Food processing machine outer cover opening and closing detection system and food processing machine

Abstract

This disclosure provides a food processor cover opening / closing detection system and a food processor, relating to the field of food processing technology. The food processor includes a main body with a receiving space and an outer cover disposed on the main body. The main body includes an outer cover opening, which is closed when the outer cover is closed. A pulverizing blade driven by a variable frequency motor is disposed within the receiving space. The detection system includes a power supply line, an outer cover opening / closing detection circuit, a switching assembly, a rectifier bridge circuit, a first electrolytic capacitor, and a second electrolytic capacitor. The switching assembly disconnects the power supply line from the first input terminal when the outer cover is open and connects the power supply line to the first input terminal when the outer cover is closed. The outer cover opening / closing detection circuit is connected to the power supply line and is located upstream of the switching assembly. The outer cover opening / closing detection circuit is used to collect electrical signals from the power supply line, and these electrical signals are used to characterize the opening / closing state of the outer cover. This improves the accuracy and reliability of the outer cover opening / closing detection and enhances the physical safety when the outer cover is open.

Description

Technical Field

[0001] This disclosure relates to the field of food processing, and in particular to a food processing machine cover opening and closing detection system and a food processing machine. Background Technology

[0002] Traditional food processors, especially those with internal high-speed rotating components such as shredders, typically require the outer lid to be closed during operation to prevent user injury from contact with the rotating parts or food splattering. Therefore, effective and reliable detection of the lid's open / closed status is crucial for these products.

[0003] In addition to basic safety testing requirements, there are some specific technical challenges in food processing machines. For example, in order to improve motor drive efficiency and adapt to different regional mains power standards (such as 220V and 110V), products usually use variable frequency motors and are designed with a rectifier drive circuit that is compatible with multiple mains power inputs.

[0004] To maintain the consistency of the rectifier bridge circuit's output voltage, it may be necessary to introduce two electrolytic capacitors for output processing. However, this approach may cause distortion or irregularities in the output waveform, making the traditional method of determining the circuit's operating state by detecting the high and low levels on the DC side after rectification unreliable. It also makes it impossible to determine the opening and closing status of the outer cover using the high level on the DC side, thus affecting the outer cover opening and closing detection based on such signals. Utility Model Content

[0005] This disclosure provides a food processing machine cover opening and closing detection system and a food processing machine, to solve the problem that when existing food processing machines introduce variable frequency motors and rectifier bridge circuits compatible with multiple mains power inputs to adapt to different regional mains power standards, the introduction of two electrolytic capacitors for output processing causes the output waveform to be distorted or irregular, making it impossible to detect the opening and closing of the cover by detecting the high and low levels of the DC side after rectification.

[0006] In a first aspect, this disclosure provides a food processor outer cover opening and closing detection system. The food processor includes a main body with a receiving space and an outer cover disposed on the main body. The main body includes an outer cover opening. When the outer cover is closed, the outer cover opening is closed. A pulverizing blade driven by a variable frequency motor is disposed in the receiving space.

[0007] The detection system includes a power supply line, an outer cover opening and closing detection circuit, a switching assembly, a rectifier bridge circuit, a first electrolytic capacitor, and a second electrolytic capacitor. The power supply line includes a neutral wire and a live wire. One of the neutral wire and the live wire is connected to the first input terminal of the rectifier bridge circuit through the switching assembly, and the other of the neutral wire and the live wire is connected to the second input terminal of the rectifier bridge circuit. The first output terminal of the rectifier bridge circuit is connected to the positive terminal of the first electrolytic capacitor and is used to supply voltage to the variable frequency motor. The second output terminal of the rectifier bridge circuit is connected to the negative terminal of the second electrolytic capacitor. The positive terminal of the second electrolytic capacitor is connected to the negative terminal of the first electrolytic capacitor and is connected to the first input terminal.

[0008] The switch assembly disconnects the power supply line from the first input terminal when the outer cover is opened, and connects the power supply line to the first input terminal when the outer cover is closed;

[0009] The outer cover opening and closing detection circuit is connected to the power supply line and is located upstream of the switch assembly. The outer cover opening and closing detection circuit is used to collect the electrical signal of the power supply line, and the electrical signal is used to characterize the opening and closing state of the outer cover.

[0010] Optionally, it also includes a main control MCU, whose signal acquisition terminal is connected to the output terminal of the outer cover opening and closing detection circuit. The main control MCU is used to acquire electrical signals and determine the opening and closing state of the outer cover based on the electrical signals.

