WO-2026094840-A1 - ELECTRIC LEAKAGE DETECTION SYSTEM AND POWER RECEPTION DEVICE USED FOR NON-CONTACT POWER SUPPLY

WO2026094840A1WO 2026094840 A1WO2026094840 A1WO 2026094840A1WO-2026094840-A1

Abstract

A power reception device (100, 100b, 100c, 100d, 100e, 100g, 100h, 100j) for use in non-contact power supply comprises: a resonant circuit (RC) that has a coil (10) and capacitors (21, 22); a rectifier circuit (REC) that is provided on an output side as compared to the resonant circuit and converts AC into DC; an X phase and a Y phase that connect the resonant circuit and the rectifier circuit; a sensor (210, 210f, 210g, 210h, V1, V2) that is provided between the resonant circuit and the rectifier circuit and detects a parameter related to a differential current value of currents flowing through the X phase and the Y phase; and an electric leakage detection unit (SC) that detects electric leakage by using the detected parameter.

Inventors

TAKAHASHI MASAYA
YAMAGUCHI NOBUHISA
NAKAYASHIKI Yusei

Assignees

株式会社デンソー

Dates

Publication Date: 20260507
Application Date: 20251027
Priority Date: 20241030

Claims (15)

A power receiving device (100, 100b, 100c, 100d, 100e, 100g, 100h, 100j) used for contactless power supply, A resonant circuit (RC) having a coil (10) and capacitors (21, 22), A rectifier circuit (REC) is provided on the output side of the aforementioned resonant circuit and converts AC to DC, X-phase and Y-phase connecting the resonant circuit and the rectifier circuit, A sensor provided between the resonant circuit and the rectifier circuit, which detects parameters related to the difference current value of the currents flowing between the X phase and the Y phase (210, 210f, 210g, 210h, V1, V2), A leakage detection unit (SC) detects leakage current using the detected parameters, A power receiving device equipped with the following features.
A power receiving device according to claim 1, The leakage detection unit determines that a leakage has occurred when the parameter is above a predetermined threshold. Power receiving device.
A power receiving device according to claim 2, The system further comprises a filter circuit (FL) provided between the resonant circuit and the rectifier circuit, The sensor is provided between the filter circuit and the rectifier circuit. Power receiving device.
A power receiving device according to claim 2, The system further comprises a filter circuit (FL) provided between the resonant circuit and the rectifier circuit, The filter circuit comprises series reactors (SL1, SL2) provided in the X phase and the Y phase, respectively, and series capacitors (SC1, SC2) connected in series to the series reactors. The sensor is provided between the series reactor and the series capacitor. Power receiving device.
A power receiving device according to claim 2, The system further comprises a filter circuit (FL) provided between the resonant circuit and the rectifier circuit, The filter circuit includes a series filter (SF) provided in series with each of the X-phase and Y-phase, and a parallel filter (PF) provided in parallel with the X-phase and Y-phase. The sensor is provided between the series filter and the parallel filter, Power receiving device.
A power receiving device according to claim 2, The system further comprises a filter circuit (FL) provided between the resonant circuit and the rectifier circuit, The filter circuit includes a parallel reactor (PL1) provided in parallel with the X phase and the Y phase, and a parallel capacitor (PC1) provided in parallel with the X phase and the Y phase. The sensor is provided between the parallel reactor and the parallel capacitor. Power receiving device.
A power receiving device according to claim 2, The system further comprises a filter circuit (FL) provided between the resonant circuit and the rectifier circuit, The sensor is provided between the capacitor and the filter circuit of the resonant circuit. Power receiving device.
A power receiving device according to any one of claims 1 to 7, The aforementioned sensor is a power receiving device composed of a ring-shaped member.
A power receiving device according to claim 8, A portion of the X phase and the Y phase is provided on a printed circuit board (PR), The sensor is composed of a first part (211g) and a second part (212g), The first part and the second part are arranged so as to sandwich the X phase and the Y phase provided on the printed circuit board in the thickness direction of the printed circuit board. Power receiving device.
A power receiving device according to claim 2, The system further comprises a filter circuit (FL) provided between the resonant circuit and the rectifier circuit, The filter circuit is provided in the X phase and the Y phase respectively and has a series reactor (SL1, SL2) including a core. The sensor is shared with the core of the series reactor in the X phase and the Y phase. Power receiving device.
A power receiving device according to claim 10, The shared sensor, the X-phase core, and the Y-phase core are composed of a single figure-eight shaped member. Power receiving device.
A power receiving device according to claim 1, It has a first parallel capacitor (PC1j) and a second parallel capacitor (PC2j) connected in parallel to the X phase and the Y phase, The first parallel capacitor and the second parallel capacitor are connected in series with each other. The first parallel capacitor and the second parallel capacitor are grounded by a grounding wire (40). The sensor detects the voltage of the first parallel capacitor and the voltage of the second parallel capacitor. The leakage detection unit detects leakage current using the voltage of the first parallel capacitor and the voltage of the second parallel capacitor as the detected parameters. Power receiving device.
A power receiving device according to claim 12, The leakage detection unit determines that a leakage current has occurred when the difference between the voltage of the first parallel capacitor and the voltage of the second parallel capacitor is greater than or equal to a predetermined threshold. Power receiving device.
A power receiving device according to claim 12, The sensor detects the voltage of the first parallel capacitor and the voltage of the second parallel capacitor over time. The leakage detection unit determines that a leakage current has occurred when the voltage waveforms of the first parallel capacitor and the voltage waveform of the second parallel capacitor do not match. Power receiving device.
Leakage current detection system (300), A plurality of power receiving devices (101, 102) each having a resonant circuit (RC1, RC2), a rectifier circuit (REC1, REC2) provided on the output side of the resonant circuit that converts AC to DC, and an X phase and a Y phase connecting the resonant circuit and the rectifier circuit, A single sensor (210i) provided between the resonant circuit and the rectifier circuit in the plurality of power receiving devices, which detects a parameter related to the difference current value of the current flowing between the X phase and the Y phase, A leakage detection unit (300) detects leakage current based on the detected parameters, A leakage current detection system equipped with the following features.

