Dual-protection power supply device suitable for medical microwave magnetron

Abstract

The utility model relates to a double-protection power supply device suitable for a medical microwave magnetron, which comprises an alternating current isolation transformer, an EMI electromagnetic compatibility protection circuit, a PFC power factor correction circuit, a half-bridge power supply topological structure, a high-frequency voltage transformation device, an output rectification circuit and an output voltage doubling rectification circuit, the AC isolation transformation device and the high-frequency transformation device are isolation devices. According to the power supply device with the dual patient protection function, the electrical gap is increased through the isolation strength of the isolation transformer device, and the creepage distance is increased through the primary and secondary input and output pins of the isolation transformer device; therefore, the requirements of the electrical clearance and the creepage distance in the medical standard are met.

Description

Technical Field

[0001] The utility model belongs to the technical field of medical devices, and particularly relates to a power supply device for a medical microwave magnetron with double patient protection. Background Art

[0002] At present, the microwave medical devices use two common sources, namely magnetron and solid-state source, as microwave emission sources. Although the solid-state source has good output microwave stability, good protection mechanism and standard power supply, the procurement, R & D, manufacturing cost and maintenance cost of the solid-state source itself are relatively high compared with the magnetron, and the solid-state source cannot ensure stability against load changes. The magnetron is the core of the microwave generator, which converts DC electrical energy into microwave energy. The magnetron has a simple structure, mature technology, convenient development and strong adaptability to load changes. Therefore, the magnetron can be the first choice with high cost performance.

[0003] Since there are many application industries and product types for magnetrons, most designs do not consider electric shock protection if not used in the medical industry. However, according to the medical standard GB 9706.1-2020, patient protection needs to be considered when used in medical microwave equipment. Among the existing magnetrons, only the protection method of grounding the outer shell is used, and the creepage distance and clearance for double patient protection are not achieved in the high-voltage control part.

[0004] The prior art cannot meet the standard of the national standard "GB 9706.1-2020 Medical Electrical Equipment - Part 1: General Requirements for Basic Safety and Essential Performance".

[0005] Furthermore, the international medical standard IEC60601-1 states that class III medical devices must meet the design requirements of BF type (Body Floating). Almost all the requirements in IEC60601-1 are related to protection against electric shock. To minimize the risk of harm to patients during electric shock as much as possible, the standards for medical electrical equipment and systems stipulate means of protection (MOP). They are subdivided into two categories: patient protection measures (MOPP) and operator protection measures (MOOP). Means of protection refer to the general preventive measures taken to protect people from harm during electric shock when contacting medical equipment. IEC60601-1 requires two protection measures (2 MOPP and 2 MOOP), including for patients and operators. Electrical medical equipment and systems must comply with the standards simultaneously to ensure that if one means of protection fails, the other protection measure can be effective. Since patients are generally weaker in constitution than medical staff and may not be able to respond (for example, the patient is under anesthesia), they must be given particularly good protection. Therefore, the requirements for patient protection measures are even more stringent than those for the protection of medical operators. Therefore, connectors used in equipment designed to come into contact with patients, or connectors that accidentally come into contact with patients, require larger creepage distances and clearances, stronger insulation, and reduced leakage current to meet the 2 MOPP specification. Increasing the creepage distance and clearance based on the risk of high voltage can effectively achieve the protection effect. Summary of the Invention

[0006] The technical problem to be solved by the present utility model is: to overcome the above-mentioned technical drawbacks and provide a power supply device that meets double protection.

[0007] To solve the above technical problem, the technical solution proposed by the present utility model is: a power supply device with double protection applicable to a medical microwave magnetron, comprising: an input isolation circuit, a start-up circuit, an EMI electromagnetic compatibility circuit, a full-bridge rectification circuit, a PFC power factor correction circuit, a half-bridge topology circuit, and a rectified output circuit. The input isolation circuit has an isolation transformer device T1, the half-bridge topology circuit has a high-frequency transformer device T2, and the rectified output circuit has a high-frequency transformer device T3.