[0011] Optionally, the switching assembly includes a micro switch and a first magnet, and a second magnet is disposed on the inner side of the outer cover; the micro switch is connected between the first input terminal of the rectifier bridge circuit and the power supply line;

[0012] The adjacent ends of the first and second magnets have the same magnetism. When the outer cover is closed, the first and second magnets trigger the micro switch to close due to their magnetic repulsion.

[0013] Optionally, the switching assembly includes an electromagnetic relay, which includes a normally open contact and a coil; the normally open contact is connected between the first input terminal of the rectifier bridge circuit and the power supply line.

[0014] A sensing device is provided between the outer cover and the main body. The sensing device is used to sense the closed state of the outer cover when it is closed and output a control signal. The coil of the electromagnetic relay is energized and attracted under the control of the control signal, and the power supply line is connected to the first input terminal.

[0015] Optionally, it also includes an AC power detection circuit, the input of which is connected to the power supply line, and the AC power detection circuit is used to detect the AC power voltage.

[0016] The mains power detection circuit is reused as the outer cover opening and closing detection circuit.

[0017] Optionally, it also includes a zero-crossing detection circuit, which is connected to the power supply line and located upstream of the switching assembly, and is used to perform zero-crossing detection;

[0018] The zero-crossing detection circuit is reused as the outer cover opening and closing detection circuit.

[0019] Optionally, it also includes an EMC circuit, which is connected to the power supply line and located upstream of the outer cover opening and closing detection circuit.

[0020] Optionally, the capacitance values ​​of the first electrolytic capacitor and the second electrolytic capacitor are equal, and the rated voltages of the first electrolytic capacitor and the second electrolytic capacitor are equal.

[0021] Optionally, the capacitance of the first electrolytic capacitor and the second electrolytic capacitor is 800μF to 1000μF, and the rated voltage is 200V to 450V.

[0022] Secondly, based on the same inventive concept, this disclosure also provides a food processing machine, including the food processing machine outer cover opening and closing detection system provided in the first aspect of this disclosure.

[0023] The technical solution provided in this disclosure has the following advantages compared with the prior art:

[0024] 1. In this disclosure, the outer cover opening / closing detection circuit is connected upstream of the switching assembly. When the outer cover is closed, i.e., when the switching assembly is on, an electrical signal, such as a voltage signal with a relatively large voltage value, can be detected. When the outer cover is open, i.e., when the switching assembly is off, another electrical signal, such as a voltage signal with a relatively small voltage value, can be detected. By detecting the change in the mains voltage between the aforementioned two voltage values, the opening / closing state of the outer cover can be clearly and reliably determined. Since the outer cover opening / closing detection circuit collects the electrical signal upstream of the switching assembly, rather than the electrical signal output from the DC side of the rectifier bridge circuit, the detection result is not affected by the distortion or irregularity of the DC side output waveform, effectively improving the accuracy and reliability of the outer cover opening / closing detection circuit provided in this disclosure.

[0025] 2. In this disclosure, the outer cover opening / closing detection circuit can determine whether the outer cover is open by detecting the voltage signal between the negative terminal of the second electrolytic capacitor and the live wire, and determine whether the outer cover is closed by detecting the voltage signal between the positive and negative terminals of the second electrolytic capacitor. This utilizes the inherent characteristics of the circuit, providing a unique voltage characteristic signal for the outer cover status. Compared to voltage detection on the complex and potentially distorted DC side, detection on the upstream AC side is more direct and simpler, reducing the complexity of the detection circuit.

[0026] 3. In this embodiment, a switching component is introduced at the first input terminal of the power supply line and the rectifier bridge circuit. When the outer cover is opened, the switching component can disconnect the power supply line from the first input terminal and cut off the power supply to the motor, ensuring physical safety when the outer cover is opened and preventing the shredder from continuing to run at high speed while the outer cover is open, which could cause injury to the user or food splattering. Attached Figure Description

[0027] The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure.

[0028] To more clearly illustrate the technical solutions in the embodiments of this disclosure or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 The diagram shown is a circuit structure schematic of a food processing machine outer cover opening and closing detection system provided in an embodiment of this disclosure;

[0030] Figure 2 The diagram shown is a schematic diagram of another circuit structure of the food processing machine outer cover opening and closing detection system provided in this embodiment of the present disclosure;

[0031] Figure 3 The diagram shown is a schematic diagram of another circuit structure of the food processing machine outer cover opening and closing detection system provided in this embodiment of the present disclosure;

[0032] Figure 4 The diagram shown is a schematic diagram of another circuit structure of the food processing machine outer cover opening and closing detection system provided in this embodiment of the present disclosure;

[0033] Figure 5 The diagram shown is a circuit diagram of a mains power detection circuit provided in an embodiment of this disclosure;

[0034] Figure 6 The diagram shown is a schematic diagram of another circuit structure of the food processing machine outer cover opening and closing detection system provided in this embodiment of the present disclosure;

[0035] Figure 7 The diagram shown is another circuit structure schematic of the food processing machine outer cover opening and closing detection system provided in this embodiment of the present disclosure. Detailed Implementation

[0036] To better understand the above-mentioned objectives, features, and advantages of this disclosure, the solutions disclosed herein will be further described below. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other.

