Tumor electric field therapy system

Abstract

This disclosure provides a tumor electric field therapy system, comprising: a DC voltage source that outputs a DC signal; a first full-bridge inverter circuit that inverts the DC signal into a first square-wave AC signal; a second full-bridge inverter circuit that inverts the DC signal into a second square-wave AC signal, wherein the first and second square-wave AC signals have a 60-degree phase difference; a first transformer that transforms the first square-wave AC signal to obtain a transformed first square-wave AC signal; a second transformer that transforms the second square-wave AC signal to obtain a transformed second square-wave AC signal, wherein the secondary side of the first transformer and the secondary side of the second transformer are connected in series, such that the transformed first square-wave AC signal and the transformed second square-wave AC signal are superimposed to generate a third square-wave AC signal; and a filter that filters the third square-wave AC signal to generate a sinusoidal AC signal for generating a tumor therapeutic electric field.

Description

Technical Field

[0001] This disclosure relates to the field of medical devices, and more particularly to a tumor electric field therapy system. Background Technology

[0002] Tumor Treating Fields (TTFields) is a tumor treatment technology based on the principle of precise targeting. Its core principle is to apply a pure sinusoidal electric field of a specific frequency to the tumor site, achieving a therapeutic effect by interfering with the tumor cell division process. The purity of the sinusoidal electric field signal applied to the body is directly related to the accuracy and safety of the treatment. Because harmonic components in the original electric field signal can weaken the therapeutic effect and may also cause non-target biological effects, current technologies use filters to filter the original electric field signal to remove harmonics and obtain a pure sinusoidal electric field signal that meets clinical requirements.

[0003] Therefore, there is a need for an improved tumor electric field therapy system that can precisely achieve optimized waveform timing control of the electric field signal to ensure good harmonic component elimination and thus achieve better therapeutic effects. Summary of the Invention

[0004] To address the aforementioned technical problems, according to one aspect of this disclosure, a tumor electric field therapy system is provided, comprising: a DC voltage source configured to output a DC signal; a first full-bridge inverter circuit configured to invert the DC signal into a first square-wave AC signal; a second full-bridge inverter circuit configured to invert the DC signal into a second square-wave AC signal, wherein the first square-wave AC signal and the second square-wave AC signal have a 60-degree phase difference; a first transformer configured to transform the first square-wave AC signal to obtain a transformed first square-wave AC signal; a second transformer configured to transform the second square-wave AC signal to obtain a transformed second square-wave AC signal, wherein the secondary side of the first transformer and the secondary side of the second transformer are connected in series, such that the transformed first square-wave AC signal and the transformed second square-wave AC signal are superimposed to generate a third square-wave AC signal; and a filter configured to filter the third square-wave AC signal to generate a sinusoidal AC signal for generating a tumor therapeutic electric field.

[0005] By designing two symmetrical full-bridge inverter circuits and superimposing them to generate a square-wave AC signal to obtain a final sinusoidal AC signal, the tumor electric field therapy system according to this disclosure can be controlled using simpler control logic and has higher fault tolerance. Therefore, the tumor electric field therapy system according to this disclosure can reduce level switching delays and timing deviations caused by complex switching control logic, thereby accurately achieving optimized waveform timing control to ensure good and stable harmonic component elimination effect. Attached Figure Description

[0006] The above and other objects, features, and advantages of this disclosure will become clearer from the detailed description of the embodiments of this disclosure in conjunction with the accompanying drawings.

[0007] Figure 1 A schematic block diagram of a tumor electric field therapy system according to the present disclosure is shown;

[0008] Figure 2 A schematic diagram illustrating an example of an electrode pad in a tumor electric field therapy system according to the present disclosure being applied to a patient's head;

[0009] Figure 3 A schematic diagram of the structure of a tumor electric field therapy system according to the present disclosure is shown;

[0010] Figure 4 The diagram shows waveforms of each node in a tumor electric field therapy system according to the present disclosure, wherein waveforms (a) to (c) correspond to the primary input of the transformer, the secondary output of the transformer, and the waveforms of the generated sinusoidal alternating current signal, respectively.

[0011] Figure 5 It shows Figure 4 Frequency analysis diagram of the waveform output from the secondary side of the transformer;

[0012] Figure 6 The diagram shows the waveforms of each node in a tumor electric field therapy system according to the present disclosure after the elimination of the third harmonic, wherein waveforms (a) to (c) correspond to the waveforms of the primary input of the transformer, the secondary output of the transformer, and the generated sinusoidal alternating current signal, respectively.

[0013] Figure 7 It shows Figure 6 The waveform of the transformer secondary output after eliminating the third harmonic is shown in the frequency analysis diagram.

[0014] Figure 8 A schematic diagram of another tumor electric field therapy system according to the present disclosure is shown;

[0015] Figure 9The diagram shows waveforms of each node in another tumor electric field therapy system according to the present disclosure, wherein waveforms (a) to (f) correspond to the primary input of the first transformer, the primary input of the second transformer, the secondary output of the first transformer, the secondary output of the second transformer, the input of the filter, and the waveform of the generated sinusoidal alternating current signal, respectively.

[0016] Figure 10 A circuit implementation of another tumor electric field therapy system according to the present disclosure is shown;

[0017] Figure 11 The diagram shows waveforms of each node in a circuit embodiment of another tumor electric field therapy system according to the present disclosure, wherein: waveforms (a) to (c) correspond to the waveforms of the control signal of the first full-bridge inverter circuit and the waveforms of the primary input of the first transformer corresponding to the first full-bridge inverter circuit, respectively; waveforms (d) to (f) correspond to the waveforms of the control signal of the second full-bridge inverter circuit and the waveforms of the primary input of the second transformer corresponding to the second full-bridge inverter circuit, respectively; waveforms (g) to (h) correspond to the waveforms of the secondary output of the transformers of the first and second full-bridge inverter circuits, respectively; and waveform (i) corresponds to the waveform of the input of the filter. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this disclosure more apparent, the tumor electric field therapy system according to this disclosure will be described below with reference to the accompanying drawings. It should be understood that the various embodiments described in this disclosure are merely illustrative and should not be construed as limiting the scope of this disclosure. Furthermore, in the description of this disclosure, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Words such as "comprising" or "including" are open-ended terms meaning "including but not limited to," and are used interchangeably with them. "Or" and "and" can mean "and / or" and are used interchangeably with them unless the context clearly indicates otherwise.

[0019] Figure 1 A schematic block diagram of a tumor electric field therapy system 100 according to this disclosure is shown. Figure 1 As shown, the tumor electric field therapy system 100 may include an AC signal generating unit 101, a switching unit 102, and an electrode array 103.

