DE202013009404U1 - Converter of an AC voltage to a DC voltage - Google Patents

Abstract

Converter of an AC voltage into a DC voltage comprising a rectifier (1) connected to the single-phase AC mains, a control unit (2) and a chain (3) consisting of N capacitors (C1, CN) (where N is more or equal to 2); which is connected to the output of the rectifier (1) and has a load (6) collection and current distribution node connected to the indicated consequent chain (3) of N capacitors such that the indicated capacitors are connected to the rectifier (1). are consistently loaded and discharged in the chain (3) of the load (6) in a parallel manner, characterized in that an electronic key (7) is added to the converter for the purpose of simplifying the construction and increasing the power coefficient of signals of the control unit (7) can be put into operation and the current flow for the load with current collecting node up to a Stromver Guaranteed dividing node at a time when the amplitude of the rectified voltage is less than the task value, and the collection and current distribution nodes with a load (6) in the form of diode combs (4, 5) are formed, and that in the consistent chain (3) additionally N current limiting resistors and N-1 or N of the diodes are included.

Description

The invention relates to a converter of an AC voltage in a DC voltage according to the preamble of the claim.

The invention belongs to the electronic technique of DC / AC conversion and can find wide application in a variety of secondary voltage sources. The anticipated field of application is LED lighting devices with a mains supply. It is also possible to use the invention in high-power converters and in converters with a pulsating output voltage.

The state of the art conversion of the normal frequency AC voltage is characterized by the well-known technical solution that consists in the rectification of a mains voltage, in the smoothing with a high voltage filtering capacitor and a further transformation using an inductive reactor. The reactor connected to a frequency upstream of a high voltage key element has a frequency much greater than the frequency of a utility network. An example of such a solution is the patent of USA 5,661,645 , 26.08.1997, Power supply for light emitting diode array, Hochstein. Features that are consistent with the features of the invention include the presence of a line voltage rectifier and the presence of a high voltage force key element. The shortcomings of such devices are firstly due to the characteristics of a rectifier characterized by a noticeable proportion of a reactive component in full power (ie, a low value of the power coefficient) that is removed from the network due to a charge of flattening capacitors. Second, such devices can not be simple and inexpensive to construct because the high voltage capacitors require a large capacitance, powerful and fast acting high voltage key and inductive reactors with qualitative cores and isolation must be present. In addition, such devices in their mass application pose a particular environmental threat (pollution) with electromagnetic radiation associated with the operation of a key high voltage element at a high frequency and with the presence of an inductive reactor.

The closest prior art is in the patent of USA 6 577 072 B2 , 10.06.2003, Power supply and LED lamp device, Saito et al. In this solution, a converter of an AC voltage is described in a DC voltage having a connected to the single-phase AC mains rectifier, a control unit and a consistent consisting of N capacitors (where N is more or equal to 2) chain. The chain is connected to the output of a rectifier and has load and current distribution nodes connected to the indicated consequent string of N capacitors so that the indicated capacitors are charged by the rectifier in a consistent manner and in the chain of one load be discharged in a parallel manner.

Shortcomings of this device are a low value of the coefficient of performance as well as a complexity of construction. The described device includes a set of switching high voltage transistors that perform the role of a key and of collection and power distribution nodes for loading.

It is an object of the invention to increase the power coefficient of the converter and to simplify the construction of the converter.

The stated object is solved by the features of claim 1.

The invention is based on a converter of an AC voltage in a DC voltage, a connected to the single-phase AC mains rectifier, a control unit and a consistent consisting of N capacitors (where N is more or equal to 2) chain, which is connected to the output of the rectifier and load sharing and distribution nodes connected to the indicated consequent chain of N capacitors so that the indicated capacitors are consistently charged by the rectifier and discharged in the chain from a load in a parallel manner. In addition, according to the invention, an electronic key is provided which is operable by the signals of the control unit and which ensures a current flow for a load from the current collecting node to the power distribution node at a time when the amplitude of the rectified voltage is less than the input value, and the collection and power distribution nodes are designed for a load in the form of diode combs, and that in the consequent chain additionally N current limiting resistors and N-1 or N diodes are accommodated.

It should be noted that the technical effect, which consists in increasing the coefficient of performance, is unexpected for realization of peculiar features of the invention. In the inventive task solution, the specified features were directed primarily to a realization of a simple circuit diagram of the consistent chain of capacitors of a charge transfer (charge pump). However, it turned out that the All of these features also ensures an increase in the coefficient of performance.

