Z-source DC / DC converter for supplying power to electroacoustic transducer

Abstract

The invention discloses a Z-source DC / DC converter for supplying power to an electroacoustic transducer, which has higher voltage gain, and the voltage gain is (1 + D) / (1-2D). Compared with a traditional DC / DC converter which does not have short-circuit protection and overvoltage protection capabilities in the transition capability during voltage drop, when the topology output end is short-circuited, due to the existence of the impedance network, the current cannot be rapidly increased instantly, and at the moment of short circuit, the Z-source network can restrain the rapid rising of the current, so that the output end of the DC / DC converter is prevented from being short-circuited, and the output end of the DC / DC converter is prevented from being short-circuited. A certain protection time is provided for the converter, and a switching device is prevented from being damaged immediately due to overlarge current, so that the circuit has the transition capability during short-time voltage drop.

Description

Technical Field

[0001] The present invention relates to a DC / DC converter, in particular to a Z-source DC / DC converter for powering electro-acoustic transducers. Background Art

[0002] The DC / DC converter is an essential part of the power supply and drive for underwater electro-acoustic transducers. It provides a stable DC terminal voltage for the pre-stage power amplifier of the electro-acoustic transducer. The three cooperate to convert direct current into underwater sonar signals. However, due to the harsh marine environment, there are two problems in powering and driving electro-acoustic transducers at sea: (1) The marine environment is humid, which easily causes the output of the power amplifier to short-circuit and generate an impact current, resulting in the power supply being burned out; (2) Due to the relatively low voltage level of the self-power supply system at sea and the relatively high impedance of the electro-acoustic transducer, the output voltage of the power supply for the electro-acoustic transducer needs to have a relatively high gain. Traditional power supplies are difficult to meet these requirements. Currently, most of the applied DC / DC converters use Buck or Boost converters and their variants, with limited boost capabilities and unable to handle short-circuit problems. When short-circuited due to various reasons, a large impact current may burn out the switching devices.

[0003] To address the above problems, engineering often uses a structure with a subsequent transformer or modular cascaded boost to meet the high-voltage requirements of the output. However, this will have problems such as more active devices, higher system costs, and larger volumes; often externally connect an overvoltage protection circuit to prevent the power supply from being burned out by short circuits. However, this still cannot handle instantaneous high-voltage and high-current problems, and the cost is high and the volume is large.

[0004] The Z-source DC converter couples the main converter circuit with the power supply or load by introducing an impedance network. Due to the special performance of the impedance network, the converter can increase the output voltage range without a transformer or cascading, and can handle instantaneous faults such as arm shoot-through and output short-circuit, overcoming the pain point that traditional converters cannot handle short-circuit problems. Therefore, its reliability is relatively high.

[0005] In recent years, a review and comparison of the research on the Z-source DC converter topology are as follows: "Improved Z-source network DC-DC converter and inverter for hydrogen fuel cells" (Publication No.: CN119182294A, Publication Date: December 24, 2024), which can achieve D 2 / (1 - 2D 1 )(D 1 、D 2The voltage gain (the duty cycles of switch 1 and switch 2 respectively), but it uses two switches to control the circuit, with a relatively complex control method and a low voltage gain. "An input-output common-ground active switched-capacitor Z-source boost chopper circuit" (Publication No.: CN109756105B, Publication Date: April 26, 2024) can achieve a voltage gain of (3 - 4D) / (1 - 4D) (D is the duty cycle of the switch), with a relatively high voltage gain, but its output cannot handle instantaneous short-circuit problems and loses the reliable characteristics of the Z-source converter. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a Z-source DC / DC converter for powering electroacoustic transducers to improve the voltage gain in view of the deficiencies of the prior art.

[0007] To solve the above technical problem, the technical solution adopted by the present invention is: A Z-source DC / DC converter for powering electroacoustic transducers, comprising:

[0008] A first diode, with the positive electrode connected to the DC power supply and the negative electrode connected to the Z-source network;

[0009] The Z-source network, connected to the voltage-doubling unit;

[0010] The voltage-doubling unit, connected to the switching device and the output filter capacitor; the switching device is connected in parallel with the output filter capacitor;

[0011] Among them, the voltage-doubling unit includes a third capacitor, one end of the third capacitor is connected to the positive output end of the Z-source network, and the other end of the third capacitor is connected to one end of the third inductor and the anode of the third diode; the third capacitor is connected in parallel with the second diode, the cathode of the second diode is connected to the other end of the third inductor and one end of the fourth capacitor, and the fourth capacitor is connected in parallel with the third diode; the cathode of the third diode and the other end of the fourth capacitor are connected to one end of the output filter capacitor.