[0020] An AC signal generating unit 101, which may also be referred to as a "host" in this disclosure, is used to generate a sinusoidal AC signal with a specific frequency. A relay unit 102 is connected to the AC signal generating unit 101 and is used to relay the sinusoidal AC signal generated by the AC signal generating unit 101 to two or more pairs of electrode pads in the electrode pad array 103. The two or more pairs of electrode pads in the electrode pad array 103 may, for example, be applied to the patient's head at a location on the body surface corresponding to the lesion site, so that the tumor electric field therapy system 100 generates an alternating electric field between the paired electrode pads targeting the patient's lesion site to inhibit the proliferation or spread of tumor cells. In this disclosure, the body surface contact location on the patient's head corresponding to a pair of electrode pads may also be referred to as a "head load." It is understood that, depending on the location and / or number of lesions in the patient, the tumor electric field therapy system 100 may generate one or more sinusoidal AC signals with the same or different specific frequencies, and select a specific number of electrode pads for treatment accordingly; this disclosure does not limit this. For example, as... Figure 1 As shown, the switching unit 102 can be configured to output a first AC signal and a second AC signal obtained by relay to a pair of first electrode plates 1031 and second electrode plates 1032 and another pair of third electrode plates 1033 and fourth electrode plates 1034, respectively, to generate an alternating electric field for tumor treatment.

[0021] Figure 2 A schematic diagram illustrating an example of an electrode pad in a tumor electric field therapy system 100 according to the present disclosure being applied to a patient's head is shown.

[0022] like Figure 2 As shown, the tumor on the patient's head is located at position 201. Accordingly, the first electrode 1031 and the second electrode 1032 are symmetrically applied to the left and right sides of position 201 on the patient's head and are connected to the first AC signal output of the transfer unit 102. Simultaneously, the third electrode 1033 and the fourth electrode 1034 are symmetrically applied to the front and back sides of position 201 on the patient's head and are connected to the second AC signal output of the transfer unit 102. By applying a sinusoidal AC signal to the first electrode 1031 and the second electrode 1032, an alternating electric field (referred to as an X-axis alternating electric field) can be generated in the left-right direction relative to position 201 on the patient's head; while by applying a sinusoidal AC signal to the third electrode 1033 and the fourth electrode 1034, an alternating electric field (referred to as a Y-axis alternating electric field) can be generated in the front-back direction relative to position 201 on the patient's head. When the tumor electric field therapy system 100 is in operation, the switching unit 102 can be configured to alternately generate an X-axis alternating electric field and a Y-axis alternating electric field at a certain switching frequency according to a control signal, so as to inhibit the proliferation or spread of tumor cells at position 201.

[0023] Figure 3 A schematic diagram of the structure of a tumor electric field therapy system 300 according to this disclosure is shown. Figure 3 As shown, the AC signal generation unit 310 in the tumor electric field therapy system 300 may include a DC voltage source 301, a full-bridge inverter circuit 302, a transformer 303, and a filter 304. The full-bridge inverter circuit 302 consists of a first switch 311, a second switch 312, a third switch 313, and a fourth switch 314, which converts the DC signal output from the DC voltage source 301 into an AC signal by controlling the state of each switch.

[0024] More specifically, in embodiments according to this disclosure, when the tumor electric field therapy system 300 is operational, a DC voltage source 301 is configured to output a DC signal to a full-bridge inverter circuit 302, which is configured to invert the DC signal into a square-wave AC signal. A transformer 303 is configured to transform the square-wave AC signal to obtain a transformed square-wave AC signal.

[0025] like Figure 3 As shown, because the circuit connections between the switches in the full-bridge inverter circuit 302 appear to be "H"-shaped, its circuit topology can also be called an "H-bridge". In this disclosure, as... Figure 3 As shown, the left side of the H-bridge can be referred to as the first side, and the right side of the H-bridge can be referred to as the second side. Furthermore, the first switch 311 and the second switch 312 are used to connect to the positive terminal of the DC voltage source, and therefore can be referred to as "high-side switches"; while the third switch 313 and the fourth switch 314 are used to connect to the negative terminal of the DC voltage source, and therefore can be referred to as "low-side switches". Therefore, as an example, the first switch 311 can also be described as the high-side switch of the first side of the full-bridge inverter circuit 302.

[0026] The aforementioned transformed square-wave AC signal can also be referred to as the "original electric field signal" in this disclosure. In the prior art, the original electric field signal is typically configured as a square wave with a positive and negative level and a duty cycle of 50%. In this case, Fourier decomposition reveals that the square wave contains a fundamental wave and a series of odd harmonic components such as the 3rd, 5th, and 7th harmonics. Since the presence of harmonic components can weaken the therapeutic effect and may also cause non-targeted biological effects, the tumor electric field therapy system 300 needs to set a filter to filter the original electric field signal, thereby filtering out harmonics and obtaining a pure fundamental wave as a sinusoidal electrical signal output. Therefore, in the embodiments according to this disclosure, the filter 304 can be configured to filter the transformed square-wave AC signal to generate a sinusoidal AC signal for generating a tumor therapeutic electric field. In the embodiments according to this disclosure, any suitable filter may be used depending on the specific implementation, and this disclosure does not limit this.

[0027] For example, such as Figure 3 As shown, the secondary output of transformer 303 is connected to the input of filter 304, and the output of filter 304 is connected to the adapter unit 320 in tumor electric field therapy system 300, and the adapter unit 320 is connected to electrode array 308.

[0028] In embodiments according to this disclosure, the switching unit 320 may be implemented as including a switch array 307 consisting of a switch group 317 for controlling the X-direction alternating electric field and a switch group 327 for controlling the Y-direction alternating electric field. The output of the filter 304 is connected in parallel to the input of the switch array 307. Figure 2 Similar to that described in the text, the switching unit 320 controls the switching of each switch in the switch array 307 according to the control signal to alternately apply the sinusoidal alternating current signal to the head load 3081 and the head load 3082, so as to inhibit the proliferation or spread of tumor cells at the head load 3081 and the head load 3082.

[0029] Specifically, the input terminals of switch array 307 are connected in parallel with the input terminals of switch group 317 and switch group 327, respectively. Two switches in switch group 317 are connected to the first electrode 318 and the second electrode 328 in electrode array 308, respectively, to output a first AC signal to head load 3081 during operation, thereby generating an X-axis alternating electric field. Two switches in switch group 327 are connected to the third electrode 338 and the fourth electrode 348 in electrode array 308, respectively, to output a second AC signal to head load 3082 during operation, thereby generating a Y-axis alternating electric field.

[0030] Furthermore, to monitor the alternating electric field applied to the patient's body surface, the tumor electric field therapy system 300 may also include a monitoring unit. In embodiments according to this disclosure, the monitoring unit may include a voltage detection module and a current detection module, and as a non-limiting example, the voltage detection module and current detection module may be arranged only between the switching unit and the filter. For example, as Figure 3As shown, the output of filter 304 is connected in parallel to voltage detection module 305 and in series to current detection module 306, and then in parallel to the input of switch array 307. Since the X-direction alternating electric field and the Y-direction alternating electric field are alternately conducted, when the X-direction alternating electric field is on, the Y-direction alternating electric field is off. The voltage and current of the AC signal detected by voltage detection module 305 and current detection module 306 are the voltage and current of the alternating electric signal output to the X-direction head load 3081, and vice versa. Therefore, according to the embodiments of this disclosure, only a single monitoring unit is needed to achieve timely, effective, and accurate monitoring of alternating electric fields in multiple directions. This not only reduces costs but also reduces system size and weight.