The invention will be explained in more detail with reference to the drawings. Show it:

1 an electrical schematic diagram of the converter,

2 the voltage and current curves of the rectifier illustrating the operation of the device in normal regime (a) and in the compensation of reactive power (b),

3 Variants of diode combs of the collection and current distribution nodes of a load - consistent combs (a), parallel combs (b), combined combs (c),

4 constructive variants of a realization of the rectifier half-wave rectifier (a), bridge full wave rectifier (b), with the current limiting (c), with protective elements at the input (d),

5 Circuit solutions for the practical realization of the electronic key and the connection types of a load - with the connection of a load to the chain of a power distribution (a), with the connection of a load to the chain of a power collection (b), with the key on a field MIH Transistor (metal-insulator-semiconductor) (c), on a thyristor (d), on an optical thyristor (e) and

6 a basic electrical diagram illustrating one of the elementary variants of an implementation of the invention.

The device ( 1 ) works the following way. The rectifier 1 converts the AC voltage of a feed network, for example a sinusoidal waveform with the frequency 50 Gz, in halfwaves with one polarity. In the field of increase of a half-wave of the rectified voltage happens a charge of condensers of the consequent chain 3 approximately up to a voltage U ₁ = √ 2 U ₀ / N, where U _{0 is} the effective value of the mains voltage and N is the number of capacitors. The remaining elements are in the off state passive: the electronic key 7 thanks to the absence of an opening control signal from the control unit 2 , and the diode combs 4 and 5 , thanks to the effect of the closing rectified voltage of the reverse polarity. In the sinking area of a half-wave everything remains without changes up to a certain threshold. In operation without compensation of the reactive power, this threshold is lower than a mean voltage value of the load 6 is selected, and when operating with the compensation, this voltage value is higher than the average value. After the decrease of a magnitude of the rectified voltage to the value of the set threshold, the control unit forms 2 a digest signal for the electronic key 7 , From this point on, the current starts to load 6 (which may be, for example, a resistor R and a flattening capacitor) of N of the consequent chain capacitors C1-CN connected in parallel 3 to be pumped, plus the current that is due to the residual voltage on the output of the rectifier 1 at the present time. The last current depends on a current limiting element of the rectifier or on its internal resistance. The determination of diodes VD1-VDN to disengage a consistent chain of capacitors at the time of their discharge allows them to be reconnected in the parallel fashion. The total current of the rectifier is on the graphs of 2 shown for operation with compensation and without compensation. The current limiting resistors R1-RN do not perform the function of ballast for the load in the ordinary sense of this term in electrical engineering. These resistors with a relatively small resistance limit the switching currents only to an acceptable level, and therein is their main purpose. The specified currents occur in the capacitors C1-CN when used together with the load of a Abflachkondensators a larger capacity and the switching disturbances on the part of the network (contact bounce when switching on). The current limiting element of the rectifier additionally reduces these currents and serves as a prophylactic means against a spontaneous activation of the electronic key because of the effect dU / dt due to the same switching disturbances of the network, but also when there is no ballast for the load.

The function of a ballast that restricts the current for a load is fulfilled by the capacitors C1-CN themselves, which correspond to the line frequency at the half-wave rectification (or the doubled line frequency at the full-wave rectification) by means of the electronic key 7 an electrical charge in the load 6 embarrassed. The discharge of the specified capacitors happens fast enough. It becomes electronic key in its extinguishing area 7 interrupted by the control unit 2 to the excess torque of a voltage value of the next half wave of the output voltage of the rectifier 1 the posted threshold is turned off in the case of the full-wave rectification or at any other moment of the next inactive half-wave for a case of the half-wave rectification. Furthermore, the work of the converter is cyclically repeated.