Description

Power receiving device and leakage detection system used for contactless power supply Cross-reference of related applications This application is based on Japanese application number 2024-190941, filed on October 30, 2024, and international application number PCT/JP2025/032329, filed on September 12, 2025, the contents of which are incorporated herein by reference. This disclosure relates to a power receiving device and a leakage current detection system used in contactless power supply. Various technologies related to contactless power supply have been proposed. For example, Patent Document 1 discloses a device for diagnosing leakage current in a power receiving device used for contactless power supply. This device detects leakage current by detecting the difference in alternating current flowing across the ends of a coil in the resonant circuit of the power receiving device. Generally, the ends of the coils used in the power receiving devices of contactless power supply systems are at high voltage. Therefore, when applying the technology disclosed in Patent Document 1, a device capable of handling high voltage is required. For this reason, there is room for improvement in the device for detecting leakage current in the power receiving device. This disclosure can be implemented in the following forms: According to a first aspect of this disclosure, a power receiving device for contactless power supply is provided. This power receiving device comprises: a resonant circuit having a coil and a capacitor; a rectifier circuit provided on the output side of the resonant circuit and converting alternating current to direct current; an X-phase and a Y-phase connecting the resonant circuit and the rectifier circuit; a sensor provided between the resonant circuit and the rectifier circuit that detects parameters related to the difference current value of the currents flowing through the X-phase and the Y-phase; and a leakage detection unit that detects leakage current using the detected parameters. According to this embodiment of the power receiving device, the sensor that detects parameters related to the difference in current value between the X-phase and Y-phase is installed between the resonant circuit and the rectifier circuit, where the voltage is lower than the voltage generated in the resonant circuit. Therefore, leakage current can be detected with a relatively simple configuration without requiring a device capable of handling high voltages. According to another aspect of this disclosure, a leakage current detection system is provided. This leakage current detection system comprises: a plurality of power receiving devices, each having a resonant circuit, a rectifier circuit provided on the output side of the resonant circuit and converting alternating current to direct current, and X-phase and Y-phase connecting the resonant circuit and the rectifier circuit; a single sensor provided between the resonant circuit and the rectifier circuit in the plurality of power receiving devices, which detects a parameter related to the difference current value of the currents flowing between the X-phase and the Y-phase; and a leakage current detection unit that detects leakage current based on the detected parameter. According to this embodiment of the leakage current detection system, a single sensor is provided between the resonant circuit and the rectifier circuit in multiple power receiving devices. This sensor detects parameters related to the difference current value between the X-phase and Y-phase currents. Therefore, leakage current occurring in either the X-phase or Y-phase of multiple power receiving devices can be detected using a single sensor. This allows for a more compact overall power receiving device system compared to a configuration using one sensor per power receiving device. The purposes and other purposes, features and benefits of this disclosure will be further clarified by the following detailed description with reference to the attached drawings. Those drawings are: Figure 1 is a circuit diagram showing a schematic configuration of a power receiving device in one embodiment of the present disclosure. Figure 2 is a circuit diagram showing the schematic configuration of the power receiving device in the second embodiment. Figure 3 is a circuit diagram showing the schematic configuration of the power receiving device in the third embodiment. Figure 4 is a circuit diagram showing the schematic configuration of the power receiving device in the fourth embodiment. Figure 5 is a circuit diagram showing the schematic configuration of the power receiving device in the fifth embodiment. Figure 6 is a diagram illustrating a sensor composed of a ring-shaped member. Figure 7 is a plan view showing the schematic configuration of the power receiving device in the seventh embodiment. Figure 8 is a cross-sectional view along the line VIII-VIII in Figure 7. Figure 9 is a circuit diagram showing the schematic conf