[0031] Figure 4 A schematic diagram of the waveforms of each node in a tumor electric field therapy system 300 according to this disclosure is shown. It is assumed that the period of the desired sinusoidal alternating current signal is T.

[0032] When the DC voltage source 301 is configured to provide a DC signal with a specific amplitude Vin, the full-bridge inverter circuit 302 can invert the DC signal. For example, it can control the first switch 311 and the fourth switch 314 to be open only within T / 2, and then control the second switch 312 and the third switch 313 to be open only within the next T / 2. Periodically controlling the switches in the full-bridge inverter circuit 302 in this way can generate a signal with a specific amplitude Vin on the primary side of the transformer 303 (i.e., between pin 1 and pin 2 of the transformer 303). Figure 4 The waveform shown in Figure (a) is a square wave AC signal 401 with a duty cycle of 50% and an amplitude of Vin.

[0033] After the square wave AC signal 401 is transformed by transformer 303, it can generate a signal with the following characteristics on the secondary side of transformer 303 (i.e., between pins 3 and 4 of transformer 303): Figure 4 The waveform shown in waveform diagram (b) is a transformed square wave AC signal 402 with a duty cycle of 50% and an amplitude of Vm. The amplitude Vm of the square wave AC signal 402 can be adjusted by adjusting the turns ratio (or simply "turns ratio") between the primary and secondary windings of transformer 303. Specifically, when the turns ratio is set to Np:Ns=1:N, .

[0034] The transformed square wave AC signal 402, after being filtered by filter 304, generates a sinusoidal AC signal 403 with the waveform shown in waveform diagram (c) at the output of filter 304. The following will combine... Figure 5 The principle of filtering the above-mentioned transformed square wave AC signal 402 is further explained. Figure 5 The frequency analysis diagram corresponding to the waveform of the transformed square wave AC signal 402 is shown.

[0035] By converting the transformed square wave AC signal 402 from a time-domain signal to a frequency-domain signal using Fourier transform, it can be expressed as the following expression (1):

[0036]

[0037] ω o The expression is , This is the fundamental frequency.

[0038] Expanding the above expression (1) yields the following expression (2):

[0039]

[0040] According to the above expression (2), the waveform of the transformed square wave AC signal 402 only contains odd harmonic components, and the intensity of the harmonic signal decreases with frequency. Among them, the fundamental signal (also known as the first harmonic) has the strongest signal intensity, followed by the third harmonic, and the other harmonics decrease in sequence, such as... Figure 5 As shown in the image.

[0041] In order to obtain a pure sinusoidal alternating current signal for generating an electric field for tumor treatment, theoretically, it is necessary to filter out all the odd harmonic components in the above expression (2), leaving only the fundamental component. That is, for example, to finally obtain a signal with the characteristics described above. Figure 4 The waveform shown in waveform diagram (c) is a sinusoidal alternating current signal 403 with an amplitude of 4Vm / π.

[0042] according to Figure 5 As can be seen, the signal strength of the third harmonic component is second only to that of the fundamental wave, and the corresponding frequency of the third harmonic component is close to that of the fundamental wave component, which makes it very challenging to design a suitable filter in practical applications.

[0043] Specifically, on the one hand, because the signal strength corresponding to the third harmonic is relatively high, the requirements for the suppression capability of the filter are relatively stringent, requiring the filter to withstand a huge harmonic attenuation load. This not only significantly increases the design complexity, size, and cost of the filter, but also leads to a significant increase in the filter's own heat generation due to the large loss of harmonic energy, thus affecting the long-term stability and service life of each device in the tumor electric field therapy system 300. On the other hand, because the corresponding frequency of the third harmonic component is close to that of the fundamental component, it is difficult to accurately match the filter's cutoff frequency—if the cutoff frequency is too high, it will be difficult to effectively suppress the third harmonic component; if it is too low, it will attenuate the fundamental signal, thus affecting the amplitude stability and waveform accuracy of the final sinusoidal alternating current signal.

[0044] One solution to the aforementioned third harmonic suppression problem is to suppress the third harmonic by optimizing the waveform timing design. Specifically, this can be achieved by designing the waveform of the original electric field signal (e.g., the waveform of a transformed square wave AC signal 402) so that the third harmonic term in its corresponding Fourier expansion is canceled out. The following will combine... Figure 6 This paper introduces the principle of suppressing third harmonics by optimizing waveform timing design.

[0045] Figure 6 The diagram shows the waveforms of each node in a tumor electric field therapy system 300 according to the present disclosure after the elimination of the third harmonic.

[0046] like Figure 6 As shown, when the DC voltage source 301 is configured to provide a DC signal with a specific amplitude Vin, the full-bridge inverter circuit 302 can, for example, invert the DC signal according to a control signal to generate a signal with a specific amplitude Vin on the primary side of the transformer 303. Figure 6 The waveform diagram (a) shows a square wave AC signal 601 with a period of T and an amplitude of Vin. The signal changes in the period according to the following: (1) 0 level for a duration of 0 to T / 6; (2) high level +Vin for a duration of T / 6 to T / 2; (3) 0 level for a duration of T / 2 to 2T / 3; (4) low level -Vin for a duration of 2T / 3 to T.

[0047] Similarly, the square wave AC signal 601 is transformed by transformer 303, and a signal with the characteristics of a square wave AC signal can be generated on the secondary side of transformer 303. Figure 6 The waveform shown in waveform diagram (b) is a transformed square wave AC signal 602 with an amplitude of Vm.

[0048] At this time, the square wave AC signal 602, after being transformed by Fourier transform, is converted from a time domain signal to a frequency domain signal, and the corresponding expression is as follows (3):

[0049]

[0050] , where the angular frequency ω o The expression is , This is the fundamental frequency.

[0051] Next, expanding the above expression (3) yields the following expression (4):

[0052]

[0053] According to expression (4), we can know that The term has been canceled. In other words, the third harmonic has been eliminated, as shown in the frequency response diagram corresponding to the waveform of the transformed square wave AC signal 602. Figure 7 As shown in the diagram. Next, the remaining odd harmonics can be filtered out using a filter, retaining only the fundamental signal, to finally obtain a sinusoidal AC signal 603 with a waveform as shown in waveform diagram (c) and an amplitude of 3Vm / π. In this way, the impact of the third harmonic on the filter design can be reduced, thereby reducing the complexity, size, and cost of the filter design and extending the device's lifespan.

[0054] However, the above-mentioned solution for suppressing the third harmonic by optimizing waveform timing design may have various problems in practical applications, which may lead to the inability to accurately achieve the optimized waveform timing design and thus affect the elimination effect of harmonic components.