gestellt, wobei U₀ der Effektivwert einer Netzspannung und N die Zahl der Kondensatoren ist, obwohl in einem solchen Schema die Spannungsverluste an den Dioden maximal sind, da die Entladung jedes Kondensators durch die Kette mindestens aus N-1 der konsequent eingeschalteten Dioden verwirklicht ist. Ein solches Schema ist für Einrichtungen mit einer Kleinleistung und in einer Integralerfüllung bevorzugt. In der 3(b) sind parallele Kämme dargestellt. In diesem Fall werden an einige Dioden der Kämme maximale Anforderungen bezüglich der Größe der zulässigen Rückspannung

gestellt, wobei U₀ der Effektivwert einer Netzspannung ist. In einem solchen Schema sind die Spannungsverluste an den Dioden minimal, da die Entladung jedes Kondensators durch die Kette aus nicht mehr als zwei konsequent eingeschalteten Dioden verwirklicht ist. Ein solches Schema ist für hochleistungsfähige Einrichtungen bevorzugt. In der 3(c) ist eine Variante mit kombinierten Kämmen dargestellt. Solche Kämme können aus spezifischen technologischen Gründen verwendet werden. Die Dioden 4 und 5 der Kämme der Sammel- und Stromverteilungsknoten einer Belastung 6 können als Stabilisatoren für eine Erhöhung der Zuverlässigkeit des Umsetzers verwendet sein. In diesem Fall werden der Abhang oder die wesentliche Verkleinerung der Kapazität eines der Kondensatoren C1–CN der konsequenten Kette 3 nicht zur katastrophalen Absage des Umsetzers führen. For the illustration of a practical realization of the invention are in the 3 Variants of a realization of the diode combs 4 . 5 the collection and power distribution node of a load 6 shown. In the 3 (a) are consistent combs shown. In such an intervention are identical and minimal requirements with respect to the size of the permissible reverse voltage to all diodes of the combs

where U _{0 is} the RMS value of a mains voltage and N is the number of capacitors, although in such a scheme the voltage losses across the diodes are maximal, since the discharge of each capacitor by the chain is realized at least from N-1 of the consistently on diodes. Such a scheme is preferred for devices with a low power and in an integral fill. In the 3 (b) parallel crests are shown. In this case, some diameters of the combs are subject to maximum requirements with regard to the size of the permissible reverse voltage

where U _{0 is} the rms value of a mains voltage. In such a scheme, the voltage losses across the diodes are minimal because the discharge of each capacitor through the chain is accomplished from no more than two consistently on diodes. Such a scheme is preferred for high performance devices. In the 3 (c) is a variant with combined combs shown. Such combs can be used for specific technological reasons. The diodes 4 and 5 the combs of the collection and power distribution nodes of a load 6 may be used as stabilizers for increasing the reliability of the converter. In this case, the slope or the substantial reduction of the capacity of one of the capacitors C1-CN become the consequent chain 3 not lead to catastrophic rejection of the converter.

In 4 are different aspects of a practical realization of the rectifier 1 shown. In 4 (a) is a half-wave rectifier shown, which consists of a diode. In 4 (b) a bridge full wave rectifier is shown, which consists of four diodes. In 4 (c) is a half-wave rectifier with a current limit shown. As a delimiter, a resistor R shown in the diagram or any other known solution with a similar determination can be used. In 4 (d) is a half-wave rectifier with protective elements at the input with a fuse F and a varistor RU shown. All of the enumerated solutions can be used in various combinations as well as in combinations with other known solutions in the field of single-phase rectifiers. The rectifier may additionally be controlled with a phase separation, that is, the control signals of the control unit 2 let through a certain part of the rectified half-waves of the voltage. Such a solution also improves the coefficient of performance.

In 5 are circuit technology solutions for the practical realization of the electronic key 7 and the connection types for a load 6 shown. In 5 (a) is a connection of the burden 6 at the power distribution node 5 represented and the unipolar electronic key 7 at the power collection node 4 the burden 6 , Such a solution is possible only with a half-wave rectification, and in this case there should be 3 N of diodes in the consequent chain. The diode VDN is in a special designation within the consistent chain 3 shown. In 5 (b) is a connection of the burden 6 through the unipolar electronic key 7 at the power collection node 4 and the power distribution node 5 the load on the busbar shown. Such a solution is possible both in the one-way as well as in the full-wave rectification. As an electronic key 7 is the use of various electronic components possible. For example, in 5 (c) for use as a single-pole electronic key 7 a force-high voltage MIH transistor shown. In 5 (d) is the use of a thyristor as the single-pole electronic key 7 shown. Such a solution is useful for powerful and / or high voltage applications. The connection types of the load are possible 6 and without their customization and the electronic key 7 at one of the output buses of the rectifier 1 , For example, in 5 (e) the use of an optical thyristor as a unipolar electronic key 7 shown. This diagram illustrates a connection type of the load 6 without flattening capacitor for feeding with a pulse current of one polarity. The electronic key 7 can also be bipolar, as it is in 1 is shown. As a burden 6 of the converter may be used a second stage, which is formed according to the scheme of the described converter. In this case, the role of the rectifier in the second stage can fulfill the electronic key of the first stage. Such a solution allows to minimize the equipment cost with large voltage reshaping coefficients.