[0012] The Z-source network includes a first inductor and a first capacitor, one end of the first inductor and one end of the first capacitor are both connected to the cathode of the first diode; the other end of the first inductor is connected to one end of the second capacitor, and the other end of the second capacitor and the other end of the first capacitor are respectively connected to both ends of the second inductor; the connection end of the second inductor and the second capacitor is connected to the negative electrode of the DC power supply; the connection end of the first inductor and the second capacitor is the positive output end of the Z-source network.

[0013] The switching device is a MOSFET; the source electrode of the MOSFET is connected to the connection end of the second inductor and the first capacitor and one end of the output filter capacitor; the drain electrode of the MOSFET is connected to the positive output end of the Z-source network.

[0014] In the continuous conduction mode of the switching device, the voltage gain of the Z-source DC / DC converter is as follows: where Vin is the input voltage, V 0 is the output voltage, and D is the duty cycle of the switching device.

[0015] In the present invention, 0 < D < 1. More preferably, 0 < D < 0.5.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: In terms of voltage gain, compared with traditional Boost converters (whose voltage gain is 1 / (1 - D)), Z-source DC converters (whose voltage gain is 1 / (1 - 2D)), Z-source boost converters (whose voltage gain is (1 - D) / (1 - 2D)), improved Z-source network DC-DC converters (whose voltage gain is D 2 / (1 - 2D 1 )) and other DC / DC converters, the present invention has a higher voltage gain, and its voltage gain is (1 + D) / (1 - 2D); in terms of the transition ability during voltage dips, compared with traditional DC / DC converters that do not have short-circuit protection and over-voltage protection capabilities, when a short circuit occurs at the output end of the topology of the present invention, due to the existence of the impedance network, the current will not increase sharply instantaneously. At the moment of short circuit, the Z-source network can suppress the rapid rise of the current and provide a certain protection time for the converter to avoid the immediate damage of the switching device due to excessive current. Therefore, the present invention has the transition ability during short-term voltage dips. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a structural diagram of an improved Z-source DC / DC converter for powering an electroacoustic transducer according to an embodiment of the present invention;

[0018] Figure 2 is the Z-source network according to an embodiment of the present invention;

[0019] Figure 3 is the voltage-doubling unit according to an embodiment of the present invention;

[0020] Figure 4 is the circuit modal diagram within one switching period T according to an embodiment of the present invention; (a) the switching device is on, Mode 1, (b) the switching device is off, Mode 2;

[0021] Figure 5 is the relationship between the output voltage and the input voltage according to an embodiment of the present invention;

[0022] Figure 6 is the gain curve of each DC converter according to an embodiment of the present invention;

[0023] Figure 7 is the voltage and current waveform diagram of the main components within one switching period according to an embodiment of the present invention. Detailed implementation mode

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0025] The embodiment of the present invention provides an improved Z-source DC / DC converter for powering an electroacoustic transducer. It includes a DC power supply, a first diode D1, a Z-source network, a switching device S, a voltage doubling unit, an output filter capacitor C0, and a load.

[0026] The switching device S is a semiconductor switching device with turn-on and turn-off functions. Any semiconductor switching device with the same functions can achieve the functions of this circuit, including but not limited to semiconductor switching devices with turn-on and turn-off functions such as metal-oxide-semiconductor field-effect transistors (MOSFETs) and insulated-gate bipolar transistors (IGBTs).

[0027] The Z-source network includes a first inductor L1, a second inductor L2, a first capacitor C1, and a second capacitor C2; the Z-source network is an X-type Z-source network formed by connecting the first inductor, the second capacitor, the second inductor, and the first capacitor end to end; the voltage doubling unit includes a third capacitor C3, a fourth capacitor C4, a third inductor L3, a second diode D2, and a third diode D3; in the voltage doubling unit, one end of the third capacitor is connected to the anode of the diode, the other end of the third capacitor is connected to one end of the third inductor, the other end of the third inductor is connected to the cathode of the second diode, the connection part between the third capacitor and the third inductor is connected to the anode of the third diode, the cathode of the third diode is connected to one end of the fourth capacitor, and the other end of the fourth capacitor is connected to the connection part between the cathode of the second diode and the third inductor.

