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1199 results about "Pre-charge" patented technology

Pre-charge of the powerline voltages in a high voltage DC application is a preliminary mode which limits the inrush current during the power up procedure. A high-voltage system with a large capacitive load can be exposed to high electric current during initial turn-on. This current, if not limited, can cause considerable stress or damage to the system components. In some applications, the occasion to activate the system is a rare occurrence, such as in commercial utility power distribution. In other systems such as vehicle applications, pre-charge will occur with each use of the system, multiple times per day. Precharging is implemented to increase the lifespan of electronic components and increase reliability of the high voltage system.

Serial and parallel switching and charging method and charging device for lithium dynamic battery unit

The invention discloses an Li traction battery series parallel change-over charging method and a charging device. The charging device comprises a power main loop comprising a rectifier circuit, a DC filtering capacitor, a pre-charging circuit, a voltage sensor, a switch bridge circuit, a charging current sensor and a series parallel change-over switch, a control circuit board comprising a parallel branch signal unit, a switch signal drive control unit, a coil signal circuit, a voltage current signal circuit, a control processor and a signal display unit, a serial charging circuit comprising a filter inductor, a filter capacitor and an output voltage sensor, and a parallel charging circuit comprising a primary coil, a feedback coil, an iron core, a plurality of secondary coils of a multi-winding transformer and a plurality of series parallel charging unit. The pre-charging, serial charging and parallel charging are carried out by the charging method according to a set pre-charging voltage value and an end voltage value. The method and the device provided by the invention reduce the cost and volume of charging devices, maintain the balance of charging capacity of every Li traction battery electrical core, ensure adequate protection and best working status for each battery unit and improve safety and service life cycle of Li traction battery.
Owner:刘云海 +2

Lithium ion battery low-temperature alternating current heating device for electric bicycle

The invention relates to a lithium ion battery low-temperature alternating current heating device for an electric bicycle. The lithium ion battery low-temperature alternating current heating device isused for performing alternating current heating on a power battery. The lithium ion battery low-temperature alternating current heating device comprises a control unit, an energy conversion circuit,an energy storage inductor, a capacitor, a pre-charging circuit and a starting switch, wherein the power battery, the energy storage inductor, the energy conversion circuit and the capacitor are sequentially connected to form a loop; the pre-charging circuit and the starting switch are parallelly connected between the power battery and the capacitor; the control unit is respectively connected withthe energy conversion circuit, the pre-charging circuit and the starting switch, and controls the on-off state of the starting switch according to the temperature information of the power battery, sothat the conversion between the alternating current heating state and the normal power supply state of the power battery can be realized; during the entering of the alternating current heating state,the control unit controls the work state of the energy conversion circuit according to the current information of the power battery in real time; the inside heating is realized in the alternating current charging and discharging process of the power battery. Compared with the prior art, the lithium ion battery low-temperature alternating current heating device has the advantages that the heatingis uniform; the efficiency is high; the newly added devices are few; the cost is low, and the like.
Owner:TONGJI UNIV

Boosting power converting circuit and control method

ActiveCN106230253AAvoid the problem of overvoltage breakdownReduce output waveform distortionDc-dc conversionElectric variable regulationCapacitanceOvervoltage
The invention provides a boosting power converting circuit and a control method. The circuit comprises N first switch modules, N second switch modules, N-1 third switch modules, N-1 flying capacitors and N-1 pre-charging units, wherein the N second switch modules are serially connected with an inductor and an input power supply so as to form a loop; N first switch modules are serially connected with a load, the inductor and the input power supply so as to form the loop; the flying capacitors and the third switch modules are connected between the first public points which are between the first switch module and the first switch module and the second public points which are between the second switch module and the second switch module; each of the flying capacitors is in parallel connection with each of the pre-charging units; each of the pre-charging units is used for pre-charging each of the flying capacitors and guaranteeing the voltage of each flying capacitor not below 0V when the third switch modules connected with the flying capacitors in parallel connection with the pre-charging units are switched off and the voltages of the flying capacitors are less than a preset threshold value, so that the problem of possibly breaking down the semiconductor device through overvoltage when the boosting power converting circuit is used in a boosting system is avoided.
Owner:HUAWEI TECH CO LTD

Mixed high-voltage direct-current circuit breaker and realization method thereof

ActiveCN104767170AReduce on-state lossRealize no arc breakingEmergency protective arrangements for automatic disconnectionMain branchEnergy absorption
The invention relates to a circuit breaker and a realization method thereof, and specifically relates to a mixed high-voltage direct-current circuit breaker and a realization method thereof. The direct-current circuit breaker is based on the principle of secondary current transfer. A main branch is composed of a quick-action mechanical switch and a current transfer module which contains a full-controlled device, which ensures the advantages of low loss and flexible current transfer control in the state of normal conduction. A first current transfer branch is composed of half-controlled device thyristors connected in series, so that the circuit breaker has strong fault flow capacity and breaking capacity, 'zero voltage and zero current' of the mechanical switch can be maintained long enough, and arc-free switching of the mechanical switch is realized. A second current transfer branch is composed of capacitors with pre-charged voltage, an inductor, and series-connected thyristors. After the thyristors of the first current transfer branch are reliably switched off, the capacitors quickly build up direct voltage high enough to resist the system, and an energy absorption circuit limits the voltage of the capacitors. Thus, the size and cost of the capacitors are well controlled.
Owner:STATE GRID CORP OF CHINA +1
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