800v power supply system for data center based on pt symmetric coreless transformer
By adopting PT symmetrical coreless transformers, the problems of low efficiency and high cost in traditional data center power supply systems have been solved, and the weight and cost of transformers have been reduced, thereby improving the power density and economy of the power supply system.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SOUTH CHINA UNIV OF TECH
- Filing Date
- 2026-04-27
- Publication Date
- 2026-07-14
AI Technical Summary
Traditional data center power supply systems are inefficient and costly. Traditional power frequency transformers are bulky and difficult to integrate, while solid-state transformers are expensive, especially in terms of core materials and manufacturing costs.
The use of PT symmetrical coreless transformers, including PT symmetrical power frequency coreless transformers and PT symmetrical DC coreless transformers, enables power frequency AC and DC voltage conversion respectively, replacing traditional cored transformers, reducing transformer weight and volume, and lowering costs.
While meeting the requirements of power conversion, it significantly reduces the weight and cost of transformers, increases power density, and improves the economics of 800V power supply systems for data centers.
Smart Images
Figure CN122393889A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the technical field of transformers and power electronic conversion, and in particular to an 800V power supply system for data centers based on a PT symmetrical coreless transformer. Background Technology
[0002] With the development of artificial intelligence (AI) technology, the demand for computing power worldwide is growing exponentially. The power of individual AI chips is constantly increasing, leading to a continuous rise in total power consumption and electricity costs. This places higher demands on the power supply systems of AI data centers. Traditional data centers use low-voltage AC power supply schemes, which first step down the voltage through a power frequency transformer before supplying power to the chips via a multi-stage AC-DC process. Therefore, the overall system efficiency is relatively low. To improve efficiency and power density, data center power supply systems are undergoing a technological transformation towards higher power, DC, and higher voltage, with 800V (HVDC) power supply becoming the mainstream solution. Furthermore, traditional power frequency transformers are bulky, occupy a large area, and are difficult to integrate, and are gradually being replaced by lightweight, highly integrated solid-state transformers (SST). However, current SST transformers have a high overall cost, especially in terms of core materials and customization, making them far less economical than power frequency transformers. Coreless transformers, also known as air-core transformers, are a disruptive new technology with the following significant advantages: greatly reduced transformer size and weight, facilitating integration; direct elimination of core manufacturing costs; absence of eddy current and hysteresis losses, and no issues with core saturation or interlayer mechanical oscillations; and no need to consider insulation issues between windings and the core. Therefore, if coreless transformers are used in data center power supply systems, they can significantly reduce transformer weight and increase power density while meeting power conversion requirements, and are expected to substantially reduce transformer costs, thereby improving the economics of the power supply system. Summary of the Invention
[0003] The purpose of this invention is to overcome the shortcomings and deficiencies of the prior art and provide a data center 800V power supply system based on PT symmetric (parity-time symmetric) coreless transformers. This system uses two types of PT symmetric coreless transformers: PT symmetric power frequency coreless transformers and PT symmetric DC coreless transformers. Both are based on the parity-time symmetry principle and respectively realize the voltage conversion of power frequency AC and DC. While meeting the requirements of power conversion, it greatly reduces the weight of the transformer, increases the power density, and is expected to significantly reduce the transformer cost and improve the economic efficiency of the data center 800V power supply system.
[0004] To achieve the above objectives, the technical solution provided by this invention is: an 800V power supply system for a data center based on a PT-symmetric coreless transformer, comprising:
[0005] PT symmetrical power frequency coreless transformer is used to step down the high voltage AC power from the power grid to low voltage AC power.
[0006] Non-isolated AC-DC unit for converting low-voltage alternating current into high-voltage direct current;
[0007] PT symmetrical DC coreless transformer is used to convert high-voltage DC to low-voltage DC.
[0008] The PT symmetrical power frequency coreless transformer, the non-isolated AC-DC unit, and the PT symmetrical DC coreless transformer are connected in sequence.