[0028] The positive pole of the DC power supply is connected to the anode of the diode, and the cathode of the diode is connected to one end of the Z-source network, that is, the connection part of the first capacitor and the first inductor; the negative pole of the power supply is connected to the connection part of the second capacitor and the second inductor in the Z-source network; the connection part of the first inductor and the second capacitor in the Z-source network is connected to the connection part of the third capacitor and the anode of the second diode in the voltage doubling unit and the drain of the MOSFET; the connection part of the second inductor and the first capacitor in the Z-source network is connected to the source of the MOSFET and one end of the output capacitor; the other end of the output capacitor is connected to the connection part of the cathode of the third diode and the fourth capacitor and the other end of the output capacitor; the load is connected in parallel across the output capacitor.

[0029] This embodiment provides an improved Z-source DC / DC converter control method for powering an electroacoustic transducer. It is applied to the above-mentioned improved Z-source DC / DC converter topology and is also the voltage gain calculation method of the circuit of the present invention. The method includes the following steps:

[0030] As shown in Figure 4 , the operating modes of the improved Z-source DC / DC converter are Mode 1 and Mode 2. The switching frequency of the high-frequency switching device is fs, and the switching period is Ts. The relationship between fs and Ts is Ts = 1 / fs. The working interval of Mode 1 is defined as DTs, and the working interval of Mode 2 is (1 - D)Ts, where D is the duty cycle of the switching device, and D is greater than 0 and less than 1.

[0031] Mode 1: As shown in (a) of Figure 4 , the switching device S is turned on. At this time, there are:

[0032]

[0033] where v L1 , v L2 , v L3 are the voltages of the first inductor, the second inductor, and the third inductor respectively, and V C1 , V C2 , V C3 are the voltages of the first capacitor, the second capacitor, and the third capacitor respectively, and V 0 is the output voltage.

[0034] Mode 2: As shown in (b) of Figure 4 , the switching device is turned off. At this time, there are:

[0035]

[0036] where v′ L1 , v′ L2 , v′ L3 are the voltages of the first inductor, the second inductor, and the third inductor respectively, and V in is the input voltage.

[0037] Within a cycle T interval, according to the volt-second balance theorem of the inductor, equations about the first inductor, the second inductor, and the third inductor can be obtained. For the first inductor and the second inductor, there are

[0038]

[0039] For the third inductor, there are

[0040]

[0041] Therefore, the capacitor voltage and the output voltage can be obtained as

[0042]

[0043] Therefore, the voltage gain in the continuous conduction mode is

[0044]

[0045] From Figure 5 it can be obtained that when the input voltage V in is 100V, the duty cycle D of the control switch device is 20%, and the theoretical derivation result is

[0046]

[0047] The output voltage V 0 of the improved Z-source DC / DC converter is 200V, which has the same gain as the theoretical derivation result.

[0048] The variation curves of the ideal maximum gains of the improved Z-source DC / DC converter, the traditional Boost boost DC converter, and the improved Z-source network DC-DC converter with respect to the duty cycle D are as Figure 6 shown. When D is greater than 0 and less than 0.5, the improved Z-source DC / DC converter has a higher DC boost ability compared to other DC converters.

[0049] Combining the equivalent circuit diagrams in the two modes, the expressions for the reverse voltages borne by the switch tube S and the diodes D1, D2, and D3 when they are turned off are as follows:

[0050]

[0051] According to the charge balance principle of the capacitor, the following relationships are obtained by applying Ampere-second balance to C 1 、C 2 、C 3 、C 4 :

[0052]

[0053] where the subscripts on and off represent the turn-on and turn-off of the switch device. Therefore, by solving this set of simultaneous equations, the average currents of the inductors L 1 、L 2 、L 3 can be obtained as

[0054]

[0055] Furthermore, the current stresses of the switch S and the diodes D 1 、D 2 、D 3 can be obtained as

[0056]

[0057] The ideal voltage and current waveforms of the main components of an improved Z-source DC / DC converter in one switching period are shown as Figure 7 follows, where: V gs is the driving signal of the switching device, I L1 , I L2 , I L3 are the currents flowing through inductors L 1 , L 2 , L 3 , V S , I S are the voltage and current of the switching device S, V D1 , V D2 , V D3 are the voltages of diodes D 1 , D 2 , D 3 respectively, and I D1 , I D2 , I D3 are the currents flowing through diodes D 1 , D 2 , D 3 respectively.