[0037] Numerous specific details are set forth in the following description in order to provide a full understanding of this disclosure, but this disclosure may also be implemented in other ways different from those described herein; obviously, the embodiments in the specification are only some, and not all, of the embodiments of this disclosure.

[0038] Figure 1 The diagram shown is a circuit structure schematic of a food processor outer cover opening and closing detection system provided in an embodiment of this disclosure. The food processor includes a main body with a receiving space and an outer cover disposed on the main body. The main body includes an outer cover opening, and the outer cover opening is closed when the outer cover is closed. A pulverizing blade driven by a variable frequency motor is provided in the receiving space.

[0039] The detection system includes a power supply line, an outer cover opening and closing detection circuit 10, a switch assembly 20, a rectifier bridge circuit U0, a first electrolytic capacitor C1, and a second electrolytic capacitor C2. The power supply line includes a neutral wire PN and a live wire PL. One of the neutral wire PN and the live wire PL is connected to the first input terminal AC1 of the rectifier bridge circuit U0 through the switch assembly 20, and the other of the neutral wire PN and the live wire PL is connected to the second input terminal AC2 of the rectifier bridge circuit U0. The first output terminal V+ of the rectifier bridge circuit U0 is connected to the positive terminal of the first electrolytic capacitor C1 and is used to supply voltage to the variable frequency motor. The second output terminal V- of the rectifier bridge circuit U0 is connected to the negative terminal of the second electrolytic capacitor C2. The positive terminal of the second electrolytic capacitor C2 is connected to the negative terminal of the first electrolytic capacitor C1 and connected to the first input terminal AC1.

[0040] The switch assembly 20 disconnects the power supply line from the first input terminal AC1 when the outer cover is opened, and connects the power supply line from the first input terminal AC1 when the outer cover is closed;

[0041] The outer cover opening and closing detection circuit 10 is connected to the power supply line and is located upstream of the switch assembly 20. The outer cover opening and closing detection circuit 10 is used to collect the electrical signal of the power supply line, and the electrical signal is used to characterize the opening and closing state of the outer cover.

[0042] Please refer to Figure 1When the switching assembly 20 is turned on, the mains power is normally input to the rectifier bridge circuit U0. With a 220V mains input, the rectifier bridge outputs a peak voltage of approximately 311V. With a 110V mains input, the peak AC voltage is approximately 155V. Through voltage multiplier rectification, the two capacitors may be charged to a voltage close to 2 × 155V = 310V, thus matching the DC voltage at a 220V input. When the switching assembly 20 is turned on and the mains power is 110V, the two capacitors work synergistically through the voltage multiplier effect, ensuring that the DC bus voltage supplied to the variable frequency motor is approximately the same as when the mains power is 220V. Therefore, the design of this disclosure allows the product to adapt to both 110V and 220V mains voltages, while maintaining a essentially consistent DC bus voltage for the motor, greatly improving the product's versatility and market adaptability.

[0043] Figure 2 The diagram shown illustrates another circuit structure of the food processing machine outer cover opening and closing detection system provided in this embodiment. This embodiment refines the rectifier bridge circuit U0, which includes diodes D1 to D4. Figure 2 For example, the switch assembly 20 is connected between the live wire PL and the first input terminal of the rectifier bridge circuit U0. When the switch assembly 20 is turned on (i.e., when the outer cover is closed), during the positive half-wave time of the AC current, the voltage of the live wire PL can normally charge the second electrolytic capacitor C2 (the electrical signal of the live wire PL flows through the switch assembly 20, the second electrolytic capacitor C2, and the diode D3, finally reaching the neutral wire PN, forming a loop). Since the outer cover opening and closing detection circuit 10 is connected upstream of the switch assembly 20, it can detect the voltage signal between the positive and negative terminals of the second electrolytic capacitor C2 when the switch assembly 20 is turned on, for example, a voltage signal with a voltage value of U (represented as a peak DC voltage). When the switch assembly 20 is disconnected (i.e., when the outer cover is opened), the live wire PL is disconnected from the first input terminal of the rectifier bridge circuit U0. During the positive half-wave time of the AC power, the live wire PL cannot charge the second electrolytic capacitor C2. Therefore, at this time, the outer cover opening and closing detection circuit 10 can detect another electrical signal between the negative terminal of the second electrolytic capacitor C2 and the live wire PL when the switch assembly 20 is disconnected. For example, a voltage signal with a voltage value of U / 2 (represented as the average AC voltage).