[0009] Furthermore, the PT symmetrical power frequency coreless transformer includes an LC filter, a first AC-AC converter, a first resonant capacitor, a first coreless winding, a second coreless winding, a second resonant capacitor, a second AC-AC converter, and a first output capacitor filter; the LC filter is connected in parallel with the input terminal of the first AC-AC converter; the first AC-AC converter is a half-bridge network composed of two single-phase bridge bidirectional switches connected in series, each single-phase bridge bidirectional switch has two arms, each arm is composed of two diodes connected in reverse series, and a semiconductor power switch is connected in series between the centers of the two arms; the output terminal of the first AC-AC converter is connected in series with the first resonant capacitor; the first coreless winding is connected in series with the first resonant capacitor and coupled to the second coreless winding; the second coreless winding is connected in series with the second resonant capacitor and then connected in series with the input terminal of the second AC-AC converter; the second AC-AC converter is a full-bridge network composed of bidirectional switches, including two parallel arms, each arm is connected in series with two bidirectional switches, each bidirectional switch is composed of two semiconductor power switches connected in reverse series; the first output capacitor filter is connected in parallel with the output terminal of the second AC-AC converter.
[0010] Furthermore, the control circuit of the PT symmetrical power frequency coreless transformer includes a first current transformer, a second current transformer, a voltage transformer, a first zero-crossing comparator, a second zero-crossing comparator, a third zero-crossing comparator, a first digital controller, a first driver, and a second driver. The first current transformer samples the current of the first coreless winding and outputs a square wave signal of the same phase to the first digital controller through the first zero-crossing comparator. The second current transformer samples the current of the second coreless winding and outputs a square wave signal of the same phase to the first digital controller through the second zero-crossing comparator. The voltage transformer samples the input voltage of the PT symmetrical power frequency coreless transformer and outputs a square wave signal of the same phase to the first digital controller through the third zero-crossing comparator. The first digital controller outputs a primary-side PWM signal and a secondary-side PWM signal based on the input square wave signal. The primary-side PWM signal outputs the drive signal of the semiconductor power switch of the first AC-AC inverter through the first driver. The secondary-side PWM signal outputs the drive signal of the semiconductor power switch of the second AC-AC inverter through the second driver.
[0011] Furthermore, the PT symmetrical DC coreless transformer includes an input capacitor filter, a half-bridge inverter, a third resonant capacitor, a third coreless winding, a fourth coreless winding, a fourth resonant capacitor, a full-bridge rectifier, and a second output capacitor filter. The output terminal of the input capacitor filter is connected in parallel with the input terminal of the half-bridge inverter. The half-bridge inverter is a half-bridge network composed of two semiconductor power switches connected in series. The output terminal of the half-bridge inverter is connected in series with the third resonant capacitor. The third coreless winding is connected in series with the third resonant capacitor and coupled to the fourth coreless winding. The fourth coreless winding is connected in series with the fourth resonant capacitor and then in series with the input terminal of the full-bridge rectifier. The full-bridge rectifier includes two parallel bridge arms, each bridge arm connected in series with two semiconductor power switches. The second output capacitor filter is connected in parallel with the output terminal of the full-bridge rectifier.
[0012] Furthermore, the control circuit of the PT symmetrical DC coreless transformer includes a third current transformer, a fourth zero-crossing comparator, a second digital controller, and a third driver; the third current transformer samples the current of the third coreless winding and outputs a square wave signal in phase to the second digital controller through the fourth zero-crossing comparator; the second digital controller outputs a PWM signal according to the input square wave signal and outputs the drive signal of the semiconductor power switch of the half-bridge inverter through the third driver.
[0013] Furthermore, the PT symmetrical power frequency coreless transformer and the PT symmetrical DC coreless transformer have the following characteristics:
[0014] For the PT symmetrical power frequency coreless transformer, the drive signal of the first AC-AC converter is controlled by the current of the first coreless winding, so that the output voltage and output current are in phase, and the first AC-AC converter is equivalent to a negative resistor; the drive signal of the second AC-AC converter is controlled by the current of the second coreless winding, so that the second AC-AC converter is equivalent to a pure positive resistor.
