# US 2017/0256972 A1 · Apparatus for discharging a high-voltage bus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2017/0256972 A1 - Document ID: US20170256972A1 - Status: Published application - Kind: A1 - Application number: 15/059,979 - Filed: 2016-03-03 - Published: 2017-09-07 - Earliest claimed: 2016-03-03 - Assignees: GM Global Technology Operations LLC - Applicants: GM Global Technology Operations LLC - Inventors: Andrew J. Namou; Mohammad N. Anwar; Ahmad Albanna; Syed M. Kadry - Web page: https://patentgrep.com/patent/US20170256972A1 ## CPC - H02M 1/32: Means for protecting converters other than automatic disconnection - B60L 3/00: Electric devices on electrically-propelled vehicles for safety purposes; Monitoring operating variables, e.g. speed, deceleration or energy consumption (methods or circuit arrangements for monitoring or controlling batteries or fuel cells B60L58/00) - B60L 15/007: {Physical arrangements or structures of drive train converters specially adapted for the propulsion motors of electric vehicles} - H02J 7/865: {Battery or charger load switching, e.g. concurrent charging and load supply (H02J7/50 takes precedence)} - H02M 7/53875: {with analogue control of three-phase output} - B60L 2240/526: Operating parameters - H02J 2207/20: Charging or discharging characterised by the power electronics converter - H02M 1/322: {Means for rapidly discharging a capacitor of the converter for protecting electrical components or for preventing electrical shock} - Y02T 10/64: Electric machine technologies in electromobility - Y02T 90/16: Information or communication technologies improving the operation of electric vehicles - H02M: APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF (transformers H01F; dynamo-electric converters H02K47/00; controlling transformers, reactors or choke coils, control or regulation of electric motors, generators or dynamo-electric converters H02P) - B60L: PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES (arrangements or mounting of electrical propulsion units or of plural diverse prime-movers for mutual or common propulsion in vehicles B60K1/00, B60K6/20; arrangements or mounting of electrical gearing in vehicles B60K17/12, B60K17/14; preventing wheel slip by reducing power in rail vehicles B61C15/08; dynamo-electric machines H02K; control or regulation of electric motors H02P); SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES (electric coupling devices combined with mechanical couplings of vehicles B60D1/64; electric heating for vehicles B60H1/00); ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL (control or regulation of electric motors H02P); MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES - H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract A power inverter including a multi-phase inverter circuit is electrically connected to a high-voltage DC power source, and includes a capacitor electrically connected between positive and negative conductors of a high-voltage bus. A normally-ON discharge switch is electrically connected in series with a discharge resistor between the positive and negative conductors of the high-voltage bus. The discharge switch includes a control gate, wherein the control gate of the discharge switch is in communication with an ignition switch. The discharge switch is controllable to an open state between the positive and negative conductors of the high-voltage bus when the ignition switch is in an ON state. The discharge switch achieves a closed state to provide a low-impedance electric current flow path through the discharge resistor between the positive and negative conductors of the high-voltage bus when the ignition switch is in an OFF state. ## Claims ### Claim 1 A power inverter electrically connected to a high-voltage DC power source via a high-voltage bus, including a capacitor electrically connected between positive and negative conductors of the high-voltage bus, the power inverter comprising: a multi-phase inverter circuit electrically connected to the positive and negative conductors of the high-voltage bus; a normally-ON discharge switch electrically connected in series with a discharge resistor between the positive and negative conductors of the high-voltage bus, the discharge switch including a control gate, wherein the control gate of the discharge switch is in communication with an ignition switch; wherein the discharge switch is controllable to an open state between the positive and negative conductors of the high-voltage bus when the ignition switch is in a key-ON state; and wherein the discharge switch achieves a closed state to provide a low-impedance electric current flow path through the discharge resistor between the positive and negative conductors of the high-voltage bus when the ignition switch is in a key-OFF state. ### Claim 2 (depends on 1) The power inverter of claim 1, further comprising a transformer having a primary circuit and a secondary circuit, wherein the secondary circuit is in communication with the control gate of the discharge switch and the primary circuit is electrically connected between a low-voltage power supply and a ground. ### Claim 3 (depends on 1) The power inverter of claim 1, further comprising a composite trigger gate having a plurality of inputs and a single output, wherein the secondary circuit of the transformer is in communication with one of the inputs of the composite trigger gate, and wherein the single output of the composite trigger gate is in communication with the control gate of the discharge switch. ### Claim 4 (depends on 3) The power inverter of claim 3, wherein the discharge switch achieves a closed state and provides a low-impedance electric current flow path through the discharge resistor between the positive and negative conductors of the high-voltage bus when one of the plurality of inputs achieves a discrete state of “1”. ### Claim 5 (depends on 1) The power inverter of claim 1, further comprising a voltage