[0044] Therefore, in this embodiment, when the outer cover opening / closing detection circuit 10 is introduced upstream of the switch assembly 20, it directly monitors the electrical signal of the AC power supply line. Regardless of how the downstream rectifier circuit processes it, and regardless of whether the DC side waveform is distorted, as long as there is a significant voltage (or power) change on the AC power supply line, it can accurately determine whether the switch assembly 20 is conducting, thereby inferring the opening / closing state of the outer cover. Since the outer cover opening / closing detection circuit 10 is located upstream of the switch assembly 20, it is no longer affected by the distortion or irregularity of the DC side output waveform when detecting the opening / closing of the outer cover, effectively improving the reliability and accuracy of the outer cover opening / closing detection circuit 10 provided in this disclosure. It should be noted that the premise of this disclosure detecting the opening / closing of the outer cover through the outer cover opening / closing detection circuit 10 is that the outer cover is opened during the normal operation of the food processing machine (the outer cover should originally be closed normally, and the micro switch is conducting), not that the outer cover is opened before the food processing machine is operating normally.

[0045] In this disclosure, when the switch assembly 20 is open (outer cover open), the outer cover opening / closing detection circuit 10 can detect a voltage signal with a relatively small average AC voltage (e.g., U / 2) between the negative terminal of the second electrolytic capacitor C2 and the live wire PL. When the switch assembly 20 is closed (outer cover closed), the outer cover opening / closing detection circuit 10 can detect a voltage signal with a relatively large peak DC voltage (e.g., U) between the positive and negative terminals of the second electrolytic capacitor C2. Therefore, the outer cover opening / closing detection circuit 10 can determine whether the outer cover is open by detecting the voltage signal between the negative terminal of the second electrolytic capacitor C2 and the live wire PL, and determine whether the outer cover is closed by detecting the voltage signal between the positive and negative terminals of the second electrolytic capacitor C2. This utilizes the inherent characteristics of the circuit, providing a unique voltage characteristic signal for the outer cover state. Compared to voltage detection on the complex and potentially distorted DC side, detection on the upstream AC side is more direct and simpler, reducing the complexity of the detection circuit.

[0046] Furthermore, in this embodiment, a switch assembly 20 is introduced into the power supply line and the first input terminal of the rectifier bridge circuit U0. When the outer cover is opened, the switch assembly 20 can disconnect the power supply line from the first input terminal and cut off the power supply to the motor, ensuring physical safety when the outer cover is opened and preventing the shredder from continuing to run at high speed while the outer cover is open, thus avoiding injury to the user or food splashing.

[0047] Figure 3 The diagram shown is a schematic representation of another circuit structure of the food processing machine cover opening and closing detection system provided in this embodiment. Please refer to the diagram. Figure 3In one optional embodiment of this disclosure, a main control MCU 30 is also included. The signal acquisition terminal of the main control MCU 30 is connected to the output terminal of the outer cover opening and closing detection circuit 10. The main control MCU 30 is used to acquire electrical signals and determine the opening and closing state of the outer cover based on the electrical signals.

[0048] This embodiment further introduces a main control MCU 30, whose signal acquisition terminal is connected to the output terminal of the outer cover opening / closing detection circuit 10. The main control MCU 30 can acquire the electrical signals output by the outer cover opening / closing detection circuit 10 in real time and determine the opening / closing state of the outer cover based on the changes in these signals. Moreover, through the main control MCU 30, the system can process the detected electrical signals more intelligently. Once the main control MCU 30 accurately determines the opening / closing state of the outer cover, it can link with other functional modules to achieve more complex control strategies. For example, when the outer cover is opened during the operation of the food processor, the main control MCU 30 can immediately cut off the power supply to the variable frequency motor and may trigger an audible and visual alarm to ensure user safety. As another example, the main control MCU 30 can display the opening / closing state of the outer cover on the product's screen (e.g., "Lid is open, please close") or provide visual feedback through indicator lights. Only when the main control MCU 30 confirms that the lid is closed will the user be allowed to start the pulverizer or adjust the operating mode, thereby preventing unsafe operation.

[0049] Please continue to refer to this. Figure 2 In one optional embodiment of this disclosure, the switch assembly 20 includes a micro switch K and a first magnet, and a second magnet is disposed on the inner side of the outer cover; the micro switch K is connected between the first input terminal of the rectifier bridge circuit U0 and the power supply line; the adjacent ends of the first magnet and the second magnet have the same magnetism, and when the outer cover is closed, the first magnet and the second magnet trigger the micro switch to close by magnetic repulsion.