[0015] For the PT symmetrical DC coreless transformer, the drive signal of the half-bridge inverter is controlled by the current of the third coreless winding, so that the output voltage and output current are in phase, and the half-bridge inverter is equivalent to a negative resistor.
[0016] Furthermore, after satisfying the above characteristics, the PT symmetrical power frequency coreless transformer can withstand the input of a 50Hz power frequency AC voltage v to the 800V power supply system of the data center. in At that time, without an iron core, it outputs a 50Hz power frequency AC voltage v. out And when the duty cycle of the primary-side PWM signal is D1, the voltage transformation ratio n1 satisfies:
[0017] ;
[0018] In the formula, L1 represents the self-inductance value of the first coreless winding, and L2 represents the self-inductance value of the second coreless winding.
[0019] Furthermore, for the aforementioned PT symmetrical DC coreless transformer, when its input DC voltage V i When there is no iron core, the output DC voltage V is... o And when the duty cycle of the primary-side PWM signal is D2, the voltage transformation ratio n2 satisfies:
[0020] ;
[0021] In the formula, L3 represents the self-inductance of the third coreless winding, and L4 represents the self-inductance of the fourth coreless winding.
[0022] Furthermore, the non-isolated AC-DC unit is a Boost converter circuit.
[0023] Compared with the prior art, the present invention has the following advantages and beneficial effects:
[0024] This invention utilizes PT symmetrical power frequency coreless transformers and PT symmetrical DC coreless transformers to replace traditional power frequency cored transformers and high-frequency DC cored transformers, respectively. This significantly reduces the weight and volume of the transformers, thereby reducing construction costs such as transportation and installation, and eliminating the production and manufacturing costs of the core. As a result, it increases the power density of artificial intelligence data centers, reduces transformer costs, and improves the economic efficiency of the 800V power supply system for data centers while meeting the requirements of power conversion. Attached Figure Description
[0025] Figure 1 This is an architecture diagram of the system of the present invention.
[0026] Figure 2 This is the circuit topology diagram of a PT symmetrical power frequency coreless transformer.
[0027] Figure 3 This is the control circuit diagram for a PT symmetrical power frequency coreless transformer.
[0028] Figure 4 This is the circuit topology diagram of a PT symmetrical DC coreless transformer.
[0029] Figure 5 This is the control circuit diagram for a PT symmetrical DC coreless transformer.
[0030] Figure 6 The input and output voltage waveforms are shown for a PT symmetrical power frequency coreless transformer.
[0031] Figure 7 The input and output voltage waveforms of a PT symmetrical DC coreless transformer are shown. Detailed Implementation
[0032] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.
[0033] like Figure 1 As shown, this embodiment discloses an 800V power supply system for a data center based on a PT symmetrical coreless transformer, including a PT symmetrical power frequency coreless transformer, a non-isolated AC-DC unit, and a PT symmetrical DC coreless transformer connected in sequence.
[0034] like Figure 2 As shown, the PT symmetrical power frequency coreless transformer includes a coreless inductor L in and capacitor C in The system comprises an input LC filter, a first AC-AC converter, a first resonant capacitor C1, a first coreless winding, a second coreless winding, a second resonant capacitor C2, a second AC-AC converter, and a first output capacitor filter C. o1 The first AC-AC inverter is a half-bridge network composed of two single-phase bridge bidirectional switches connected in series. These two single-phase bridge bidirectional switches can be further divided into a first single-phase bridge bidirectional switch and a second single-phase bridge bidirectional switch. In the first single-phase bridge bidirectional switch, diodes D1 and D3 are connected in reverse series to form one bridge arm, and diodes D2 and D4 are connected in reverse series to form another bridge arm. A semiconductor power switch S1 is connected in series along the center line connecting the two bridge arms. Similarly, the second single-phase bridge bidirectional switch is composed of diodes D5, D6, D7, D8, and a semiconductor power switch S2. S1 and S2 can be IGBT modules or MOSFETs. The self-inductance value of the first coreless winding is L1, and the self-inductance value of the second coreless winding is L2. The first coreless winding is connected in series with the first resonant capacitor C1 and coupled to the second coreless winding. The second coreless winding is connected in series with the second resonant capacitor C2. The second AC-AC inverter is a full-bridge network composed of bidirectional switches, each bidirectional switch consisting of two MOSFETs connected in reverse series. The output capacitor filter C... o1 It is connected in parallel with the output of the second AC-AC inverter.
