A half bridge switching resonant inverter

Abstract

Invention relates to a half-bridge switching resonant inverter comprising a circuit board (10); an inverter (12) having one or more of an inductor (14), a capacitor (16), a diode (18), and an isolated gate bipolar transistor (20) connected to a circuit path on the circuit board (10); a DC phase input (22) connected via the circuit bus to the inverter (12); a half-bridge switch (30) that converts the phase (24) from the direct current phase input (22) to an alternating current phase output (26) and is connected in the circuit path on the inverter (12) to operate at a switching frequency above a resonant frequency and a soft switch (34) is connected to the inverter (12) via the circuit path, operating at a switching frequency value below or above the resonant frequency of the inverter (12) and providing power control in the range of 1 kW to 5kW.

Description

[0001] A HALF BRIDGE SWITCHING RESONANT INVERTER

[0002] TECHNICAL FIELD

[0003] The invention relates to a half-bridge switching resonant inverter with series resonant connection soft switch, which can operate in a wider load range.

[0004] PRIOR ART

[0005] A resonant inverter is a special electrical power conversion circuit used to change direct current (DC) to alternating current (AC). There are different types of electric inverters used for different purposes. This often requires conversion of the power supply, both direct and alternative means. For example, resonant inverters are used in uninterruptible power supply (UPS) devices, electric induction heaters, microwaves, surface sensing devices or sonar systems, medical diagnostic equipment, high-frequency radio and communications equipment, fluorescent lighting, and inductive power dual transmission systems.

[0006] The main difference between typical inverters and a resonant inverter is that resonant inverters convert electrical energy through an unmodulated single-phase system whose structure depends on the nature of the DC source. In other words, it can transmit electrical waves directly from voltage or current power sources. Another difference of the resonant inverter is that it is based on an electronic oscillator with unidirectional or bidirectional switches, depending on the type of current used. Switches are made of controlled components to which a diode is connected. The controlled components determine the exchange mechanism of the keys.

[0007] EP0527053 relates to an auxiliary half-resonant DC link converter. The invention comprises soft switch converters and a half resonant dc coupling converter using auxiliary resonant commutation circuitry with a minimum number of devices. In the invention, when the converter is connected to a DC source with positive and negative terminals, a half-resonance voltage is produced in an inverter via a resonance path, thus controlling the voltage of the converter. BRIEF DESCRIPTION OF THE INVENTION

[0008] The object of the invention is to develop a half-bridge switching resonant inverter that provides power control over a wide range by operating at a switching frequency value above or below the resonant frequency.

[0009] In order to achieve the aforementioned objective, the invention relates to a half-bridge switching resonant inverter comprising a circuit board; an inverter having one or more of an inductor, a capacitor, a diode, and an isolated gate bipolar transistor connected to a circuit path on the circuit board; a DC phase input connected via the circuit bus to the inverter; a half-bridge switch that converts the phase from the direct current phase input to an alternating current phase output and is connected in the circuit path on the inverter to operate at a switching frequency above a resonant frequency. According to the invention a soft switch is connected to the inverter via the circuit path, operating at a switching frequency value below or above the resonant frequency of the inverter and providing power control in the range of 1kW to 5kW. Thus, a greater range of power control in a half-bridge switching resonant inverter is provided by a soft switch, which works as an auxiliary circuit inside the inverter.

[0010] A preferred embodiment of the invention comprises the half-bridge switch is having one or more main switch circuits with parallel resonance. Thus, half-bridging the incoming phase to an inverter is achieved by interconnecting the main switches.

[0011] A preferred embodiment of the invention includes one or more series resonant auxiliary switch circuits of soft switch. Thus, by performing a soft switch, wide ranges of power control in the inverter are ensured.

[0012] In a preferred embodiment of the invention a main switching circuit is comprising a capacitor, a diode and an isolated gate bipolar transistor. Thus, a main switching circuit can be formed.

[0013] In a preferred embodiment of the invention an auxiliary switching circuit is having a diode and an isolated gate bipolar transistor. Thus, an auxiliary switching circuit can be formed.