[0050] Traditional mechanical contact switches may require direct physical pressure or a push rod for triggering. However, the design of the first and second magnets in this disclosure utilizes magnetic repulsion to achieve non-contact inductive triggering. When the outer cover approaches the closed position, the repulsive force between the two magnets is sufficient to actuate the microswitch, achieving precise triggering. This non-contact characteristic reduces mechanical wear, improving the switch's lifespan and reliability. Because the triggering is not based on direct physical contact, the direct impact and wear on the microswitch's mechanical parts are significantly reduced, extending its lifespan. Furthermore, compared to some open-type mechanical switches, magnetic induction is less susceptible to contamination from dust, liquid splashes, etc., that may be present in food processing environments, thus improving system reliability. Moreover, magnetic triggering allows for non-precise alignment within a certain range; as long as the repulsive force between the two magnets is sufficient to actuate the microswitch, even slight deviations in the outer cover's closing position ensure reliable triggering, thus providing greater tolerance during product assembly and manufacturing.

[0051] In another optional embodiment of this disclosure, the switching assembly 20 includes an electromagnetic relay, which includes a normally open contact and a coil; the normally open contact is connected between the first input terminal of the rectifier bridge circuit U0 and the power supply line; a sensing device is provided between the outer cover and the main body, which is used to sense the closed state of the outer cover when the outer cover is closed and output a control signal; the coil of the electromagnetic relay is energized and attracted under the control of the control signal, and conducts the power supply line and the first input terminal.

[0052] This embodiment provides another implementation of the switching assembly 20. When the switching assembly 20 includes an electromagnetic relay, the electromagnetic relay achieves electrical isolation through its coil and contacts. In this case, the sensing device (e.g., a Hall sensor, photoelectric sensor, etc.) used to sense the closed state of the outer cover can operate in a low-voltage or low-current environment, while the relay contacts are responsible for switching on and off high-current circuits such as mains power. This separation design improves system safety and simplifies the design of the sensing device, as it does not need to directly handle high voltage and high current. In addition, the electromagnetic relay uses normally open contacts, which naturally remain open in the absence of a control signal (outer cover not closed or sensing device malfunction), cutting off the power supply to the rectifier bridge and thus ensuring safety.

[0053] In this embodiment, a sensing device is provided between the outer cover and the main body. The control signal output by the sensing device is usually a digital or analog signal, which can be easily and directly input to the main control MCU. The main control MCU can use this signal to control whether the relay coil is energized or not, thereby achieving more precise logic control.

[0054] Figure 4The diagram shown is another circuit structure schematic of the food processing machine outer cover opening and closing detection system provided in an embodiment of this disclosure. In an optional embodiment of this disclosure, it further includes a mains power detection circuit. The input terminal of the mains power detection circuit is connected to the power supply line. The mains power detection circuit is used to detect the mains voltage. The mains power detection circuit is reused as the outer cover opening and closing detection circuit 10.

[0055] In this disclosure, the mains power detection circuit is integrated with the function of the cover opening / closing detection circuit 10, eliminating the need for a separate cover opening / closing detection circuit 10. By integrating two functions that would otherwise require separate circuits, the number of electronic components required can be significantly reduced. This not only reduces bill of materials costs but also saves PCB space, which is particularly important for compact home appliances such as food processors. Furthermore, reducing independent circuit modules means reducing the complexity of the overall circuit design. This helps shorten development cycles, simplify the manufacturing process, and potentially reduce potential points of failure. Regardless of whether the mains power detection circuit outputs an analog voltage value or a digital signal, it is typically connected to the main control MCU. The main control MCU can be programmed to parse the same signal, both to determine the current mains input voltage and to identify voltage changes caused by cover opening / closing (e.g., detecting a voltage change from U to U / 2 when the switching assembly 20 is disconnected on the live wire PL side).

[0056] Figure 5 The diagram shown is a schematic of a mains power detection circuit provided in an embodiment of this disclosure. It consists of components such as resistors R1-R4, capacitor C01, and diodes D01-D02. The input terminal of the mains power detection circuit is connected to the neutral wire PN and the live wire PL of the power supply line, and the output terminal is connected to the main control MCU. It should be noted that... Figure 5 This illustration only shows one feasible circuit structure for the mains power detection circuit and does not limit the actual structure of the mains power detection circuit. In some other embodiments of this disclosure, the mains power detection circuit may also adopt other feasible circuit structures.