[0035] like Figure 3As shown, the control circuit of the PT symmetrical power frequency coreless transformer includes a first current transformer, a second current transformer, a voltage transformer, a first zero-crossing comparator, a second zero-crossing comparator, a third zero-crossing comparator, a first digital controller, a first driver, and a second driver. The first current transformer samples the first coreless winding current i1 and outputs a square wave signal in phase with i1 to the first digital controller through the first zero-crossing comparator. The second current transformer samples the second coreless winding current i2 and outputs a square wave signal in phase with i2 to the first digital controller through the second zero-crossing comparator. The voltage transformer controls the input voltage v of the PT symmetrical power frequency coreless transformer. in Sampling is performed, and the result is output to the first digital controller via a third zero-crossing comparator, which is in relation to v. in A square wave signal with the same phase; the first digital controller outputs a primary-side PWM signal and a secondary-side PWM signal based on the input square wave signal; the primary-side PWM signal is output as a drive signal V for the first AC-AC inverter through the first driver. S1 V S2 The secondary-side PWM signal is output as the drive signal V of the second AC-AC inverter via the second driver. Q1A V Q1B V Q2A V Q2B V Q3A V Q3B V Q4A V Q4B .
[0036] The input terminal of the non-isolated AC-DC unit is connected to the output terminal of a PT symmetrical power frequency coreless transformer, and the output terminal of the non-isolated AC-DC unit is connected to the input terminal of a PT symmetrical DC coreless transformer. In this embodiment, the non-isolated AC-DC unit uses a Boost converter circuit.
[0037] The PT symmetrical DC coreless transformer includes an input capacitor filter C. in2 Half-bridge inverter, third resonant capacitor C3, third coreless winding, fourth coreless winding, fourth resonant capacitor C4, full-bridge rectifier, and second output capacitor filter C o2 ,like Figure 4 As shown, in this embodiment, the half-bridge inverter is a half-bridge network composed of two MOSFETs S3 and S4 connected in series; the self-inductance value of the third coreless winding is L3, and the self-inductance value of the fourth coreless winding is L4; the output terminal of the half-bridge inverter is connected in series with C3, and then in series with the third coreless winding; the third coreless winding is connected in series with the third resonant capacitor C3, and coupled to the fourth coreless winding; the fourth coreless winding is connected in series with the fourth resonant capacitor C4, and then in series with the input terminal of the full-bridge rectifier; the full-bridge rectifier consists of diodes D9 and D1.10 D 11 D 12 Composition; C o2 It is connected in parallel at the output of the full-bridge rectifier.
[0038] The control circuit of the PT symmetrical DC coreless transformer includes a third current transformer, a fourth zero-crossing comparator, a second digital controller, and a third driver. For example... Figure 5 As shown, the third current transformer samples the current i3 of the third coreless winding and outputs a square wave signal in phase with i3 to the second digital controller through the fourth zero-crossing comparator; the second digital controller outputs a PWM signal based on the input square wave signal and outputs the drive signal V of the semiconductor power switch of the half-bridge inverter through the third driver. S3 V S4 .