[0055] For example, in the tumor electric field therapy system 300 described above, in order to form such a field on the primary side of the transformer 303... Figure 6 The waveform shown in waveform diagram (a) requires applying a control signal to the full-bridge inverter circuit 302 at times T / 6, T / 2, 2T / 3, and T within the period, respectively, to control the switching changes. Generating such a waveform involves a complex method for generating the control signal corresponding to the full-bridge inverter circuit 302. Furthermore, due to the numerous level changes involved in a single control signal, issues such as level switching delays and timing deviations may easily occur, making it difficult to accurately and stably generate a waveform like the one shown in the diagram. Figure 6 The optimized waveform is shown in waveform diagram (a).

[0056] For example, depending on the type and location of the tumor, the operating frequency of tumor electric field therapy (TEF) technology can range from 100kHz to 300kHz. When the TEF system 300 operates at higher frequencies (e.g., 300kHz), the switching states in the full-bridge inverter circuit 302 change frequently, resulting in a high rate of voltage / current change. This leads to electromagnetic interference (EMI) and heat generation, thereby reducing the lifespan of the components in the system. Furthermore, to achieve better therapeutic effects, the TEF system 300 typically needs to operate continuously for extended periods (e.g., more than 18 hours). In high-frequency operating scenarios, this may further exacerbate the heat generation problem of the switches in the full-bridge inverter circuit 302, and in severe cases, may even lead to the damage of components in the TEF system 300.

[0057] Therefore, to solve the aforementioned technical problems, in the following embodiments according to this disclosure, an improved tumor electric field therapy system is provided. This system uses two symmetrical full-bridge inverter circuits to invert DC signals and then superimpose them to generate the original electric field signal. This enables precise and stable realization of the aforementioned optimized waveform and achieves superior performance in high-frequency operating scenarios. The following will combine... Figure 8 and Figure 9 The improved tumor electric field therapy system described above is described in detail.

[0058] Figure 8 A schematic diagram of the structure of a tumor electric field therapy system 800 according to the present disclosure is shown, while Figure 9 The waveform diagrams of each node in the tumor electric field therapy system 800 are shown accordingly.

[0059] like Figure 8 As shown, the tumor electric field therapy system 800 includes a DC voltage source 801, a first full-bridge inverter circuit 802 and a first transformer 804, a second full-bridge inverter circuit 803 and a second transformer 805, and a filter 806. The first full-bridge inverter circuit 802 and the second full-bridge inverter circuit 803 have the same topology and each includes four switches.

[0060] like Figure 8As shown, the positive terminal of the DC voltage source 801 is simultaneously connected to the first terminals of the first switches 8021 and 8031 ​​and the first terminals of the second switches 8022 and 8032 in the two full-bridge inverter circuits, and the negative terminal of the DC voltage source 801 is simultaneously connected to the second terminals of the third switches 8023 and 8033 and the second terminals of the second switches 8024 and 8034 in the two full-bridge inverter circuits. The first full-bridge inverter circuit 802 and the second full-bridge inverter circuit 803 are respectively connected to the first transformer 804 and the second transformer 805, wherein the specific connection method of each full-bridge inverter circuit and each transformer is as follows: Figure 3 The description of the full-bridge inverter circuit 302 is similar to that of the transformer 303, so for the sake of brevity, it will not be repeated here.

[0061] Pin 3 of the first transformer 804 is connected to pin 4 of the second transformer 805. At the same time, pin 4 of the first transformer 804 is connected to pin 1 of the filter 806, while pin 3 of the second transformer 805 is connected to pin 2 of the filter 806, thereby connecting the secondary sides of the first transformer 804 and the second transformer 805 in series.

[0062] By using two symmetrical full-bridge inverter circuits connected to the same DC voltage source, the power distributed by a single switch in the tumor electric field therapy system 800 can be reduced, resulting in faster on / off switching speeds. This reduces the voltage-current overlap area, thereby decreasing ineffective energy loss during switching and improving overall system efficiency. Furthermore, because the voltage stress and losses of individual switches are lower, heat accumulation and EMI issues at high frequencies are easier to control, allowing the topology to support higher switching frequencies and better meet the operational requirements of the tumor electric field therapy system at higher frequencies.

[0063] When the tumor electric field therapy system 800 is operating, the DC voltage source 801 can be configured to output a DC signal, wherein the amplitude Vin of the DC signal is configurable. The first full-bridge inverter circuit 802 can be configured to invert the DC signal into a first square-wave AC signal 901, and the second full-bridge inverter circuit 803 can be configured to invert the DC signal into a second square-wave AC signal 902. The amplitude of both the first square-wave AC signal 901 and the second square-wave AC signal 902 is Vin, and their duty cycles are both 50%.

[0064] The first square wave AC signal 901 and the second square wave AC signal 902 can have a phase difference of 60 degrees. In the time domain, this means that the moments when the waveforms of the first square wave AC signal 901 and the second square wave AC signal 902 change from low level -Vin to high level +Vin are configured to have a phase difference of 60 degrees. , where n is an integer. In an embodiment according to this disclosure, as a non-limiting example, the waveform of the second square wave AC signal 902 is set to lag behind the first square wave AC signal 901 by 60 degrees, such as... Figure 9 The waveforms (a) and (b) are shown in the figure.

[0065] The first transformer 804 can be configured to transform the first square wave AC signal to obtain the transformed first square wave AC signal 903, and the second transformer 805 can be configured to transform the second square wave AC signal to obtain the transformed second square wave AC signal 904, as shown below. Figure 9 The waveforms (c) and (d) are shown in the figure.

[0066] As described above, the secondary side of the first transformer 804 is connected in series with the secondary side of the second transformer 805, which allows the transformed first square wave AC signal 903 and the transformed second square wave AC signal 904 to be superimposed to generate a third square wave AC signal 905, i.e. Figure 9 The waveform diagram (e) is shown in the figure. Figure 9 The waveform diagram (e) above is based on... Figure 6 The waveform after eliminating the third harmonic. Filter 806 can be configured to filter the third harmonic AC signal 905 to generate a sinusoidal AC signal 906 for generating an electric field for tumor treatment, such as... Figure 9 The waveform diagram (f) is shown in the figure.

[0067] Understandably, compared to Figure 3 The implementation method described herein, which requires level changes at times T / 6, T / 2, 2T / 3, and T within the period, utilizes a single full-bridge inverter circuit. Since two symmetrically topologically aligned full-bridge inverter circuits are superimposed to obtain the original electric field signal of the waveform after third harmonic elimination, embodiments of this disclosure allow for simpler control logic that only requires applying control switching changes at time T / 2 within the period to each full-bridge inverter circuit. This reduces the likelihood of level switching delays and timing deviations, enabling precise optimization of waveform timing design to ensure effective elimination of the third harmonic component. Furthermore, the first full-bridge inverter circuit 802 and the second full-bridge inverter circuit 803 can serve as redundancy for each other, or individually carry power in the event of a component failure in one of them, thereby improving the fault tolerance of the tumor electric field therapy system 800.