[0057] Figure 6 The diagram shown is a schematic representation of another circuit structure of the food processing machine cover opening and closing detection system provided in this embodiment. Please refer to the diagram. Figure 6 In one optional embodiment of this disclosure, a zero-crossing detection circuit is further included. The zero-crossing detection circuit is connected to the power supply line and located upstream of the switching assembly 20. The zero-crossing detection circuit is used to perform zero-crossing detection. The zero-crossing detection circuit is also used as the outer cover opening and closing detection circuit 10.

[0058] When the zero-crossing detection circuit is located upstream of the switching assembly 20, this disclosure can also reuse the zero-crossing detection circuit as the outer cover opening and closing detection circuit 10. Similarly, there is no need to set up a separate outer cover detection circuit, which helps reduce additional hardware requirements, thereby significantly reducing manufacturing costs and saving valuable PCB space. Furthermore, integrating dual functions into a single circuit simplifies the overall circuit architecture, reduces the number of components and connection points, and helps improve manufacturing efficiency and reduce potential failure risks.

[0059] When the switching component 20 is on, the zero-crossing detection circuit can detect a complete and normal AC waveform, thus providing a continuous and stable zero-crossing signal. When the switching component 20 is off, the integrity or amplitude of the AC waveform changes significantly. Although there may still be a certain form of "zero-crossing point," the characteristics of the signal will change (e.g., the waveform may no longer be a complete sine wave, or the interval or amplitude of the zero-crossing points may be abnormal). The main control MCU 30 can determine the open / closed state of the outer cover by analyzing the presence, frequency, period, or characteristic changes of these zero-crossing signals. The output of the zero-crossing detection circuit is usually a pulse signal or a level transition signal. The MCU can use an internal timer or an external interrupt to capture these signals and use programming logic to distinguish between normal mains power state (outer cover closed) and abnormal mains power state (outer cover open), thereby realizing the judgment and safety control of the outer cover state.

[0060] It should be noted that the specific circuit structure of the zero-crossing detection circuit can be referenced from relevant technologies, and this disclosure does not impose any specific limitations on it.

[0061] Figure 7 The diagram shows another circuit structure of the food processor lid opening / closing detection system provided in this embodiment. In an optional embodiment, it further includes an EMC circuit 40, which is connected to the power supply line and located upstream of the lid opening / closing detection circuit 10. Food processors typically contain components such as high-speed rotating motors and switching power supplies, which generate significant electromagnetic interference during operation. The EMC circuit 40 can filter out conducted and radiated interference from the mains power or the equipment itself. Placing the EMC circuit 40 upstream of the lid opening / closing detection circuit 10 ensures that the mains signal received by the lid detection circuit is filtered and purified. This significantly reduces noise and spurious signals, enabling the lid opening / closing detection circuit 10 to more accurately and stably identify voltage changes, thereby improving the reliability and anti-interference capability of the judgment and reducing the risk of misjudgment. In addition, the EMC circuit 40 is located upstream of the outer cover opening and closing detection circuit 10, and can serve as the "first line of defense" to effectively absorb and attenuate abnormal signals such as transient high voltage and surge that may occur on the mains line, thereby protecting the downstream outer cover opening and closing detection circuit 10, rectifier bridge circuit, main control MCU 30 and other sensitive electronic components, and extending their lifespan.

[0062] Please refer to Figure 1 and Figure 2 In one optional embodiment of this disclosure, the capacitance values ​​of the first electrolytic capacitor C1 and the second electrolytic capacitor C2 are equal, and the rated voltages of the first electrolytic capacitor C1 and the second electrolytic capacitor C2 are equal.

[0063] In this embodiment, the rectifier bridge circuit U0 is a voltage multiplier rectifier circuit, where the first electrolytic capacitor C1 and the second electrolytic capacitor C2 work together to achieve a voltage multiplication effect. When the capacitance and rated voltage of the two electrolytic capacitors are set to be equal, uniform charging can be achieved. For example, in alternating half-waves of AC power, the two capacitors can be charged to similar voltage levels uniformly. Furthermore, during voltage superposition or output filtering, the two capacitors can more evenly share the voltage stress. This is crucial for the stability of the DC bus voltage and reducing ripple, especially when it is necessary to multiply the 110V AC mains voltage to the same DC voltage level as the 220V AC mains voltage; the symmetrical capacitor configuration helps to achieve a more accurate and stable voltage multiplication effect. In addition, when the two capacitors are used for output filtering after rectification, equal capacitance values ​​help to form a more symmetrical and effective filtering network. This can reduce output voltage ripple, providing a smoother and more stable DC power supply for the variable frequency motor, thereby improving motor operating efficiency and reducing noise.

[0064] Furthermore, using capacitors with the same capacitance and rated voltage simplifies the product's bill of materials. On the production line, operators can more easily identify and install the same components, thereby reducing errors caused by confusing capacitors of different specifications.

