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An Improved Passive Discharge Circuit for Inverter System Controller to Reduce Power Loss and Cost

IP.com Disclosure Number: IPCOM000193930D
Publication Date: 2010-Mar-15
Document File: 2 page(s) / 52K

Publishing Venue

The IP.com Prior Art Database

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An Improved Passive Discharge Circuit for Inverter System Controller

To avid any possible injury to customer, passive discharge circuitry must be designed in the Inverter System Controller(ISC) to gradually eliminate the energy stored on the capacitors should the ISC shut down in any malfunctions. Fig.1 shows one conventional solution for current passive discharge circuit design, a resistor R1 is connected across the main capacitor Co, and a resistor R2 is connected across the Variable Voltage Converter (VVC) input capacitor Ci. The drawback associated with this design is that high power losses due to continuous high voltage across both resistors R1 and R2. As a result, the passive discharge resistors R1 and R2 are usually designed in big physical size and costly. Fig. 2 shows another conventional solution for current passive discharge design, only the main capacitor Co is equipped with a passive discharge resistor R1. The VVC input capacitor Ci will be discharged through inductor L1 and diode D1. The drawbacks associated with this design includes: (1). The VVC input capacitor Ci cannot be discharged faster than the ISC main cap Co. (2). If either the inductor L1 or diode D1 is damaged during ISC malfunctions, the VVC input cap Ci cannot be effectively discharged, which could result in injury to customer.

Fig 1: Conventional design 1

Fig 2: Conventional design 2

Method

Fig. 3 shows one proposed solution for the ISC passive discharge circuit. A resistor R1 is connected across the ISC main cap Co, and unlike conventional solutions, the resistor R2 is connected between the VVC input and output. This circuit is designed for the case that the inverter side should be discharged faster than the VVC input side. Fig. 4 shows another proposed solution for the ISC passive discharge circuit. A resistor R2 is connected across the VVC input cap Ci, and similarly, the resistor R1...