[0068] The amplitudes of the first square wave AC signal 903 and the second square wave AC signal 904 can be adjusted by adjusting the coil turns ratio Np:Ns between the primary and secondary sides of the corresponding transformer.

[0069] In embodiments according to this disclosure, the amplitude of the DC signal output by the DC voltage source and the transformer amplitudes of the two transformers can be determined based on the amplitude of the desired original electric field signal. In other words, assuming the third-wave AC signal 905 is configured to have a predetermined voltage amplitude Vm, the amplitude of the DC signal output by the DC voltage source 801 and the turns ratio of the two transformers can be determined based on the predetermined voltage amplitude Vm.

[0070] Optionally, the turns ratio of the first transformer 804 and the second transformer 805 can be configured to be the same. As a non-limiting example, the DC signal output by the DC voltage source 801 can be configured to have a first voltage amplitude Vin, and the turns ratio of the first transformer 804 and the second transformer 805 can be configured to be the same as 1:0.5N, where N is the ratio of the predetermined voltage amplitude Vm of the third-wave AC signal 905 to the first voltage amplitude Vin. For example, assuming the predetermined voltage amplitude Vm of the third-wave AC signal 905 is 160V, the first voltage amplitude Vin of the DC signal output by the DC voltage source 801 can be configured to 40V, and the turns ratio of the first transformer 804 and the second transformer 805 can be configured to be the same as Np:Ns=1:2.

[0071] However, in the circuit design and manufacturing process, the size and manufacturing cost of electronic power devices are often related to the voltage stress they need to withstand. For example, higher voltage stress often means larger size and higher manufacturing cost, because electronic power devices that need to withstand high voltage stress often require more complex processes and structures, and in some cases, even require customization and cannot use commercially available general-purpose devices. To solve the above problems, in the embodiments according to this disclosure, the turns ratio of the first transformer 804 and the second transformer 805 can be adjusted to reduce the amplitude of the DC signal output by the DC voltage source 801.

[0072] For example, as another non-limiting example, the DC signal output by the DC voltage source 801 can be configured to have a second voltage amplitude, and the turns ratio of the first transformer 804 and the second transformer 805 can be configured to be 1:N, where the second voltage amplitude is half of the first voltage amplitude. For example, assuming the predetermined voltage amplitude Vm of the third-wave AC signal 905 is still 160V, the voltage amplitude of the DC signal output by the DC voltage source 801 can be configured to 20V, and the turns ratio of the first transformer 804 and the second transformer 805 can be configured to be Np:Ns=1:4. In this way, the amplitude of the DC voltage source output voltage can be set to a smaller value, thereby reducing the voltage stress borne by each device in the tumor electric field therapy system 800, allowing for the selection of more compact and lower-cost devices in circuit design. Simultaneously, since the voltage stress borne by each device is reduced, the corresponding losses are also reduced, thus resulting in better performance in high-frequency operating scenarios.

[0073] like Figure 8 As shown, the tumor electric field therapy system 800 may further include a voltage detection module 807, a current detection module 808, a switch array 809, and an electrode array 810, the specific connection methods of which are consistent with reference. Figure 3 The voltage detection module 305, current detection module 306, switch array 307, and electrode array 308 are described similarly, and therefore will not be repeated here for the sake of brevity. Switch array 809 and electrode array 810 are configured to apply sinusoidal alternating current signal 906 to the corresponding head loads 8101 and 8102 for treatment.

[0074] In embodiments according to this disclosure, the tumor electric field therapy system 800 may further include: a microcontroller unit (MCU) configured to generate a drive control signal; and a drive circuit configured to drive switches in the first full-bridge inverter circuit and the second full-bridge inverter circuit based on the drive control signal.

[0075] In embodiments according to this disclosure, the switches in the first full-bridge inverter circuit 802 and the second full-bridge inverter circuit 803, as well as the switches in the switch array 809, can be implemented by any one or a combination of devices capable of performing switching functions, such as N-type metal-oxide-semiconductor (NMOS) field-effect transistors (NMOS transistors for short), insulated gate bipolar transistors (IGBTs), gallium nitride (GaN) field-effect transistors, and silicon carbide (SiC) field-effect transistors.

[0076] Furthermore, in embodiments according to this disclosure, either half-bridge driver chips or full-bridge driver chips can be used to design the drive circuits to drive the first full-bridge inverter circuit 802 and the second full-bridge inverter circuit 803. When using half-bridge driver chips, the tumor electric field therapy system 800 may include four half-bridge driver chips, wherein each full-bridge inverter circuit is configured to be controlled by two half-bridge driver chips. Alternatively, when using full-bridge driver chips, the tumor electric field therapy system 800 may include two full-bridge driver chips, wherein each full-bridge inverter circuit is configured to be controlled by a single full-bridge driver chip.

[0077] The following describes a specific circuit implementation of the tumor electric field therapy system 800 according to this disclosure, using a half-bridge driver chip and NMOS transistors as an example. For example, Figure 10 A circuit implementation of a tumor electric field therapy system 800 according to this disclosure is shown. Figure 10 In, with Figure 8 Identical or similar components are described using the same reference numerals.

[0078] like Figure 10 As shown, the tumor electric field therapy system 800 includes Figure 8 The DC voltage source 801, the first full-bridge inverter circuit 802, the second full-bridge inverter circuit 803, the first transformer 804, and the second transformer 805 have already been described in detail. For each full-bridge inverter circuit, as defined above, the NMOS transistor connected to the positive terminal of the DC voltage source 801 in the H-bridge of each full-bridge inverter circuit can be called a "high-side NMOS transistor," while the NMOS transistor connected to the negative terminal of the DC voltage source 801 in the H-bridge of each full-bridge inverter circuit can be correspondingly called a "low-side NMOS transistor." Figure 10 As shown, taking the first full-bridge inverter circuit 802 as an example, the drains of the high-side NMOS transistors Q1 and Q2 are simultaneously connected to the positive terminal of the DC voltage source 801, and their sources are respectively connected to the drains of the low-side NMOS transistors Q3 and Q4, while the sources of the low-side NMOS transistors Q3 and Q4 are simultaneously connected to the negative terminal of the DC voltage source 801. Specifically, the source of the high-side NMOS transistor Q1 and the drain of the low-side NMOS transistor Q3 are simultaneously connected to pin 1 of the primary side of the first transformer 804, and the source of the high-side NMOS transistor Q2 and the drain of the low-side NMOS transistor Q4 are simultaneously connected to pin 2 of the primary side of the first transformer 804.