In 6 Fig. 12 is an electrical schematic diagram illustrating an elementary variant of a practical implementation of the invention. The rectifier 1 is with the diode VD19, one Current limiting R8 and a fuse F protected. The electronic key 7 is satisfied with the transistor VT1. The Stabilitron VD21 is intended to protect a shutter from breakdown, and the resistor R10 ensures closing of the key 7 in the absence of a control signal. The control unit 2 is realized with the transistor VT2. For its launch, the starter resistor R12 is included in the enclosure. The analysis of a voltage level of the network is realized by the resistor R9. The diode VD20 ensures protection of the emitter-pn junction of the transistor VT2 from the breakdown with the reverse voltage. The control signal for the electronic key 7 is formed with the resistor R11. Through the decoupling capacitor C8, this control signal occurs on the closure of the transistor VT1.

The consistent chain 3 as well as the diode combs of electricity collection and distribution of burden 4 . 5 are realized with the elements C1-C7, R1-R7, VD1-VD18. The load 6 is represented by consistently lit white light emitting diodes VD23-VD29, which are connected in parallel by an electrolytic capacitor with a large capacitance C9. The Stabilitron VD22 is intended for load protection with excess voltage in emergency applications. In 6 For reasons of simplicity, the quenching cells of the light-emitting diodes are not shown when switching off and other auxiliary elements are not shown. With the same capacitance of each of the seven capacitors C1-C7 with 1 microfarad, the absorption current from the mains is 1.5 MA, at the mains voltage of 220 volts. This creates a load current of 6.5 mA at a load voltage of 20 volts. The efficiency is about 40%.

The structurally considered converter can be designed in a variety of configurations depending on the output power and the mains voltage. In particular, for micromachined applications, such as current-indicating lamps and flexible LED rulers with a 220 volt AC supply, the indicated SMD surface-mount device may be mounted on a flexible pad or hard die. Full or partial fabrication of the integrated circuit converter is possible. In individual cases, high current resistance of the diodes or of the capacitors of a special construction can be used as current limiting resistors R1-RN, which does not change the technical character and the claim.

The considered converter has only two basically necessary high-voltage elements, the rectifier 1 and the electronic key 7 , on. High demands on speed are not made. The remaining elements may be low-voltage elements. The simplicity and low demands on the elements make it possible to keep the implementation value of the converter in mass production very low, that is to say, in some cases a real and more environmentally friendly alternative to the transformers and the high-frequency pulse setters is provided.

Immediately after disconnection from the grid, this device no longer has any dangerous voltage sources when selecting the number of capacitors. In addition, the device has no inductive reactors and operates at low frequency, which minimizes the level of electromagnetic emissions.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 5661645 [0003]
• US 6577072 B2 [0004]

Claims (1)

Converter of an alternating voltage into a direct current voltage, a rectifier connected to the single-phase alternating current network ( 1 ), a control unit ( 2 ) as well as one consisting of N capacitors (C1, CN) (where N is more or equal to 2) 3 ) connected to the output of the rectifier ( 1 ) and collection and power distribution nodes for a load ( 6 ) with the specified consistent chain ( 3 ) of N capacitors are connected in such a way that the specified capacitors are connected by the rectifier ( 1 ) loaded in a consistent manner and in the chain ( 3 ) of the burden ( 6 ) are discharged in a parallel manner, characterized in that, for the purpose of simplifying the construction and increasing the power coefficient in the converter, an electronic key ( 7 ), which is dependent on signals from the control unit ( 7 ) and provides a current flow for loading current collection nodes to a power distribution node at a time when the amplitude of the rectified voltage is less than the duty value, and the collection and power distribution nodes having a load ( 6 ) in the form of diode combs ( 4 . 5 ) and in doing so in the consistent chain ( 3 ) in addition N current limiting resistors and N-1 or N of the diodes are included.

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