combining power from an array of solar cells on a solar panel and can be embedded in each panel as an integral part of each panel. The panels can then be connected to each other mechanically and electrically.

As used herein, "input-regulating" has its usual meaning. That is, the power converter senses the input voltage and maintains it at a certain level.

As used herein, "high output impedance" has its usual meaning. That is, the output seems to be a current source.

Examples

Example 1

및

이었다. 다이오드 D3은 ZLLS400 정류기(Zetex Semiconductor plc, Chadderton, Oldham, UK)였다. 전술한 바와 같이, 비교기는 LVM7271 비교기(National Semiconductor, Santa Clara, CA)였고 스위치에 사용되는 바이폴라 트랜지스터는 ZXTN23015CPH 바이폴라 트랜지스터(Zetex Semiconductor plc, Chadderton, Oldham, UK)였다. 전원은 2mA의 전류원으로서 모델링되었고 전력 변환기의 입력 전압은 0.32 볼트였다. 이 전력 변환기의 시뮬레이트된 효율은 75%였다.This example demonstrates the operation of one embodiment of the power converter of the present invention. The circuit diagram of this embodiment is shown in FIG. The operation of this power converter circuit was simulated using SIMETRIX circuit simulation software (Catena Software LTD, Berkshire, UK). The components used are

And

It was. Diode D3 was a ZLLS400 rectifier (Zetex Semiconductor plc, Chadderton, Oldham, UK). As mentioned above, the comparator was an LVM7271 comparator (National Semiconductor, Santa Clara, Calif.) And the bipolar transistor used for the switch was a ZXTN23015CPH bipolar transistor (Zetex Semiconductor plc, Chadderton, Oldham, UK). The power source was modeled as a 2mA current source and the input voltage of the power converter was 0.32 volts. The simulated efficiency of this power converter was 75%.

Example 2

= 없음,

,

듀얼 바이폴라 트랜지스터(ON Semiconductor)였다. U1은 LVM7271 비교기(National Semiconductor, Santa Clara, CA)였고 Q1은 Si5856DC MOSFET + 쇼트키 다이오드(Vishay Semiconductor, Vishay Intertechnology, Inc., Malvern, PA)였다. 이 전원은 병렬 접속된 단결정 실리콘 태양 전지들의 쌍이었다. 실제 태양 조건 하에서 최선으로 관찰된 효율은 80%였다.This example demonstrates the construction and operation of one embodiment of the power converter of the present invention shown in FIG. 6 similar to that simulated in Example 1. FIG. The components used are

= None,

,

It was a dual bipolar transistor (ON Semiconductor). U1 was an LVM7271 comparator (National Semiconductor, Santa Clara, Calif.) And Q1 was a Si5856DC MOSFET + Schottky diode (Vishay Semiconductor, Vishay Intertechnology, Inc., Malvern, PA). This power supply was a pair of parallel connected single crystal silicon solar cells. The best observed efficiency under real solar conditions was 80%.

Example 3

This example demonstrates a power combiner for an embodiment in which the same circuits are assigned to the two power supplies and the circuits are complete hysteretic input-regulating power converter circuits. The circuit diagram is shown in FIG. The operation of this power combiner circuit was simulated using SIMETRIX circuit simulation software (Catena Software LTD, Berkshire, UK). The two supplies were simulated with output powers of 640mV and 2V. The efficiency of this power combiner was found to be 83%.

Example 4

This example demonstrates a power combiner for an embodiment in which the same circuits assigned to the two power supplies share elements rather than complete power converter circuits. The shared elements are inductors and diodes. A circuit diagram for this power combiner is shown in FIG. The operation of this power combiner circuit was simulated using SIMETRIX circuit simulation software (Catena Software LTD, Berkshire, UK). The input power of the two power supplies was 8.737 kW and 8.6 kW. The output waveforms are shown in FIG. The output power was 14.86 kW and the efficiency of the power converter was 87.5%.

Example 5

This example demonstrates a power combiner for an embodiment in which the same circuits assigned to the two power supplies share elements rather than complete power converter circuits. This circuit is the same as the circuit used in Example 4 except that the shared elements are an inductor and a synchronous rectifier. A circuit diagram for this power combiner is shown in FIG. The operation of this power combiner circuit was simulated using SIMETRIX circuit simulation software (Catena Software LTD, Berkshire, UK). The efficiency of this power converter was 94.1% and shows the advantage of using a synchronous rectifier instead of a diode.