[0079] The tumor electric field therapy system 800 also includes an MCU 1001 and four half-bridge driver chips U1, U2, U3, and U4. Each full-bridge inverter circuit is configured to be controlled by two half-bridge driver chips, and each half-bridge driver chip controls the on / off state of two NMOS transistors located on the same side of the H-bridge circuit in its corresponding full-bridge inverter circuit. For example, half-bridge driver chip U1 controls two NMOS transistors Q1 and Q3 located on the left side of the H-bridge in the first full-bridge inverter circuit 802, while half-bridge driver chip U2 controls the remaining NMOS transistors Q2 and Q4 in the first full-bridge inverter circuit 802, thus jointly controlling the first full-bridge inverter circuit 802. Furthermore, for simplicity, components such as the filter 806, voltage detection module 807, current detection module 808, switch array 809, and electrode array 810 in the tumor electric field therapy system 800 are shown in a simplified form as the subsequent circuit 1002.

[0080] The MCU 1001 is connected to four half-bridge driver chips U1, U2, U3 and U4 via its output terminals (i.e. I / O terminals, also known as "input / output terminals"), and is configured to generate control signals and send them to the corresponding half-bridge driver chips via the corresponding output terminals.

[0081] Each half-bridge driver chip can include 8 pins, for example... Figure 10 As shown, the pins are: pin 1 (chip power supply, VDD), pin 2 (high-side bootstrap power supply, HB), pin 3 (high-side drive output, HO), pin 4 (high-side drive reference, HS), pin 5 (high-side drive input, HI), pin 6 (low-side drive input, LI), pin 7 (chip ground, VSS), and pin 8 (low-side drive output, LO). Pin 1 is connected to the DC power supply Vcc to provide operating power to the half-bridge driver chip; pins 5 and 6 are used to receive external control signals; pins 3 and 8 are used to output signals; and pin 7 is connected to ground. In embodiments according to this disclosure, any type of half-bridge driver chip can be selected for implementation, and this disclosure does not limit this.

[0082] In embodiments according to this disclosure, the HI and LI terminals of each half-bridge driver chip are coupled to corresponding output terminals of the MCU 1001 to receive drive control signals for controlling two NMOS transistors in the corresponding full-bridge inverter circuit. For example, as Figure 10 As shown, taking the half-bridge driver chip U1 as an example, the output terminals IO1 and IO3 of MCU 1001 are connected to pins 5 and 6 of the half-bridge chip U1, respectively, providing drive control signals for controlling NMOS transistors Q1 and Q3 in the full-bridge inverter circuit 802.

[0083] Optionally or additionally, the HI terminal of at least one of the four half-bridge driver chips U1, U2, U3, and U4 can be connected in series with a first resistor to the corresponding terminal of the MCU 1001, and the HI terminal is grounded via a first capacitor, wherein the first resistor and the first capacitor form a low-pass filter. For example, as... Figure 10 As shown, pin 5 of the half-bridge driver chip U1 is connected in series with the output terminal IO1 of the MCU 1001 through resistor R1. At the same time, pin 5 is grounded through capacitor C1, so that resistor R1 and capacitor C1 form a low-pass filter, thereby filtering out noise signals in the drive control signal and ensuring the purity of the drive control signal output from the output terminal IO1 of the MCU 1001 to pin 5 of the half-bridge driver chip U1.

[0084] Similarly, the LI terminal of at least one of the four half-bridge driver chips U1, U2, U3, and U4 can also be connected in series with the corresponding output terminal of the MCU through a second resistor, and the LI terminal is grounded through a second capacitor, wherein the second resistor and the second capacitor form a low-pass filter. For example, resistor R2 and capacitor C2 can form a low-pass filter to filter the drive control signal output by IO3.

[0085] In embodiments according to this disclosure, the VDD terminal of at least one of the four half-bridge driver chips U1, U2, U3, and U4 can be connected in series with a third capacitor to ground. For example, as Figure 10 As shown, the half-bridge driver chip U1 is connected to the DC power supply Vcc, which provides operating power to the half-bridge driver chip U1, and is connected in series with capacitor C3 to ground. In this disclosure, the third capacitor can also be referred to as a "decoupling capacitor," which can be used to filter out noise signals in the Vcc power supply to avoid noise signals interfering with the control logic of the half-bridge driver chip; at the same time, the decoupling capacitor, as an energy storage device, can also release the stored charge for compensation when needed to ensure the stability of the Vcc voltage.

[0086] In embodiments according to this disclosure, the HO and LO terminals of each half-bridge driver chip are respectively coupled to the high-side NMOS transistor and the low-side NMOS transistor on the same side of the corresponding full-bridge inverter circuit to drive the high-side NMOS transistor and the low-side NMOS transistor based on the drive control signal. For example, as shown, the HO and LO terminals of half-bridge driver chip U1 can be coupled to the gates of NMOS transistors Q1 and Q3 in the first full-bridge inverter circuit 802 to provide control signals.

[0087] Optionally or additionally, the HO terminal of at least one of the four half-bridge driver chips U1, U2, U3, and U4 is connected in series with the gate of the corresponding NMOS transistor via a third resistor. For example, the HO terminal of half-bridge driver chip U1 can be connected to the gate of NMOS transistor Q1 via resistor R3. The function of this resistor is to limit the gate current, suppress oscillation spikes, stabilize the drive waveform, and protect the gate of the NMOS transistor.

[0088] Similarly, the LO terminal of at least one of the four half-bridge driver chips U1, U2, U3, and U4 can also be connected in series with the gate of the corresponding NMOS transistor via a fourth resistor. For example, the LO terminal of half-bridge driver chip U1 can be connected to the gate of NMOS transistor Q3 via resistor R4.

[0089] In embodiments according to this disclosure, the HB terminal of at least one of the four half-bridge driver chips U1, U2, U3, and U4 is connected in series to the HS terminal via a fourth capacitor, and the HS terminal is simultaneously connected to the source of the high-side NMOS transistor and the drain of the low-side NMOS transistor. For example, as Figure 10 As shown, pin 2 of the half-bridge driver chip U1 is connected to pin 4 via capacitor C4, and pin 4 is connected to the junction of NMOS transistors Q1 and Q3. The voltage at this junction is floating; it rises to Vin when Q1 needs to be turned on. At this point, the gate voltage of NMOS transistor Q1 needs to be "raised" above the voltage at this junction to turn on NMOS transistor Q1. Therefore, the aforementioned fourth capacitor (e.g., capacitor C4) is also called a bootstrap capacitor. Its function is to utilize the characteristic that the voltage across the capacitor does not change abruptly, working in conjunction with a bootstrap diode (not shown), to "raise" the gate voltage of the high-side NMOS transistor when it needs to be turned on, ensuring that the high-side NMOS transistor can function normally.

[0090] It is understood that the specific specifications of the capacitors and resistors mentioned in the above description may be determined depending on the specific device selection and circuit design requirements, and this disclosure does not impose any restrictions on them.