[0058] Z-source DC converter (Reference: Wang Limin, Qian Zhaoming, Peng Fangzheng. Z-source DC converter [J]. Electrical Application, 2005(2): 123-124, 49.), Z-source boost converter (Reference: Wang Limin, Qian Zhaoming, Peng Fangzheng. Z-source boost converter [J]. Electric Drive, 2006(1): 28-29, 32.), traditional Boost boost DC converter, improved Z-source network DC-DC converter (see CN119182294A), phase-shifted full-bridge converter. The comparison of attributes such as the ideal voltage gain, the number of switching tubes, and the maximum voltage stress of the switching tubes of the proposed improved Z-source DC / DC converter is shown in Table 1.

[0059] Table 1

[0060]

[0061] Combined with Table 1, it can be obtained that compared with other boost converters, the proposed improved Z-source DC / DC converter realizes a larger voltage gain with fewer switching tubes, reducing the cost; and the proposed improved Z-source DC / DC converter can effectively reduce the voltage stress of the internal components of the circuit, improving the reliability and service life.

[0062] Although the preferred embodiments of the present application have been described, additional changes and modifications can be made to these embodiments by those skilled in the art once they learn of the basic inventive concept. Therefore, the appended claims are intended to be construed to include the preferred embodiments as well as all changes and modifications that fall within the scope of the present application.

[0063] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalent technologies, the present application is also intended to include these modifications and variations.

Claims

1. A Z-source DC / DC converter for powering an electroacoustic transducer, characterized in that: include: A first diode, with its positive electrode connected to the DC power supply and its negative electrode connected to the Z source network; Z source network, connected to the voltage doubling unit; A voltage doubling unit is connected to a switch device and an output filter capacitor; the switch device is connected in parallel with the output filter capacitor; Among them, the voltage doubling unit includes a third capacitor, one end of the third capacitor is connected to the positive output end of the Z source network, and the other end of the third capacitor is connected to one end of the third inductor and the anode of the third diode; the third capacitor is connected in parallel with the second diode, the cathode of the second diode is connected to the other end of the third inductor and one end of the fourth capacitor, and the fourth capacitor is connected in parallel with the third diode; the cathode of the third diode and the other end of the fourth capacitor are connected to one end of the output filter capacitor.

2. The Z-source DC / DC converter for powering an electroacoustic transducer according to claim 1, characterized in that: The Z source network includes a first inductor and a first capacitor, one end of the first inductor and one end of the first capacitor are both connected to the cathode of the first diode; the other end of the first inductor is connected to one end of the second capacitor, and the other end of the second capacitor and the other end of the first capacitor are respectively connected to the two ends of the second inductor; the connection end of the second inductor and the second capacitor is connected to the negative electrode of the DC power supply; the connection end of the first inductor and the second capacitor is the positive output end of the Z source network.

3. The Z-source DC / DC converter for powering an electroacoustic transducer according to claim 2, characterized in that: The switch device is a MOSFET; the source of the MOSFET is connected to the connection end of the second inductor and the first capacitor and one end of the output filter capacitor; the drain of the MOSFET is connected to the positive output end of the Z source network.

4. The Z-source DC / DC converter for powering an electroacoustic transducer according to claim 1, characterized in that: In the continuous conduction mode of the switching device, the voltage gain of the Z-source DC / DC converter is: Among them, V in is the input voltage, V0 is the output voltage, and D is the duty cycle of the switching device.

5. The Z-source DC / DC converter for powering an electroacoustic transducer according to claim 4, characterized in that: 0＜D＜1。 6. The Z-source DC / DC converter for powering an electroacoustic transducer according to claim 3 or 4, characterized in that: 0＜D＜0.5。

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