[0014] A preferred embodiment of the invention is arranged so that the inverter provides a zero- voltage transition in the capacitive region and a zero current transition in the inductive region. Thus, the inverter shows different characteristics according to the incoming phase. In a preferred embodiment of the invention, the soft switch of the inverter and the half-bridge switch are connected to each other in a way that provides a bridge connection to the inductor and capacitor connected in series. Thus, a soft switch as an auxiliary circuit is added to the half-bridge resonant inverter circuit and soft switch is obtained for a half-bridge resonant inverter.

[0015] BRIEF DESCRIPTION OF THE FIGURES

[0016] Figure 1 is a circuit diagram illustration of a half-bridge switching resonant inverter, which is the subject of the invention.

[0017] DETAILED DESCRIPTION OF THE INVENTION

[0018] In this detailed explanation, the subject development of the invention is explained without any limitation and only with reference to examples to better explain the subject.

[0019] Figure 1 shows the circuit diagram of a half-bridge switching resonant inverter design. A half bridge switching resonant inverter comprises an inverter (12) circuit structure, which can be utilized for example in an induction heating hob and can provide an auxiliary circuit feature for resonant inverters. The inverter (12) is comprising electronic circuit elements (14) (16) (18) (20) on its circuit board. In order for the circuit structure to be operational, it must be arranged on a suitable material. In order to assemble the electronic circuit elements (14) (16) (18) (20) of the inverter (12), a circuit board (10) in the form of a plate made of various insulating materials, consisting of conductive (for example copper) paths on its surface and holes covered with solder between the surfaces are used. The circuit elements (14) (16) (18) (20) of the half-bridge switched resonant inverter (12), according to the subject of the invention, mounted on the circuit board (10) basically comprising the following electronic materials;

[0020] • An inductor (14) that creates an alternating current phase output (induction current) (26) by changing the magnetic flux, in circuits fed with an alternating current phase or converting a direct current phase (22) (24) into an alternating current phase.

[0021] • A capacitor (16), which is the basic electrical and electronic circuit element formed by disposing between two metal layers of an insulating material, which is used to store electric charge, reactive power control, prevent information loss, convert between AC / DC (Alternative Current / Direct Current) (22) (26) and can be polarized by electrons and store their electrical charge in the electric field • A diode (18) that passes current in only one direction and provides direct current transmission from the anode tip to the cathode tip, which can also be used in circuit design and structures such as signal limiting, voltage regulator, and switching.

[0022] • An isolated gate bipolar transistor (IGBT- Isolated, gate, bipolar, transistor) (20) that can be used as as a diode (18), which acts like a bipolar transistor (high current) and can be used as a diode (18) that you can turn on and off with the help of a circuit, and can be used as a triac that you can control with the gate end, while operating in a way that provides voltage control, or like a mosfet transistor that you can control with gate while driving the electronic circuit element.