[0091] As mentioned earlier, a square wave AC signal is generated by controlling the state of each switch included in each full-bridge inverter circuit. Since the first full-bridge inverter circuit 802 and the second full-bridge inverter circuit 803 have a symmetrical topology, the principle of third harmonic cancellation is achieved by ensuring a 60-degree phase difference between the first square wave AC signal 901 and the second square wave AC signal 902 obtained by the first full-bridge inverter circuit 802 and the second full-bridge inverter circuit 803. Assuming the desired sinusoidal AC signal has a period of T, the period of the MCU drive control signal is also T, and the control signal output by the MCU needs to control the waveform of the square wave AC signal obtained by the first full-bridge inverter circuit 802 and the second full-bridge inverter circuit 803 to be a square wave with a timing difference of T / 6 and a duty cycle of 50%.

[0092] In embodiments according to this disclosure, for each full-bridge inverter circuit, the drive control signal can be configured to control each full-bridge inverter circuit to conduct only the high-side NMOS transistor on the first side and the low-side NMOS transistor on the second side during a first duration of period T, and only the low-side NMOS transistor on the first side and the high-side NMOS transistor on the second side during a second duration of period T, wherein the duration of both the first and second durations is T / 2, thereby causing each full-bridge inverter circuit to invert the DC signal output from the DC voltage source 801 into a square wave AC signal with a duty cycle of 50%. Furthermore, the drive control signal for controlling the first full-bridge inverter circuit 802 (i.e., the drive control signal output via output terminals IO1 to IO4 of the MCU 1001) and the drive control signal for controlling the second full-bridge inverter circuit 803 (i.e., the drive control signal output via output terminals IO5 to IO8 of the MCU 1001) can be configured to be T / 6 apart in timing.

[0093] Next, we will combine Figure 11 This will further describe how the half-bridge driver chip specifically controls the full-bridge inverter circuit to achieve third harmonic elimination. Figure 11 A waveform diagram of each node is shown in one circuit embodiment of another tumor electric field therapy system according to this disclosure. The period of the drive control signal is T.

[0094] The switching state of the NMOS transistors in each full-bridge inverter circuit is controlled by the level of the drive control signal. Specifically, if the drive control signal output from the MCU 1001 is high, the NMOS transistor controlled by the corresponding half-bridge driver chip is turned on; conversely, if the drive control signal is low, the NMOS transistor controlled by the corresponding half-bridge driver chip is turned off. For example, as... Figure 10As shown, if the output terminal IO1 or IO3 of MCU 1001 outputs a high-level signal, the corresponding HO or LO terminal of the half-bridge driver chip U1 will output a high-level signal to control the NMOS transistor Q1 or Q3 to turn on; conversely, if the output terminal IO1 or IO3 of MCU 1001 outputs a low-level signal, the corresponding HO or LO terminal of the half-bridge driver chip U1 will output a low-level signal to control the NMOS transistor Q1 or Q3 to turn off. Accordingly, in order for each full-bridge inverter circuit to invert the DC signal output from the DC voltage source 801 into a square wave AC signal with a duty cycle of 50%, and for the two square wave AC signals to be time-separated by T / 6, in an embodiment according to this disclosure, for each full-bridge inverter circuit, the drive control signal can be configured to: during a first duration, cause the HO terminal of the first half-bridge driver chip used to drive the full-bridge inverter circuit to output a high level and the LO terminal to output a low level, and cause the HO terminal of the second half-bridge driver chip used to drive the full-bridge inverter circuit to output a low level and the LO terminal to output a high level; and during a second duration, cause the HO terminal of the first half-bridge driver chip to output a low level and the LO terminal to output a high level, and cause the HO terminal of the second half-bridge driver chip to output a high level and the LO terminal to output a low level. The lengths of the first duration and the second duration are T / 2, and the start time of the first duration corresponding to the first full-bridge inverter circuit 802 differs from the start time of the first duration of the second full-bridge inverter circuit 803 by a factor of T / 6. , where n is an integer.

[0095] For example, in the first full-bridge inverter circuit 802, the first half-bridge driver chip and the second half-bridge driver chip can refer to half-bridge driver chips U1 and U2, respectively. The waveforms of the drive control signals used for NMOS transistors Q1 and Q4 are as follows: Figure 11 The waveform diagram (a) shows that, within one cycle starting from T=0, the NMOS transistors Q1 and Q4 are kept at a high level +Ve for the first T / 2 seconds to turn them on, and then kept at a low level for the next T / 2 seconds to turn them off. The waveforms of the drive control signals for NMOS transistors Q2 and Q3 are as follows: Figure 11 As shown in waveform diagram (b), within one cycle, a low level is maintained during the first T / 2 to turn off NMOS transistors Q2 and Q3, and a high level +Ve is maintained during the last T / 2 to turn on NMOS transistors Q2 and Q3. By using such a drive control signal to control the first full-bridge inverter circuit 802, a signal can be obtained on the primary side of the first transformer 804 as shown in the diagram. Figure 11 The waveform diagram (c) shows the first square wave AC signal 901.

[0096] Similarly, for the second full-bridge inverter circuit 803, the drive control signals output from the output terminals IO5 and IO8 of the MCU 1001 are jointly controlled by the half-bridge driver chips U3 and U4, while the drive control signals output from the output terminals IO6 and IO7 of the MCU 1001 are jointly controlled by the half-bridge driver chips U3 and U4. Compared to the drive control signals output from the output terminals IO1 to IO4 of the MCU 1001, the drive control signals output from the output terminals IO5 to IO8 are delayed by T / 6 in timing. Figure 11 As shown, the waveforms of the drive control signals used for NMOS transistors Q5 and Q8 are as follows: Figure 11 The waveform diagram (d) shows that, within one cycle starting from T=T / 6, a high level +Ve is maintained for the first T / 2 minutes to turn on NMOS transistors Q5 and Q8; while the waveforms of the drive control signals for NMOS transistors Q6 and Q7 are as follows. Figure 11 As shown in waveform (e), it maintains a high level +Ve for one cycle starting from T=T / 6, and then for the next T / 2 to turn on NMOS transistors Q6 and Q7. By using such a drive control signal to control the second full-bridge inverter circuit 803, a signal can be obtained on the primary side of the second transformer 805 as shown in the waveform diagram (e). Figure 11 The waveform diagram (f) shows the second square wave AC signal 902.

[0097] The first square wave AC signal 901 and the second square wave AC signal 902 can be transformed by the first transformer 804 and the second transformer 805 respectively, to correspondingly obtain the transformed first square wave AC signal 903 and the transformed second square wave AC signal 904, as shown below. Figure 11 The waveforms (g) and (h) are shown in the figure. Next, the first square wave AC signal 903 and the second square wave AC signal 904, after being transformed, are superimposed to generate the waveform shown in the figure. Figure 11 The third harmonic AC signal 905 shown in waveform diagram (i) is the waveform after the third harmonic is eliminated.