sensor arranged to monitor electrical potential between the positive conductor and the negative conductor of the high-voltage bus, wherein the voltage sensor includes a plurality of sensing resistors arranged in series with the discharge resistor. ### Claim 6 (depends on 1) The power inverter of claim 1, wherein the discharge switch is an N-channel depletion mode MOSFET device. ### Claim 7 A device electrically connected to a high-voltage DC power source via a high-voltage bus including a capacitor electrically connected between positive and negative conductors of the high-voltage bus, comprising: a discharge switch electrically connected in series with a discharge resistor between the positive and negative conductors of the high-voltage bus, the discharge switch including a control gate; a composite trigger gate having a plurality of input lines and an output line in communication with the control gate of the discharge switch; and a transformer having a primary circuit and a secondary circuit, wherein the secondary circuit is in communication with one of the input lines of the composite trigger gate and the primary circuit is electrically connected between a low-voltage power supply and a ground; wherein the discharge switch is controllable to a closed state to provide a low-impedance electric current flow path through the discharge resistor between the positive and negative conductors of the high-voltage bus in response to an activation signal to one of the input lines of the composite trigger gate that is communicated to the gate of the discharge switch. ### Claim 8 (depends on 7) The power inverter of claim 7, wherein the discharge switch is controllable to the closed state to provide a low-impedance electric current flow path through the discharge resistor between the positive and negative conductors of the high-voltage bus in response to the ignition switch being in a key-OFF state. ### Claim 9 (depends on 7) The power inverter of claim 7, wherein the discharge switch is controllable to an open state to provide a high-impedance resistance to current flow through the discharge resistor between the positive and negative conductors of the high-voltage bus when the ignition switch is in a key-ON state and the input lines to the composite trigger gate are in a high state. ### Claim 10 (depends on 7) The power inverter of claim 7, wherein the power inverter electrically connects to an electric machine. ### Claim 11 (depends on 7) The power inverter of claim 7, wherein the discharge resistor comprises a resistor having an impedance that is selected to discharge the capacitor within a specified time period. ### Claim 12 (depends on 7) The power inverter of claim 7, wherein the capacitor is electrically connected between the positive and negative conductors of the high-voltage bus in parallel with the discharge switch that is electrically connected in series with the discharge resistor. ### Claim 13 (depends on 7) The power inverter of claim 7, wherein each of the first and second trigger circuits comprises an inductive device that electrically connects to a signal line that is electrically connected to the respective first or second contactor via a resistance-capacitance circuit and a diode, and wherein an output line communicates with a one-shot multi-vibrator that is in communication with the gate of the discharge switch. ### Claim 14 A power inverter disposed to control an electric machine, the power inverter being electrically connected to a high-voltage DC power source via a high-voltage bus, the power inverter comprising: a multi-phase inverter circuit electrically connected to positive and negative conductors of the high-voltage bus; a capacitor electrically connected between the positive and negative conductors of the high-voltage bus; and a passive discharge circuit disposed between the positive and negative conductors of the high-voltage bus, including a discharge switch electrically connected in series with a discharge resistor between the positive and negative conductors of the high-voltage bus, the discharge switch including a control gate, wherein the control gate of the discharge switch is in communication with an ignition switch; wherein the discharge switch achieves a closed state to provide a low-impedance electric current flow path through the discharge resistor between the positive and negative conductors of the high-voltage bus when the ignition switch is in a key-OFF state. ### Claim 15 (depends on 14) The power inverter of claim 14, further comprising a transformer having a primary circuit and a secondary circuit, wherein the secondary circuit is in communication with the control gate of the discharge switch and the primary circuit is electrically connected between a low-voltage power supply and a ground. ### Claim 16 (depends on 14) The power inverter of claim 14, further comprising a composite trigger gate having a plurality of inputs and a single output, wherein the secondary circuit of the transformer is in communication with one of the inputs of the composite trigger gate, and wherein the single output of the composite trigger gate is in communication with the control gate of the discharge switch. ### Claim 17 (depends on 16) The power inverter of claim 16, wherein the discharge switch achieves a closed state and provides a low-impedance electric current flow path through the discharge resistor between the positive and negative conductors of the high-voltage bus when one of the plurality of inputs achieves a discrete state of “1”. ### Claim 18 (depends on 14) The power inverter of claim 14, further comprising a voltage sensor arranged to monitor electrical potential between the positive conductor and the negative conductor of the high-voltage bus, wherein the voltage sensor includes a plurality of sensing resistors arranged in series with the discharge resistor. ### Claim 19 (depends on 14) The power inverter of claim 14, wherein the discharge switch is a normally-ON device.