[0008] Furthermore, the isolation transformer device T1 includes a primary coil, a secondary coil, and a magnetic core; the creepage distance between the primary coil and the secondary coil is 10 mm, and the clearance is 5 mm.

[0009] Furthermore, the high-frequency transformer device T2 includes an N1 / N5 primary coil, an N2 / N3 / N4 secondary coil, and a magnetic core. The creepage distance between the primary coil and all secondary coils is 20 mm, and the clearance is 5 mm.

[0010] Further, the high-frequency transformer device T3 includes a primary coil N1, a secondary coil N2, and a magnetic core. The creepage distance between the primary coil and the secondary coil is 50 mm, and the electrical clearance is 15 mm.

[0011] Further, the isolation transformer device has over-temperature protection, over-current protection, and overload protection functions.

[0012] Further, the topology circuit has real-time feedback and control functions, specifically feedback over-voltage protection, over-current protection, and power output regulation.

[0013] The power supply device applicable to a medical microwave magnetron provided by the present utility model has a two-fold protection, increases the electrical clearance through an isolation transformer and a high-frequency transformer, and increases the creepage distance by isolating the transformer and the high-frequency transformer with an isolator; uses a medical isolation transformer to reduce it so as to meet the requirements of the medical standard regarding the electrical clearance and creepage distance. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The present utility model will be further described below with reference to the drawings.

[0015] Figure 1 It is a schematic diagram of the power supply device of a preferred embodiment of the present utility model.

[0016] Figure 2 is Figure 1 the electrical schematic diagram of the isolation transformer device T1 in

[0017] Figure 3 is Figure 1 the electrical schematic diagram of the high-frequency transformer device T3 in

[0018] Figure 4 is Figure 1 the electrical schematic diagram of the high-frequency transformer device T2 in DETAILED DESCRIPTION OF THE EMBODIMENTS Embodiment

[0019] The power supply device applicable to a medical microwave magnetron in this embodiment has a two-fold protection. As Figure 1 shown, it includes an input isolation circuit, a startup circuit, an EMI electromagnetic compatibility circuit, a full-bridge rectification circuit, a PFC power factor correction circuit, a half-bridge topology circuit, and a rectification output circuit. The input isolation circuit has an isolation transformer device T1, the half-bridge topology circuit has a high-frequency transformer device T2, and the rectification output circuit has a high-frequency transformer device T3.

[0020] The input isolation circuit includes fuses F1 / F2, Y capacitors C6 / C7, isolation transformer device T1, fuses F3 / F4; the startup circuit includes relay K1, isolated power supply PWR1; the EMI electromagnetic compatibility circuit; the full-bridge rectifier circuit B1; the PFC power factor correction circuit includes inductors L1 / L2, MOS transistors Q5 / Q6, diodes D1 / D2; the half-bridge topology circuit includes electrolytic capacitor C5, MOS transistors Q1 / Q2, high-voltage capacitors C1 / C2, high-frequency transformer device T2, rectifier circuit D3 / D4 / D5; the rectified output circuit includes relay K2, MOS transistors Q3 / Q4, high-voltage capacitors C3 / C4, high-frequency transformer device T3, voltage-doubling rectifier circuit D6. There is an isolation transformer device T1 between fuses F1 / F2 and fuses F3 / F4; it includes a primary coil, a secondary coil, an over-temperature protection self-resetting fuse, and a magnetic core. There is a high-frequency transformer device T2 between MOS transistors Q1 / Q2 and rectifier circuit D3 / D4 / D5; there is a high-frequency transformer device T3 between MOS transistors Q3 / Q4 and voltage-doubling rectifier circuit D6.

[0021] As Figure 2 shown, the isolation transformer device T1 includes an N1 primary coil, an M magnetic core, an N2 secondary coil, an A over-temperature protection, a B over-current protection, a C overload protection. The normal operating voltage of the N1 primary coil is AC220V, and the normal operating voltage of the N2 secondary coil is AC220V. The creepage distance of the primary is 10mm, and the electrical clearance is 5mm; the withstand voltage strength of the isolator is AC4000V, and the insulation class is B - 130°C.