[0065] In one optional embodiment of this disclosure, the capacitance of the first electrolytic capacitor C1 and the second electrolytic capacitor C2 is 800μF to 1000μF, and the rated voltage is 200V to 450V.

[0066] When the rated voltage of an electrolytic capacitor is set between 200V and 450V, this range effectively covers the DC bus voltage generated after rectification or voltage doubler rectification of different mains inputs (110V and 220V). For 220V mains, the peak voltage after rectification is approximately 311V, and the 450V rated voltage provides sufficient margin. For 110V mains, after voltage doubler rectification, it can reach approximately 310V, also within the 200V–450V rated voltage range. Selecting an appropriate rated voltage ensures that the capacitor will not be damaged by overvoltage during normal circuit operation, thus guaranteeing the reliability and lifespan of the circuit. A rated voltage higher than the actual operating voltage provides the necessary safety margin for mains fluctuations and transient overvoltages, enhancing product stability.

[0067] When the capacitance of the electrolytic capacitor is set between 800μF and 1000μF, the sufficiently large capacitance can effectively smooth the pulsating DC voltage after rectification, significantly reducing the ripple of the DC bus. Lower ripple means a cleaner power supply to the variable frequency motor, which helps the motor run smoothly, reduces noise and vibration, and improves efficiency. When the motor starts or the load changes suddenly, it requires a large instantaneous current. As an energy storage device, the capacitor can quickly release the stored energy to meet this instantaneous demand, preventing a large drop in DC bus voltage, thereby ensuring the stable performance of the motor under dynamic loads.

[0068] Optionally, both the first electrolytic capacitor C1 and the second electrolytic capacitor C2 have a capacitance of 820μF and a rated voltage of 250V. This meets the voltage doubler rectification requirement for 110V AC mains power. When the mains power is 110V, the peak AC voltage is approximately 155V. Through the voltage doubler rectifier circuit, the two capacitors, connected in series, can theoretically achieve a DC voltage of 2 × 155V = 310V. A rated voltage of 250V for a single capacitor means that during a specific operating cycle of the voltage doubler circuit, the peak voltage each capacitor bears must be below 250V. In the voltage doubler circuit, each capacitor typically charges to the peak value of the input AC voltage (or slightly above), and then bears a higher total voltage when superimposed. If the rated voltage of a single capacitor is 250V, it ensures that the highest voltage a single capacitor bears in 110V voltage doubler mode will not exceed its rated value, thus guaranteeing its safety margin and lifespan.

[0069] Setting the capacitance of both the first electrolytic capacitor C1 and the second electrolytic capacitor C2 to 820μF provides a stable DC power supply for the variable frequency motor. This effectively smooths the pulsating DC voltage after rectification, significantly reducing DC bus ripple. Furthermore, the 820μF capacitance is sufficient to provide the necessary instantaneous high current during motor startup or load transients, preventing significant drops in DC bus voltage and ensuring stable motor performance under dynamic loads.

[0070] It should be noted that in some other embodiments of this disclosure, the capacitance values ​​of the first electrolytic capacitor C1 and the second electrolytic capacitor C2 can be selected from any other value in the range of 800μF to 1000μF, and the rated voltage can be selected from any other value in the range of 200V to 450V. This disclosure does not specifically limit these values.

[0071] Based on the same inventive concept, this disclosure also provides a food processor, including the food processor lid opening / closing detection system of any of the foregoing embodiments. When the food processor lid is opened, the current flowing into the rectifier bridge circuit U0 is immediately cut off or prevented by the switching assembly 20 (e.g., a magnetic repulsion microswitch or an electromagnetic relay controlled by a sensing device). This ensures that the high-speed rotating pulverizer blade will not be accidentally activated under any circumstances, thereby effectively avoiding the risk of injury or food splattering caused by the user contacting high-speed components. The system arranges the lid opening / closing detection circuit 10 (which can reuse the mains detection circuit or the zero-crossing detection circuit) upstream of the switching assembly 20, i.e., directly connected to the power supply line. This means that no matter how complex the downstream variable frequency motor drive circuit is, or how the two parallel capacitors cause output waveform distortion, the detection of the lid opening / closing state is based on the change of the original mains signal, thereby ensuring the accuracy and reliability of the detection. The built-in variable frequency motor drive circuit and the special two-capacitor voltage doubler rectifier design enable the food processor to automatically adapt to the mains voltage (110V or 220V) of different regions. With a 110V input, the DC bus voltage is boosted to a level similar to that with a 220V input (approximately 310V) through a voltage multiplier effect. This significantly improves the product's versatility and competitiveness in the international market. By reusing the mains detection circuit or zero-crossing detection circuit as the outer cover opening / closing detection circuit 10, and by placing the EMC circuit 40 upstream of the power supply line and detection circuit, this design achieves a high degree of hardware integration. This not only significantly reduces manufacturing costs and PCB space but also improves the overall system's anti-interference capability, ensuring the product remains stable and reliable even in complex electromagnetic environments.