[0039] The PT symmetrical power frequency coreless transformer and the PT symmetrical DC coreless transformer should have the following characteristics:
[0040] For the PT symmetrical power frequency coreless transformer, the drive signal of the first AC-AC converter is controlled by the current of the first coreless winding, so that the output voltage and the output current are in phase, and the first AC-AC converter can be equivalent to a negative resistor; the drive signal of the second AC-AC converter is controlled by the current of the second coreless winding, so that the second AC-AC converter can be equivalent to a pure positive resistor.
[0041] For the PT symmetrical DC coreless transformer, the drive signal of the half-bridge inverter is controlled by the current of the third coreless winding, so that the output voltage and output current are in phase, and the half-bridge inverter can be equivalent to a negative resistor.
[0042] Furthermore, after satisfying the above characteristics, the PT symmetrical power frequency coreless transformer can withstand the input of a 50Hz power frequency AC voltage v to the 800V power supply system of the data center. in At that time, without an iron core, it outputs a 50Hz power frequency AC voltage v. out And when the duty cycle of the primary-side PWM signal is D1, the voltage transformation ratio n1 satisfies:
[0043] ;
[0044] In the formula, L1 represents the self-inductance value of the first coreless winding, and L2 represents the self-inductance value of the second coreless winding.
[0045] Furthermore, for the aforementioned PT symmetrical DC coreless transformer, when its input DC voltage V i When there is no iron core, the output DC voltage V is... o And when the duty cycle of the primary-side PWM signal is D2, the voltage transformation ratio n2 satisfies:
[0046] ;
[0047] In the formula, L3 represents the self-inductance of the third coreless winding, and L4 represents the self-inductance of the fourth coreless winding.
[0048] To illustrate the feasibility of this invention, this embodiment designs a PT symmetrical power frequency coreless transformer and a PT symmetrical DC coreless transformer. The parameters of the designed PT symmetrical power frequency coreless transformer are as follows: input voltage RMS value of 10kV, frequency of 50Hz power frequency, rated power of 70kW, output voltage RMS value of 380V; the first coreless winding has 44 turns, self-inductance of 800μH, winding height of 8cm, winding outer diameter of 32cm, and area of 804cm². 2 The first coreless winding has a wire diameter of 4.0mm and an AC resistance of 303mΩ; the second coreless winding has 7 turns, a self-inductance of 18.5μH, a winding height of 4cm, and an outer diameter of 34cm; the second coreless winding has a wire diameter of 10mm and an AC resistance of 4mΩ; the first resonant capacitor is 1.9nF, and the second resonant capacitor is 81nF; under the same input voltage and load conditions, if a silicon steel sheet core with a saturation magnetic flux density of 1.5T is used, the cross-sectional area A... c Take 804cm 2 According to the formula for calculating induced voltage, the primary winding of a traditional iron-core power transformer requires at least 373 turns. Therefore, this embodiment will reduce the number of turns of the power frequency transformer in the power supply system by 80%, and will no longer require the use of silicon steel sheet cores.
[0049] The designed PT symmetrical DC coreless transformer has the following parameters: input DC voltage of 800V, rated power of 1.5kW, and output DC voltage of 48V; the third coreless winding has 50 turns, a self-inductance of 198μH, a winding height of 4cm, a winding outer diameter of 8cm, and an area of 50.3cm². 2 The wire diameter is 2.5mm and the AC resistance is 100mΩ; the fourth coreless winding has 16 turns, an outer diameter of 8cm, a height of 2cm, a self-inductance of 20.6μH, a wire diameter of 4mm, and an AC resistance of 8mΩ; the third resonant capacitor is 8.9nF and the fourth resonant capacitor is 85.4nF.
[0050] The input and output voltage waveforms of the designed PT symmetrical power frequency coreless transformer under full load are as follows: Figure 6As shown, the input power factor is 0.988 under full load, and the load regulation rate is 2.4% under half load. When switching transistor losses and resonant capacitor losses are ignored, and only winding losses are considered, the calculated efficiency of the proposed coreless power frequency transformer under full load is 99.3%. When the switching transistor losses and resonant capacitor losses account for less than 1% of the total input power, the transformer efficiency under full load can reach over 98.3%.