[0023] The half-bridge switched resonant inverter also converts the direct current phase (24) coming from the direct current phase input (22) into the alternating current phase output (26) with a half-bridge switch (30) and a soft switch (34) in the inverter (12). Here, half-bridge switch (30) is provided by preferably 2 main switch circuits (32) as a sub-circuit in the inverter (12) circuit structure. Each main switching circuit (32) consists of capacitor (16), diode (18) and insulated gate bipolar transistor (20) mounted on the circuit path of the circuit board (10) in parallel resonance to each other. Switching is created by connecting the main switch circuits (32) to each other end-to-end and is connected from a capacitor negative end (17) of the capacitor (16) to form a bridge from the end-to-end connection point of the main switches (32). The capacitor (16) is connected in series to the inductor (14) via the circuit path. Soft switch, on the other hand, is preferably provided with 2 auxiliary switch circuits (36) in a sub-circuit feature in the inverter (12) circuit structure. Each auxiliary switching circuit (36) is comprising a diode (18) and an isolated gate bipolar transistor (20) mounted on the circuit path of the circuit board (10) in series resonance to each other. Auxiliary switch circuits (36) are connected end-to-end to each other to create switching and are connected from an inductor positive end (15) of the inductor (14) to form a bridge from the end-to-end connection point of the auxiliary switches (36). Thus, a half-bridge switching resonant inverter (12) circuit can be obtained, and an inverter (12) that can operate at a switching (30) (34) frequency value below or above the inverter (12) resonance frequency value is obtained by adding soft switch as an auxiliary circuit. This feature makes it possible for the inverter (12) to provide power control in the range of 1kW to 5kW. The operating frequency is selected higher than the resonance frequency in the half-bridge switch (30) circuit part of the inverter (12), in which semiconductors are used and fully controlled, such as the mosfet and IGBT (20) used here, that is, in the main switching circuit (32). Thus, the losses occurring during current transmission can be eliminated by this means. However, there is an inverse proportionality between the power in this region and the switching (30) (34) frequency. That is, the power decreases as the switching (30) (34) frequency increases. Because the maximum switching (30) (34) frequency of the semiconductor is limited, the maximum value of the resonant frequency of the system is limited. This determines the value of the minimum transferred power. As a solution, the inverter (12) which is the subject of the invention can provide power control in a wider range since it can operate with soft switch (34) above or below the resonant frequency. For this purpose, a more efficient half-bridge series resonant inverter (12), which can operate in a wider load range, has been designed. In addition, the half-bridge switched resonant inverter (12) is arranged to provide a zero-voltage transition in the capacitive region and a zero current transition in the inductive region. Thus, the circuit structure of the inverter (12), which can switch to different characteristic options according to the phase (24), has been obtained.

[0024] REFERENCE NUMBERS

[0025] 10 Circuit board 12 Inverter

[0026] 14 Inductor

[0027] 15 Inductor positive end

[0028] 16 Capacitor

[0029] 17 Capacitor negative end

[0030] 18 Diode

[0031] 20 Insulated gate bipolar transistor 22 DC phase input 24 Incoming DC phase 26 Alternating current phase output 30 Half-bridge switch 32 Main switching circuit 34 Soft switch

[0032] 36 Auxiliary switching circuit

Claims

CLAIMS1- A half-bridge switching resonant inverter comprising a circuit board (10); an inverter (12) having one or more of an inductor (14), a capacitor (16), a diode (18), and an isolated gate bipolar transistor (20) connected to a circuit path on the circuit board (10); a DC phase input (22) connected via the circuit bus to the inverter (12); a half-bridge switch (30) that converts the phase (24) from the direct current phase input (22) to an alternating current phase output (26) and is connected in the circuit path on the inverter (12) to operate at a switching frequency above a resonant frequency characterized in that a soft switch (34) is connected to the inverter (12) via the circuit path, operating at a switching frequency value below or above the resonant frequency of the inverter (12) and providing power control in the range of 1kW to 5kW.2- A half-bridge switching resonant inverter according to Claim 1, wherein the half-bridge switch (30) is having one or more main switch circuits (32) with parallel resonance.3- A half-bridge switching resonant inverter according to claim 1, wherein the soft switch (34) is having one or more auxiliary switch circuits (36) with series resonance.4- A half-bridge switching resonant inverter according to claim 2, wherein a main switching circuit (32) is comprising a capacitor (16), a diode (18) and an isolated gate bipolar transistor (20).5- A half-bridge switching resonant inverter according to claim 3, wherein an auxiliary switching circuit (36) is having of a diode (18) and an isolated gate bipolar transistor (20).6- A half-bridge switching resonant inverter according to any one of the preceding claims, wherein the inverter (12) is arranged to provide a zero-voltage transition in the capacitive region and a zero current transition in the inductive region.7- A half-bridge switching resonant inverter according to any of the preceding claims, wherein the soft switch (34) and half-bridge switch (30) of the inverter are connected in a way that provides a bridge connection to the inductor (14) and capacitor (16) connected in series.

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