Claims (31)

A power converter for converting power provided by a power source, the power converter is a hysteretic input-regulating high-output impedance power converter, which is larger than the input voltage and not dependent on the input voltage. Does not provide an output current at the output voltage of the power converter. The power converter of claim 1 wherein the power converter comprises a hysteretic voltage comparator. The method of claim 2, wherein the power converter,
(Iii) first and second input terminals for connecting to a power supply providing an input voltage;
(Ii) a capacitor having a first terminal connected to the first input terminal and a second terminal connected to the second input terminal;
(Iii) a hysteresis voltage comparator having at least three terminals, the first of which terminals being an input terminal connected to the first terminal of the capacitor, the second terminal being an input terminal for inputting a reference voltage, and a third The terminal is an output terminal;
(Iii) a switch having a first terminal connected to a third terminal of the hysteresis voltage comparator for receiving an output signal from the hysteresis voltage comparator, a second terminal and a third terminal connected to the second terminal of the capacitor; The output signal from the hysteresis voltage comparator is closed when the voltage on the capacitor exceeds the high threshold voltage of the hysteresis voltage comparator and the voltage on the capacitor is the low threshold of the hysteresis voltage comparator. opening and closing the switch to open the switch when the voltage decreases;
(Iii) an inductor having a first terminal connected to the first terminal of the capacitor and a second terminal connected to the third terminal of the switch;
(Iii) an output rectifier having a first terminal and a second terminal connected to a second terminal of the inductor; And
(Iii) first and second output terminals, wherein the first output terminal is connected to a second terminal of the output rectifier and the second output terminal is connected to a second terminal of the switch;
Power converter having a circuit comprising a. 4. The power converter of claim 3 wherein the output rectifier is a diode or synchronous rectifier structure. 5. The power converter of claim 4, wherein the output rectifier further comprises a capacitor having a first terminal connected to the second terminal of the output rectifier and a second terminal connected to the second terminal of the switch. 4. The power converter of claim 3, wherein the second input terminal, the second terminal of the capacitor, the second terminal of the switch and the second output terminal are all connected to ground. The method of claim 2, wherein the power converter,
(Iii) first and second input terminals for connecting to a power supply providing an input voltage;
(Ii) a capacitor having a first terminal connected to the first input terminal and a second terminal connected to the second input terminal;
(Iii) a hysteresis voltage comparator having at least three terminals, the first of which terminals being an input terminal connected to the first terminal of the capacitor, the second terminal being an input terminal for inputting a reference voltage, and a third The terminal is an output terminal;
(Iii) a switch having a first terminal connected to a third terminal of the hysteresis voltage comparator for receiving an output signal from the hysteresis voltage comparator, a second terminal and a third terminal connected to the second terminal of the capacitor; The output signal from the hysteresis voltage comparator is closed when the voltage on the capacitor exceeds the high threshold voltage of the hysteresis voltage comparator and the switch is opened when the voltage on the capacitor decreases to the low threshold voltage of the hysteresis voltage comparator. To open and close the switch;
(Iii) a primary winding having a first terminal connected to the first terminal of the capacitor and a second terminal connected to the third terminal of the switch and a secondary winding having the first terminal and the second terminal a transformer having a secondary winding;
(Iii) an output rectifier having a first terminal and a second terminal connected to the first terminal of the transformer secondary winding; And
(Iii) first and second output terminals, wherein the first output terminal is connected to a second terminal of the output rectifier and the second output terminal is connected to a second terminal of the transformer secondary winding;
Power converter having a circuit comprising a. 8. The power converter of claim 7, wherein the output rectifier is a diode or synchronous rectifier structure. 9. The power converter of claim 8, wherein the output rectifier further comprises a capacitor having one terminal connected to the second terminal of the output rectifier and a second terminal connected to the second terminal of the switch. 8. The power converter of claim 7, wherein the second input terminal, the second terminal of the capacitor, the second terminal of the switch and the second output terminal are all connected to ground. A power combiner that combines the output power of a plurality of power supplies into one output, the power combiner comprising a parallel arrangement of circuits, different circuits of the circuits assigned to each of the plurality of power supplies, each of these circuits Is a fully input-regulated high output impedance power converter circuit or a power combiner that forms a complete input-regulated high output impedance power converter circuit when connected to one or more shared elements that these circuits share. 12. The power combiner of claim 11, wherein each of said circuits is a fully input-regulated high output impedance power converter circuit. 13. The power combiner of claim 12, further comprising a controller for operating the power converter circuits. 13. The power combiner of claim 12, wherein each of the circuits is a complete history input-regulated high output impedance power converter circuit including a history voltage comparator. The method of claim 14, wherein the power combiner,