[0098] Understandably, compared to the simultaneous switching of four switches in a single full-bridge inverter circuit implementation, the switching actions according to the embodiments of this disclosure are more dispersed and current / voltage changes are smoother due to the use of two symmetrical full-bridge inverter circuits to execute control logic with a time difference. This results in lower electromagnetic interference (EMI). Since the tumor electric field therapy system 800 according to the embodiments of this disclosure has better EMI suppression, high-precision, bulky filters are not required in the filter design, further reducing device costs. Furthermore, because the control logic in the two full-bridge inverter circuits is essentially the same with only a time difference, the heat generated by NMOS transistor state switching is evenly distributed across the two full-bridge inverter circuit structures, preventing hot spots due to uneven control. This effectively alleviates the overheating problem of the switches, especially ensuring good and stable performance in high-frequency operating scenarios.

[0099] The foregoing description of various aspects of this disclosure is provided to enable any person skilled in the art to make or use this disclosure. Various modifications to these aspects will be apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects without departing from the scope of this disclosure. Therefore, this disclosure is not intended to be limited to the aspects shown herein, but rather to be carried out within the widest scope consistent with the principles and novel features disclosed herein.

[0100] The above description has been given for purposes of illustration and description. Furthermore, the above description is not intended to limit the embodiments of this disclosure to the forms disclosed herein. Although numerous exemplary aspects and embodiments have been discussed above, those skilled in the art will anticipate certain variations, modifications, alterations, additions, and sub-combinations thereof.

Claims

1. A tumor electric field therapy system, comprising: A DC voltage source is configured to output a DC signal. The first full-bridge inverter circuit is configured to invert the DC signal into a first square wave AC signal. The second full-bridge inverter circuit is configured to invert the DC signal into a second square wave AC signal, wherein the first square wave AC signal and the second square wave AC signal have a 60-degree phase difference. The first transformer is configured to transform the first square wave AC signal to obtain a transformed first square wave AC signal. A second transformer is configured to transform the second square-wave AC signal to obtain a transformed second square-wave AC signal, wherein the secondary side of the first transformer is connected in series with the secondary side of the second transformer, such that the transformed first square-wave AC signal and the transformed second square-wave AC signal are superimposed to generate a third square-wave AC signal; and A filter is configured to filter the third-wave AC signal to generate a sinusoidal AC signal for producing an electric field for tumor treatment.

2. The tumor electric field therapy system as described in claim 1, wherein, The third-wave AC signal is configured to have a predetermined voltage amplitude, and wherein, The DC signal is configured to have a first voltage amplitude, and the turns ratio of the first transformer and the second transformer is configured to be 1:N / 2, where N is the ratio of the predetermined voltage amplitude to the first voltage amplitude, or The DC signal is configured to have a second voltage amplitude and the turns ratio of the first transformer and the second transformer is configured to be 1:N, wherein the second voltage amplitude is half of the first voltage amplitude.

3. The tumor electric field therapy system as described in claim 1, further comprising: The microcontroller unit (MCU) is configured to generate drive control signals; as well as The drive circuit is configured to drive the switches in the first full-bridge inverter circuit and the second full-bridge inverter circuit based on the drive control signal.

4. The tumor electric field therapy system as described in claim 3, wherein, The switches in the first full-bridge inverter circuit and the second full-bridge inverter circuit are NMOS transistors.

5. The tumor electric field therapy system as described in claim 4, wherein, The drive circuit includes four half-bridge drive chips, and each full-bridge inverter circuit is configured to be controlled by two half-bridge drive chips, wherein: The high-side drive input HI and low-side drive input LI of each half-bridge driver chip are coupled to the corresponding outputs of the MCU to receive the drive control signals. The high-side drive output HO terminal and the low-side drive output LO terminal of each half-bridge driver chip are respectively coupled to the high-side NMOS transistor and the low-side NMOS transistor on the same side of the corresponding full-bridge inverter circuit, so as to drive the high-side NMOS transistor and the low-side NMOS transistor based on the drive control signal.

6. The tumor electric field therapy system as described in claim 5, wherein, The HI terminal of at least one of the four half-bridge driver chips is connected in series with the corresponding output terminal of the MCU through a first resistor, and the HI terminal is grounded through a first capacitor, wherein the first resistor and the first capacitor form a low-pass filter.

7. The tumor electric field therapy system as described in claim 5, wherein, The LI terminal of at least one of the four half-bridge driver chips is connected in series with the corresponding output terminal of the MCU through a second resistor, and the LI terminal is grounded through a second capacitor, wherein the second resistor and the second capacitor form a low-pass filter.

8. The tumor electric field therapy system as described in claim 5, wherein, The power supply VDD terminal of at least one of the four half-bridge driver chips is connected in series with the third capacitor and grounded.

9. The tumor electric field therapy system as described in claim 5, wherein, The HO terminal of at least one of the four half-bridge driver chips is connected in series with the gate of the corresponding NMOS transistor via a third resistor.

10. The tumor electric field therapy system as described in claim 5, wherein, The LO terminal of at least one of the four half-bridge driver chips is connected in series with the gate of the corresponding NMOS transistor via a fourth resistor.

11. The tumor electric field therapy system as described in claim 5, wherein, At least one of the four half-bridge driver chips has its high-side bootstrap power supply HB terminal connected in series with the high-side drive reference HS terminal via a fourth capacitor, and the HS terminal is connected to the source of the corresponding high-side NMOS transistor and the drain of the low-side NMOS transistor.

12. The tumor electric field therapy system as described in claim 4, wherein, Each signal cycle of the drive control signal consists of a first duration and a second duration following the first duration, and for each full-bridge inverter circuit, the drive control signal is configured as follows: Each full-bridge inverter circuit is controlled to conduct only the high-side NMOS transistor on the first side and the low-side NMOS transistor on the second side during the first duration, and only the low-side NMOS transistor on the first side and the high-side NMOS transistor on the second side during the second duration.

13. The tumor electric field therapy system as described in claim 12, wherein, For each full-bridge inverter circuit, the drive control signal is configured as follows: During the first duration, the HO terminal of the first half-bridge driver chip used to drive the full-bridge inverter circuit outputs a high level and the LO terminal outputs a low level, and the HO terminal of the second half-bridge driver chip used to drive the full-bridge inverter circuit outputs a low level and the LO terminal outputs a high level; and During the second duration, the first half-bridge driver chip outputs a low level at its HO terminal and a high level at its LO terminal, and the second half-bridge driver chip outputs a high level at its HO terminal and a low level at its LO terminal. Wherein, the period length of the drive control signal is T, the lengths of the first duration and the second duration are T / 2, and the start time of the first duration corresponding to the first full-bridge inverter circuit and the start time of the first duration corresponding to the second full-bridge inverter circuit differ by a certain amount. , where n is an integer.

14. The tumor electric field therapy system according to any one of claims 1 to 13, further comprising: An adapter unit is connected to the filter and configured to alternately apply the sinusoidal alternating current signal to at least two pairs of electrode plates; as well as The at least two pairs of electrode plates are configured to generate an alternating electric field for tumor treatment based on the sinusoidal alternating current signal, wherein a voltage detection module and a current detection module are provided between the transfer unit and the filter.

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