[0022] As Figure 3 shown, the high-frequency transformer device T3 includes an N1 primary coil, an M magnetic core, an N2 secondary coil. The normal operating voltage of the N1 primary coil is DC390V, and the normal operating voltage of the N2 secondary coil (1 / 2 of DC4) is DC1000V. The creepage distance between the primary and secondary coils is 50mm, and the electrical clearance is 15mm.

[0023] As Figure 4 shown, the high-frequency transformer device T2 includes N1 / N5 primary coils, an M magnetic core, N2 / N3 / N4 secondary coils. The normal operating voltage of the N1 / N5 primary coils is DC 390V. The normal operating voltage of the N2 secondary coil (DC3) is DC3.3V, the normal operating voltage of the N3 secondary coil (DC2) is DC24V, and the normal operating voltage of the N4 secondary coil (DC1) is DC12V. The creepage distance between the primary and all secondary coils is 20mm, and the electrical clearance is 5mm;. The topology circuit has real-time feedback and control functions, specifically feedback over-voltage protection, over-current protection, and power output regulation.

[0024] In this embodiment, the medical isolation transformer complies with the medical standard IEC60601. The creepage distance between the primary and secondary windings is selected to be greater than 8 mm to increase the creepage distance, and the clearance is selected to be greater than 5 mm. In this embodiment, from the mains power supply end to the control magnetron end, it passes through the isolation transformer device T1 and the high-frequency transformer devices T2 / T3, and finally outputs to the magnetron after two-stage isolation.

[0025] The output voltage is boosted to DC4 through the voltage multiplier rectifier circuit, and the DC4 voltage is applied to the anode of the magnetron to excite the magnetron to emit microwave energy. The operating voltage of the medical microwave magnetron is 2000V, so the voltage output by the high-frequency transformer device T3 is DC4 * 1 / 2 = 1000V. Referring to the standard "GB 9706.1-2020 Medical Electrical Equipment - Part 1: General Requirements for Basic Safety and Essential Performance", according to the national standard regulations, for a 1000V voltage difference level to achieve two-stage patient protection, the creepage distance needs to meet 24 mm and the clearance needs to meet 13 mm. Through the above design of creepage distance and clearance, the standard is fully met, and a 4000V withstand voltage test is carried out from the mains power input to the output end.

Claims

1. A power supply device with double protection for medical microwave magnetron, comprising: Input isolation circuit, startup circuit, EMI electromagnetic compatibility circuit, full-bridge rectifier circuit, PFC power factor correction circuit, half-bridge topology circuit, rectifier output circuit, characterized in that: the input isolation circuit has an isolation transformer T1, the half-bridge topology circuit has a high-frequency transformer T2, and the rectifier output circuit has a high-frequency transformer T3.

2. The medical microwave magnetron has a double-protection power supply device according to claim 1, characterized in that: The isolation transformer device T1 includes a primary coil, a secondary coil, and a magnetic core; the creepage distance between the primary coil and the secondary coil is 10 mm, and the electrical gap is 5 mm.

3. The medical microwave magnetron has a double-protection power supply device according to claim 1, characterized in that: The high-frequency transformer T2 includes primary coils N1 and N5, secondary coils N2, N3 and N4, and a magnetic core. The creepage distance between the primary coil and all secondary coils is 20 mm, and the electrical clearance is 5 mm.

4. The medical microwave magnetron has a double-protection power supply device according to claim 1, characterized in that: The high-frequency transformer T3 includes a primary coil N1, a secondary coil N2, and a magnetic core. The creepage distance between the primary coil and the secondary coil is 50 mm, and the electrical clearance is 15 mm.

5. The medical microwave magnetron has a double-protection power supply device according to claim 1, characterized in that: The isolation transformer T1 has over-temperature protection, over-current protection and overload protection functions.

6. The medical microwave magnetron has a double-protection power supply device according to claim 1, characterized in that: The topology circuit has real-time feedback and control functions, specifically feedback of overvoltage protection, overcurrent protection, and power output regulation.

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