[0051] The input and output voltage waveforms of the designed PT symmetrical DC coreless transformer under full load are as follows: Figure 7 As shown. The load regulation rate at half load is 1.5%. When switching transistor losses and resonant capacitor losses are ignored, and only winding losses are considered, the calculated efficiency at full load of 1.5kW is 98.6%. When switching transistor losses and resonant capacitor losses account for less than 2% of the total input power, the efficiency at full load can reach over 96.6%.
[0052] Based on the above analysis, this invention replaces the traditional power frequency transformer in a data center power supply system with a PT symmetrical power frequency coreless transformer, significantly reducing the number of winding turns of the power frequency transformer. Furthermore, the absence of a power frequency transformer core results in a substantial reduction in size and weight. This invention also replaces the high-frequency iron-core transformer in a traditional DC-DC converter with a PT symmetrical DC coreless transformer, eliminating the high-frequency iron core and resulting in reduced weight and significantly increased power density. Therefore, this invention can completely replace the traditional data center power supply system, its advantages are obvious, and it is worthy of widespread adoption.
[0053] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.
Claims
1. A data center 800V power supply system based on a PT symmetrical coreless transformer, characterized in that, include: PT symmetrical power frequency coreless transformer is used to step down the high voltage AC power from the power grid to low voltage AC power. Non-isolated AC-DC unit for converting low-voltage alternating current into high-voltage direct current; PT symmetrical DC coreless transformer is used to convert high-voltage DC to low-voltage DC. The PT symmetrical power frequency coreless transformer, the non-isolated AC-DC unit, and the PT symmetrical DC coreless transformer are connected in sequence.
2. The 800V power supply system for data centers based on a PT-symmetric coreless transformer according to claim 1, characterized in that, The PT symmetrical power frequency coreless transformer includes an LC filter, a first AC-AC converter, a first resonant capacitor, a first coreless winding, a second coreless winding, a second resonant capacitor, a second AC-AC converter, and a first output capacitor filter. The LC filter is connected in parallel with the input terminal of the first AC-AC converter. The first AC-AC converter is a half-bridge network composed of two single-phase bridge bidirectional switches connected in series. Each single-phase bridge bidirectional switch has two arms, each arm consisting of two diodes connected in reverse series, and a semiconductor power switch is connected in series between the centers of the two arms. The output terminal of the first AC-AC converter is connected in series with the first resonant capacitor. The first coreless winding is connected in series with the first resonant capacitor and coupled to the second coreless winding. The second coreless winding is connected in series with the second resonant capacitor and then in series with the input terminal of the second AC-AC converter. The second AC-AC converter is a full-bridge network composed of bidirectional switches, including two parallel arms. Each arm has two bidirectional switches connected in series, and each bidirectional switch consists of two semiconductor power switches connected in reverse series. The first output capacitor filter is connected in parallel with the output terminal of the second AC-AC converter.
3. The 800V power supply system for a data center based on a PT-symmetric coreless transformer according to claim 2, characterized in that, The control circuit of the PT symmetrical power frequency coreless transformer includes a first current transformer, a second current transformer, a voltage transformer, a first zero-crossing comparator, a second zero-crossing comparator, a third zero-crossing comparator, a first digital controller, a first driver, and a second driver. The first current transformer samples the current of the first coreless winding and outputs a square wave signal of the same phase to the first digital controller through the first zero-crossing comparator. The second current transformer samples the current of the second coreless winding and outputs a square wave signal of the same phase to the first digital controller through the second zero-crossing comparator. The voltage transformer samples the input voltage of the PT symmetrical power frequency coreless transformer and outputs a square wave signal of the same phase to the first digital controller through the third zero-crossing comparator. The first digital controller outputs a primary-side PWM signal and a secondary-side PWM signal based on the input square wave signal. The primary-side PWM signal outputs the drive signal of the semiconductor power switch of the first AC-AC inverter through the first driver. The secondary-side PWM signal outputs the drive signal of the semiconductor power switch of the second AC-AC inverter through the second driver.