(a) a power converter circuit assigned to each of said power sources, each power converter circuit comprising:
(Iii) first and second input terminals for connecting to a power source designated for the power converter circuit;
(Ii) a capacitor having a first terminal connected to the first input terminal and a second terminal connected to the second input terminal;
(Iii) a hysteresis voltage comparator having at least three terminals, the first of which terminals being an input terminal connected to the first terminal of the capacitor, the second terminal being an input terminal for inputting a reference voltage, and a third The terminal is an output terminal;
(Iii) a switch having a first terminal connected to a third terminal of the hysteresis voltage comparator for receiving an output signal from the hysteresis voltage comparator, a second terminal and a third terminal connected to the second terminal of the capacitor; The output signal from the hysteresis voltage comparator is closed when the voltage on the capacitor exceeds the high threshold voltage of the hysteresis voltage comparator and the switch is opened when the voltage on the capacitor decreases to the low threshold voltage of the hysteresis voltage comparator. To open and close the switch;
(Iii) an inductor having a first terminal connected to the first terminal of the capacitor and a second terminal connected to the third terminal of the switch; And
(Iii) an output rectifier having a first terminal and a second terminal connected to a second terminal of the inductor; And
(b) an output having a first terminal connected to the second terminal of the output rectifier of each power converter circuit and a second terminal connected to the second terminal of the switch of each power converter circuit.
Power combiner comprising a. 16. The power combiner of claim 15, wherein said output rectifier of each power converter circuit is a diode or synchronous rectifier structure. 17. The power combiner of claim 16, further comprising a capacitor having a first terminal connected to the first terminal of the output and a second terminal connected to the second terminal of the output. 16. The circuit of claim 15, wherein the second input terminal of each power converter circuit, the second terminal of the capacitor of each power converter circuit, the second terminal and the second output terminal of the switch of each power converter circuit are all connected to ground. Power combiner. 12. The circuit of claim 11, wherein each of the circuits, when connected to the one or more shared elements, forms a complete input-regulated high output impedance power converter circuit and only one to the one or more shared elements at any given time. The power combiner of which circuit is connected. 20. The power combiner of claim 19, wherein the shared elements are an inductor and an output rectifier. 21. The power combiner of claim 20, wherein each said circuit comprises a capacitor and a switch. 20. The power combiner of claim 19, further comprising a controller that periodically cycles through the circuits to connect and disconnect the circuits to the shared elements and thereby process each of the power supplies. 22. The system of claim 21, further comprising a controller that periodically cycles through the circuits to connect and disconnect the circuits to the shared elements and thereby process each of the power supplies, with only one switch at any given time. Power coupler closed. The method of claim 23, wherein each of the circuits,
(Iii) a first input terminal and a second input terminal for connecting to a power supply designated for the circuit;
(Ii) a capacitor having a first terminal connected to the first input terminal and a second terminal connected to the second input terminal; And
(Iii) a switch having a first terminal and a second terminal connected to the first terminal of the capacitor,
The shared elements,
(a) an inductor having a first terminal connected to a second terminal of a switch of each said circuit and a second terminal connected to a second terminal of a capacitor of each said circuit; And
(b) an output rectifier having a first terminal and a second terminal connected to a second terminal of the inductor,
One output having a first terminal connected to the second terminal of the output rectifier and a second terminal connected to the first terminal of the inductor. 25. The power combiner of claim 24, wherein the second terminal of the switch of each of the circuits, the first terminal of the inductor and the second terminal of the output are all connected to ground. 25. The power combiner of claim 24, wherein the output rectifier is a diode or synchronous rectifier structure. 27. The power combiner of claim 26, further comprising a capacitor having a first terminal connected to the output terminal and a second terminal connected to ground. 3. The power converter of claim 2, wherein the power source is a photovoltaic cell and the hysteresis voltage comparator has a reference voltage adjusted such that the photovoltaic cell operates essentially at its maximum power point. The power combiner of claim 13, wherein the power supplies are photovoltaic cells and the controller adjusts the operation of each photovoltaic cell such that each photovoltaic cell operates essentially at its maximum power point. 23. The power combiner of claim 22, wherein the power supplies are photovoltaic cells and the controller adjusts the operation of each photovoltaic cell such that each photovoltaic cell operates essentially at its maximum power point. 24. The power combiner of claim 23, wherein said controller and said switches from each circuit are included in a silicon chip.

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