[0072] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0073] The above description is merely a specific embodiment of this disclosure, enabling those skilled in the art to understand or implement it. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this disclosure. Therefore, this disclosure is not to be limited to the embodiments described herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A food processing machine outer cover opening and closing detection system, characterized in that, The food processing machine includes a main body with a receiving space and an outer cover disposed on the main body. The main body includes an outer cover opening, which is closed when the outer cover is closed. A pulverizing blade driven by a variable frequency motor is disposed inside the receiving space. The detection system includes a power supply line, an outer cover opening / closing detection circuit, a switch assembly, a rectifier bridge circuit, a first electrolytic capacitor, and a second electrolytic capacitor. The power supply line includes a neutral wire and a live wire. One of the neutral wire and the live wire is connected to the first input terminal of the rectifier bridge circuit through the switch assembly, and the other of the neutral wire and the live wire is connected to the second input terminal of the rectifier bridge circuit. The first output terminal of the rectifier bridge circuit is connected to the positive terminal of the first electrolytic capacitor and is used to supply voltage to the variable frequency motor. The second output terminal of the rectifier bridge circuit is connected to the negative terminal of the second electrolytic capacitor. The positive terminal of the second electrolytic capacitor is connected to the negative terminal of the first electrolytic capacitor and is connected to the first input terminal. The switch assembly disconnects the power supply line from the first input terminal when the outer cover is opened, and connects the power supply line from the first input terminal when the outer cover is closed; The outer cover opening and closing detection circuit is connected to the power supply line and is located upstream of the switch assembly. The outer cover opening and closing detection circuit is used to collect the electrical signal of the power supply line, and the electrical signal is used to characterize the opening and closing state of the outer cover.

2. The food processing machine outer cover opening and closing detection system according to claim 1, characterized in that, It also includes a main control MCU, whose signal acquisition terminal is connected to the output terminal of the outer cover opening and closing detection circuit. The main control MCU is used to acquire the electrical signal and determine the opening and closing state of the outer cover based on the electrical signal.

3. The food processing machine outer cover opening and closing detection system according to claim 1, characterized in that, The switching assembly includes a micro switch and a first magnet, and a second magnet is disposed on the inner side of the outer cover; the micro switch is connected between the first input terminal of the rectifier bridge circuit and the power supply line; The adjacent ends of the first magnet and the second magnet have the same magnetism. When the outer cover is closed, the first magnet and the second magnet trigger the micro switch to close due to magnetic repulsion.

4. The food processing machine outer cover opening and closing detection system according to claim 1, characterized in that, The switching assembly includes an electromagnetic relay, which includes a normally open contact and a coil; the normally open contact is connected between the first input terminal of the rectifier bridge circuit and the power supply line. A sensing device is provided between the outer cover and the main body. The sensing device is used to sense the closed state of the outer cover when it is closed and output a control signal. The coil of the electromagnetic relay is energized and attracted under the control of the control signal, and the power supply line is connected to the first input terminal.

5. The food processing machine outer cover opening and closing detection system according to claim 1, characterized in that, It also includes a mains power detection circuit, the input terminal of which is connected to the power supply line, and the mains power detection circuit is used to detect the mains voltage; The mains power detection circuit is reused as the outer cover opening and closing detection circuit.

6. The food processing machine outer cover opening and closing detection system according to claim 1, characterized in that, It also includes a zero-crossing detection circuit, which is connected to the power supply line and located upstream of the switching assembly, and is used to perform zero-crossing detection; The zero-crossing detection circuit is reused as the outer cover opening and closing detection circuit.

7. The food processing machine outer cover opening and closing detection system according to claim 1, characterized in that, It also includes an EMC circuit, which is connected to the power supply line and is located upstream of the outer cover opening and closing detection circuit.

8. The food processing machine outer cover opening and closing detection system according to claim 1, characterized in that, The first electrolytic capacitor and the second electrolytic capacitor have the same capacitance value and the same rated voltage.

9. The food processing machine outer cover opening and closing detection system according to claim 8, characterized in that, The capacitance of the first electrolytic capacitor and the second electrolytic capacitor is 800μF to 1000μF, and the rated voltage is 200V to 450V.

10. A food processing machine, characterized in that, The food processing machine outer cover opening and closing detection system includes any one of claims 1 to 9.

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