4. The 800V power supply system for data centers based on a PT-symmetric coreless transformer according to claim 3, characterized in that, The PT symmetrical DC coreless transformer includes an input capacitor filter, a half-bridge inverter, a third resonant capacitor, a third coreless winding, a fourth coreless winding, a fourth resonant capacitor, a full-bridge rectifier, and a second output capacitor filter. The output terminal of the input capacitor filter is connected in parallel with the input terminal of the half-bridge inverter. The half-bridge inverter is a half-bridge network composed of two semiconductor power switches connected in series. The output terminal of the half-bridge inverter is connected in series with the third resonant capacitor. The third coreless winding is connected in series with the third resonant capacitor and coupled to the fourth coreless winding. The fourth coreless winding is connected in series with the fourth resonant capacitor and then in series with the input terminal of the full-bridge rectifier. The full-bridge rectifier includes two parallel bridge arms, each bridge arm connected in series with two semiconductor power switches. The second output capacitor filter is connected in parallel with the output terminal of the full-bridge rectifier.
5. The 800V power supply system for a data center based on a PT-symmetric coreless transformer according to claim 4, characterized in that, The control circuit of the PT symmetrical DC coreless transformer includes a third current transformer, a fourth zero-crossing comparator, a second digital controller, and a third driver. The third current transformer samples the current of the third coreless winding and outputs a square wave signal of the same phase to the second digital controller through the fourth zero-crossing comparator. The second digital controller outputs a PWM signal according to the input square wave signal and outputs the drive signal of the semiconductor power switch of the half-bridge inverter through the third driver.
6. The 800V power supply system for a data center based on a PT-symmetric coreless transformer according to claim 5, characterized in that, The PT symmetrical power frequency coreless transformer and the PT symmetrical DC coreless transformer have the following characteristics: For the PT symmetrical power frequency coreless transformer, the drive signal of the first AC-AC converter is controlled by the current of the first coreless winding, so that the output voltage and output current are in phase, and the first AC-AC converter is equivalent to a negative resistor; the drive signal of the second AC-AC converter is controlled by the current of the second coreless winding, so that the second AC-AC converter is equivalent to a pure positive resistor. For the PT symmetrical DC coreless transformer, the drive signal of the half-bridge inverter is controlled by the current of the third coreless winding, so that the output voltage and output current are in phase, and the half-bridge inverter is equivalent to a negative resistor.
7. The 800V power supply system for a data center based on a PT-symmetric coreless transformer according to claim 6, characterized in that, After the aforementioned characteristics are met, the PT symmetrical power frequency coreless transformer can operate when a 50Hz power frequency AC voltage is input to the 800V power supply system of the data center. in At that time, without an iron core, it outputs a 50Hz power frequency AC voltage v. out And when the duty cycle of the primary-side PWM signal is D1, the voltage transformation ratio n1 satisfies: ； In the formula, L1 represents the self-inductance value of the first coreless winding, and L2 represents the self-inductance value of the second coreless winding.
8. The 800V power supply system for a data center based on a PT-symmetric coreless transformer according to claim 7, characterized in that, For the aforementioned PT symmetrical DC coreless transformer, when its input DC voltage V i When there is no iron core, the output DC voltage V is... o And when the duty cycle of the primary-side PWM signal is D2, the voltage transformation ratio n2 satisfies: ； In the formula, L3 represents the self-inductance of the third coreless winding, and L4 represents the self-inductance of the fourth coreless winding.
9. The 800V power supply system for a data center based on a PT-symmetric coreless transformer according to claim 8, characterized in that, The non-isolated AC-DC unit is a Boost converter circuit.